If you eat a healthy diet, do you need to take vitamins? Not long ago, the answer from most experts would have been a resounding "no". Today, though, there's good evidence that taking a daily multivitamin makes sense for most adults.

What's changed? Not only have scientists determined why we need pyridoxine (vitamin B6), but they are also accumulating evidence that this vitamin and others do much more than ward off the so-called diseases of deficiency, things like scurvy and rickets. Intake of several vitamins above the minimum daily requirement may prevent heart disease, cancer, osteoporosis, and other chromic diseases.

This summary will focus on vitamins with newly recognized or suspected roles in health and disease. It will present some of the evidence about vitamins' possible new roles, point out how to get more of these in your diet, and assess the value of taking a daily multivitamin.

Our cells must constantly contend with nasty substances called free radicals. They can damage DNA, the inside or artery walls, proteins in the eye--just about any substance or tissue imaginable. Some free radicals are made inside the body, inevitable byproducts of turning food into energy. Others come from the air we breathe and the food we eat.

We aren't defenseless against free radicals. We extract free-radical fighters, called antioxidants, from food. Fruits, vegetables, and other plant-based foods deliver dozens, if not hundreds, of antioxidants. The most common are vitamin C, vitamin E, beta-carotene and related carotenoids. Food also supplies minerals such as selenium and manganese, which are needed by enzymes that destroy free radicals.

During the 1990s, the term antioxidants became a huge nutritional buzz word. Antioxidants were promoted as wonder agents that could prevent heart disease, cancer, cataracts, memory loss, and a host of other conditions.

It's true that the package of antioxidants, minerals, fiber, and other substances found in fruits, vegetables, and whole grains help prevent a variety of chronic diseases. Whether high doses vitamin C, vitamin E, or other antioxidants can accomplish the same feat is an open question. The evidence accumulated so far isn't promising. Randomized trials of vitamin C, vitamin E, and beta-carotene haven't revealed much in the way of protection from heart disease, cancer, or aging-related eye diseases. Ongoing trials of other antioxidants, such as lutein and zeaxanthin for macular degeneration and lycopene for prostate cancer, are underway.

A standard multivitamin supplement doesn't come close to making up for an unhealthy diet. It provides a dozen or so of the vitamins known to maintain health, a mere shadow of what's available from eating plenty of fruits, vegetables, and whole grains. Instead, a daily multivitamin provides a sort of nutritional safety net.

Learn more at: http://www.hsph.harvard.edu/nutritionsource/vitamins.html