Toxic products found in blood of BBQ lovers

Last Updated: Tuesday, April 24, 2007 | 6:42 PM ET

CBC News

As barbecue season gets underway, a new study suggests a class of toxic chemicals released by grilling, broiling and frying meat may increase the risk for life-threatening diseases.

Dr. Helen Vlassara says her study found the toxic products are linked to inflammation, heart disease, diabetes, and kidney disease.
(CBC)

"Advanced glycation end products," also known as AGE products or AGEs, are produced and absorbed into the body when meat or cheese is cooked at high temperatures, or foods are sterilized or pasteurized, researchers at Mount Sinai School of Medicine in New York said.

When AGEs build up in the body, oxidative stress — damage linked to aging — results.

In a study appearing in the April issue of the Journal of Gerontology: Medical Sciences, Dr. Helen Vlassara and her colleagues tie AGE products to heart disease, diabetes and kidney disease. The results are an indicator of a link between high-temperature cooking, AGEs, and activation of the immune system that triggers inflammation.

"A sustained and chronic inflammation damages the tissues," Vlassara told CBC News. "Therefore it will damage the heart, it will damage the kidneys and the brain."

Put levels on labels: researcher

The study involved 172 healthy men and women who were divided into two age groups, those 18 to 45 and those 60 to 80. Participants had their body weight and body fat measured, completed a three-day food diary, and had blood samples collected for lab testing.

The findings add to the reasons to avoid high-temperature cooking.
(CBC)

AGE levels tended to be higher in older people, whose bodies seem to have less ability to remove the chemicals, the researchers found.

"Excessive intake of fried, broiled, and grilled foods can overload the body's natural capacity to remove AGEs," said Vlassara, who called for the levels to be put on nutrition labels, just as trans fat, calorie and sugar content are identified.

The researchers also found that the more people ate foods rich in the compounds, the higher their blood levels of AGE and markers for inflammation such as C-reactive protein. Levels of AGEs in some healthy adults were similar to those seen in people with diabetes in earlier studies, according to the researchers.

Cooking alternatives

It is clear that AGEs are another factor in the aging process, said nutrition researcher Dr. David Jenkins of St. Michael's Hospital in Toronto.

Jenkins joined Vlassara in suggesting that boiling, steaming and stewing are the safest ways to cook food, not only because of AGEs, but also given warnings about cancer-causing byproducts of high-temperature cooking such as acrylamide.

"I'm a great one for recommending people have a pretty, pretty drab life," Jenkins said. "So I like them having things that are boiled, tofu, all sort of things that everyone sort of turns up their nose at."

The occasional barbecue is probably OK, Vlassara said, noting AGEs also give foods desired tastes and smells.

The researchers used laboratory tests to measure AGE levels in the blood, but a clinical version of the test is not available.  

For people who enjoy their steaks marinated, there is some evidence that adding acidic liquids such as lemon or vinegar might help to counteract some of the AGEs, Vlassara said.