Listening to the rhetoric of dietary supplement sales people and self-styled nutrition experts one might conclude that anyone who does not take vitamin and mineral supplements is placing himself or herself in significant jeopardy. These so called authorities are fond of pointing out that processing destroys vitamins, and that American agricultural practices have depleted the soil of nutrients, hence any foods grown in these soils are nutrient deficient to begin with. It's true that processing can and does reduce the nutritional value of some foods. Take a potato. If baked it retains much of its nutrients, but once it is peeled, sliced, and fried it become little more than a starchy sponge full of oil. Yet processing isn't always bad. In fact the American food supply is among the most nutritious in the world in part because of the nutrients added to refined grain products, milk, and some citrus juices during processing.
The position of The American Dietetic Association with respect to dietary supplements has always been that people who eat a well rounded diet do not need to take vitamin and mineral supplements. Supplements may serve a purpose, however, if your eating habits are erratic (such as the "grab-and-go" eating style so common among college students). Taking a balanced One-A-Day style vitamin and mineral supplement specially formulated for a person of your age-range and gender can provide extra insurance without any health risk. All responsible health care authorities caution against taking large doses of individual nutrients unless directed to do so by a physician or registered dietitian. Chronic excesses of certain nutrients can create metabolic imbalances, and even lead to toxicity syndromes.
Recent evidence indicates that consuming more than the traditionally recommended doses (Recommended Dietary Allowances and Adequate Intakes) of calcium, vitamin E, vitamin C, and folate may have specific health benefits. Many healthcare practitioners have pointed out that it would be very difficult to consume the newly suggested higher levels of these nutrients without using dietary supplements. If such evidence continues to mount it may eventually change official attitudes toward supplementation. Until then, the best way to get the vitamins and minerals you need is to eat a wide variety of foods, including dairy products, fruits and vegetables each day, and take a multi vitamin/mineral supplement for insurance on days your diet is less optimal.