Eating too many superfoods 'can harm health by overdosing on antioxidants

ranchgirl

By Daniel Martin and Liz Hull
28th January 2010

For years they have been hailed for their apparently age-defying effects on the body.
From sweet potatoes to blueberries, from lentils to broccoli, the health conscious couldn't get enough of so-called superfoods.
But now it seems you really can have too much of a good thing.
Scientists say the delicate balance of nutrients required by the body could be affected by stuffing it full of the antioxidants contained in the foods.
Nutritionists claim these antioxidants can lengthen your life by cutting the risk of heart disease and cancer. They have even linked them to better sex.
But researchers say too much of the superfoods could mean there are not enough 'pro-oxidants' - usually considered the evil twin of antioxidants - in the body.
While the antioxidants slow down the damage to muscles and other organs by the process known as oxidisation, the pro-oxidants speed it up.

But too many antioxidants can tilt the balance and make it harder for the elderly to breathe and stop them from doing the exercise that could help them stay fit.
The researchers, from Kansas State University in the U.S. tested animals with different doses of antioxidants.
Those that were given too much showed impaired muscle function, reported the study published in the Journal of Applied Physiology.

Researcher Steven Copp said: 'I think what a lot of people don't realise is that the antioxidant and pro-oxidant balance is really delicate.
'One of the things we've seen in our research is that you can't just give a larger dose of antioxidants and presume that there will be some sort of beneficial effect. In fact, you can actually make a problem worse.'

Nutrionists claim that antioxidants can slow down and even reverse some of the effects of ageing - which is why foods like blueberries have been hailed for their benefits on dementia victims.
But some of these changes are not good for an ageing body as it stops some of ways in which blood cells flow by taking out the chemicals known as vasodilators which help open blood vessels.
This makes older people get out of breath more quickly, for instance, which in turn prevents them from exercise and keeping fit.
Mr Copp said: 'If you have a person trying to recover from a heart attack and you put them in cardiac rehab, when they walk on a treadmill they might say it's difficult.
'Their muscles get sore and stiff. We try to understand why the blood cells aren't flowing properly and why they can't get oxygen to the muscles, as happens in healthy individuals.
'We're now learning that if antioxidant therapy takes away hydrogen peroxide - or other naturally occurring vasodilators - you impair the body's ability to deliver oxygen to the muscle so that it doesn't work properly.
'It's really a cautionary note that before we start recommending people get more antioxidants, we need to understand more about how they function in physiological systems and circumstances like exercise.'

ranchgirl

thanks 多伦多短刀客 by mentioning "蓝莓伤害肌肉"

I don't understand it, and did a google search, now I understand. It is not "蓝莓伤害肌肉", but too much antioxidents will 伤害 our health including 肌肉.

Read the above article carefully, very classical on 老子的物极必反， 虽然他并没有提到老子。

谢谢多伦多短刀客！