Materiały źródłowe

• #1 Vitamin B12 Deficiency – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK441923/

  The epidemiology of vitamin B12 deficiency varies based on the etiology. In the general population, some studies have shown that among patients with anemia, approximately 1% to 2% is due to B12 deficiency. Other studies have shown that among patients with clinical macrocytosis (defined as a mean corpuscular volume, MCV, 100), 18% to 20% were due to B12 deficiency. Vitamin B12 deficiency is more common in older patients, regardless of the cause. B12 deficiency due to pernicious anemia is more common in people of Northern European ancestry. The incidence of pernicious anemia is lower in people of African descent or people from other areas of Europe. […] Vitamin B12 deficiency has 4 primary etiologies: Autoimmune: Pernicious anemia is an autoimmune condition in which antibodies to intrinsic factors are produced. Anti-intrinsic factor antibodies bind to and inhibit the effects of intrinsic factors, resulting in an inability of B12 to be absorbed by the terminal ileum.

• #2 Vitamin B12 or folate deficiency anaemia

  https://www2.hse.ie/conditions/vitamin-b12-or-folate-deficiency-anaemia/

  Vitamin B12 or B9 (folate) deficiency anaemia happens when you have a shortage of either of these vitamins. The body responds by producing abnormally large red blood cells that do not function properly. […] A deficiency is more common in older people. […] It affects around: 1 in 10 people age 75 or over; 1 in 20 people age 65 to 74. […] Several other causes can lead to a vitamin B12 or folate deficiency. […] Pernicious anaemia is where your immune system attacks healthy cells in your tummy. This prevents your body from absorbing vitamin B12 from the food you eat. It’s the most common cause of vitamin B12 deficiency. […] Coeliac disease is a condition where your immune system attacks your own tissues when you eat gluten. This can also lead to B12 deficiency anaemia. […] Vitamin B12 or folate deficiency can lead to complications. But this is not common. […] Complications are more likely if you have a deficiency in the vitamin for some time. Some will improve with the right treatment. Others can be permanent, such as problems with the nervous system.

• #3

  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. […] Both vitamin B12 deficiency and folate deficiency are more common in older people, affecting around 1 in 10 people aged 75 or over and 1 in 20 people aged 65 to 74. […] 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.

• #4 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. […] In the United States and the United Kingdom, the prevalence of vitamin B12 deficiency is approximately 6% in persons younger than 60 years, and nearly 20% in those older than 60 years. […] Latin American countries have a clinical or subclinical deficiency rate of approximately 40%. […] Certain risk factors increase the prevalence of vitamin B12 deficiency. […] Dietary insufficiency, pernicious anemia (i.e., an autoimmune process that reduces available intrinsic factor and subsequent absorption of vitamin B12), and long-term use of metformin or acid-suppressing medications have been implicated in B12 deficiency. […] Maternal vitamin B12 deficiency during pregnancy or while breastfeeding may lead to neural tube defects, developmental delay, failure to thrive, hypotonia, ataxia, and anemia.

• #4 Vitamin B12 Deficiency: Recognition and Management | AAFP

  https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html

  Screening persons at average risk of vitamin B12 deficiency is not recommended. […] Screening should be considered in patients with risk factors, and diagnostic testing should be considered in those with suspected clinical manifestations. […] 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, particularly if other autoimmune disorders are present. […] Vitamin B12 deficiency can be treated with intramuscular injections of cyanocobalamin or oral vitamin B12 therapy. […] Because of potential interactions from prolonged medication use, physicians should consider screening patients for vitamin B12 deficiency if they have been taking proton pump inhibitors or H2 blockers for more than 12 months, or metformin for more than four months. […] Vitamin B12 deficiency is a much more common cause of hyperhomocysteinemia in developed countries than folate deficiency because of widespread fortification of food with folate.

• #5 Vitamin B12 deficiency – Wikipedia

  https://en.wikipedia.org/wiki/Vitamin_B12_deficiency

  Vitamin B12 deficiency is common and occurs worldwide. In the US and UK, around 6 percent of the general population have the deficiency; in those over the age of sixty, around 20 percent are deficient. In under-developed countries, the rates are even higher: across Latin America 40 percent are deficient; in some parts of Africa, 70 percent; and in some parts of India, 70 to 80 percent. […] According to the World Health Organization (WHO), vitamin B12 deficiency may be considered a global public health problem affecting millions of individuals. However, the incidence and prevalence of vitamin B12 deficiency worldwide is unknown due to the limited population-based data available. […] Vitamin B12 deficiency is one of the main causes of anemia. In countries where B12 deficiency is common, it is generally assumed that there is a greater risk of developing anemia. However, the overall contribution of vitamin B12 deficiency to the global incidence of anemia may not be significant, except in elderly individuals, vegetarians, cases of malabsorption and some genetic disorders. […] Megaloblastic anemia caused by vitamin B12 deficiency is characterized by red blood cells that are larger than normal and are unable to deliver oxygen to the body’s organs.

