抗氧化维生素可影响抗糖尿病的效果

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This is Scientific American's 60-second Science. I'm Karen Hopkin. This will just take a minute.

Exercise is good for you. Antioxidants are good for you, but put them together, and it’s not as good as you think because a recent study shows that some vitamins block the beneficial effects of exercise. A good workout not only get your heart pumping, it makes you body better able to process glucose and decreases your risk of diabetes and it does so, in part, by firing up you cell’s mitochondria.  Stoking those mitochondrial flames boosts your metabolism, but it also throws off so-called “free radicals” which are usually considered harmful. So adding antidioxidants, which get rid of free radicals, should make your workout even healthier, right?

Well, no, forty men took part in a four-week training program, half the group also received daily doses of vitamins C&E. The researchers discovered that exercise on its own improves insulin sensitivity, which keeps diabetes at bay, but taking the vitamins erased that gain, findings that appear in the May 12th issue of Proceedings of the National Academy Sciences. So you actually need a burst of potentially damaging radicals to reap some of the important awards of a good sweat, which means that even on a molecular level: no pain, no gain.

Thanks for the minute for Scientific American's 60-second Science. I'm Karen Hopkin.

antioxidant: substance that inhibits oxidation or inhibits reactions promoted by oxygen or peroxides 抗氧化剂

keep(hold)at bay: 牵制，使不能迫近

mitochondria：线粒体

free radical: an atom or group of atoms with at least one unpaired electron; in the body it is usually an oxygen molecule than has lost an electron and will stabilize itself by stealing an electron from a nearby molecule 自由基，游离基[带有单电子的原子或原子基团]

insulin: 胰岛素