26 April 2011

Obesity and oxidative stress

Ever wondered why exactly obese people are more likely to develop heart disease than healthy people? A new study has found the answer.


Ever wondered why exactly obese people are more likely to develop heart disease than healthy people? A new study has found the answer.

Researchers at the Boston University School of Medicine in Massachusetts, USA, discovered that obese people have very high levels of oxidative stress, which is caused by a build-up of free radicals that damage the body's cells.

The report was published in Arteriosclerosis, Thrombosis and Vascular Biology: Journal of the American Heart Association.

Oxidative stress
Obesity has long been considered as a risk factor for diabetes and heart disease and according to study leader Dr John Keaney, oxidative stress is one of the reasons why obesity is so dangerous.

Oxidative stress is a natural by product of body processes, but it is also known to contribute to a number of diseases and the aging process.

These findings, warn the study authors, are still too premature to send overweight people running to their chemist to buy antioxidant vitamins that counteract free radicals.

Keaney's study does however show a clear association between obesity and elevated levels of tell tale chemicals that are related to oxidative stress.

Measuring oxidative stress levels
Thanks to a new technology, scientists are finally able to asses oxidative stress chemicals in the body. The new method lets researchers measure the levels of 8-epi-PGF (2-alpha), an oxidative stress-related chemical found in the body.

Scientists can now examine the relationship between oxidative stress and conditions such as arteriosclerosis, high blood pressure and diabetes.

In order to understand how much oxidative stress contributes to heart disease, Keaney's team tested urine samples from 2828 male and female participants and looked for the presence of 8-epi-PGF (2-alpha), the chemical that would show the degree of oxidative stress.

Challenging popular beliefs
The study results challenged popular beliefs that oxidative stress is caused by high cholesterol and high blood pressure.

The research team did however find that smoking and diabetes still contributes to higher levels of oxidative stress.

But the main finding, and indeed the most surprising finding, was that body mass index (or BMI, a measurement that indicates whether or not someone is obese) is actually also a marker for oxidative stress.

Keaney's team noted that the higher one's BMI, the higher their levels of 8-epi-PGF (2-alpha) were. This shows that more oxidative stress is present in one's body.

Obesity, therefore, is an independent predictor of oxidative stress.

How dangerous is oxidative stress?
Researchers still have to find out how dangerous high levels of oxidative stress are. Keaney's team will have to monitor the participants with high levels of oxidative stress to see if they have higher rates of heart attack and death compared to those with lower oxidative stress levels.

Study authors noted that there is more and more literature that points to the link between high oxidative stress and blood vessel disease.

Keaney's team thinks that oxidative stress may be the "connector" between obesity and other diseases. – (Health24)

Read more:
How belly fat points to diabetes
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