Paging Dr. Frischer: Multivitamins

Chances are you take a multivitamin. Over 50% of Americans view them as insurance against dietary gaps, and this statistic agrees with my own (now small) household. My wife conscientiously takes vitamins, and I have just never bothered. Does the scientific evidence show that a daily multivitamin helps to fill those gaps in the diet, and prevents disease?

What are the advantages of taking a multivitamin?

■They are safe. Multivitamins that do not contain mega doses pose no risk to health, although some high-dose supplements might.

■Multivitamins are affordable; most cost about 10-30 cents a day. (Some vitamins can cost much more, but lack much evidence that they are better than their cheaper counterparts.)

■While the ideal diet would contain sufficient amounts of fruit, vegetables, and whole grains every day, most of us fall short of that goal. Taking a multivitamin can bring us closer to recommended intakes of essential vitamins and minerals. They may also allow fussy or inconsistent eaters (whether adults or children) more regular levels of essential vitamins.

■Studies suggest that long-term use of multivitamins *may* reduce the risk of coronary vascular disease, cancer and cataracts, and slow the rate of cognitive decline. Research is ongoing.

What are the disadvantages?

■Multivitamins may be unnecessary and a waste of money. If your diet is already filled with fruits, vegetables, and whole grains, then they are not likely to help significantly. For many nutritional experts, multivitamins are nothing more than a multibillion-dollar industry that
offers little in the way of health benefits.

■Taking a multivitamin may tempt some of us to skip nutritionally dense foods, thinking that we already have it covered. However, there are many natural compounds found in foods that do not appear in a multivitamin. A pill should never be a substitute for eating good foods; a multivitamin simply does not contain everything we need.

■Be cautious about excess! There may be a risk of toxicity from taking large doses. Many water-soluble vitamins are simply excreted by the body if we consume more than necessary. However, fat-soluble vitamins (including A, D, E and K) can be stored in the body and may cause toxicity when taken in high amounts. (Taken in excess, even water-soluble vitamins
B-6 and C can lead to toxicity.) Toxicity symptoms range from mild, such as itching, headache, flushed skin and upset stomach, to severe, such as kidney stones, heart rhythm issues and confusion.

■Multivitamins interact with some medications and conditions; always check with your doctor. For example, those who take blood thinners should avoid supplemental vitamins E and K. Certain antioxidant vitamins like beta-carotene can increase health risks for smokers. Pregnant women should avoid excessive amounts of vitamin A, as this may increase the risk of
birth defects.

■The size of some multivitamins makes them difficult to easily swallow. This is especially true for the elderly. Liquid multivitamins are available but can be much more expensive.

■Bioavailability (how easily nutrients are available for use) may be an issue. Not all vitamins are the same. A United States Pharmacopeial (USP) marking on vitamins indicates (among other things) that they have met the standards for dissolvability, one indication of bioavailability.

Who appears to benefit the most from multivitamins? Pregnant women, those who consume fewer than 1,200 calories per day, strict vegetarians and vegans, those deficient in vitamin D, and people who have conditions that decrease how much is absorbed from food (including smokers, the elderly, and those with gastric bypass surgery).

Further research into supplemental vitamins and minerals continues. However, this is certain, and we’ve all heard it before: the very best things we can do for our health are to eat a nutrient-dense, vitamin rich-diet, to be active, and to avoid obviously harmful lifestyle choices.

There is just no substitute for a healthful lifestyle.