• #6 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 causes the body to produce abnormally large red blood cells that cant function properly. […] Both vitamin B12 deficiency and folate deficiency are more common in older people, affecting around 1 in 10 people aged 75 or over, and 1 in 20 people aged 65 to 74. […] Vitamin B12 or folate deficiency anaemia can cause a wide range of symptoms. […] A diagnosis of vitamin B12 or folate deficiency anaemia can often be made by your GP based on your symptoms and the results of blood tests. […] If your symptoms and blood test results suggest a vitamin B12 or folate deficiency, your GP may arrange further tests. […] As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare.

• #6 Vitamin B12 & folate anaemia | NHS inform

  https://www.nhsinform.scot/illnesses-and-conditions/nutritional/vitamin-b12-or-folate-deficiency-anaemia/

  A lack of vitamin B12 (with or without anaemia) can cause neurological problems (issues affecting your nervous system), such as: vision problems, memory loss, pins and needles (paraesthesia), loss of physical coordination (ataxia), which can affect your whole body and cause difficulty speaking or walking, damage to parts of the nervous system (peripheral neuropathy), particularly in the legs. […] A lack of folate (with or without anaemia) can also cause complications, some of which are outlined below.

• #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

  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. […] 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.

• #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

  In elderly patients vitamin B12 deficiency is caused primarily by inadequate production of IF causing malabsorption of food cobalamin and PA. It also occurs in pancreatic insufficiency, because of a lack of the enzymes needed to liberate cobalamin from the cobalaminHC complex. […] PA is a classic cause of cobalamin deficiency and one of the most frequent among elderly patients; 20-50% of cases according to two studies and 15% in another patient series. […] 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. However, vitamin B12 deficiency often goes unrecognized because the initial clinical manifestations are subtle and non-specific or are attributed to the normal ageing process.

• #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

  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 has been suggested that it may be possible to categorize at-risk elderly for vitamin B12 deficiency using haematological variables; measured routinely in clinical practice. However, when this hypothesis was tested using clinical data from a UK hospital, it was found that regardless of the comparisons made there was no relationship between the prevalence of abnormal haematology and vitamin B12 deficiency. […] As long as there still remains a lack of a reliable clinical test for the diagnosis of true vitamin B12 deficiency, any fortification programme should be accompanied by appropriate systems to ensure that the elderly at risk of vitamin B12 deficiency are identified.

• #8 Vitamin B12 Deficiency – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK441923/

  Malabsorption: Parietal cells in the stomach produce intrinsic factors; therefore, any patient with a history of gastric bypass surgery may be at risk for developing a B12 deficiency because their new alimentary pathway bypasses the site of intrinsic factor production. […] Dietary insufficiency: Vitamin B12 is stored in excess in the liver; however, patients who have followed a strict vegan diet for approximately 3 years may develop a B12 deficiency from a lack of dietary intake. […] Toxin exposure: Exposure to nitrous oxide can cause vitamin B12 deficiency and neurologic symptoms. Metformin treatment can cause B12 deficiency.

• #9 Epidemiology of Vitamin B12 Deficiency | IntechOpen

  https://www.intechopen.com/chapters/50982

  Vitamin B12 deficiency among vegetarians was found to be between 21 and 85% regardless of age, address, type of vegetarianism, and demographics of the individuals concerned. […] Although it is thought that vitamin B12 deficiency is rarely seen except in strict vegetarians, it is, in fact, commonly seen in all vegetarian groups (lactovegetarians, ovovegetarians, lactoovovegetarians, and vegans), as well as among the elderly and for reasons related to medicine and drug use. […] The prevalence of vitamin B12 deficiency was reported to be very high over the last decade that is why national programs have been established to prevent it. […] Consequently, vitamin B12 deficiency has been found to be very common in specific groups of the population, and there is a high risk of vitamin B12 deficiency as far as vegetarians, infants, pregnant and breastfeeding mothers, and the elderly are concerned.

• #9 Epidemiology of Vitamin B12 Deficiency | IntechOpen

  https://www.intechopen.com/chapters/50982

  Vitamin B12 deficiency is one of the most frequent vitamin deficiencies worldwide. […] This deficiency is a highly important public health issue because of its serious complications if it is not detected and treated appropriately, although its treatment is very simple. […] Epidemiological studies in this field are, therefore, of great value. […] Vitamin B12 deficiency is one of the most common causes of macrocytic anemia. […] Vitamin B12 deficiency is still a public health problem in these regions. […] The main reasons for vitamin B12 deficiency are nutritional deficiencies that affect large sectors of the population including vegetarians and their children who are affected during and after pregnancy, the elderly, frequent drug users as well as nutritional deficiency linked to low socioeconomic level.

• #10 Pernicious Anaemia and B12 Deficiency | Doctor

  https://patient.info/doctor/pernicious-anaemia-and-b12-deficiency

  Data from USA and Netherlands indicates that it affects at least 3% of those aged 20-39 years old, 4% of those aged 40-59 years, 6% of those 60 years or over, and over 20% aged 85 and older. […] Marginal depletion affects 15% of those aged 20-59 years old and more than 20% of those aged 60 years or over. […] For people with vegan diets, around 11% are deficient in vitamin B12.

