Supplements provide all of the benefits of eating fruits and vegetables?
WHAT THEY’RE SAYING
Dietary supplements offer the same health benefits as a diet rich in fruits and vegetables.
WHAT WE KNOW
Food provides not only essential nutrients needed for life but also other bioactive compounds for health promotion and disease prevention. Regular consumption of fruits and vegetables is associated with reduced risks of cancer, cardiovascular disease, stroke, cataracts, and other functional declines associated with aging. Thousands of bioactive compounds have been identified in foods, most are phytochemicals (also called phytonutrients), non-nutritive plant chemicals that have protective or disease-preventive properties. Phytochemicals have antioxidant qualities that protect against the oxidative stress caused by free radicals which naturally exist in your body. These free radicals can participate in unwanted side reactions resulting in cell damage. Free radicals have been correlated with a wide range of chronic diseases.
At question is whether a purified isolated phytochemical (as found in supplements) has the same health benefit as the phytochemicals present in whole food or a mixture of foods. Evidence shows that the antioxidant qualities provided by phytochemicals are best acquired through whole food consumption (i.e. fruits and vegetables!). Therefore, the consumption of fruits and vegetables is crucial!
HOW DO WE KNOW THIS?
Individual antioxidants studied in many clinical trials do not appear to have consistent preventative effects as whole food. The isolated pure compound either loses its bioactivity or needs to work synergistically with other compounds found in the food to have the protective effect.
For example, one study questioned the effects of Beta-carotene and the prevention of skin cancer. The consumption of green and yellow vegetables and fruits has been inversely related to the risk of developing cancer. Beta-carotene (which is present in these vegetables) is said to be the anti-cancer agent. Therefore, Beta-carotene as a supplement should have the same anti-cancer effect. However, the study found that the incidence of nonmelanoma skin cancer was unchanged in patients receiving a Beta-carotene supplement.*
Antioxidant qualities provided by the phytochemicals found in fruits and vegetables are best acquired through whole food consumption, not as a pill or an extract. So instead of buying expensive nutritional supplements, eat a diverse diet incorporating lots of fruits and vegetables which contain the widest variety of protective compounds of all food groups.
Remember that there is not a magic pill to protect you and your family from the development of several leading causes of death. However, eating a balanced diet, which includes adequate fruits and vegetables, is the best way to keep you and your family protected! So it’s important to consume your recommended amount each and every day to protect your body from many diseases and disorders.
Also, obtaining antioxidants from dietary intake rather than taking multiple supplements is unlikely to result in consuming toxic quantities of phytochemicals. The Recommended Dietary Allowances (RDA) has not yet been set for the antioxidants in phytochemicals. Therefore, it is not wise to take mega-doses of purified phytochemicals as supplements before strong scientific evidence supports doing so.
Like all fad diets, there will always be fad remedies (such as pills and extracts) that claim to cure certain health concerns. However, the natural antioxidant qualities of the phytochemicals in fruits and vegetables along with all their other health-promoting benefits will keep your body strong and working effectively. Fruits and vegetables are the safe, delicious, and most beneficial way to keep your body protected!
*Liu RH. "Health Benefits of Fruit and Vegetables are from Additive and Synergistic Combinations of Phytochemicals." Am J Clin Nutr 2003;78 (suppl): 517S-20S.