MONDAY, Nov. 11, 2002 (HealthDayNews) -- Diabetics may want to start slow-roasting that Thanksgiving bird today: Slow, low-temperature cooking reduces chemicals that drive up blood levels of vessel-harming molecules, research shows.
The study found that blood sugar patients on a two-week diet of gently cooked foods had 40 percent less of the harmful molecules, called advanced glycation end products (AGEs), than when they ate meals cooked on high. That led to much lower levels of blood chemicals associated with heart and vessel disease. The findings are reported this week in the Proceedings of the National Academy of Sciences.
Vessel disease "is what kills diabetics," says Dr. Elliot J. Rayfield, an endocrinologist at Mount Sinai School of Medicine in New York City and a co-author of the study. "This is speeding up the process."
High temperatures scorch the natural sugars in food, creating AGEs in the process. AGEs have been implicated in vessel damage and abnormal folding of proteins, and they may even disrupt wound healing.
Evidence suggests that about 10 percent of AGEs absorbed in food can retain their ability to interact with cells in the body. Mouse studies have found that feeding diabetic animals low-AGE diets shields them from vessel lesions associated with their sugar disorder, regardless of how much fat or glucose they had in their blood.
In the latest study, researchers fed 24 men and women with diabetes two diets. One was a normal meal plan sanctioned by the American Heart Association as being appropriate for people with the blood sugar condition. It consisted of foods like broiled chicken and tuna, boiled pasta and the yolks of hard-boiled eggs.
The other diet was engineered to provide five times fewer AGEs by using lower temperatures and prolonging cooking times. Volunteers spent two weeks on each diet, spaced by a "wash-out" period of a week or two.
The high-AGE diet drove up blood levels of the burned sugars nearly 70 percent, on average, while two weeks on the low-AGE diet led to a drop of 30 percent in the substances.
At the same time, eating the low-AGE diet lowered levels of other potentially harmful blood molecules, including low-density lipoprotein, which is better known as the "bad" cholesterol. And it led to declines in major inflammatory chemicals -- like C-reactive protein and tumor necrosis factor-alpha -- that can damage vessels. Eating high-AGE foods, on the other hand, kicked these substances up several notches.
Rayfield and his colleagues are now writing a cookbook with meals that are low in AGEs. They advise diabetics to shun toast, red meat and processed foods. Barbecues and microwave ovens are out, too, as they cook things too quickly.
Better are foods such as fish and vegetables that can be braised. Marinades and dry wines are also good because they impede the formation of AGEs. "It's not just the percentage of carbohydrates, protein or fat in your diet, but it's how you prepare it that's going to make a difference," Rayfield says.
Kim Janda, a chemist at the Scripps Research Institute in La Jolla, Calif., who studies AGEs, says the latest work isn't surprising, since other researchers have noted the link between the substances and vessel damage.
However, Janda says it might not be so easy to avoid AGEs in foods that have to be cooked. In fact, even raw meat can generate AGEs through oxidation, which is one step in the process of creating them. Furthermore, scientists aren't sure if all AGEs are bad, or how bad the bad ones can be. "It's kind of a black box," Janda says.
What To Do
An estimated 17 million Americans suffer from Type II diabetes, in which their cells stop responding to the hormone insulin. For more on diabetes, try the American Diabetes Association or the U.S. Centers for Disease Control and Prevention.