• #11 Folate Deficiency: Recognize Symptoms & Causes | Ada

  https://ada.com/conditions/folate-deficiency/

  Folate deficiency is most commonly found in pregnant and lactating women, people with chronic conditions of the gastrointestinal tract, people following restricted diets due to weight-loss regimes or medical conditions, people with alcohol dependence and people more than 65 years of age. […] Folate deficiency will not go away on its own. Treatment is required and may involve dietary changes and/or oral supplements and treatment of underlying causes, if any are present. If left untreated, folate deficiency may result in folate deficiency anemia, which can cause severe complications. […] Anemia, particularly megaloblastic anemia, is often the first sign that there is an underlying folate deficiency, and doctors will usually test for folate and Vitamin B12 deficiencies when they encounter anemia.

• #11 Folate Deficiency: Recognize Symptoms & Causes | Ada

  https://ada.com/conditions/folate-deficiency/

  Megaloblasts are large, poorly-formed red blood cells that form in cases of anemia caused by, among others, folate or B12 deficiencies. Megaloblastic anemia is a result of folate deficiency as well as one of the most easily-identified symptoms: sometimes, a deficiency is only identified when anemia presents. If it results from folate deficiency, this anemia, is treated by taking oral or intravenous folate supplements. […] Folic acid is very important in the correct development of cells and is crucial for the correct development of fetuses. Pregnant women and women planning to become pregnant should increase their folic acid intake to 400 micrograms a day. […] Folic acid deficiency in the mother can cause defects in the neural tube, which is the structure that eventually develops into the babys spinal cord. Neural tube defects (NTDs) can include spina bifida, caudal regressive (affecting the lowest part of the spine), and cleft palate.

• #12 Pernicious Anemia: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/204930-overview

  Adult pernicious anemia usually occurs in people aged 40-70 years. One study found 1.9% of patients older than 60 had undiagnosed pernicious anemia. Congenital pernicious anemia usually manifests in children younger than 2 years. […] Whereas the disease originally was believed to be restricted primarily to whites of Scandinavian and Celtic origin, subsequent evidence shows that it occurs in all races. In general, the prevalence of pernicious anemia is probably underestimated, due to the complexity of the diagnosis. A female predominance has been reported in England, Scandinavia, and among persons of African descent (1.5:1). However, data in the United States show an equal sex distribution. […] Pernicious anemia likely has a genetic predisposition. The disease is diagnosed more commonly in family members of patients diagnosed with pernicious anemia and is associated with human leukocyte antigen (HLA) types A2, A3, and B7 and blood group type A. Approximately 20% of relatives of patients with pernicious anemia are diagnosed with the same condition.

• #13 Prevalence of iron, folate, and vitamin B12 deficiencies in 20 to 49 years old women: Ensanut 2012

  https://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0036-36342015000500009

  Prevalence of iron, folate, and vitamin B12 deficiencies in 20 to 49 years old women: Ensanut 2012. […] The deficiency of folate was 1.9% (95%CI 1.3-2.8), B12 deficiency was 8.5% (95%CI 6.7-10.1) and iron deficiency was 29.4% (95%CI 26.5-32.2). […] The vitamin B12 deficiency is still a problem for women of reproductive age and their offspring in Mexico, while folate deficiency disappeared as a problem. […] Despite the lack of information from national surveys, it is estimated that there is a high prevalence of deficiencies of folate and B12 in women. […] The overall national prevalence of vitamin B12 deficiency for women 20-49 years old was 8.5% (95%CI 6.7-10.1). […] Indigenous women had 18.6% (95%CI 13.0-25.9), greater than for non-indigenous women 7.4% (95%CI 5.6-9.9). […] The prevalence of vitamin B12 deficiency in women of reproductive age is a problem in Mexico, primarily in rural areas; however, folate deficiency is no longer a problem.

• #14 M.C.V. should not be the only criteria to order vitamin B12 for anemia under evaluation

  https://www.scirp.org/html/9-1900050_25072.htm

  The seroprevalence of vitamin B12 deficiency is 36.5%. […] Every third person is vitamin B12 deficient in the region. There is no correlation between vitamin B12 levels and MCV in majority of the cases. MCV should not be the only criteria for ordering vitamin B12 for patients with anemia under evaluation.

