Are Antioxidants Overrated?

Are Antioxidants Overrated?

For decades, antioxidants have occupied the seat of honor among nutrients thought to promote health and long life. Believed to be the first line of defense against heart disease and cancer, they also quickly became the focus of research on aging. However, all that glitters is not always gold…

Are antioxidants good for you?

They are, but with certain qualifications. A diet rich in plant-based foods is packed with beta-carotene, vitamin C, and other antioxidants. Furthermore, numerous epidemiological studies point to the powerful correlation between eating more fruits and vegetables and reduced incidence of cancer. Consequently, researchers quickly moved to the conclusion that adding antioxidant supplements to one’s diet would further reduce cancer risk.

Many well-designed studies have shown the opposite! A 1996 study of 18,000 heavy smokers revealed that experimental groups given either beta-carotene or retinol, vitamin A precursors, had 28% more lung cancers than a control group given neither antioxidant; in addition, 17% more died in the antioxidant groups! Further studies only confirmed these results.

By 2007, a powerful meta-analysis of 47 exceptionally well-designed studies of antioxidant supplements concluded that adding them to the diets of test subjects — especially beta-carotene, vitamin A, or vitamin E — increased the likelihood of early death 5%! After decades of believing the myth of antioxidant protection, researchers and the public alike were back at square one.

Don’t antioxidants protect against free radical damage?

Finally, we are getting to the root of the problem! An emerging consensus suggests that our understanding of the role of free radicals in pathology, as well as healthy physiological function, is incomplete. 

In an experiment conducted at McGill University, worms were genetically modified to overproduce superoxide radicals. Astoundingly, adding to the worms’ oxidative stress increased their lifespan 32%! The benefits disappeared when the worms were given vitamin C, an antioxidant.

However, the connection between oxidative damage and cancer is equally indisputable. Additionally, in a study conducted at the University of Washington, mice genetically engineered to produce more of the antioxidant enzyme catalase lived longer.

As a result, some researchers have suggested that free radicals are part of the body’s defense mechanisms.

How could free radicals cause these positive changes?

Free radicals are the frontline response to illness and injury, but also to intense exercise. Researchers at UCSF have studied one gene, HIF-1, turned on by free radicals. The HIF-1 gene product is a transcription factor that regulates expression of more than 60 other genes, including some involved in DNA repair. It seems that in order for the body to properly adjust to stress, it requires specific free radicals to initiate its repair processes.

Taking antioxidants may interfere with the body’s functioning. When German researchers compared the health of exercisers who took antioxidant supplements with those who did not, they found the latter group was healthier! The role of antioxidants is equivocal. Eating antioxidant-rich foods promotes health, but taking supplements may add risk!

As in all things, the best policy is to honor nature rather than trying to defeat it, and to adopt a lifestyle that optimizes the body’s innate capacity to heal itself. Until the parameters governing that capacity are better understood, let us be moderate in diet and exercise, and above all else curious to know more.