November 25, 2014
You may want to think twice before throwing the steaks on the grill. A new report suggests that compounds formed when meats are grilled or broiled may increase the risk for Alzheimer’s disease.
Grilled meats have been tied to other risks, including a possible link to certain cancers and diabetes. Now research suggests that high-temperature grilling produces chemical that may have harmful effects on the brain as well. The findings are only preliminary, but they raise interesting questions about measures we may take to reduce our risk of Alzheimer’s.
Scientists at the Icahn School of Medicine at Mount Sinai in New York looked at substances called advanced glycation endproducts, or AGEs, which are formed when animal products are exposed to high temperatures, such as with grilling and broiling. While AGEs are found naturally at lower levels, the Western diet, which tends to be high in meats, is especially high in these compounds.
The researchers found that mice raised on a diet rich in AGEs had low levels of a protein in the body called sirtuin, which helps the body fight inflammation. Persistent low-level inflammation have been linked to Alzheimer’s disease, heart disease and other ills.
Other studies in mice have shown that suppressing levels of sirtuin promotes brain damage typical of that seen in Alzheimer’s disease. Conversely, activating sirtuin has been shown to suppress Alzheimer’s in mouse models. Researchers are looking further into drugs that enhance sirtuin’s actions as a possible way to help ward off the disease.
In the current study, mice fed the AGE-rich diets had high levels of brain plaques typical of those seen in people with Alzheimer’s disease. The mice also did worse on tests of memory than mice raised on ordinary animal chow. The findings were reported in the Proceedings of the National Academy of Sciences.
In a separate experiment, the Mount Sinai team also studied 93 healthy men and women over 60 years of age. Over a nine-month study period, those who had high blood levels of AGEs did worse on thinking and memory tests than those with low levels of AGEs. Those with high AGE levels also had signs of impending diabetes, which has also been linked to an increased risk of Alzheimer’s disease.
The findings are only a correlation, and nobody is saying that eating a grilled burger will lead to Alzheimer’s disease. But the research raises interesting questions about the role of diet in Alzheimer’s disease.
“The new findings emphasize the importance of not just what we eat, but also how we prepare what we eat,” said. Dr. Helen Vlassara of Mount Sinai, the study leader. “By cutting AGEs, we bolster the body’s own natural defenses against Alzheimer’s disease as well as diabetes.”
AGEs are found in meat and dairy products. Levels rise when the food is exposed to high temperatures and little moisture, such as during grilling, broiling or frying. Cooking methods like poaching, sautéing, stewing or baking would produce lower levels of these potentially hazardous compounds.
While advancing age and genetic factors appear to be the largest risk factors for Alzheimer’s, lifestyle factors may also play a role in dementia onset, studies like these suggest. Being overweight and smoking, for example, have been linked to an increased risk for dementia.
Getting regular exercise and eating a heart-healthy Mediterranean style diet rich in olive oil rather than saturated fats, and rich in fish, fruits and vegetables may lessen Alzheimer’s risk. Mentally challenging activities, including possibly crossword puzzles, may also help to keep the brain sharp, some research suggests.
Source: Weijing Cai, Helen Vlassara, M.D., Jeremy Koppel, M.D. et al: Oral glycotoxins are a modifiable cause of dementia and the metabolic syndrome in mice and humans
Proceedings of the National Academy of Sciences, online, Feb. 24, 2014