• #15 Prevalence of Vitamin B12 and Folate Deficiencies in Indian Children and Adolescents

  https://www.mdpi.com/2072-6643/15/13/3026

  Deficiencies of vitamin B12 (B12) and folate (FA) are of particular interest due to their pleiotropic role in 1-carbon metabolism. […] The recent Comprehensive National Nutrition Survey (CNNS-2016-18) provided estimates of the prevalence of B12 and FA deficiency at the national and state levels among preschool (1–4 years: 9976 and 11,004 children, respectively), school-age children (5–9 years: 12,156 and 14,125) and adolescents (10–19 years: 11,748 and 13,621). […] The prevalence of B12 and FA deficiency was high among adolescents (31.0%, CI: 28.7–33.5 and 35.6%, CI: 33.1–8.2) compared to school-age (17.3%, CI: 15.4–19.3 and 27.6%, CI: 25.5–29.9) and preschool children (13.8%, CI: 11.7–16.2 and 22.8%, CI: 20.5–25.2, respectively). […] The national prevalence of B12 deficiency among preschool or school-age children was <20% (the cut-off that indicates a public health problem). However, FA deficiency in these age groups and both FA and B12 deficiencies in adolescents were >20%, warranting further investigation.

• #16 Practice Nursing – Understanding vitamin B12 and folate deficiency

  https://www.practicenursing.com/content/clinical/understanding-vitamin-b12-and-folate-deficiency/

  Vitamin B12 and folate deficiencies are common and have a big impact on sufferers’ lives. […] Vitamin B12 deficiency is a condition that occurs around the world. Although more frequently seen in older adults, it can occur at any age and in any ethnic group and can affect both males and females alike, although there is some indication that women are more commonly affected than men and the condition tends to run in families. […] Diagnosis can often be problematic as many of the symptoms patients present with are shared with other conditions and can easily be attributed to other causes. […] Some patients will also have folate deficiency and this aspect will be briefly covered as the two deficiencies can occur concurrently. […] Vitamin B12 is vital for health and is essential for a number of physiological functions in the body, including the formation of healthy red blood cells, DNA synthesis and the healthy function of the nervous system and the brain. Folate has a similar role and is essential for the production of red blood cells, DNA and RNA synthesis, and is also important in helping to maintain brain function.

• #17 Megaloblastic anaemia: Folic acid and vitamin B12 metabolism | Revista Médica del Hospital General de México

  https://www.elsevier.es/en-revista-revista-medica-del-hospital-general-325-articulo-megaloblastic-anaemia-folic-acid-vitamin-S0185106315000426

  Megaloblastic anaemia: Folic acid and vitamin B12 metabolism […] Deficiency in one or both of these vitamins causes megaloblastic anaemia, a disease characterized by the presence of megaloblasts. […] An understanding of the metabolism of these vitamins will enable clinicians to make the best use and interpretation of laboratory studies and monitor therapeutic strategies, which consist mainly of administering supplements to restore body reserves. […] Megaloblastic anaemia is a general term used to describe a group of anaemias caused by impaired DNA synthesis. […] Folic acid deficiency is usually due to low folate content in the diet, or to an imbalance between folate demand and intake. Cobalamin deficiency is usually caused by poor absorption of this vitamin in the digestive tract. […] The clinical spectrum of megaloblastic anaemia is shown in Table 3, where the minor differences between the clinical manifestations of megaloblastic anaemia caused by folate deficiency and by cobalamin deficiency are highlighted.

• #18

  https://link.springer.com/article/10.1007/s11606-022-07451-2

  Folate and vitamin B12 deficiencies are the most common causes of megaloblastic anemia, characterized by marked macrocytosis. Therefore, we hypothesized that these deficiencies would be dominant in patients with marked macrocytosis. […] In contrast, in our study, only 10.7% of patients with marked macrocytosis had severe serum folate or vitamin B12 deficiency. […] In conclusion, vitamin B12 and folate deficiencies are associated with a minority of cases of marked macrocytic anemia.

• #19 Vitamin deficiency anemia – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/vitamin-deficiency-anemia/symptoms-causes/syc-20355025

  Vitamin deficiency anemia is a lack of healthy red blood cells caused by lower than usual amounts of vitamin B-12 and folate. […] Vitamin deficiency anemia can occur if you don’t eat enough foods containing vitamin B-12 and folate, or if your body has trouble absorbing or processing these vitamins. […] A lack of folate can cause birth defects during pregnancy. However, folate deficiency is less common now in countries that routinely add folate to food products such as breads, cereals and pasta. […] Being deficient in vitamin B-12 or folate increases your risk of many health problems, including pregnancy complications. […] Untreated, vitamin B-12 deficiency can lead to neurological problems, such as persistent tingling in the hands and feet or problems with balance.

• #20

  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 folate (with or without anaemia) can also cause complications. […] 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). […] This increases the risk of neural tube defects, such as spina bifida, developing in the unborn baby.

• #21 Cobalamin (vitamin B12) and Folate Deficiency – Province of British Columbia

  https://www2.gov.bc.ca/gov/content/health/practitioner-professional-resources/bc-guidelines/vitamin-b12

  Between 2019 and 2021, 2.17 million B12 tests were performed for 1.39 million patients in BC. Approximately 33% of patients had two or more tests during this time period. Nine percent of all B12 tests had an abnormal result. The cost of a B12 test in BC is $14.38. […] There is no evidence to support regular B12 screening for asymptomatic patients. In asymptomatic patients with risk factors consider supplementation in lieu of testing. […] There is no evidence to support regular folate screening for asymptomatic patients. Consider supplementation in asymptomatic patients with risk factors. […] In rare cases, folate deficiency is associated with megaloblastic anemia and birth defects, especially neural tube defects, in children born to mothers with folate deficiency.

