Many people equate vitamins, minerals, and other nutritional supplements with only positive effects. Because something is sold as a "health food product," however, does not mean it's safe. When these supplements are taken in amounts greater than the Recommended Dietary Allowances, they no longer serve a nutrient function; they are considered drugs. Taken in excessive doses these supplements can interfere with the intended action of a medication, as well as negatively affect a person's health status.
Some examples of what can happen when a person takes excessive doses of the following supplements are:
Vitamin A: fatigue, lethargy
Vitamin D: possible kidney failure
Vitamin C: gas and diarrhea; dehydration as a result of diarrhea
Vitamins A, D, and K: reaction to toxicity
Niacin: flushed skin; impaired liver function
Iodine: enlargement of the thyroid gland resembling goiter
Magnesium: diarrhea
Tryptophan: a rare blood disease with an abnormal increase in certain white cells; symptoms include severe muscle pain, fever, joint pain
(The FDA has declared tryptophan unsafe. DO NOT TAKE IT! If you have any tryptophan in your home, throw it out!)
In addition to affecting nutritional status, use of supplements can counter the effect of certain drugs. The table on the next page lists some interactive examples that occur when a supplement and medication are taken together.
Be careful! If you feel you need to take nutritional supplements, first discuss your concerns with your doctor, pharmacist, or other qualified health care professional, for example, a registered nurse or dietician. DO NOT self-medicate with large doses of vitamins, minerals, or other nutritional supplements without seeking medical advice.
