Niedokrwistość z niedoboru witaminy b12 lub kwasu foliowego
Rokowania, prognozy i postęp choroby

Niedokrwistość z niedoboru witaminy B12 lub kwasu foliowego wymaga szybkiej diagnostyki i leczenia, aby zapobiec nieodwracalnym powikłaniom neurologicznym, które mogą wystąpić nawet przy braku wyraźnej niedokrwistości. Kluczowe czynniki wpływające na rokowanie to czas trwania i nasilenie niedoboru, obecność powikłań neurologicznych oraz szybkość wdrożenia terapii. Niedobór witaminy B12 może prowadzić do uszkodzeń neurologicznych u 20-30% pacjentów, zaburzeń płodności, zwiększonego ryzyka raka żołądka (zwłaszcza w niedokrwistości złośliwej) oraz powikłań ciążowych, takich jak wady cewy nerwowej. Niedobór kwasu foliowego wiąże się z ryzykiem chorób sercowo-naczyniowych, raka jelita grubego oraz powikłań okołoporodowych, w tym niskiej masy urodzeniowej i porodu przedwczesnego. Suplementacja doustna (1-2 mg/dobę witaminy B12) jest skuteczna, choć w ciężkich przypadkach zalecane jest podawanie domięśniowe. Monitorowanie terapii i edukacja pacjenta są niezbędne dla optymalizacji wyników leczenia.

  1. Niedokrwistość z niedoboru witaminy B12 lub kwasu foliowego – rokowanie
    1. Czynniki wpływające na rokowanie
    2. Powikłania niedoboru witaminy B12
    3. Powikłania niedoboru kwasu foliowego
    4. Znaczenie wczesnego rozpoznania i leczenia
    5. Szczególne aspekty rokowania u osób starszych
    6. Interwencje poprawiające rokowanie
    7. Genetyczne uwarunkowania rokowania
    8. Potencjalne zagrożenia związane z suplementacją kwasu foliowego
    9. Długookresowe konsekwencje subklinicznego niedoboru
    10. Podsumowanie rokowania
    11. Kolejne rozdziały

Niedokrwistość z niedoboru witaminy B12 lub kwasu foliowego – rokowanie

Niedokrwistość z niedoboru witaminy B12 lub kwasu foliowego to stan kliniczny, który wymaga szybkiej diagnozy i leczenia, ponieważ chociaż wiele objawów można skutecznie leczyć, niektóre konsekwencje mogą być nieodwracalne, szczególnie jeśli niedobór trwa przez dłuższy czas.12 Powikłania są rzadkie, gdy niedobory są szybko diagnozowane i leczone, jednak mogą wystąpić, szczególnie w przypadkach długotrwałego deficytu.3

Czynniki wpływające na rokowanie

Rokowanie w niedokrwistości z niedoboru witaminy B12 lub kwasu foliowego zależy od kilku kluczowych czynników:

  • Czas trwania niedoboru – długotrwały niedobór zwiększa ryzyko nieodwracalnych powikłań4
  • Nasilenie niedoboru – cięższe niedobory mogą prowadzić do poważniejszych konsekwencji klinicznych5
  • Obecność powikłań neurologicznych – badania wskazują na odwrotną zależność między nasileniem niedokrwistości megaloblastycznej a stopniem uszkodzenia neurologicznego6
  • Szybkość wdrożenia leczenia – wczesne rozpoznanie i leczenie mogą zapobiec powikłaniom7
  • Współistniejące schorzenia – szczególnie u osób starszych mogą wpływać na skuteczność leczenia8

Powikłania niedoboru witaminy B12

Niedobór witaminy B12, z towarzyszącą niedokrwistością lub bez niej, może prowadzić do poważnych powikłań, jeśli nie jest odpowiednio leczony.9 Do najważniejszych powikłań należą:

  • Uszkodzenia neurologiczne – mogą być nieodwracalne, nawet po wdrożeniu leczenia; uszkodzenia neurologiczne stwierdzono u 20-30% pacjentów z niedoborem witaminy B12 przy braku niedokrwistości1011
  • Zaburzenia płodności – niedobór witaminy B12 może powodować czasową niepłodność, która ustępuje po wyrównaniu niedoborów12
  • Zwiększone ryzyko nowotworów – u pacjentów z niedokrwistością złośliwą (pernicious anaemia) występuje podwyższone ryzyko raka żołądka13
  • Powikłania w ciąży – niedobór witaminy B12 podczas ciąży zwiększa ryzyko wad cewy nerwowej u płodu, opóźnień rozwojowych, zaburzeń neurologicznych oraz niedokrwistości1415

Powikłania niedoboru kwasu foliowego

Niedobór kwasu foliowego również może prowadzić do istotnych konsekwencji zdrowotnych:16

  • Zaburzenia płodności – podobnie jak w przypadku witaminy B1217
  • Zwiększone ryzyko chorób układu sercowo-naczyniowego – badania wykazały związek między niedoborem folianów a podwyższonym ryzykiem chorób sercowo-naczyniowych18
  • Zwiększone ryzyko nowotworów – szczególnie raka jelita grubego19
  • Powikłania w ciąży – zwiększone ryzyko porodu przedwczesnego, niskiej masy urodzeniowej oraz zaburzeń rozwoju płodu20

Znaczenie wczesnego rozpoznania i leczenia

Wczesne rozpoznanie i leczenie niedoboru witaminy B12 i kwasu foliowego ma kluczowe znaczenie dla poprawy rokowania:21

  • Zapobieganie nieodwracalnym uszkodzeniom neurologicznym – szczególnie ważne w przypadku niedoboru witaminy B12, gdyż objawy neurologiczne mogą nie ustąpić, jeśli terapia zostanie opóźniona22
  • Normalizacja parametrów hematologicznych – większość przypadków niedokrwistości z niedoboru dobrze reaguje na suplementację23
  • Zapobieganie powikłaniom – wczesne leczenie może zapobiec rozwojowi powikłań sercowo-naczyniowych, neurologicznych i innych24

Szczególne aspekty rokowania u osób starszych

Niedokrwistość z niedoboru witaminy B12 lub kwasu foliowego jest szczególnie powszechna wśród osób starszych i może mieć istotny wpływ na rokowanie w tej grupie wiekowej:25

  • Wysoka częstość występowania – niedobór witaminy B12 występuje u około 20% osób powyżej 65 roku życia, a odsetek ten wzrasta do 46% wśród osób przebywających w instytucjach opiekuńczych2627
  • Utrudniona diagnostyka – klasyczne objawy niedoboru witaminy B12, takie jak ciężka niedokrwistość megaloblastyczna z objawami neuropsychiatrycznymi, rzadko występują w obecnych czasach28
  • Objawy neuropsychiatryczne – mogą być jedynym objawem niedoboru kobalaminy bez towarzyszącej makrocytozy czy niedokrwistości29
  • Współistnienie z innymi niedoborami – około 20% przypadków niedokrwistości u osób starszych jest spowodowanych niedoborem żelaza w połączeniu z niedoborem folianów lub witaminy B1230

Interwencje poprawiające rokowanie

Odpowiednie interwencje mogą znacząco poprawić rokowanie u pacjentów z niedokrwistością z niedoboru witaminy B12 lub kwasu foliowego:31