• #22 Folate Deficiency: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/200184-overview

  Flour fortification with folic acid has been shown to result in significant improvements in folate status among women of reproductive age, in areas where folate deficiency is high. […] Possible pregnancy complications secondary to maternal folate status may include spontaneous abortion, abruption placentae, congenital malformations (eg, neural tube defect), and severe language delay in the offspring. […] Several observational and controlled trials have shown that neural tube defects can be reduced by 80% or more when folic acid supplementation is started before conception. […] In countries like the United States and Canada, the policy of widespread fortification of flour with folic acid has proved effective in reducing the number of neural tube defects. […] The debate over the safety of widespread folic acid supplementation will certainly continue in the medical literature in the years to come.

• #22 Folate Deficiency: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/200184-overview

  The current standard of practice is that serum folate levels less than 3 ng/mL and a red blood cell (RBC) folate level less than 140 ng/mL puts an individual at high risk of folate deficiency. The RBC folate level generally indicates folate stored in the body, whereas the serum folate level tends to reflect acute changes in folate intake. […] Data from the National Health and Nutrition Examination Survey (NHANES) 1999-2000 indicate the prevalence of low serum folate concentrations ( 6.8 nmol/L) decreased from 16% before folic acid fortification to 0.5% after folic acid fortification. […] In elderly persons, the prevalence of high serum folate concentrations (45.3 nmol/L) increased from 7% before fortification to 38% after fortification. […] Subsequent to the initial NHANES studies, subjects in the 2003-2006 cohort were asked about their daily supplement use in order to better quantify their total daily intake of folic acid.

• #22 Folate Deficiency: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/200184-overview

  It was discovered that 34.5% of the participants took supplements containing folic acid. […] Certain groups were over-supplementing, while other groups were still receiving inadequate doses. […] The participants ages 51-70 years took the highest doses of folate (combined food and supplement), with 5% exceeding the tolerable upper intake level. […] Two groups were most likely to consume inadequate folate (below the recommended dietary allowance): women of childbearing age (17-19%) and non-Hispanic black women (23%). […] The study authors concluded that efforts need to be made both to monitor for over-supplementation in certain groups and to target increased supplementation in the groups at risk for deficiency. […] Nearly every country in the western hemisphere has mandatory folic acid flour fortification, and most European countries have policies recommending folic acid supplementation prior to conception and for the first 3 months of pregnancy.

• #23 Anaemia, vitamin B12 and folate deficiency | Nursing Times

  https://www.nursingtimes.net/archive/anaemia-vitamin-b12-and-folate-deficiency-06-02-2009/

  In some cases, a deficiency in these vitamins can result in complications, particularly if you have been deficient in vitamin B12 or folate for some time. […] Research has shown that a lack of folate in your body may increase your risk of developing cardiovascular disease. […] Research has shown that folate deficiency can be linked to some cancers.

• #24 Vitamin B12 Deficiency | AAFP

  https://www.aafp.org/pubs/afp/issues/2003/0301/p979.html

  Vitamin B12 (cobalamin) deficiency is a common cause of macrocytic anemia and has been implicated in a spectrum of neuropsychiatric disorders. […] The true prevalence of vitamin B12 deficiency in the general population is unknown. The incidence, however, appears to increase with age. In one study, 15 percent of adults older than 65 years had laboratory evidence of vitamin B12 deficiency. […] Vitamin B12 deficiency is associated with hematologic, neurologic, and psychiatric manifestations. It is a common cause of macrocytic (megaloblastic) anemia and, in advanced cases, pancytopenia. […] In addition to hematologic and neuropsychiatric manifestations, vitamin B12 deficiency may exert indirect cardiovascular effects. […] The classic disorder of malabsorption is pernicious anemia, an autoimmune disease that affects the gastric parietal cells.

• #24 Vitamin B12 Deficiency | AAFP

  https://www.aafp.org/pubs/afp/issues/2003/0301/p979.html

  The phenomenon of food-bound malabsorption occurs when vitamin B12 bound to protein in foods cannot be cleaved and released. […] The widespread and prolonged use of histamine H2-receptor blockers and proton pump inhibitors for ulcer disease also may cause impaired breakdown of vitamin B12 from food, causing malabsorption and eventual depletion of B12 stores. […] Once vitamin B12 deficiency is confirmed, a search for the etiology should be initiated. Causes of vitamin B12 deficiency can be divided into three classes: nutritional deficiency, malabsorption syndromes, and other gastrointestinal causes. […] Because most clinicians are generally unaware that oral vitamin B12 therapy is effective, the traditional treatment for B12 deficiency has been intramuscular injections. However, since as early as 1968, oral vitamin B12 has been shown to have an efficacy equal to that of injections in the treatment of pernicious anemia and other B12 deficiency states. […] After the diagnosis of vitamin B12 deficiency has been made and a treatment plan has been initiated, follow-up is important to determine the patient’s response to therapy.

