Some of the beneficial effects of the workout might be undone by taking vitamins after exercise, suggests research.
Some recommand to take antioxidants, such as vitamin C and E, in order to help protect the body from harmful chemical by-products it creates in breaking into a sweat.
However, German scientists now believe these “free radicals” may actually be good for us and even buffer against diabetes, PNAS reports. They also say that it may do more harm than good to swab them up with antioxidants.
Antioxidant vitamins are believed to be able to prevent damage to the body’s tissues called “oxidative stress” because they eliminate 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.
Yet free radicals may have a positive effect on the body, showed Dr Michael Ristow, of the University of Jena, and his team, as they increase its sensitivity to insulin, something that is lost in type 2 diabetes.
But this effect is blocked by antioxidant vitamins.
‘Healthy and varied diet’
In a test, men who took vitamin C and E supplements showed no changes in their free radical levels, while those who did not take these antioxidants showed increased levels of free radical oxidative stress.
After four weeks of intensive exercise training, only the group of men who did not take antioxidant supplements showed an insulin sensitivity that was restored.
The men who took the vitamin supplements fared worse, metabolically.
“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”, said Dr Sarah Aldred, a lecturer in exercise biochemistry at the School of Sport and Exercise Sciences at the University of Birmingham.
“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.”