  • Suplementacja doustna lub parenteralna – wysokie dawki doustne (1-2 mg dziennie) są równie skuteczne jak podawanie pozajelitowe w korygowaniu niedokrwistości i objawów neurologicznych32
  • Przestrzeganie zaleceń terapeutycznych – British Society for Haematology zaleca domięśniowe podawanie witaminy B12 w przypadku ciężkiego niedoboru i zespołów złego wchłaniania, natomiast suplementacja doustna może być rozważana u pacjentów z bezobjawowym, łagodnym niedoborem bez problemów z wchłanianiem lub przestrzeganiem zaleceń33
  • Monitorowanie odpowiedzi na leczenie – regularne badania kontrolne pozwalają na ocenę skuteczności terapii i wczesne wykrycie nawrotu niedoboru34
  • Wzbogacanie żywności – szczególnie w krajach rozwijających się może mieć znaczący wpływ na poprawę statusu witaminy B12 w populacji35

Genetyczne uwarunkowania rokowania

Najnowsze badania wskazują na istotny wpływ czynników genetycznych na status witaminy B12 i związane z nim rokowanie:36

  • Ochronny wpływ wyższego genetycznie uwarunkowanego poziomu witaminy B12 – wyższy genetycznie uwarunkowany poziom witaminy B12 w surowicy wiąże się ze zmniejszeniem ryzyka niedokrwistości złośliwej (o 71%) i niedokrwistości megaloblastycznej (o 65%) na każde odchylenie standardowe wzrostu poziomu witaminy B123738
  • Potencjalny wpływ na inne choroby – zmienność poziomu witaminy B12 została powiązana z szeregiem chorób występujących w ciągu życia, w tym z zaburzeniami funkcji poznawczych i chorobami układu sercowo-naczyniowego39

Potencjalne zagrożenia związane z suplementacją kwasu foliowego

Chociaż suplementacja kwasu foliowego jest korzystna, szczególnie w profilaktyce wad cewy nerwowej, istnieją pewne obawy związane z jej wpływem na niedobór witaminy B12:40

  • Maskowanie niedokrwistości megaloblastycznej – przyjmowanie dodatkowego kwasu foliowego (jako syntetycznego kwasu pteroiloglutaminowego) z żywności wzbogacanej może zwiększać ryzyko maskowania niedokrwistości megaloblastycznej spowodowanej niedoborem witaminy B124142
  • Ryzyko opóźnionej diagnozy – może to prowadzić do opóźnienia diagnozy niedoboru witaminy B12, co może skutkować postępem nieodwracalnych uszkodzeń neurologicznych43
  • Przyspieszenie uszkodzeń neurologicznych – sugeruje się, że podawanie wysokich dawek kwasu foliowego może przyspieszać degenerację neurologiczną u pacjentów z niedoborem witaminy B1244

Długookresowe konsekwencje subklinicznego niedoboru

Znaczące rezerwy wątrobowe witaminy B12 mogą opóźniać pojawienie się klinicznych objawów niedoboru nawet o 10 lat od jego wystąpienia.45 Długoterminowe konsekwencje subklinicznego niedoboru witaminy B12 nie są w pełni poznane, ale mogą obejmować:46

  • Negatywny wpływ na wyniki ciąży47
  • Zaburzenia naczyniowe – chociaż stosowanie witaminy B12 u pacjentów z podwyższonym poziomem homocysteiny i chorobą sercowo-naczyniową nie zmniejsza ryzyka zawału mięśnia sercowego ani udaru mózgu48
  • Zaburzenia funkcji poznawczych – stosowanie witaminy B12 nie wpływa na zahamowanie spadku funkcji poznawczych49
  • Problemy ze zdrowiem kości50
  • Zaburzenia widzenia51

Podsumowanie rokowania

Rokowanie w niedokrwistości z niedoboru witaminy B12 lub kwasu foliowego jest zazwyczaj dobre, jeśli stan zostanie wcześnie rozpoznany i odpowiednio leczony.52 Większość objawów hematologicznych ustępuje po wdrożeniu suplementacji, jednak powikłania neurologiczne mogą być nieodwracalne, szczególnie jeśli leczenie zostało opóźnione.53 Kluczowe dla poprawy rokowania jest:

  • Wczesna diagnoza – przed rozwojem nieodwracalnych powikłań54
  • Odpowiednie leczenie – dostosowane do przyczyny i nasilenia niedoboru55
  • Regularne monitorowanie – szczególnie u pacjentów z grupy ryzyka (osoby starsze, pacjenci z chorobami autoimmunologicznymi, wegetarianie)56
  • Edukacja pacjenta – dotycząca znaczenia przestrzegania zaleceń terapeutycznych57

W przypadku współistnienia niedoboru witaminy B12 i kwasu foliowego, szczególnie istotne jest, aby najpierw wyrównać niedobór witaminy B12, aby zapobiec podostrej kombinowanej degeneracji rdzenia kręgowego.58 U pacjentów z niedokrwistością złośliwą wymagane są większe suplementy doustne (np. 500-1000 μg/dobę) lub iniekcje domięśniowe.59

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  1. 09.04.2026
  2. www.leksykon.com.pl