• #25 Identify Vitamin B12 and Folate Deficiency Symptoms

  https://www.medicinesteam.co.uk/post/vitamin-b12-and-folate-deficiency-anemia

  Understanding the underlying causes of these deficiencies can help in prevention and management. A lack of vitamin B12 and folate in the diet is a common cause. Vitamin B12 is primarily found in animal products, making vegans and vegetarians more susceptible. […] Early diagnosis is crucial for effective treatment. Blood tests can measure vitamin levels and help identify deficiencies. […] Treatment varies depending on the cause and severity of the deficiency. Vitamin B12 injections are often used for rapid replenishment, especially in cases of pernicious anaemia. […] Ignoring vitamin B12 and folate deficiencies can lead to serious health issues. Prolonged deficiency can cause irreversible nerve damage, leading to mobility issues and chronic pain. Deficiencies can increase homocysteine levels, a risk factor for heart disease. […] Vitamin B12 and folate deficiency anaemia is a common but often overlooked condition that can have significant health implications. By understanding the symptoms, causes, and treatments, you can take proactive steps to protect your health.

• #25 Identify Vitamin B12 and Folate Deficiency Symptoms

  https://www.medicinesteam.co.uk/post/vitamin-b12-and-folate-deficiency-anemia

  Recent studies suggest that up to 20% of people over the age of 60 may suffer from vitamin B12 or folate deficiency anaemia. This condition often goes unnoticed until it significantly impacts daily life. This deficiency doesn’t just sap your energy; it can lead to a range of symptoms from cognitive disturbances to serious neurological complications if left untreated. […] Vitamin B12 and folate deficiency anaemia is a condition in which the body lacks sufficient levels of these essential vitamins. This leads to the production of large, dysfunctional red blood cells, which cannot transport oxygen efficiently, resulting in a range of health issues. Understanding this condition’s causes, symptoms, and treatments is crucial for optimal health. […] Recognising the symptoms of vitamin B12 and folate deficiency is essential for early diagnosis and treatment. Common symptoms include fatigue and weakness, neurological issues, mouth and vision problems, and psychological symptoms.

• #26 Appropriate use of tests for folate and vitamin B12 deficiency – Australian Prescriber

  https://australianprescriber.tg.org.au/articles/appropriate-use-of-tests-for-folate-and-vitamin-b12-deficiency.html

  A full blood count which shows anaemia and macrocytosis should prompt the practitioner to look for a deficiency of vitamin B12 or folate. […] Laboratory tests for folate and vitamin B12 are essential for the diagnosis of a deficiency of these vitamins, and for the investigation of some forms of anaemia. Untreated, deficiency of folate or B12 may lead to severe anaemia, and in B12 deficiency, crippling neurological disease. […] The clinical indications for testing are broad. Often the indication for testing is an abnormality found in a full blood examination, such as unexplained anaemia or macrocytosis. […] Serum B12 should therefore be checked, even in the absence of haematological abnormality, in patients with some unexplained neurological or neuropsychiatric abnormalities. […] In the investigation of patients with macrocytic anaemia, it is essential to assay both serum B12 and serum and red cell folate in view of the reciprocal changes which may take place in the tests. […] After folate or B12 deficiency has been identified by suitable tests, a cause for the deficiency must be sought.

• #27 Vitamin Deficiency Anemia – Blood Disorders – Merck Manual Consumer Version

  https://www.merckmanuals.com/home/blood-disorders/anemia/vitamin-deficiency-anemia

  Vitamin B12 deficiency and folate (folic acid) deficiency cause megaloblastic anemia. […] Deficiency of vitamin B12 or folate deficiency most often develops due to a lack of these vitamins in the diet or an inability to absorb these vitamins from the digestive tract. […] Anemia due to vitamin B12 or folate deficiency is suspected when large (macrocytic) red blood cells and multilobed (hypersegmented) neutrophils (a type of white blood cell) are seen in a blood sample that is examined under a microscope. […] The blood levels of vitamin B12 and folate are measured, and other tests may be done to determine the cause of the vitamin B12 deficiency. […] The treatment of anemia due to vitamin B12 deficiency or folate deficiency consists of replacing the deficient vitamin.

