Folic acid safety and toxicity: a brief review

Article Abstract:

The use of folic acid, a member of the Vitamin B complex, is reviewed with particular attention to the possibility of toxic effects from folic acid treatment. In general the dose level normally present in the diet or in the level achieved by over-the-counter medication is safe. However, folic acid has long been known to be able to cause spinal cord paralysis when administered to some patients who have unsuspected pernicious anemia. Even in these cases the risk of folic acid toxicity appears to be exceedingly low, and because of medical ethics it will probably never be accurately judged. Folate can also interfere with the maintenance of medications in some, but not all epileptic patients. Recently there has been experimental data showing a relationship between folic acid and zinc. There is data to suggest that zinc-containing enzymes are involved in the absorption of folic acid from the intestines and holding folic acid in the liver. A large study of 450 pregnant women has demonstrated a correlation between fetal distress and the combination of low zinc and high folic acid concentrations in the maternal circulation. In some cases there is reason to suspect that iron-folate supplements may be harmful. However, a recent article shows no difficulty of absorption of zinc with simultaneous treatment of folic acid. It is difficult to reconcile the reports of many studies that have considered the relationship of zinc and folic acid; perhaps some of this confusion results from the widely divergent experimental protocols that have been used. Recently antifolate medications have been used for the treatment of a widely dissimilar group of diseases (e.g., cancer, leukemia, psoriasis, arthritis, asthma, cholangitis, cirrhosis, bacterial infection, gout and epilepsy), yet virtually nothing is known about the safety or toxicity of these compounds. Further experimental data and analysis is urgently required concerning folic acid, and antifolate medications.

Care and treatment, Complications and side effects, Chemical inhibitors, Pernicious anemia, Folic acid deficiency

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Evaluation of the deoxyuridine suppression test by using whole blood samples from folic-acid supplemented individuals

Article Abstract:

Supplementation with folic acid (folate), a water-soluble B vitamin, may have beneficial effects on the condition of the cervix in women who have mild or moderate cervical dysplasia; one study has suggested a role for folic acid in these individuals. Cervical dysplasia is defined as abnormal changes in the tissue covering the cervix, which is the neck or opening of the uterus. Pap smears and cervical biopsies are used to diagnose this condition. As part of a study on folate status and cervical dysplasia in young women, a laboratory test called the deoxyuridine suppression test (dUST) was evaluated. The dUST test was performed on blood samples from 136 normal women and 109 women with cervical dysplasia; tests were repeated over six months while half the subjects with dysplasia received 10 milligram folic acid supplements daily and the other half received inert placebos. Folate in the blood and red blood cells of the supplemented group increased as expected and dUST values were inversely correlated with blood and red blood cell folate levels. The dUST test is also used for distinguishing between folic acid and vitamin B-12 deficiencies, which have similar effects and are frequently confused with each other. The relationship between folate supplementation and cervical dysplasia in these subjects was not reported, as the study was still in progress. (Consumer Summary produced by Reliance Medical Information, Inc.)

Research, Abnormalities, Testing, Cervix uteri, Nutritional aspects, Dysplasia, Folic acid in human nutrition

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Folate deficiency and cervical dysplasia

Article Abstract:

Folate deficiency may increase the risk of cervical dysplasia in women with other known risk factors, particularly oral contraceptive use, cigarette smoking and exposure to human papillomavirus type 16 (HPV). Cervical dysplasia is an abnormal change in the shape or size of cervical cells. It can be a precursor of cancer. Potential risk factors and folate deficiency were assessed in 294 women diagnosed with cervical dysplasia and 170 women without cervical dysplasia. Blood samples were taken and the concentration of folate in red blood cells was measured. This provides a more accurate assessment of folate levels than serum folate, which can increase after a meal. Women with low folate levels who were oral contraceptive users, smokers or HPV-positive were more likely to have cervical dysplasia than women with the same risk factors but normal folate levels. Women exposed to HPV were actually five times more likely to have cervical dysplasia if their folate was low.

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