Materiały źródłowe

  • #1
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/
    Vitamin B12 or B9 (commonly called folate) deficiency anaemia occurs when a lack of vitamin B12 or folate causes the body to produce abnormally large red blood cells that cannot function properly. […] It’s important for vitamin B12 or folate deficiency anaemia to be diagnosed and treated as soon as possible. […] This is because although many of the symptoms improve with treatment, some problems caused by the condition can be irreversible. […] Although it’s uncommon, vitamin B12 or folate deficiency (with or without anaemia) can lead to complications, particularly if you have been deficient in vitamin B12 or folate for some time. […] Some complications improve with appropriate treatment, but others, such as problems with the nervous system, can sometimes be permanent.
  • #2 Vitamin B12 & folate anaemia | NHS inform
    https://www.nhsinform.scot/illnesses-and-conditions/nutritional/vitamin-b12-or-folate-deficiency-anaemia/
    Vitamin B12 or folate deficiency anaemia occurs when a lack of vitamin B12 or folate affects the body’s ability to produce fully functioning red blood cells. […] It’s important for vitamin B12 or folate deficiency anaemia to be diagnosed and treated as soon as possible because, although many of the symptoms improve with treatment, some problems caused by the condition can be irreversible. […] Most cases of vitamin B12 and folate deficiency can be easily treated with injections or tablets to replace the missing vitamins. […] Although it’s uncommon, vitamin B12 or folate deficiency (with or without anaemia) can lead to complications, particularly if you’ve been deficient in vitamin B12 or folate for some time. […] As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] However, complications can occasionally develop, particularly if you’ve been deficient in either vitamin for some time.
  • #3 Vitamin B12 & folate anaemia | NHS inform
    https://www.nhsinform.scot/illnesses-and-conditions/nutritional/vitamin-b12-or-folate-deficiency-anaemia/
    Vitamin B12 or folate deficiency anaemia occurs when a lack of vitamin B12 or folate affects the body’s ability to produce fully functioning red blood cells. […] It’s important for vitamin B12 or folate deficiency anaemia to be diagnosed and treated as soon as possible because, although many of the symptoms improve with treatment, some problems caused by the condition can be irreversible. […] Most cases of vitamin B12 and folate deficiency can be easily treated with injections or tablets to replace the missing vitamins. […] Although it’s uncommon, vitamin B12 or folate deficiency (with or without anaemia) can lead to complications, particularly if you’ve been deficient in vitamin B12 or folate for some time. […] As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] However, complications can occasionally develop, particularly if you’ve been deficient in either vitamin for some time.
  • #4
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] But complications can occasionally develop, particularly if you have been deficient in either vitamin for some time. […] A lack of vitamin B12 (with or without anaemia) can cause complications. […] If neurological problems do develop, they can sometimes be irreversible. […] Vitamin B12 deficiency can sometimes lead to temporary infertility, an inability to conceive. […] If you have a vitamin B12 deficiency caused by pernicious anaemia, a condition where your immune system attacks healthy cells in your stomach, your risk of developing stomach cancer is increased. […] If you’re pregnant, not having enough vitamin B12 can increase the risk of your baby developing a serious birth defect known as a neural tube defect.
  • #5 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Vitamin B12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms, and other clinical manifestations. […] Use of vitamin B12 in patients with elevated serum homocysteine levels and cardiovascular disease does not reduce the risk of myocardial infarction or stroke, or alter cognitive decline. […] Vitamin B12 deficiency affects multiple systems, and sequelae vary in severity from mild fatigue to severe neurologic impairment. […] The substantial hepatic storage of vitamin B12 can delay clinical manifestations for up to 10 years after the onset of deficiency. […] Clinical evaluation seems to show an inverse relationship between the severity of megaloblastic anemia and the degree of neurologic impairment. […] Maternal vitamin B12 deficiency during pregnancy or while breastfeeding may lead to neural tube defects, developmental delay, failure to thrive, hypotonia, ataxia, and anemia.
  • #6 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Vitamin B12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms, and other clinical manifestations. […] Use of vitamin B12 in patients with elevated serum homocysteine levels and cardiovascular disease does not reduce the risk of myocardial infarction or stroke, or alter cognitive decline. […] Vitamin B12 deficiency affects multiple systems, and sequelae vary in severity from mild fatigue to severe neurologic impairment. […] The substantial hepatic storage of vitamin B12 can delay clinical manifestations for up to 10 years after the onset of deficiency. […] Clinical evaluation seems to show an inverse relationship between the severity of megaloblastic anemia and the degree of neurologic impairment. […] Maternal vitamin B12 deficiency during pregnancy or while breastfeeding may lead to neural tube defects, developmental delay, failure to thrive, hypotonia, ataxia, and anemia.
  • #7 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    Detection and treatment of the early stages of cobalamin deficiency is important, particularly in patients with neuropsychiatric symptoms because they may fail to respond if therapy is delayed. […] The early stages of vitamin B12 deficiency will not lead to macrocytosis or anaemia, because biochemical vitamin B12 deficit precedes overt clinical deficiency with macro-ovalocytes and falling Hb levels. […] The concept that patients suffering from cobalamin deficiency may have neuropsychiatric symptoms without macrocytosis or anaemia was not widely accepted until relatively recently. […] Thus, it has been realized that neuropsychiatric illness may be the only symptom of cobalamin deficiency and, importantly, the neurological symptoms are considered of most concern because they may fail to remit on therapy.
  • #8 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    In the UK vitamin B12 deficiency occurs in approximately 20% of adults aged 65 years. This incidence is significantly higher than that among the general population. The reported incidence invariably depends on the criteria of deficiency used, and in fact estimates rise to 24% and 46% among free-living and institutionalised elderly respectively when methylmalonic acid is used as a marker of vitamin B12 status. […] It is argued that consuming additional folic acid (as synthetic pteroylglutamic acid) from fortified foods increases the risk of masking megaloblastic anaemia caused by vitamin B12 deficiency. […] The impact of folate and vitamin B12 deficiencies in the elderly cannot be underestimated. Among older participants of the National Health and Nutrition Examination Survey III 14% of anaemia was caused by folate and/or vitamin B12 deficiencies. A further 20% were caused by Fe deficiency combined with either folate or vitamin B12 deficiency. Thus, folate and/or vitamin B12 deficiencies are the cause of approximately one-third (34%) of cases of anaemia in the USA. Vitamin B12 deficiency is more common among the elderly than among younger adults.
  • #9
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] But complications can occasionally develop, particularly if you have been deficient in either vitamin for some time. […] A lack of vitamin B12 (with or without anaemia) can cause complications. […] If neurological problems do develop, they can sometimes be irreversible. […] Vitamin B12 deficiency can sometimes lead to temporary infertility, an inability to conceive. […] If you have a vitamin B12 deficiency caused by pernicious anaemia, a condition where your immune system attacks healthy cells in your stomach, your risk of developing stomach cancer is increased. […] If you’re pregnant, not having enough vitamin B12 can increase the risk of your baby developing a serious birth defect known as a neural tube defect.
  • #10 Vitamin B12 in Health and Disease
    https://pmc.ncbi.nlm.nih.gov/articles/PMC3257642/
    Vitamin B12 deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. […] The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health. […] The long term consequences are not fully known but may include adverse effects on pregnancy outcomes and aspects of ageing. […] The potential masking of vitamin B12 deficiency by folate fortification of the food supply has also raised some safety concerns. […] Neurological damage in the absence of anaemia has been reported in 20-30% of cases of vitamin B12 deficiency. […] Vitamin B12 deficiency will also develop after gastric antrum resection as this is the site of secretion of IF and acid. […] Patients with pernicious anaemia require larger oral supplements (e.g., 500-1,000 g/d) or intramuscular injections. […] In developing countries, fortification could potentially have a more significant impact as the populations intake is often low.
  • #11