• #28 The difference between B12 Deficiency and Pernicious Anaemia

  https://pernicious-anaemia-society.org/b12deficiencyandperniciousanaemia/

  Vitamin B12 deficiency is a worldwide problem. In the United Kingdom and United States the prevalence of vitamin B12 deficiency is around 6% in people aged less than 60 years, and closer to 20% in those aged more than 60 years. One author has calculated that nearly 6 million people in the UK are deficient, whilst the figure for the USA is over 26.5 million. In India over 586,000,000 people are deficient in the vitamin. However, these figures need to be treated with caution, not because they may be exaggerated but quite the opposite; they are probably an understatement. This is because of four major problems. Firstly, nearly 40% of members of the Pernicious Anaemia Society had their deficiency wrongly diagnosed the symptoms were attributed to some other illness. And so that means that there are probably many millions of people who are feeling ill but who have yet to be told that they are B12 deficient. Secondly, there is no consensus amongst scientists as to what levels constitute a deficiency and this is further complicated by the fact that different countries and different areas within countries UK will have different thresholds used to determine a deficiency. That means that in one particular part of a country you will be told your B12 levels are normal, yet if you lived in another part of the country you might be identified as being deficient. Some scientists believe even the highest thresholds that are used to define a deficiency are far too low. Thirdly, there is the tricky issue of sub-clinical deficiency where the patients serum B12 might be above the threshold used to define a deficiency yet he or she will have all of the symptoms of a deficiency in the vitamin. Finally, there is now widespread acknowledgement that the machines used to determine the amount of B12 in patients are seriously flawed and give false high readings in many cases. All of the above make the task of diagnosing patients as being deficient in vitamin B12 often very difficult.

• #29 Prevalence of anaemia, iron, and vitamin deficiencies in the health system in the Republic of Ireland: a retrospective cohort study | BJGP Open

  https://bjgpopen.org/content/8/2/bjgpo.2023.0126

  The proportion screened for iron, vitamin B12, and folate deficiency was determined within a 3-month follow-up period and the corresponding prevalence for each deficiency determined. […] Screening for folate and B12 deficiency was 17.6% and 19.8%, respectively. […] Low screening rates for iron, B12, and folate deficiency are common and warrant quality improvement initiatives. […] Screening for deficiencies of iron, B12, and folate was generally low, with limited testing for serum ferritin (33.7%), TSAT and serum iron (11.2% each), and vitamin B12 and folate levels (19.8% and 17.6%, respectively) with CRP measurements available for 21.0% of patients with anaemia. […] The prevalence of B12 and folate deficiency was 6.3% and 5.8%, respectively, increasing modestly with worsening severity of anaemia. […] Despite the substantial burden of anaemia, screening rates for treatable anaemia subtypes were remarkably low during the 3-month follow-up period with only modest increases at 12 month follow-up.

• #30 Vitamin B12 or Folate Deficiency Anaemia – Oakwood Medical Centre

  https://www.oakwoodmedicalcentrebarnton.nhs.uk/clinics-and-services/vitamin-b12-or-folate-deficiency-anaemia/

  The treatment for vitamin B12 or folate deficiency anaemia depends on whats causing the condition. Most people can be easily treated with injections or tablets to replace the missing vitamins. […] Vitamin B12 deficiency anaemia is usually treated with injections of vitamin B12, called hydroxocobalamin. […] The most common cause of vitamin B12 deficiency in the UK is pernicious anaemia, which is not related to your diet. […] If your vitamin B12 deficiency is not caused by a lack of vitamin B12 in your diet, youll usually need to have an injection of hydroxocobalamin every 2 to 3 months for the rest of your life. […] To treat folate deficiency anaemia, your GP will usually prescribe daily folic acid tablets to build up your folate levels. […] Most people need to take folic acid tablets for about 4 months. But if the underlying cause of your folate deficiency anaemia continues, you may have to take folic acid tablets for longer, possibly for life.

• #30 Vitamin B12 or Folate Deficiency Anaemia – Oakwood Medical Centre

  https://www.oakwoodmedicalcentrebarnton.nhs.uk/clinics-and-services/vitamin-b12-or-folate-deficiency-anaemia/

  Before you start taking folic acid, your GP will check your vitamin B12 levels to make sure theyre normal. […] If a vitamin B12 deficiency is not detected and treated, it could affect your nervous system. […] Most people who have had a vitamin B12 or folate deficiency will not need further monitoring unless their symptoms return or their treatment is ineffective.

• #31 Vitamin deficiency anemia – Diagnosis & treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/vitamin-deficiency-anemia/diagnosis-treatment/drc-20355031

  To help diagnose vitamin deficiency anemias, you might have blood tests that check for: […] The amount of vitamin B-12 and folate in the blood. […] Vitamin deficiency anemia is treated with doses of whichever vitamin is lacking. […] For pernicious anemia, vitamin B-12 is usually delivered via injection and may need to be taken regularly for the rest of your life. […] Medications to boost folate levels usually come as pills to be swallowed, but some versions can be delivered through a narrow, flexible tube into a vein (intravenously). […] Means RT, et al. Clinical manifestations and diagnosis of vitamin B12 and folate deficiency. […] Means RT, et al. Causes and pathophysiology of vitamin B12 and folate deficiency. […] Means RT, et al. Treatment of vitamin B12 and folate deficiency. […] Vitamin B12: Fact sheet for health professionals.

