Though supplements containing 0.8 mg of folic acid are available over-the-counter, tablets and injectable forms that contain more than 1 mg of folic acid are available only with a prescription. The vitamin is used to treat anemia caused by folic acid deficiency, which may result from poor absorption, a dietary deficiency, or pregnancy.
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Summary of Interactions with Vitamins, Herbs, & Foods
Though some studies indicate that supplementing with folic acid reduces blood levels of zinc, most show no interaction between the two nutrients when folic acid is taken at moderate levels.1 Therefore, until more convincing evidence is available, people taking moderate amounts of folic acid do not need to supplement with zinc. Zinc supplementation is recommended when folic acid intake is high. A doctor should be consulted to determine the appropriate time to add zinc supplementation to folic acid therapy.
One controlled study showed that taking folic acid together with an antacid containing aluminum and magnesium hydroxide reduced the absorption of the vitamin.2 Therefore, individuals should take folic acid one hour before or two hours after taking antacids containing aluminum and magnesium hydroxide.
Folic acid and vitamin B6 have been used to reduce elevated blood levels of homocysteine, which has been associated with atherosclerosis. One controlled study showed that taking 0.3 mg of folic acid together with 120 mg of vitamin B6 reduced homocysteine levels more than taking either vitamin alone. The study also revealed that long-term supplementation with vitamin B6 alone might reduce blood folic acid levels.3 Therefore, people with elevated blood homocysteine levels should supplement with both folic acid and vitamin B6.
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.
1. Campbell RC. How safe are folic acid supplements? Arch Intern Med 1996;156:1638-44 [review].
2. Russell RM, Golner BB, Krasinski SD, et al. Effect of antacid and H2 receptor antagonists on the intestinal absorption of folic acid. J Lab Clin Med 1988;112:458-63.
3. Mansoor MA, Kristensen O, Hervig T, et al. Plasma total homocysteine response to oral doses of folic acid and pyridoxine hydrochloride (vitamin B6) in healthy individuals. Oral doses of vitamin B6 reduce concentrations of serum folate. Scand J Clin Lab Invest 1999;59:139-46.
Please read the disclaimer about the limitations of the information provided here. Do NOT rely solely on the information in this article. The Aisle7 knowledgebase does not contain every possible interaction.
The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2015.
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