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] But complications can occasionally develop, particularly if you have been deficient in either vitamin for some time. […] A lack of vitamin B12 (with or without anaemia) can cause complications. […] If neurological problems do develop, they can sometimes be irreversible. […] Vitamin B12 deficiency can sometimes lead to temporary infertility, an inability to conceive. […] If you have a vitamin B12 deficiency caused by pernicious anaemia, a condition where your immune system attacks healthy cells in your stomach, your risk of developing stomach cancer is increased. […] If you’re pregnant, not having enough vitamin B12 can increase the risk of your baby developing a serious birth defect known as a neural tube defect.
  • #12
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] But complications can occasionally develop, particularly if you have been deficient in either vitamin for some time. […] A lack of vitamin B12 (with or without anaemia) can cause complications. […] If neurological problems do develop, they can sometimes be irreversible. […] Vitamin B12 deficiency can sometimes lead to temporary infertility, an inability to conceive. […] If you have a vitamin B12 deficiency caused by pernicious anaemia, a condition where your immune system attacks healthy cells in your stomach, your risk of developing stomach cancer is increased. […] If you’re pregnant, not having enough vitamin B12 can increase the risk of your baby developing a serious birth defect known as a neural tube defect.
  • #13
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] But complications can occasionally develop, particularly if you have been deficient in either vitamin for some time. […] A lack of vitamin B12 (with or without anaemia) can cause complications. […] If neurological problems do develop, they can sometimes be irreversible. […] Vitamin B12 deficiency can sometimes lead to temporary infertility, an inability to conceive. […] If you have a vitamin B12 deficiency caused by pernicious anaemia, a condition where your immune system attacks healthy cells in your stomach, your risk of developing stomach cancer is increased. […] If you’re pregnant, not having enough vitamin B12 can increase the risk of your baby developing a serious birth defect known as a neural tube defect.
  • #14 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Vitamin B12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms, and other clinical manifestations. […] Use of vitamin B12 in patients with elevated serum homocysteine levels and cardiovascular disease does not reduce the risk of myocardial infarction or stroke, or alter cognitive decline. […] Vitamin B12 deficiency affects multiple systems, and sequelae vary in severity from mild fatigue to severe neurologic impairment. […] The substantial hepatic storage of vitamin B12 can delay clinical manifestations for up to 10 years after the onset of deficiency. […] Clinical evaluation seems to show an inverse relationship between the severity of megaloblastic anemia and the degree of neurologic impairment. […] Maternal vitamin B12 deficiency during pregnancy or while breastfeeding may lead to neural tube defects, developmental delay, failure to thrive, hypotonia, ataxia, and anemia.
  • #15
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] But complications can occasionally develop, particularly if you have been deficient in either vitamin for some time. […] A lack of vitamin B12 (with or without anaemia) can cause complications. […] If neurological problems do develop, they can sometimes be irreversible. […] Vitamin B12 deficiency can sometimes lead to temporary infertility, an inability to conceive. […] If you have a vitamin B12 deficiency caused by pernicious anaemia, a condition where your immune system attacks healthy cells in your stomach, your risk of developing stomach cancer is increased. […] If you’re pregnant, not having enough vitamin B12 can increase the risk of your baby developing a serious birth defect known as a neural tube defect.
  • #16
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    A lack of folate (with or without anaemia) can also cause complications. […] As with a lack of vitamin B12, a folate deficiency can also affect your fertility. […] Research has shown a lack of folate in your body may increase your risk of cardiovascular disease (CVD). […] Research has shown that folate deficiency can increase your risk of some cancers, such as colon cancer. […] A lack of folate during pregnancy may increase the risk of the baby being born prematurely (before the 37th week of pregnancy) or having a low birth weight. […] As with a vitamin B12 deficiency, a lack of folate can also affect an unborn baby’s growth and development in the womb (uterus).
  • #17
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    A lack of folate (with or without anaemia) can also cause complications. […] As with a lack of vitamin B12, a folate deficiency can also affect your fertility. […] Research has shown a lack of folate in your body may increase your risk of cardiovascular disease (CVD). […] Research has shown that folate deficiency can increase your risk of some cancers, such as colon cancer. […] A lack of folate during pregnancy may increase the risk of the baby being born prematurely (before the 37th week of pregnancy) or having a low birth weight. […] As with a vitamin B12 deficiency, a lack of folate can also affect an unborn baby’s growth and development in the womb (uterus).
  • #18
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    A lack of folate (with or without anaemia) can also cause complications. […] As with a lack of vitamin B12, a folate deficiency can also affect your fertility. […] Research has shown a lack of folate in your body may increase your risk of cardiovascular disease (CVD). […] Research has shown that folate deficiency can increase your risk of some cancers, such as colon cancer. […] A lack of folate during pregnancy may increase the risk of the baby being born prematurely (before the 37th week of pregnancy) or having a low birth weight. […] As with a vitamin B12 deficiency, a lack of folate can also affect an unborn baby’s growth and development in the womb (uterus).
  • #19
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    A lack of folate (with or without anaemia) can also cause complications. […] As with a lack of vitamin B12, a folate deficiency can also affect your fertility. […] Research has shown a lack of folate in your body may increase your risk of cardiovascular disease (CVD). […] Research has shown that folate deficiency can increase your risk of some cancers, such as colon cancer. […] A lack of folate during pregnancy may increase the risk of the baby being born prematurely (before the 37th week of pregnancy) or having a low birth weight. […] As with a vitamin B12 deficiency, a lack of folate can also affect an unborn baby’s growth and development in the womb (uterus).
  • #20
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    A lack of folate (with or without anaemia) can also cause complications. […] As with a lack of vitamin B12, a folate deficiency can also affect your fertility. […] Research has shown a lack of folate in your body may increase your risk of cardiovascular disease (CVD). […] Research has shown that folate deficiency can increase your risk of some cancers, such as colon cancer. […] A lack of folate during pregnancy may increase the risk of the baby being born prematurely (before the 37th week of pregnancy) or having a low birth weight. […] As with a vitamin B12 deficiency, a lack of folate can also affect an unborn baby’s growth and development in the womb (uterus).
  • #21 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    Detection and treatment of the early stages of cobalamin deficiency is important, particularly in patients with neuropsychiatric symptoms because they may fail to respond if therapy is delayed. […] The early stages of vitamin B12 deficiency will not lead to macrocytosis or anaemia, because biochemical vitamin B12 deficit precedes overt clinical deficiency with macro-ovalocytes and falling Hb levels. […] The concept that patients suffering from cobalamin deficiency may have neuropsychiatric symptoms without macrocytosis or anaemia was not widely accepted until relatively recently. […] Thus, it has been realized that neuropsychiatric illness may be the only symptom of cobalamin deficiency and, importantly, the neurological symptoms are considered of most concern because they may fail to remit on therapy.
  • #22 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    Detection and treatment of the early stages of cobalamin deficiency is important, particularly in patients with neuropsychiatric symptoms because they may fail to respond if therapy is delayed. […] The early stages of vitamin B12 deficiency will not lead to macrocytosis or anaemia, because biochemical vitamin B12 deficit precedes overt clinical deficiency with macro-ovalocytes and falling Hb levels. […] The concept that patients suffering from cobalamin deficiency may have neuropsychiatric symptoms without macrocytosis or anaemia was not widely accepted until relatively recently. […] Thus, it has been realized that neuropsychiatric illness may be the only symptom of cobalamin deficiency and, importantly, the neurological symptoms are considered of most concern because they may fail to remit on therapy.
