Is it safe to take vitamin supplements
Recent scientific evidence advises caution and recommends a whole-food dietary approach.

By Jeff Novick, M.S., R.D.

Sales of supplements are soaring, doubling about every four to five years. According to The Hartman Group, a marketing research and consulting company, the antioxidants (vitamins E, C, A, betacarotene, and selenium) account for a large segment of the supplement market. Sales figures for vitamin E topped $1.057 billion in the United States. Vitamin C was the next largest with $724 million. Betacarotene accounted for $80.9 million and selenium $71.2 million.

Antioxidants cleanse the body of the damaging oxygen molecules known as “free radicals,” which are byproducts of the body’s use of oxygen. Free radicals disrupt molecules and damage cells. That damage is thought to contribute to aging, cancer, and other health problems.

Supplement problems

With so many antioxidant supplements being sold, it might be reasonable to expect that people are reaping considerable benefits. But more and more research suggests otherwise. Scientists are lining up to caution against large doses of vitamins and are urging people to take a “whole food” approach to nutrient sufficiency.

Researchers agree that it is almost always better to obtain your vitamins from food than from supplements.

A 2000 study from the Institute of Medicine of the National Academy of Sciences [Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids] found that not only have
health claims for antioxidant supplements not been substantiated, large doses of the dietary supplements selenium, vitamins C and E, and betacarotene actually can harm you.The study cited a host of problems, and since it became clear that it was possible to take too much of these “purified nutrients,” the researchers recommended that upper limits be set for these vitamins. The conclusion of the researchers was that dietary supplements are not cures and in some cases can be dangerous.They stated that the solution to the problem of getting sufficient vitamins is to eat a healthful diet.

Interestingly, the report recommended that people increase their daily consumption of vitamins C and E, but from “food sources,” not from supplements. The recommendations for vitamin C went up from 60 milligrams per day for everyone to 75 milligrams for women and 90 milligrams for men. Because of the cell damage caused by smoking, the panel said smokers should take an additional 35 milligrams. No one should take more than 2,000 milligrams each day because large doses of vitamin C may cause diarrhea.

Vitamin E levels were set at 15 milligrams each day (up from 8-10), with an upper limit of 1,000 milligrams. Taking more than the upper limit means a risk of internal bleeding because vitamin E can have an anti-clotting effect.

Selenium levels were set at 55 micrograms daily with an upper limit of 400 micrograms. Large amounts of selenium can cause a toxic reaction marked by loss of hair and nails. A typical multi-vitamin contains 200 mg of vitamin C and 100 IU of vitamin E. These are three or more times the daily requirements of these vitamins.

The report did not set a level for betacarotene because, as the researchers noted, a huge number of studies have shown that a diet rich in vegetables and fruit decreases the risk for cancer and heart disease. However, it was noted that it is not certain that carotenoids (the colors in fruit and vegetables) provide the benefits. It could be that one or more of the other 20,000 different chemicals in fruit and vegetables might be interacting in some way that is beneficial.

Hip fractures

A study in the Journal of the American Medical Association (JAMA 2002;287:47-54) concluded that too much vitamin A may increase the risk of hip fractures in older women. Vitamin A is important for such things as healthy skin and hair and bone growth, but researchers found that women with the highest total intake, both from food and vitamin supplements had doubled the risk of hip fractures compared with women who had the lowest intake.

Food, not supplements

Norman Krinsky, a professor at Tufts University School of Medicine in Boston, says people falling short of recommended levels of vitamins should improve their diets, “particularly improving the intake of such things as fruit and vegetables, which we know are rich in these nutrients.”

A study presented at the American Heart Association’s 40th Annual Conference on Cardiovascular Disease Epidemiology and Prevention found that vitamin C supplements may actually “increase” one’s risk for atherosclerosis (arterial disease that can cause heart attack or stroke). James H. Dwyer of the University of California Los Angeles, who led the study, stated that these findings seem only to apply to vitamin C in pill form, not vitamin C from food.

Commenting on the study, Dr. Joseph Vita, a cardiac researcher at Boston University, said that patients should not worry about dietary vitamin C intake.“I certainly would not change my recommendations to people,which is that they should eat a diet that’s rich in fruit and vegetables, including foods that are high in vitamin C,” he said.

Healthful diet is best

As you may know,Dr. Fuhrman and I recommend a whole-food, plantbased diet that maximizes nutrient intake—and ensures superior nutrition— with food, not supplements. Those who attempt to achieve superior nutrition through the use of supplements while still eating an inadequate diet will find that they are unable to achieve the high level of health they are seeking.We should be relying on high-quality food to supply our nutrients and to help provide solutions to many of our current health problems.You cannot expect to find health in a bottle.

Choose supplements wisely

The vitamin supplements you take must be carefully designed, with attention given to the dangers of excessive intake of nutrients that are risky in higher doses. It is especially important not to get too much betacarotene, selenium, and vitamins A, E, and C because synthetic versions of these nutrients actually may cause disease. Supplementation is quite appropriate for nutrients such as vitamins D and B12,which are not easily obtainable from food.

There are likely to be hundreds of accessory nutrients in foods that enable vitamins to work the way they were designed. Supplements never can contain all of the needed nutrients because we have yet to discover them all. This is why it is so critical to eat whole unprocessed food whenever possible.

Here are your healthiest sources of dietary vitamin C, betacarotene, and vitamin E.

Vitamin C:
melons, berries, oranges, kiwifruit, cabbage, cauliflower, broccoli, peppers, tomato

Betacarotene:
dark leafy greens (spinach, kale, collard greens, turnip greens, mustard greens, beet greens, broccoli, and asparagus); deep orange fruits (apricots, cantaloupe, mango, and papaya); deep orange vegetables (squash, carrots, sweet potatoes, and pumpkin)

Vitamin E:
whole grains, seeds, nuts, asparagus, avocados, berries, green leafy vegetables, and tomato.