There is no denying that Americans are big fans of barbecues. In fact, figures state that 62% of us use our grills all year round. But new research published in the Proceedings of the National Academy of Sciences suggests that consuming heat-processed animal products, such as grilled or broiled meats, may increase the risk of Alzheimer's disease and diabetes.
Researchers from the Icahn School of Medicine at Mount Sinai in New York, NY, say that heat-processed meats contain high levels of advanced glycation endproducts (AGEs). These compounds have been associated with the worsening of many degenerative diseases, including diabetes and Alzheimer's disease.
AGEs already naturally exist in the body at low levels. But in their study, the researchers found that consuming foods with high levels of AGEs increases the body's levels of AGEs, therefore raising the risk of associated diseases.
To reach their findings, the investigators monitored the cognitive health of mice that consumed foods with high levels of AGEs - foods that are commonly found in the Western diet. This diet is high is saturated fats, red meats and "empty" carbohydrates, and low in seafood, poultry, whole grains and fresh fruit and vegetables.
Western diet led to Alzheimer's and metabolic syndrome in mice
Mice that consumed foods with high levels of AGEs demonstrated high levels of AGEs in their brains, compared with mice that ate a diet low in AGEs.
Researchers found that eating grilled meat may increase the risk of Alzheimer's disease and diabetes.
High levels of AGEs were found to suppress a substance called SIRT1 in the blood and brain tissue of the mice.
SIRT1 is a deacetylase responsible for regulating neuronal, immune and endocrine function. People with metabolic diseases - such as diabetes - and neurodegenerative diseases tend to have suppressed SIRT1.
Mice with high levels of AGEs were found to develop problems with cognitive and motor abilities. They also had deposits of amyloid-beta in their brains - amino acids crucial to the development of Alzheimer's disease, which form amyloid plaques in the brain.
Furthermore, mice with high AGE levels developed metabolic syndrome, therefore increasing their risk of diabetes and heart disease.
High AGE levels affect humans in similar way
To see how high levels of AGEs affected humans, the researchers carried out a clinical health study of healthy individuals over the age of 60, some of whom had high AGE levels in their blood and some who had low levels.
After monitoring these subjects for 9 months, the investigators found that the subjects with high AGE levels in their blood developed cognitive decline, showed SIRT1 suppression in their blood and demonstrated signs of insulin resistance. Individuals with low AGE levels in their blood remained healthy.
The researchers say their findings suggest that following a diet in non-AGE-rich foods could help stave off Alzheimer's disease and diabetes.
But it is not just a matter of what foods we eat. The cooking method is equally important, according to the researchers.
"The findings point to an easily achievable goal that could reduce the risk of these conditions through the consumption of non-AGE-rich foods," says study author Dr. Helen Vlassara, professor and director of the Division of Experimental Diabetes and Aging in the Brookdale Department of Geriatrics at Mount Sinai.
"For example, foods that are cooked or processed under lower heat levels and in the presence of more water - cooking methods employed for centuries."
"While more research needs to be done to discover the exact connection of food AGEs to metabolic and neurological disorders, the new findings again emphasize the importance of not just what we eat, but also how we prepare what we eat.
By cutting AGEs, we bolster the body's own natural defenses against Alzheimer's disease as well as diabetes."
Medical News Today recently reported on a study suggesting that a daily dose of vitamin E may combat functional decline from Alzheimer's disease.