  • #23 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Patients diagnosed with vitamin B12 deficiency whose history and physical examination do not suggest an obvious dietary or malabsorptive etiology should be tested for pernicious anemia with anti-intrinsic factor antibodies (positive predictive value = 95%), particularly if other autoimmune disorders are present. […] If vitamin B12 deficiency coexists with folate deficiency, vitamin B12 should be replaced first to prevent subacute combined degeneration of the spinal cord. […] A 2005 Cochrane review involving 108 patients with vitamin B12 deficiency found that high-dose oral replacement (1 mg to 2 mg per day) was as effective as parenteral administration for correcting anemia and neurologic symptoms. […] There is insufficient data to recommend other formulations of vitamin B12 replacement (e.g., nasal, sublingual, subcutaneous). […] The British Society for Haematology recommends intramuscular vitamin B12 for severe deficiency and malabsorption syndromes, whereas oral replacement may be considered for patients with asymptomatic, mild disease with no absorption or compliance concerns.
  • #24
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/
    Vitamin B12 or B9 (commonly called folate) deficiency anaemia occurs when a lack of vitamin B12 or folate causes the body to produce abnormally large red blood cells that cannot function properly. […] It’s important for vitamin B12 or folate deficiency anaemia to be diagnosed and treated as soon as possible. […] This is because although many of the symptoms improve with treatment, some problems caused by the condition can be irreversible. […] Although it’s uncommon, vitamin B12 or folate deficiency (with or without anaemia) can lead to complications, particularly if you have been deficient in vitamin B12 or folate for some time. […] Some complications improve with appropriate treatment, but others, such as problems with the nervous system, can sometimes be permanent.
  • #25 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    In the UK vitamin B12 deficiency occurs in approximately 20% of adults aged 65 years. This incidence is significantly higher than that among the general population. The reported incidence invariably depends on the criteria of deficiency used, and in fact estimates rise to 24% and 46% among free-living and institutionalised elderly respectively when methylmalonic acid is used as a marker of vitamin B12 status. […] It is argued that consuming additional folic acid (as synthetic pteroylglutamic acid) from fortified foods increases the risk of masking megaloblastic anaemia caused by vitamin B12 deficiency. […] The impact of folate and vitamin B12 deficiencies in the elderly cannot be underestimated. Among older participants of the National Health and Nutrition Examination Survey III 14% of anaemia was caused by folate and/or vitamin B12 deficiencies. A further 20% were caused by Fe deficiency combined with either folate or vitamin B12 deficiency. Thus, folate and/or vitamin B12 deficiencies are the cause of approximately one-third (34%) of cases of anaemia in the USA. Vitamin B12 deficiency is more common among the elderly than among younger adults.
  • #26 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    In the UK vitamin B12 deficiency occurs in approximately 20% of adults aged 65 years. This incidence is significantly higher than that among the general population. The reported incidence invariably depends on the criteria of deficiency used, and in fact estimates rise to 24% and 46% among free-living and institutionalised elderly respectively when methylmalonic acid is used as a marker of vitamin B12 status. […] It is argued that consuming additional folic acid (as synthetic pteroylglutamic acid) from fortified foods increases the risk of masking megaloblastic anaemia caused by vitamin B12 deficiency. […] The impact of folate and vitamin B12 deficiencies in the elderly cannot be underestimated. Among older participants of the National Health and Nutrition Examination Survey III 14% of anaemia was caused by folate and/or vitamin B12 deficiencies. A further 20% were caused by Fe deficiency combined with either folate or vitamin B12 deficiency. Thus, folate and/or vitamin B12 deficiencies are the cause of approximately one-third (34%) of cases of anaemia in the USA. Vitamin B12 deficiency is more common among the elderly than among younger adults.
  • #27 Associations of Genetically Predicted Vitamin B12 Status across the Phenome
    https://pmc.ncbi.nlm.nih.gov/articles/PMC9740080/
    Variation in vitamin B12 levels has been associated with a range of diseases across the life-course, the causal nature of which remains elusive. […] Clinical vitamin B12 deficiency, manifested as megaloblastic anaemia, is associated with a range of health outcomes, such as impaired cognitive decline and cardiovascular disease. […] Vitamin B12 deficiency, defined as circulating B12 levels below 148 pmol/L, occurs in 6% of individuals aged less than 60 and 20% in those aged more than 60, and its prevalence is increasing, especially in older adults. […] Our study highlights that higher genetically predicted vitamin B12 status is potentially protective of risk of vitamin B12 deficiency associated with pernicious anaemia diagnosis, and reduces risk of megaloblastic anaemia. […] Higher genetically predicted serum vitamin B12 levels were found to have a protective effect on pernicious anaemia (OR = 0.29, 95% CI: 0.190.45) and megaloblastic anaemia (0.35, 0.200.50).
  • #28 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    Inadequate intake or nutritional deficiency of cobalamin is rare among healthy adults in industrialized countries, even among elderly adults; 5% according to one report. It is limited to rare instances of patients on strict vegetarian diets and those who are already malnourished, such as elderly patients, patients in institutions or patients in psychiatric hospitals. […] Estimates among the elderly vary widely; from 5% (based upon a low serum vitamin B12 concentration) among institutionalized elderly adults in Germany, The Netherlands and Belgium to 46% (based on multiple criteria including serum vitamin B12 and methylmalonic acid (MMA)) among institutionalized elderly adults in the UK. […] Cobalamin deficiency can take years to develop. Consequently, the clinical symptoms of classical cobalamin deficiency, i.e. of severe megaloblastic anaemia combined with neuropsychiatric symptoms, are rarely seen today.
  • #29 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    Detection and treatment of the early stages of cobalamin deficiency is important, particularly in patients with neuropsychiatric symptoms because they may fail to respond if therapy is delayed. […] The early stages of vitamin B12 deficiency will not lead to macrocytosis or anaemia, because biochemical vitamin B12 deficit precedes overt clinical deficiency with macro-ovalocytes and falling Hb levels. […] The concept that patients suffering from cobalamin deficiency may have neuropsychiatric symptoms without macrocytosis or anaemia was not widely accepted until relatively recently. […] Thus, it has been realized that neuropsychiatric illness may be the only symptom of cobalamin deficiency and, importantly, the neurological symptoms are considered of most concern because they may fail to remit on therapy.
  • #30 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    In the UK vitamin B12 deficiency occurs in approximately 20% of adults aged 65 years. This incidence is significantly higher than that among the general population. The reported incidence invariably depends on the criteria of deficiency used, and in fact estimates rise to 24% and 46% among free-living and institutionalised elderly respectively when methylmalonic acid is used as a marker of vitamin B12 status. […] It is argued that consuming additional folic acid (as synthetic pteroylglutamic acid) from fortified foods increases the risk of masking megaloblastic anaemia caused by vitamin B12 deficiency. […] The impact of folate and vitamin B12 deficiencies in the elderly cannot be underestimated. Among older participants of the National Health and Nutrition Examination Survey III 14% of anaemia was caused by folate and/or vitamin B12 deficiencies. A further 20% were caused by Fe deficiency combined with either folate or vitamin B12 deficiency. Thus, folate and/or vitamin B12 deficiencies are the cause of approximately one-third (34%) of cases of anaemia in the USA. Vitamin B12 deficiency is more common among the elderly than among younger adults.
  • #31 Vitamin B12 & folate anaemia | NHS inform
    https://www.nhsinform.scot/illnesses-and-conditions/nutritional/vitamin-b12-or-folate-deficiency-anaemia/
    Vitamin B12 or folate deficiency anaemia occurs when a lack of vitamin B12 or folate affects the body’s ability to produce fully functioning red blood cells. […] It’s important for vitamin B12 or folate deficiency anaemia to be diagnosed and treated as soon as possible because, although many of the symptoms improve with treatment, some problems caused by the condition can be irreversible. […] Most cases of vitamin B12 and folate deficiency can be easily treated with injections or tablets to replace the missing vitamins. […] Although it’s uncommon, vitamin B12 or folate deficiency (with or without anaemia) can lead to complications, particularly if you’ve been deficient in vitamin B12 or folate for some time. […] As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] However, complications can occasionally develop, particularly if you’ve been deficient in either vitamin for some time.
