Mon May 7, 2007 12:19PM EDT

By Anne Harding

NEW YORK (Reuters Health) - By relying more on steaming, boiling and stewing to cook foods and using acidic marinades on meat cooked with dry heat, people may be able to stay healthier, a New York City researcher suggests.

These strategies will reduce the amount of advanced gycation end products (AGEs), or glycotoxins that people consume with their food says Dr. Helen Vlassara of Mt. Sinai School of Medicine. With her colleagues, Vlassara has found that the more AGEs healthy people eat, the greater their levels of inflammation and oxidative stress.

"It is time that we pay more attention to these toxic substances ... because they are extremely abundant in our foods as we have developed them today," Vlassara told Reuters Health. "They do cause inflammation and they tend to accumulate in the body. Over a long time the constant low-grade inflammation can lead to organ damage and disease."

Vlassara points out that inflammation plays a key role in a host of increasingly common aging-related illnesses, including Alzheimer's disease, diabetes, and heart disease.

AGEs are produced by the interaction of sugars with proteins and certain fats, and are found in animal foods. Cooking foods for a longer time at a higher temperature, in the absence of water, significantly boosts their AGE content, as does processing them.

AGEs are also a byproduct of normal metabolism, but high levels are found in people with diabetes and heart disease, Vlassara and her team note in the Journal of Gerontology: Medical Sciences. As people age they may be less able to clear AGEs from their bodies, they add, while kidney disease also makes it more difficult for people to excrete glycotoxins.

She and her colleagues had previously shown that diabetic individuals who ate a diet low in AGEs had lower levels of molecules involved in inflammation. The researchers have also found that aging mice have less oxidative stress and insulin resistance -- and live longer -- when they consume a low-AGE diet.

To understand whether the amount of AGEs healthy people consume might be related to their level of inflammation, Vlassara and her colleagues looked at 172 healthy men and women. One group of study participants were younger than 45, while the others were over 60.

The more AGEs people ate, the researchers found, the higher their blood levels of two types of AGEs in their blood. Consumption of AGEs also correlated directly with key indicators of inflammation and oxidative stress.

People can reduce their AGE consumption, and possibly their risk of disease, by using high temperatures to cook foods less frequently, and cutting down on processed foods, Vlassara and her team note.

Anyone concerned about AGE consumption should try to cook with water as often as possible, for example using boiling, steaming or stewing, rather than frying, Vlassara said in an interview. But people do not need to abstain from barbecue or grilling entirely; "moderation is the message, not eliminating something completely from the diet," she added. And marinating foods in lemon juice, vinegar or other acidic substances before cooking them with dry heat greatly reduces AGE formation, Vlassara noted.

Extrapolation from findings in both animals and humans suggests it's conceivable that people could extend their lives by reducing AGE consumption, she adds; to date, one of the only other interventions that has stretched lifespan in mammals is severe restriction of calorie intake.

"Our study shows that this can be done just by changing moderately the way we cook," Vlassara said. "In other words, we do not have to suffer any calorie restriction."

SOURCE: Journal of Gerontology: Medical Sciences, April 2007.