Research in the last couple of years has begun to question the wisdom of the anti-oxidant/ free radical theory.
A small amount of free radicals may in fact be essential and overwhelming them with powerful anti-oxidant supplements may be begging for serious trouble.
Surprising Study: Put Down the Vitamins & Free the Free Radicals
In recent years, antioxidants have been touted as a secret to healthy living: The molecules bind to reactive oxygen compounds called “free radicals” that are known to damage the body’s tissues. The amount of oxidative damage increases with age, and according to one theory of aging it is a major cause of the body’s decline [The New York Times]. But a new study examined the effects of the antioxidant vitamins C and E when combined with an exercise regimen, and found a considerably more complicated story. The researchers found that free radicals may be beneficial in small doses, and may even help protect against diabetes. And mopping them up with antioxidants may do more harm than good [BBC News].
During a workout, the muscles metabolize glucose to create energy, but in the process some free radicals are released. The body has a natural defense mechanism to combat these free radicals, but many researchers had theorized that the body can’t catch all of the harmful compounds, which makes antioxidant supplements sound like a logical solution.
In the new study, published in the Proceedings of the National Academy of Sciences, the researchers tested this proposition by having young men exercise, giving half of them moderate doses of vitamins C and E and measuring sensitivity to insulin as well as indicators of the body’s natural defenses to oxidative damage.The [researchers] found that in the group taking the vitamins there was no improvement in insulin sensitivity and almost no activation of the body’s natural defense mechanism against oxidative damage [The New York Times]. The loss of insulin sensitivity is thought to be a prime cause of adult-onset diabetes.
The researchers suggest that the small amount of free radicals produced by exercise may be necessary to trigger both insulin sensitivity and the body’s natural defense mechanisms. Since the volunteers who were taking vitamins swept free radicals from their systems, those responses lay dormant. But researchers say the surprising findings don’t mean that people should avoid healthy vegetables that contain antioxidants, just that they may want to skip nutritional supplements with artificially high levels of antioxidants. Nutrition expert Elisabeth Weichselbaum comments: “If you stick to a healthy and varied diet, you generally get enough of the nutrients you need and you don’t run the risk of consuming large amounts that may be harmful for you” [BBC News].
Printable version
Vitamins 'undo exercise efforts'
Woman exercising
Exercise triggers chemical changes in the body
Taking vitamins after exercise may undo some of the beneficial effects of the workout, research suggests.
Some advocate taking antioxidants like vitamin C and E to help protect the body from harmful chemical by-products it creates in breaking into a sweat.
But German scientists now believe these "free radicals" may actually be good for us and even buffer against diabetes, PNAS reports.
And mopping them up with antioxidants may do more harm than good.
Sometimes we need to consider whether taking supplements is actually beneficial
Dr Sarah Aldred
Exercise biochemistry expert at the University of Birmingham
It is thought that antioxidant vitamins may be able to prevent damage to the body's tissues called "oxidative stress" by eliminating the free radicals which are said to cause it.
This damage has been implicated in several major diseases including cancer and heart disease as well as normal ageing.
But Dr Michael Ristow, of the University of Jena, and his team have shown free radicals may have a positive effect on the body by increasing its sensitivity to insulin - something that is lost in type 2 diabetes.
And this effect is blocked by antioxidant vitamins.
Too much of a good thing
Men who took vitamin C and E supplements showed no changes in their free radical levels, whereas those who did not take these antioxidants showed increased levels of free radical oxidative stress.
After four weeks of intensive exercise training, insulin sensitivity was restored only in the group of men who did not take antioxidant supplements.
The men who took the vitamin supplements fared worse, metabolically.
Dr Sarah Aldred, a lecturer in exercise biochemistry at the School of Sport and Exercise Sciences at the University of Birmingham, said: "It doesn't mean that antioxidants like vitamin C and vitamin E are bad for us, it just means that sometimes we need to consider whether taking supplements is actually beneficial.
"As this study shows it is not actually always the case."
Dr Elisabeth Weichselbaum of the British Nutrition Foundation said: "Antioxidants protect the cells in your body from damage and therefore help to reduce the risk of certain diseases such as cancer.
"But you should not consume high doses on a regular basis as this can have negative effects on your body.
"If you stick to a healthy and varied diet, you generally get enough of the nutrients you need and you don't run the risk of consuming large amounts that may be harmful for you."
Cheers