  • #32 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Patients diagnosed with vitamin B12 deficiency whose history and physical examination do not suggest an obvious dietary or malabsorptive etiology should be tested for pernicious anemia with anti-intrinsic factor antibodies (positive predictive value = 95%), particularly if other autoimmune disorders are present. […] If vitamin B12 deficiency coexists with folate deficiency, vitamin B12 should be replaced first to prevent subacute combined degeneration of the spinal cord. […] A 2005 Cochrane review involving 108 patients with vitamin B12 deficiency found that high-dose oral replacement (1 mg to 2 mg per day) was as effective as parenteral administration for correcting anemia and neurologic symptoms. […] There is insufficient data to recommend other formulations of vitamin B12 replacement (e.g., nasal, sublingual, subcutaneous). […] The British Society for Haematology recommends intramuscular vitamin B12 for severe deficiency and malabsorption syndromes, whereas oral replacement may be considered for patients with asymptomatic, mild disease with no absorption or compliance concerns.
  • #33 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Patients diagnosed with vitamin B12 deficiency whose history and physical examination do not suggest an obvious dietary or malabsorptive etiology should be tested for pernicious anemia with anti-intrinsic factor antibodies (positive predictive value = 95%), particularly if other autoimmune disorders are present. […] If vitamin B12 deficiency coexists with folate deficiency, vitamin B12 should be replaced first to prevent subacute combined degeneration of the spinal cord. […] A 2005 Cochrane review involving 108 patients with vitamin B12 deficiency found that high-dose oral replacement (1 mg to 2 mg per day) was as effective as parenteral administration for correcting anemia and neurologic symptoms. […] There is insufficient data to recommend other formulations of vitamin B12 replacement (e.g., nasal, sublingual, subcutaneous). […] The British Society for Haematology recommends intramuscular vitamin B12 for severe deficiency and malabsorption syndromes, whereas oral replacement may be considered for patients with asymptomatic, mild disease with no absorption or compliance concerns.
  • #34 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    It is now commonly accepted that there are five stages of vitamin B12 deficiency that between them encompass the range from normal status to severe deficiency. […] Importantly, it is still not clear at which stage neurological damage first appears during decreasing vitamin B12 status. […] The use of any marker as a diagnostic test for the detection or exclusion of vitamin B12 deficiency is only useful if its diagnostic accuracy is sufficiently high. […] The Haematological Markers and Vitamin B12 Deficiency in the Elderly Study has confirmed previous findings that MCV is not a good predictor of vitamin B12 status. […] The definition of, or diagnosis of, a disease based purely on abnormal biochemical variables is, however, problematic and invokes the danger of circular reasoning, especially if the diagnostic approach no longer includes clinical criteria.
  • #35 Vitamin B12 in Health and Disease
    https://pmc.ncbi.nlm.nih.gov/articles/PMC3257642/
    Vitamin B12 deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. […] The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health. […] The long term consequences are not fully known but may include adverse effects on pregnancy outcomes and aspects of ageing. […] The potential masking of vitamin B12 deficiency by folate fortification of the food supply has also raised some safety concerns. […] Neurological damage in the absence of anaemia has been reported in 20-30% of cases of vitamin B12 deficiency. […] Vitamin B12 deficiency will also develop after gastric antrum resection as this is the site of secretion of IF and acid. […] Patients with pernicious anaemia require larger oral supplements (e.g., 500-1,000 g/d) or intramuscular injections. […] In developing countries, fortification could potentially have a more significant impact as the populations intake is often low.
  • #36 Associations of Genetically Predicted Vitamin B12 Status across the Phenome
    https://pmc.ncbi.nlm.nih.gov/articles/PMC9740080/
    Variation in vitamin B12 levels has been associated with a range of diseases across the life-course, the causal nature of which remains elusive. […] Clinical vitamin B12 deficiency, manifested as megaloblastic anaemia, is associated with a range of health outcomes, such as impaired cognitive decline and cardiovascular disease. […] Vitamin B12 deficiency, defined as circulating B12 levels below 148 pmol/L, occurs in 6% of individuals aged less than 60 and 20% in those aged more than 60, and its prevalence is increasing, especially in older adults. […] Our study highlights that higher genetically predicted vitamin B12 status is potentially protective of risk of vitamin B12 deficiency associated with pernicious anaemia diagnosis, and reduces risk of megaloblastic anaemia. […] Higher genetically predicted serum vitamin B12 levels were found to have a protective effect on pernicious anaemia (OR = 0.29, 95% CI: 0.190.45) and megaloblastic anaemia (0.35, 0.200.50).
  • #37 Associations of Genetically Predicted Vitamin B12 Status across the Phenome
    https://pmc.ncbi.nlm.nih.gov/articles/PMC9740080/
    Variation in vitamin B12 levels has been associated with a range of diseases across the life-course, the causal nature of which remains elusive. […] Clinical vitamin B12 deficiency, manifested as megaloblastic anaemia, is associated with a range of health outcomes, such as impaired cognitive decline and cardiovascular disease. […] Vitamin B12 deficiency, defined as circulating B12 levels below 148 pmol/L, occurs in 6% of individuals aged less than 60 and 20% in those aged more than 60, and its prevalence is increasing, especially in older adults. […] Our study highlights that higher genetically predicted vitamin B12 status is potentially protective of risk of vitamin B12 deficiency associated with pernicious anaemia diagnosis, and reduces risk of megaloblastic anaemia. […] Higher genetically predicted serum vitamin B12 levels were found to have a protective effect on pernicious anaemia (OR = 0.29, 95% CI: 0.190.45) and megaloblastic anaemia (0.35, 0.200.50).
  • #38 Associations of Genetically Predicted Vitamin B12 Status across the Phenome
    https://pmc.ncbi.nlm.nih.gov/articles/PMC9740080/
    We highlight a risk reduction of 71% and 65% in pernicious anaemia risk and megaloblastic anaemia risk, respectively, for every SD increase in genetically predicted vitamin B12 status. […] Our study offers novel and previously unreported effects of genetically determined vitamin B12 status. We highlight a potential protective effect of higher vitamin B12 status on risk of pernicious anaemia and megaloblastic anaemia.
  • #39 Associations of Genetically Predicted Vitamin B12 Status across the Phenome
    https://pmc.ncbi.nlm.nih.gov/articles/PMC9740080/
    Variation in vitamin B12 levels has been associated with a range of diseases across the life-course, the causal nature of which remains elusive. […] Clinical vitamin B12 deficiency, manifested as megaloblastic anaemia, is associated with a range of health outcomes, such as impaired cognitive decline and cardiovascular disease. […] Vitamin B12 deficiency, defined as circulating B12 levels below 148 pmol/L, occurs in 6% of individuals aged less than 60 and 20% in those aged more than 60, and its prevalence is increasing, especially in older adults. […] Our study highlights that higher genetically predicted vitamin B12 status is potentially protective of risk of vitamin B12 deficiency associated with pernicious anaemia diagnosis, and reduces risk of megaloblastic anaemia. […] Higher genetically predicted serum vitamin B12 levels were found to have a protective effect on pernicious anaemia (OR = 0.29, 95% CI: 0.190.45) and megaloblastic anaemia (0.35, 0.200.50).
  • #40 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    The most important benefit of folic acid fortification of staple foods (such as flour) is its ability to optimize folic acid intakes without any need for the consumer to change his/her food intake. Its accompanying disadvantage is the provision of additional folic acid to those who do not need it or who may in fact be in danger as a result of consuming it. […] Accepting that vitamin B12 deficiency may only manifest clinically in some patients as neurological damage, it has been suggested that administration of high doses of folic acid might have precipitated neurological degeneration. […] It is not possible to predict the effect on the incidence of irreversible vitamin B12 neuropathy, although arguments can be put forward to suggest it might increase as a result of a delay in the diagnosis, which can depend on detecting anaemia. […] There is a danger that excitement about the benefits of folic acid fortification to one subset of the population (babies at risk of NTD) may obscure the clear necessity to assess its possible drawbacks to another population group (the elderly).
  • #41 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    In the UK vitamin B12 deficiency occurs in approximately 20% of adults aged 65 years. This incidence is significantly higher than that among the general population. The reported incidence invariably depends on the criteria of deficiency used, and in fact estimates rise to 24% and 46% among free-living and institutionalised elderly respectively when methylmalonic acid is used as a marker of vitamin B12 status. […] It is argued that consuming additional folic acid (as synthetic pteroylglutamic acid) from fortified foods increases the risk of masking megaloblastic anaemia caused by vitamin B12 deficiency. […] The impact of folate and vitamin B12 deficiencies in the elderly cannot be underestimated. Among older participants of the National Health and Nutrition Examination Survey III 14% of anaemia was caused by folate and/or vitamin B12 deficiencies. A further 20% were caused by Fe deficiency combined with either folate or vitamin B12 deficiency. Thus, folate and/or vitamin B12 deficiencies are the cause of approximately one-third (34%) of cases of anaemia in the USA. Vitamin B12 deficiency is more common among the elderly than among younger adults.
