Causes of Folate Deficiency
Humans can only store a small proportion of their daily requirement of folic acid or 'folate' (which is stored mainly in the liver). Deficiency therefore develop quite quickly if dietary intake is insufficient. The possibility of this happening is higher under certain circumstances.
- Insufficient dietary intake
A poor diet (see malnutrition) is the most common reason for folate deficiency. Different types of and reasons for poor diets include:
- attempts to lose weight by reducing food intake - but failing to ensure that the food eaten forms a balanced diet that needs the person's needs.
- excessive consumption of alcohol e.g. by alcoholics. There are many calories in alcohol so some people might be tempted to reduce intake of other foods to avoid gaining weight. Even if this is not the case, alcohol is an antinutrient (listed on the page about common antinutrients). The effects of significant consumption of alcohol include increasing the body's requirement for several vitamins, including B vitamins, while also decreasing the body's ability to make use of certain vitamins and minerals including folic acid (folate).
- elderly people tend to have smaller appetites than more active younger people so often eat smaller quantities such that particular attention is needed to ensure that they receive enough of all essential nutrients including vitamins and minerals.
- low income groups in both rich and poorer countries may include people who cannot afford or obtain an ideal diet and so may lack certain nutrients according to seasonal availability, income fluctuation or education about what constitutes a balanced diet and how to obtain appropriate nutrients cost-effectively.
- infancy (a child's first few years)
- teenage years (adolescence)
- inflammatory conditions
is a decrease in number of red blood cells or a reduction in the normal quantity of hemoglobin in the blood due to hemolysis - which is the abnormal breakdown of red blood cells and can occur either in the blood vessels (intravascular hemolysis) or elsewhere in the human body (extravascular).
This may result from certain diseases and conditions of the digestive system, such as:
- coeliac disease
- following gut resection e.g. to treat intestinal obstruction, injuries, cancer, precancerous polyps or infection as a result of diverticulitis
Some types of medicines, including prescribed medicines, can reduce the amount of ingested folate that is available for use by the body, or make it more difficult for the body to absorb the folate that is present (which has the same overall effect). Examples of some drugs whose effects on folate levels may be taken into consideration include:
- dihydrofolate reductase inhibitors, such as methotrexate
- some anticonvulsants impair absorption of folate, e.g. phenytoin and phenobarbitone
- some antimalarial drugs, e.g. pyrimethamine
Even if a person consumes sufficient folic acid (folate) as part of his or diet, and has no malabsorption problems or other relevant conditions, folate deficiency can still occur if the person is deficient in vitamin B12.
Briefly, this is due to biochemical reactions happening in the body in which 5,6,7,8-tetrahydrofolate - which is sometimes referred to as simply "THF" and is the active form of vitamin B9 (which is also called "folic acid" and/or "folate") plays important roles. Omitting the biochemical detail, it is possible for THF to become "trapped" in one intermediate in a metabolic pathway if vitamin B12 is not available to participate in a reaction necessary to release the THF for re-use in subsequent reactions.
In general it is useful to know that folic acid (folate) can only be stored in the body in small quantities.
That is, only a small proportion of a person's daily folate requirement can be stored so folate deficiency can develop quickly, e.g. over weeks or just a few months, if dietary intake is insufficient. There is a higher risk of folate deficiency when the person's need for folic acid is highest, e.g. due to stage of life (such as during rapid growth or pregnancy), when the body has been supporting recovery from illness, and in cases of reduced absorption of the dietary intake of folate - whether due to malabsorption conditions, the effects of antinutrients such as alcohol or drugs, or for another reason.