We've been told and have believed for some time, that antioxidants reduce the risk of several health conditions by helping taxed cells in the body minimize or repair the adverse effects of free radicals and oxidative stress.
However, Dr. Shawn Talbott, a sports medicine, nutrition and fitness expert and author of 10 books, including his upcoming "Deadly Antioxidants" which is set for release in February 2015, says that roughly half of us — those who regularly take antioxidant supplements — might be getting too much of a good thing.
Free radicals cause a chain reaction in your body by altering chemicals on the cellular level that can trigger cell damage.
They’re naturally formed when you exercise, when your body converts food into energy, and by a variety of environmental factors, such as smoking, too much sun exposure and air pollution.
The emphasis on getting enough antioxidants to maintain good health, vitality and ward off harmful oxidative damage associated with a slew of chronic health conditions — such as cancer, cardiovascular disease, diabetes, Alzheimer’s disease, Parkinson’s disease, macular degeneration and aging — have led some of us to overdose on dietary supplements.
“Humans have a tendency to presume if a little of something is good for us, then more has to be better,” said Talbott. When it comes to antioxidant supplements, too much of a good thing could actually be causing irreparable harm, from accelerating the aging process to potentially encouraging cancer to more rapidly grow and spread.
So far research has not shown antioxidant supplements to be beneficial in preventing diseases, according to the National Cancer Institute. In fact, supplementing our diets with megadoses of vitamins A, C, E, D, beta carotene, lutein and lycopene and the trace element selenium, may actually cause more problems than they prevent.
A growing number of recent studies show taking high-dose antioxidant supplements — that’s any amount above the recommended 100 percent daily requirement—“can have a dark side by upsetting our body’s natural protective defenses,” Talbott said.
For example, high doses of beta-carotene supplements appear to increase the risk of lung cancer in smokers and former smokers, several studies suggest, by fueling the cancer to grow and or spread.
And high doses of vitamin E supplements may actually increase the incidence of prostate cancer and one type of stroke. These supplements may also interfere with some prescription medications.
Recent studies showing adverse effects have led the U.S. Preventive Services Task Force and the American Academy of Family Physicians to recommend against taking vitamin E or beta-carotene supplements for the prevention of cancer. Foods containing naturally rich vitamin E and beta-carotene are still considered to help reduce cancer risk however.
The best way to get antioxidants is in natural forms, by eating 10-12 servings each day of various vegetables, fruits, whole grains, seeds and nuts, Talbott said.
•Beta-carotene is found in colorful fruits and vegetables, including carrots, peas, cantaloupe, apricots, papayas, mangoes, peaches, pumpkin, apricots, broccoli, sweet potatoes and squash. It can also be found in some leafy green vegetables, including beet greens, spinach and kale.
•Lutein is rich in green leafy vegetables, such as spinach, collards and kale, broccoli, corn, peas, papayas and oranges.
•Think pink for lycopene and Vitamin C found in fruits and vegetables, such as papayas, strawberries, pink grapefruit, watermelon, apricots and tomatoes.
•Selenium can be found in cereals (corn, wheat and rice), nuts, legumes, animal products (beef, fish, turkey, chicken, eggs and cheese), bread and pasta.
•Vitamin E is found in almonds, sunflower seeds, hazelnuts and peanuts. It can also be found in green leafy vegetables such as spinach and kale, and in oils such as soybean, sunflower, corn and canola oils.
If you opt to use antioxidant supplements, Talbott warned not to exceed 100 percent of the daily-recommended amount for more than a couple of days, unless directed by your physician. To minimize risk, it's important to tell your health care providers about any antioxidants you use.
Antioxidants and Cancer Prevention. NCI.
National Center for Complementary and Alternative Medicine. Antioxidants and Health.
Nrf2 Antioxidant Stress Response: Managing its Dark Side. Olivia L. May. Cayman Chemical
Shawn E. Talbott. Interview. 16 June 16, 2014.
Reviewed June 17, 2014
by Michele Blacksberg RN
Edited by Jody Smith