  • #42 Vitamin B12 in Health and Disease
    https://pmc.ncbi.nlm.nih.gov/articles/PMC3257642/
    Vitamin B12 deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. […] The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health. […] The long term consequences are not fully known but may include adverse effects on pregnancy outcomes and aspects of ageing. […] The potential masking of vitamin B12 deficiency by folate fortification of the food supply has also raised some safety concerns. […] Neurological damage in the absence of anaemia has been reported in 20-30% of cases of vitamin B12 deficiency. […] Vitamin B12 deficiency will also develop after gastric antrum resection as this is the site of secretion of IF and acid. […] Patients with pernicious anaemia require larger oral supplements (e.g., 500-1,000 g/d) or intramuscular injections. […] In developing countries, fortification could potentially have a more significant impact as the populations intake is often low.
  • #43 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    The most important benefit of folic acid fortification of staple foods (such as flour) is its ability to optimize folic acid intakes without any need for the consumer to change his/her food intake. Its accompanying disadvantage is the provision of additional folic acid to those who do not need it or who may in fact be in danger as a result of consuming it. […] Accepting that vitamin B12 deficiency may only manifest clinically in some patients as neurological damage, it has been suggested that administration of high doses of folic acid might have precipitated neurological degeneration. […] It is not possible to predict the effect on the incidence of irreversible vitamin B12 neuropathy, although arguments can be put forward to suggest it might increase as a result of a delay in the diagnosis, which can depend on detecting anaemia. […] There is a danger that excitement about the benefits of folic acid fortification to one subset of the population (babies at risk of NTD) may obscure the clear necessity to assess its possible drawbacks to another population group (the elderly).
  • #44 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    The most important benefit of folic acid fortification of staple foods (such as flour) is its ability to optimize folic acid intakes without any need for the consumer to change his/her food intake. Its accompanying disadvantage is the provision of additional folic acid to those who do not need it or who may in fact be in danger as a result of consuming it. […] Accepting that vitamin B12 deficiency may only manifest clinically in some patients as neurological damage, it has been suggested that administration of high doses of folic acid might have precipitated neurological degeneration. […] It is not possible to predict the effect on the incidence of irreversible vitamin B12 neuropathy, although arguments can be put forward to suggest it might increase as a result of a delay in the diagnosis, which can depend on detecting anaemia. […] There is a danger that excitement about the benefits of folic acid fortification to one subset of the population (babies at risk of NTD) may obscure the clear necessity to assess its possible drawbacks to another population group (the elderly).
  • #45 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Vitamin B12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms, and other clinical manifestations. […] Use of vitamin B12 in patients with elevated serum homocysteine levels and cardiovascular disease does not reduce the risk of myocardial infarction or stroke, or alter cognitive decline. […] Vitamin B12 deficiency affects multiple systems, and sequelae vary in severity from mild fatigue to severe neurologic impairment. […] The substantial hepatic storage of vitamin B12 can delay clinical manifestations for up to 10 years after the onset of deficiency. […] Clinical evaluation seems to show an inverse relationship between the severity of megaloblastic anemia and the degree of neurologic impairment. […] Maternal vitamin B12 deficiency during pregnancy or while breastfeeding may lead to neural tube defects, developmental delay, failure to thrive, hypotonia, ataxia, and anemia.
  • #46 Vitamin B12 in Health and Disease
    https://pmc.ncbi.nlm.nih.gov/articles/PMC3257642/
    Vitamin B12 deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. […] The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health. […] The long term consequences are not fully known but may include adverse effects on pregnancy outcomes and aspects of ageing. […] The potential masking of vitamin B12 deficiency by folate fortification of the food supply has also raised some safety concerns. […] Neurological damage in the absence of anaemia has been reported in 20-30% of cases of vitamin B12 deficiency. […] Vitamin B12 deficiency will also develop after gastric antrum resection as this is the site of secretion of IF and acid. […] Patients with pernicious anaemia require larger oral supplements (e.g., 500-1,000 g/d) or intramuscular injections. […] In developing countries, fortification could potentially have a more significant impact as the populations intake is often low.
  • #47 Vitamin B12 in Health and Disease
    https://pmc.ncbi.nlm.nih.gov/articles/PMC3257642/
    Vitamin B12 deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. […] The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health. […] The long term consequences are not fully known but may include adverse effects on pregnancy outcomes and aspects of ageing. […] The potential masking of vitamin B12 deficiency by folate fortification of the food supply has also raised some safety concerns. […] Neurological damage in the absence of anaemia has been reported in 20-30% of cases of vitamin B12 deficiency. […] Vitamin B12 deficiency will also develop after gastric antrum resection as this is the site of secretion of IF and acid. […] Patients with pernicious anaemia require larger oral supplements (e.g., 500-1,000 g/d) or intramuscular injections. […] In developing countries, fortification could potentially have a more significant impact as the populations intake is often low.
  • #48 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Vitamin B12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms, and other clinical manifestations. […] Use of vitamin B12 in patients with elevated serum homocysteine levels and cardiovascular disease does not reduce the risk of myocardial infarction or stroke, or alter cognitive decline. […] Vitamin B12 deficiency affects multiple systems, and sequelae vary in severity from mild fatigue to severe neurologic impairment. […] The substantial hepatic storage of vitamin B12 can delay clinical manifestations for up to 10 years after the onset of deficiency. […] Clinical evaluation seems to show an inverse relationship between the severity of megaloblastic anemia and the degree of neurologic impairment. […] Maternal vitamin B12 deficiency during pregnancy or while breastfeeding may lead to neural tube defects, developmental delay, failure to thrive, hypotonia, ataxia, and anemia.
  • #49 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Vitamin B12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms, and other clinical manifestations. […] Use of vitamin B12 in patients with elevated serum homocysteine levels and cardiovascular disease does not reduce the risk of myocardial infarction or stroke, or alter cognitive decline. […] Vitamin B12 deficiency affects multiple systems, and sequelae vary in severity from mild fatigue to severe neurologic impairment. […] The substantial hepatic storage of vitamin B12 can delay clinical manifestations for up to 10 years after the onset of deficiency. […] Clinical evaluation seems to show an inverse relationship between the severity of megaloblastic anemia and the degree of neurologic impairment. […] Maternal vitamin B12 deficiency during pregnancy or while breastfeeding may lead to neural tube defects, developmental delay, failure to thrive, hypotonia, ataxia, and anemia.
  • #50 Vitamin B12 in Health and Disease
    https://pmc.ncbi.nlm.nih.gov/articles/PMC3257642/
    Vitamin B12 deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. […] The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health. […] The long term consequences are not fully known but may include adverse effects on pregnancy outcomes and aspects of ageing. […] The potential masking of vitamin B12 deficiency by folate fortification of the food supply has also raised some safety concerns. […] Neurological damage in the absence of anaemia has been reported in 20-30% of cases of vitamin B12 deficiency. […] Vitamin B12 deficiency will also develop after gastric antrum resection as this is the site of secretion of IF and acid. […] Patients with pernicious anaemia require larger oral supplements (e.g., 500-1,000 g/d) or intramuscular injections. […] In developing countries, fortification could potentially have a more significant impact as the populations intake is often low.
  • #51 Vitamin B12 in Health and Disease
    https://pmc.ncbi.nlm.nih.gov/articles/PMC3257642/
