Originally published in Mayo Clinic Health Letter, August 1998

You can get your entire daily requirement of vitamin C by just popping a pill. It's easy and convenient. Or you can get the same amount by eating an orange.

So which is better? In most cases, the orange — a "whole food." That's because whole foods — fruits, vegetables, grains, lean meats and dairy products — have many benefits you can't find in a bottle.

While vitamin and nutritional supplements are recommended in certain situations, there are many reasons to favor whole foods as your primary source of nutrition.

Complex nutrient packages

Your body needs many nutrients to stay healthy. These include macronutrients (protein, carbohydrates and fat) for energy, as well as micronutrients (vitamins and minerals) that serve many functions, including disease prevention.

Whole foods are an excellent source. They're a complex package that provides many essential nutrients — not just the few you may choose to take in supplement form.

For example, an orange provides not only vitamin C but also carotene, calcium and simple sugars for energy. A vitamin C supplement is lacking in these other nutrients. Similarly, a glass of milk provides you with protein, calcium, vitamin D, phosphorous and magnesium. If you took only calcium supplements and skipped calcium-rich foods, such as dairy products, you could miss out on the full complement of nutrients you need for healthy bones.

Beyond vitamins and minerals

Even if you take a daily multivitamin, you still need to eat a balanced diet with whole foods as the centerpiece. They provide not only vitamins and minerals but other important food substances as well.

Take dietary fiber, for example. Fiber is important for digestion and in preventing certain diseases. Soluble fiber, which is found in most fruits, some vegetables and certain beans and grains, may help prevent heart disease and diabetes. Insoluble fiber, found in most vegetables, some fruits and many breakfast cereals, can help prevent constipation. It's also associated with a reduction in colon cancer and other cancers.

In addition to fiber, whole foods contain hundreds to thousands of other substances (some of which have yet to be identified and studied) that may be important for good health. For example, fruits and vegetables contain food substances called phytochemicals, which have been linked to potential protective effects against cancer, heart disease, osteoporosis and diabetes.

Broccoli contains phytochemicals called isothiocyanates (i-so-thi-o-SI-uh-nates). In laboratory studies, these have been shown to retard cancer cell growth. Studies also indicate that people who eat broccoli and related vegetables may have a lower risk of colon cancer.

However, it's too early to tell for sure what substances — isothiocyanates or some other component — may be responsible for the apparent benefit. It's also not known if taking such an ingredient by itself, as in a supplement, will result in the same benefits found among people who eat the actual food.

In fact, some food components may actually be detrimental to your health when taken as an isolated substance, such as in a supplement. For example, some studies found an increased risk of lung cancer in smokers who took beta carotene supplements. Meanwhile, people who consumed adequate amounts of fruits and vegetables (which contain beta carotene in a mix with many other nutrients) were found to have a lower incidence of cancer.

There's much data to suggest that a diet high in fruits and vegetables reduces your risk of cancer, heart disease and stroke, plus many other diseases. But there is very little evidence to suggest the degree of protection individual phytochemical supplements may offer. Until more is known about these, you're better off sticking with whole foods rather than supplements of these substances.

The joy of eating

There's one additional benefit of whole foods that must be mentioned — taste.

How can washing down a few relatively tasteless supplements with a glass of water ever compare to eating a sweet, juicy orange or savoring a healthful dinner with family or friends? One of the greatest benefits of eating a varied, balanced diet is the joy — the colors, flavors, aromas and textures — that only whole foods can provide.

Benefits add up