Whole foods provide more than dietary supplements
By Debra Levey Larson, Media/Communications Specialist University of Illinois College of ACES
URBANA, Ill.Although it may seem easier, quicker and less fattening to pop a few dietary supplements every morning rather than eating a plate of real food, you may be missing out on more than you think.
Dietary supplements represent just one component from a food, said Elizabeth Jeffery, nutritional scientist at the University of Illinois. But, there may be hidden benefits gained from the way multiple components in a single food work together.
Jeffery explained that vegetables and fruits contain natural metabolites that appear to prevent a number of chronic diseases, particularly cardiovascular disease and cancer.
Scientists are trying to find ways to create healthful dietary supplements that contain these bioactive components, Jeffery said, but we havent identified all the healthful components yet and cant afford to ignore the whole food.
Jeffery used vitamin C as an example, citing the old story about British sailors being given a ration of limes to avoid getting scurvy while aboard a ship for long periods.
Notice that in our thinking we went right from the whole foodthe limeto an isolated compoundvitamin C, Jeffery said. In thinking that limes were solely a source of vitamin C, we overlook the existence of other bioactive compounds not yet identified.
For example, today we know that limes and other citrus fruits contain a number of additional antioxidants. Taking a vitamin C supplement is certainly good for your health, but will not provide some other factors present in limesand may risk overuse.
Nutritional scientists carefully isolated vitamin C and worked out how much is needed on a daily basis to maximize the benefit of C on white blood cells ability to fight disease, while minimizing the loss of C in urine, Jeffery said. Most Americans eat a diet that contains enough C to avoid getting scurvy, but, its not so easy to see if the white cells are working well, so people take supplements to be on the safe side.
Jeffery cautioned that taking too much C can cause diarrhea and, over a prolonged period, people sometimes experience more dangerous side effects, such as kidney stone formation and excess iron absorption.
When choosing to take a supplement, its important to keep in perspective what it claims to do. In the United States, proof of efficacy of dietary supplements is not required, since the products are not legally sold with the intended use of treating a disease. Legally, one can describe a dietary supplement as supporting normal physiological function (calcium builds strong bones) but not as treating a disease (calcium rebuilds bone in postmenopausal women with osteoporosis).
Jeffery said no single food contains all of the necessary fats, carbohydrates, proteins, vitamins and minerals that we need to maintain a healthy body. So, until true food concentrates are developed, dietary supplements cannot replace the need to eat a balanced diet composed of whole foods.