    Vitamin B12 deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. […] The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health. […] The long term consequences are not fully known but may include adverse effects on pregnancy outcomes and aspects of ageing. […] The potential masking of vitamin B12 deficiency by folate fortification of the food supply has also raised some safety concerns. […] Neurological damage in the absence of anaemia has been reported in 20-30% of cases of vitamin B12 deficiency. […] Vitamin B12 deficiency will also develop after gastric antrum resection as this is the site of secretion of IF and acid. […] Patients with pernicious anaemia require larger oral supplements (e.g., 500-1,000 g/d) or intramuscular injections. […] In developing countries, fortification could potentially have a more significant impact as the populations intake is often low.
  • #52 Vitamin B12 & folate anaemia | NHS inform
    https://www.nhsinform.scot/illnesses-and-conditions/nutritional/vitamin-b12-or-folate-deficiency-anaemia/
    Vitamin B12 or folate deficiency anaemia occurs when a lack of vitamin B12 or folate affects the body’s ability to produce fully functioning red blood cells. […] It’s important for vitamin B12 or folate deficiency anaemia to be diagnosed and treated as soon as possible because, although many of the symptoms improve with treatment, some problems caused by the condition can be irreversible. […] Most cases of vitamin B12 and folate deficiency can be easily treated with injections or tablets to replace the missing vitamins. […] Although it’s uncommon, vitamin B12 or folate deficiency (with or without anaemia) can lead to complications, particularly if you’ve been deficient in vitamin B12 or folate for some time. […] As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] However, complications can occasionally develop, particularly if you’ve been deficient in either vitamin for some time.
  • #53
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/
    As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare. […] But complications can occasionally develop, particularly if you have been deficient in either vitamin for some time. […] A lack of vitamin B12 (with or without anaemia) can cause complications. […] If neurological problems do develop, they can sometimes be irreversible. […] Vitamin B12 deficiency can sometimes lead to temporary infertility, an inability to conceive. […] If you have a vitamin B12 deficiency caused by pernicious anaemia, a condition where your immune system attacks healthy cells in your stomach, your risk of developing stomach cancer is increased. […] If you’re pregnant, not having enough vitamin B12 can increase the risk of your baby developing a serious birth defect known as a neural tube defect.
  • #54
    https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/
    Vitamin B12 or B9 (commonly called folate) deficiency anaemia occurs when a lack of vitamin B12 or folate causes the body to produce abnormally large red blood cells that cannot function properly. […] It’s important for vitamin B12 or folate deficiency anaemia to be diagnosed and treated as soon as possible. […] This is because although many of the symptoms improve with treatment, some problems caused by the condition can be irreversible. […] Although it’s uncommon, vitamin B12 or folate deficiency (with or without anaemia) can lead to complications, particularly if you have been deficient in vitamin B12 or folate for some time. […] Some complications improve with appropriate treatment, but others, such as problems with the nervous system, can sometimes be permanent.
  • #55 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Patients diagnosed with vitamin B12 deficiency whose history and physical examination do not suggest an obvious dietary or malabsorptive etiology should be tested for pernicious anemia with anti-intrinsic factor antibodies (positive predictive value = 95%), particularly if other autoimmune disorders are present. […] If vitamin B12 deficiency coexists with folate deficiency, vitamin B12 should be replaced first to prevent subacute combined degeneration of the spinal cord. […] A 2005 Cochrane review involving 108 patients with vitamin B12 deficiency found that high-dose oral replacement (1 mg to 2 mg per day) was as effective as parenteral administration for correcting anemia and neurologic symptoms. […] There is insufficient data to recommend other formulations of vitamin B12 replacement (e.g., nasal, sublingual, subcutaneous). […] The British Society for Haematology recommends intramuscular vitamin B12 for severe deficiency and malabsorption syndromes, whereas oral replacement may be considered for patients with asymptomatic, mild disease with no absorption or compliance concerns.
  • #56 Folate and vitamin B12: friendly or enemy nutrients for the elderly* | Proceedings of the Nutrition Society | Cambridge Core
    https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/folate-and-vitamin-b12-friendly-or-enemy-nutrients-for-the-elderly/D8C38CD6D49977957C5B098623459519
    In the UK vitamin B12 deficiency occurs in approximately 20% of adults aged 65 years. This incidence is significantly higher than that among the general population. The reported incidence invariably depends on the criteria of deficiency used, and in fact estimates rise to 24% and 46% among free-living and institutionalised elderly respectively when methylmalonic acid is used as a marker of vitamin B12 status. […] It is argued that consuming additional folic acid (as synthetic pteroylglutamic acid) from fortified foods increases the risk of masking megaloblastic anaemia caused by vitamin B12 deficiency. […] The impact of folate and vitamin B12 deficiencies in the elderly cannot be underestimated. Among older participants of the National Health and Nutrition Examination Survey III 14% of anaemia was caused by folate and/or vitamin B12 deficiencies. A further 20% were caused by Fe deficiency combined with either folate or vitamin B12 deficiency. Thus, folate and/or vitamin B12 deficiencies are the cause of approximately one-third (34%) of cases of anaemia in the USA. Vitamin B12 deficiency is more common among the elderly than among younger adults.
  • #57 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Patients diagnosed with vitamin B12 deficiency whose history and physical examination do not suggest an obvious dietary or malabsorptive etiology should be tested for pernicious anemia with anti-intrinsic factor antibodies (positive predictive value = 95%), particularly if other autoimmune disorders are present. […] If vitamin B12 deficiency coexists with folate deficiency, vitamin B12 should be replaced first to prevent subacute combined degeneration of the spinal cord. […] A 2005 Cochrane review involving 108 patients with vitamin B12 deficiency found that high-dose oral replacement (1 mg to 2 mg per day) was as effective as parenteral administration for correcting anemia and neurologic symptoms. […] There is insufficient data to recommend other formulations of vitamin B12 replacement (e.g., nasal, sublingual, subcutaneous). […] The British Society for Haematology recommends intramuscular vitamin B12 for severe deficiency and malabsorption syndromes, whereas oral replacement may be considered for patients with asymptomatic, mild disease with no absorption or compliance concerns.
  • #58 Vitamin B12 Deficiency: Recognition and Management | AAFP
    https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html
    Patients diagnosed with vitamin B12 deficiency whose history and physical examination do not suggest an obvious dietary or malabsorptive etiology should be tested for pernicious anemia with anti-intrinsic factor antibodies (positive predictive value = 95%), particularly if other autoimmune disorders are present. […] If vitamin B12 deficiency coexists with folate deficiency, vitamin B12 should be replaced first to prevent subacute combined degeneration of the spinal cord. […] A 2005 Cochrane review involving 108 patients with vitamin B12 deficiency found that high-dose oral replacement (1 mg to 2 mg per day) was as effective as parenteral administration for correcting anemia and neurologic symptoms. […] There is insufficient data to recommend other formulations of vitamin B12 replacement (e.g., nasal, sublingual, subcutaneous). […] The British Society for Haematology recommends intramuscular vitamin B12 for severe deficiency and malabsorption syndromes, whereas oral replacement may be considered for patients with asymptomatic, mild disease with no absorption or compliance concerns.
  • #59 Vitamin B12 in Health and Disease
    https://pmc.ncbi.nlm.nih.gov/articles/PMC3257642/
    Vitamin B12 deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. […] The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health. […] The long term consequences are not fully known but may include adverse effects on pregnancy outcomes and aspects of ageing. […] The potential masking of vitamin B12 deficiency by folate fortification of the food supply has also raised some safety concerns. […] Neurological damage in the absence of anaemia has been reported in 20-30% of cases of vitamin B12 deficiency. […] Vitamin B12 deficiency will also develop after gastric antrum resection as this is the site of secretion of IF and acid. […] Patients with pernicious anaemia require larger oral supplements (e.g., 500-1,000 g/d) or intramuscular injections. […] In developing countries, fortification could potentially have a more significant impact as the populations intake is often low.

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niedokrwistość złośliwa niedobór folianów suplementacja doustna degeneracja neurologiczna zaburzenie funkcji poznawczych poród przedwczesny zawał mięśnia sercowego udar mózgu zespół złego wchłaniania niedokrwistość megaloblastyczna makrocytoza rak jelita grubego wada cewy nerwowej niedobór żelaza homocysteina niedokrwistość z niedoboru witaminy B12 zaburzenie neuropsychiatryczne suplementacja parenteralna kwas foliowy niepłodność choroba układu sercowo-naczyniowego uszkodzenie neurologiczne rak żołądka