Can these so-called life savers, heralded as cancer fighters, actually harm you?
Walk into a vitamin or health food store — or simply browse the supplement shelves of your local pharmacy — and you’ll find an array of pills and potions promising better skin, more energy, improved memory and a longer life in general.
In particular, anti-oxidants such as Vitamin A, C and E, as well as beta-carotene, have been hailed as the “good guys” in the fight against cognitive decline, heart disease and cancer by acting against “free radicals,” defined by The National Cancer Institute as “highly reactive chemicals that have the potential to harm cells.”
According to the NCI website: “They are created when an atom or a molecule (a chemical that has two or more atoms) either gains or loses an electron (a small negatively charged particle found in atoms). Free radicals are formed naturally in the body and play an important role in many normal cellular processes.”
Problems arise when an excess of these chemicals occur, causing cellular damage, leading to serious health concerns, including cancer.
Anti-oxidants — some produced by the body, some taken in supplements — work to offset this damage and, thus, keep us healthy.
Or do they?
Recent research has cast some doubts on that notion.
Writing for consumer.healthday.com, Dennis Thompson cites a 2014 Swedish study published earlier this year in Science Translational Medicine which suggests that “smokers and other people at high risk for lung cancer could make matters worse if they take anti-oxidant supplements.”
In this study, mice with lung cancer were given anti-oxidants N-acetylcysteine (NAC) and Vitamin E. Instead of improving their survival rate, this anti-oxidant supplementation, the authors report, “markedly increases tumor progression and reduces survival.”
Ironically, the difficulty is that anti-oxidants were doing the job for which they were intended: repairing cells damaged by free radicals. Unfortunately, some of the cells they repaired appeared to be cancer cells, which the free radicals would otherwise have a role in destroying.
This in effect accelerated the growth of cancer.
The study is of particular concern to smokers and others at high risk for lung cancer, as well as patients with chronic obstructive pulmonary disease, commonly known as COPD, who are often given N-acetylcysteine to aid in breathing.
Yet even before this study was published, other research showed the same concern. For example, early results of a 1994 study in Finland, says the NCI, in which middle-aged male smokers received supplements of alpha-tocopherol and/or beta-carotene, showed that participants taking beta-carotene had an increased incidence of lung cancer. (Alpha-tocopherol was shown to have no effect on cancer incidence.)
Another study, also reported by the NCI, the Selenium and Vitamin E Cancer Prevention Trial (SELECT), examined daily supplementation of selenium (200 μg), Vitamin E (400 IU) or a combination in lessening “the incidence of prostate cancer in men ages 50 and older.” Results did not bode well. “Updated findings from the study, reported in 2011, showed that, after an average of 7 years (5.5 years on supplements and 1.5 years off supplements), there were 17 percent more cases of prostate cancer among men taking Vitamin E alone than among men taking a placebo.” At best, the trial found, “no increase in prostate risk was observed for men assigned to take selenium alone or Vitamin E plus selenium compared with men assigned to take a placebo.”
So, is it time to toss your supplements in the trash? Not necessarily. The Harvard School of Public Health Department of Nutrition cites “one bright spot for anti-oxidant vitamins. A six-year trial, the Age-Related Eye Disease Study, found that a combination of Vitamin C, Vitamin E, beta-carotene and zinc offered some protection against the development of advanced age-related macular degeneration, but not cataract, in people who were at high risk of the disease.”
However, it is important to evaluate the information critically and consult with a doctor, especially if you’re at risk for or have cancer.
Those taking prescription medicine or chemotherapy should be especially cautious. Drug interactions are not limited to prescription drugs. As reported in the website of emedicinehealth.com, “dietary supplements may cause side effects, trigger allergic reactions, or interact with prescription and nonprescription medicines or other supplements you are taking.
“A side effect or interaction with another medicine or supplement may make your health worse.”
Area nutritionist Joanna Chodorowska, in an email, agreed on the importance of a healthy diet and “eliminating the toxic foods which compromise the immune system,” among them, “sugar, wheat, processed foods, artificial colors and preservatives.”
And besides a diet rich in “green and leafy vegetables,” she urges readers to “decrease your stress and increase your movement — don’t sit on the couch.”
Diane McManus is a seasoned writer specializing in health issues. This article originally appeared in the special section, "Fighting Cancer."