The truth about antioxidants in foods

Eating food containing antioxidants has little effect on health outcomes

The truth about antioxidants in foods FREE to media subscribers

VANCOUVER, BC, Mar 28, 2015/ Troy Media/ – We are told to eat plenty of blueberries, pomegranates, nuts, and dark green vegetables because they are rich in antioxidants. Antioxidants are chemicals which are supposed to roam around the body soaking up free radicals, which we are told cause disease, aging and immune deficiency.

Some research has associated the oxidation of free radicals in the body with cancer, heart disease and Lou Gehrig’s disease. It’s also accepted that free radicals play a role in animal aging. In the early 1990s, biological antioxidants, which counteract oxidation, were given to animals which then appeared to live longer. Giving these antioxidant compounds to people also correlated with less cancer in humans.

The science behind antioxidants

We can only imagine the sense of affirmation among healthy-eating food faddists when foods like carrots and pomegranates, which don’t contain much fat, simple sugar or salt, were found to be rich in antioxidants. Excitement heated up, with the predictable exaggeration of health benefit claims, and the antioxidant diet era was born.

This got me to wondering about how scientific this all was, so I delved into the evidence supporting eating antioxidant-rich food. The Cochrane Collaboration, an authoritative source of evaluation of health science, did a review of antioxidant supplements back in 2008 and “found no evidence to support antioxidant supplements for primary or secondary prevention.” But I noticed that it also found that supplementing vitamin A, beta-carotene and vitamin E could increase mortality.

A lot of the information about the benefit or harm from antioxidants concerns supplements, which are not exactly diet. When we look at diet itself, one low-quality observational study associated antioxidant-rich food with helping avoid cancer of the esophagus, but found no relationship with stomach cancer. Other studies also found no protection from other cancers, with many of them repeating concerns about antioxidant supplements. Another study connected eating papaya and oranges with slowing down the development of cancer of the cervix, but the participants all had virus infections known to progress to cancer.

In other words, the overall evidence on dietary antioxidants and cancer is a scatter of conflicting findings consistent with no significant causal relationship, good or bad.

There is also conflicting evidence about the effect of maternal antioxidants on infants avoiding allergy, while dementia was found less likely with dietary antioxidants in one study but more likely in another. There was also no association found between dietary antioxidants and asthma, and studies on prevention of cardiovascular disease by eating antioxidant-rich food concluded there was no benefit.

Other studies I reviewed found that poverty early in life, as well as heavy alcohol consumption or cigarette smoking, were associated with people having low blood levels of antioxidant substances, which means they’re not eating many fruits and vegetables. So when people who don’t eat “healthy” get sick or die, it could be because they are poor or addicted and have nothing to do with diet.

Many otherwise responsible people change their diet as soon they read about the latest food fad. This means that, when you compare what people say they eat to their health outcomes, you are also comparing the extent to which they do what they’re told to their health outcomes. The same conclusion goes for antioxidants as for salt, sugar, and fat: people who follow rules may live a bit longer, no matter what they eat or say they eat.

May do more harm than good

My research has shown me that bad health outcomes are actually more likely if you take antioxidant-substance pills. Wouldn’t it be a perversion of good intentions if, in attempting to increase the health outcomes of underprivileged people by switching them to an antioxidant-rich diet we were actually doing them, however minutely, more harm than good?

If I eat blueberries, it’s because I enjoy them. If I avoid vegetables, it’s because, for me, many of them are “empty calories”: food energy intake that isn’t justified by the pleasure of eating it. The scientific evidence is pretty clear: eating antioxidant-containing food makes no consistent difference to health outcomes, and unlike some other food fads it could increase your risk of cancer.

John Sloan is a family physician whose practice is confined to home care of frail elderly people, and avoiding institutional care of these patients. He has published numerous articles and several books on healthcare. His most recent ebook is Forbidden Food: How Science Says you can Eat what you Like and Like what you Eat.

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