Can too many antioxidants be bad for health?

Resveratrol, a natural antioxidant compound found in red wine and the skin of red grapes, has long been touted as a potential "super food" for health.

But a new pivotal study suggests that too much of a good thing – in this case, antioxidants – could be detrimental to health.

Resveratrol and exercise

Resveratrol has received positive attention because of its anti-aging properties, but the new research asserts that a diet rich in antioxidants might actually counteract some of the health benefits of exercise – especially in older men – like reduced blood pressure and cholesterol.

Researchers at the University of Copenhagen found that reactive oxygen species, which are generally thought to cause aging and disease through oxidant stress, might actually be necessary for the body to work properly. Otherwise, healthy responses to stressors like exercise will not take place, the team noted. Therefore, too many antioxidants could have a negative impact on health.

The study

The study included 27 healthy, physically inactive men about the age of 65. For eight weeks, all of the men performed high-intensity exercise training and half the group received resveratrol supplements, whereas the other half received a placebo pill.

“We found that exercise training was highly effective in improving cardiovascular health parameters, but resveratrol supplementation attenuated the positive effects of training on several parameters, including blood pressure, plasma lipid concentrations and maximal oxygen uptake," said Leslie Gliemann, a Ph.D. student who worked on the study, in a statement.

While the amount of resveratrol given to participants was much higher than what would be consumed in a normal diet, researchers said the implications are interesting – especially given that the results contradict other animals studies on the subject.

Michael Joyner, from The Mayo Clinic USA, elaborated:

In addition to the surprising findings on exercise and resveratrol, this study shows the continuing need for mechanistic studies in humans. Too often human studies focus on large scale outcomes and clinical trials and not on understanding the basic biology of how we adapt.

The study was published in The Journal of Physiology.

Source: Science Daily