Could Grilled Meats Increase Your Risk of Alzheimer’s and Diabetes?

Heat-processed animal products, such as grilled or fried meats, may increase the risk of developing Alzheimer’s disease and diabetes, according to a new study in the Proceedings of the National Academy of Sciences.

“Cooking food, especially meat, at higher temperatures in dry conditions, generates large amounts of advanced glycation end products (AGEs),” says study author Jaime Uribarri, MD, a nephrologist and professor of medicine at Mount Sinai School of Medicine in New York, NY. “AGEs produce inflammation and increase oxidative stress, the two final pathways leading to chronic diseases such as diabetes, cardiovascular disease, renal disease, and Alzheimer’s.”

The body naturally generates AGEs at a small rate, but their formation is markedly enhanced in diabetes and other clinical conditions characterized by high oxidative stress. “When people consume foods rich in AGEs, a percent of these compounds gets absorbed into the body, adding up to the endogenously produced AGEs and eventually leading to disease,” Uribarri explains. “Diabetic and chronic kidney disease patients are at particular risk because they already have high endogenous production of AGEs.”

Uribarri and his colleagues monitored the cognitive health of mice that consumed a high AGE diet, similar to the typical Western diet. High in saturated fats, red meats, and empty carbohydrates, the diet contained little seafood, poultry, whole grains, and fresh fruit and vegetables.

Compared to mice on a low AGE diet, the mice that consumed foods with high levels of AGEs showed many deleterious health effects:

• They had high levels of AGEs in their brains.

• Their blood and brain tissue showed suppressed levels of sirtuin (SIRT1), a key defense against Alzheimer’s disease as well as metabolic syndrome.

• They developed declines in cognitive function and motor ability.

• Their brains had amyloid-beta deposits, a component of the plaques characteristic of Alzheimer’s disease.

• They developed metabolic syndrome, increasing their risk of diabetes and heart disease.

On the other hand, the mice that were fed a low AGE diet remained healthy.

The researchers also looked at how high levels of AGEs affect humans, performing a clinical study of healthy individuals ages 60 and above. Some of the patients had high AGE levels in their blood, and some had low levels. After 9 months of monitoring, the researchers found that the people with high AGE levels showed signs of cognitive decline, SIRT1 suppression, and insulin resistance. Like the mice, humans with low AGE levels in their blood remained healthy.

What can patients do to avoid or reduce this risk?

“A simple and inexpensive way of cooking can significantly decrease your chances of chronic disease without necessarily changing the type of nutrients that you eat,” Uribarri says. “The advice is very clear and simple—change cooking methods to reduce temperature and duration of heat exposure as well as increasing humidity.”

For example, instead of grilling or frying, switch to stewing, steaming, and poaching. “This, together with high intake of fruits and vegetables and avoidance of smoking, will reduce significantly the exposure to exogenous AGEs and, therefore, the risk for chronic diseases,” Uribarri explains.

The researchers are currently studying the effect of an AGE-restricted diet on different markers of metabolic syndrome, a significant precursor of diabetes. “Ideally, long-term application of the low AGE diet to a population at particular risk for Alzheimer’s will allow us to demonstrate whether this way of cooking is really effective in preventing development of this condition,” Uribarri says

For more information, visit www.theage-lessway.com. 

—Colleen Mullarkey

Reference

Cai W, Uribarri J, Zhu L, Chen X, Swamy S, Zhao Z, et al. Oral glycotoxins are a modifiable cause of dementia and the metabolic syndrome in mice and humans. Proc Natl Acad Sci U S A. 2014 Feb 24. [Epub ahead of print].