Excess of Folic Acid

See also: folic acid deficiency - folic acid - quiz about folic acid - folic acid in pregnancy

Maximum recommended contribution

The risk of toxicity resulting from an excessive intake of folic acid is reduced.

According to the US Institute of Medicine's Food and Nutrition Board, the upper limit uptake for an adult is 1000 mcg per day, compared to a recommended intake of 400 mcg of folate per day. The upper limit uptake indicates the maximum daily intake of a nutrient compatible with the absence of side effects from overdose; this value takes into account the total intake, thus adding the food intake with the contribution of any drugs or supplements.

During pregnancy, however, particularly at-risk pregnant women can get up to 5 mg of folic acid a day, in the form of specific supplements. In these situations, in fact, the achievable benefits in terms of prevention on the closure defects of the neural tube of the unborn child, far outweigh the hypothetical risks of a possible overdose.

Folic Acid in Foods

Folic acid is contained in dark green leafy vegetables, whole grains, liver, brewer's yeast and fortified foods. The intake of folic acid is therefore tendentially higher in populations that follow a vegetarian or raw food diet (a good part of folic acid is lost through cooking) compared to omnivorous ones.

Health risks

The most dangerous pitfall of excessive dietary intake of folic acid is that it tends to hide the early effects of a possible B12 deficiency, a vitamin contained almost exclusively in animal foods.

Therefore, a vegetarian who for his misfortune is struck by atrophic gastritis, Crohn's disease, celiac disease or other malabsorption syndromes, can be exposed without his knowledge to the serious consequences of untreated pernicious anemia.

This pathology - caused by the protracted vitamin B12 deficiency - in an advanced stage causes lesions of the nervous system, up to the irreversible degeneration of the posterior spinal cords, with the appearance of paresthesia, alterations of sensitivity and motor disorders up to paralysis.

The consequences that an excess of folic acid can have in certain situations is a further starting point for condemning the indiscriminate use of vitamin megadoses, so unconsciously advertised in some websites.