• #32 Vitamin Deficiency Anemia: Symptoms & Causes

  https://my.clevelandclinic.org/health/diseases/17732-vitamin-deficiency-anemia

  Vitamin deficiency anemia occurs when you have low vitamin B12 or folate levels. Causes of vitamin deficiency anemia may include health conditions that affect nutrient absorption. […] Your healthcare provider can use blood tests to diagnose vitamin deficiency anemia. This blood test may evaluate folate and vitamin B12 levels. […] Treatment for vitamin deficiency anemia aims to increase your levels of the vitamin you’re lacking. […] You can lower your risk of vitamin deficiency anemia by eating foods rich in vitamins B12 and B9. […] Most people don’t have long-term complications from vitamin deficiency anemia. With treatment, the condition often goes away. […] It’s important to get treatment for vitamin deficiency anemia. Without treatment, vitamin deficiency anemia could lead to heart problems, including heart failure.

• #33 3.7 Vitamin B12 and Folate Deficiency Anemia – Health Alterations

  https://wtcs.pressbooks.pub/healthalts/chapter/3-7-vitamin-b12-and-folate-deficiency-anemia/

  Clinical manifestations of anemia caused by vitamin B12 and folate deficiencies are related to the body’s inability to form red blood cells and other rapidly dividing cells. Vitamin B12 deficiency is also more likely to affect the nervous system, although folate deficiency may also cause neurocognitive symptoms. […] A variety of lab tests may be ordered by a provider to diagnose vitamin B12 or folate deficiency. […] During the evaluation stage, nurses determine the effectiveness of nursing interventions for a specific client. Lab results showing improvement of anemia resulting from vitamin B12 or folate deficiency should improve within one to two weeks and normalize within one to two months.

• #34 Vitamin B12 and Folate Deficiency Among Elderly Patients: Is there a window of opportunity? | British Geriatrics Society

  https://www.bgs.org.uk/vitamin-b12-and-folate-deficiency-among-elderly-patients-is-there-a-window-of-opportunity

  Vitamin B12 and folate are essential for normal red blood cell production, tissue and cell repair, and DNA synthesis. […] Geriatric patients are more susceptible to Vitamin B12 and folate deficiency due to inadequate oral intake, malabsorption caused by pernicious anaemia, achlorhydria, and poor bioavailability. […] Vitamin B12 and folate deficiency are associated with neuro-cognitive, psychotic, and mood symptoms. […] The prevalence of Vitamin B12 deficiency was 8.8%, while the prevalence of Folate deficiency was 31.3%. […] The prevalence of Vitamin B12 and folate deficiency is high among elderly patients. Early detection and treatment are vital to prevent irreversible neuropsychiatric sequelae.

• #35 Prevalence and possible factors associated with anaemia, and vitamin B 12 and folate deficiencies in women of reproductive age in Pakistan: analysis of national-level secondary survey data | BMJ Open

  https://bmjopen.bmj.com/content/7/12/e018007

  The prevalence and local factors associated with anaemia, and vitamin B12 and folate deficiencies in women have not been previously identified in literature. […] We estimated the prevalence of anaemia, and folate and vitamin B12 deficiencies among WRA from a nationally representative sample in Pakistan. Substantially, more than half of Pakistani WRA were found to be anaemic, and vitamin B12 and folate deficient in 2011. […] Our study identified women from the poorest households as having a lower likelihood of deficiency compared with those living in the richest households. […] We also found interprovincial differences in anaemia, vitamin B12 and folate deficiency. This can be due to difference in SES of households, exposure to available interventions in each province and food consumption practices at household levels.

• #36 Nutritional status of iron, vitamin B12, vitamin A and anemia in Mexican children: results from the Ensanut 2018-19

  http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0036-36342021000300359

  In the adjusted model, relatively older age (OR=0.66, p=0.016), belonging within the third HWI tertile (OR=0.08, p0.001), and supplement consumption (OR=0.04, p=0.002) were conditions associated to lower odds of B12D in pre-school-age children. In contrast, residing in the South (OR=6.02, p=0.006), having VADp (OR=5.3, p0.001) and being a beneficiary of Liconsa (p=0.017) or Prospera (p=0.053) were associated with higher odds of B12D. Among the school-age children, older age (OR=1.28, p=0.003) was associated to higher odds of B12D; while the consumption of supplements (OR=0.28, p=0.029), and belonging within the second tertile of HWI (OR=0.45 p=0.013) were associated with lower odds of B12D. […] In conclusion, MDs and anemia affect the younger children in a larger proportion. These MDs are associated with poor child development and negative health effects in later life. Fortification and supplementation programs should be reinforced in order to support proper child growth and development.

• #37 B12 and folate deficiency – Hospitals and Science – NHSBT

  https://hospital.blood.co.uk/patient-services/patient-blood-management/anaemia/b12-and-folate-deficiency/

  Vitamin B12 and folate deficiency are common conditions which are often overlooked in patient blood management. […] Better awareness of these deficiencies, their management and the patient groups most at risk will help promote effective identification and treatment to correct or prevent any resulting anaemia. […] Find NHS information for the public about vitamin B12 or folate deficiency anaemia.

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