Diabetes significantly increases the risk of Alzheimer's disease, highlighting the urgent need to understand this concerning link. A new study conducted on mice provides insights into this complex puzzle, adding to a growing body of research on the connections between type 2 diabetes and Alzheimer's, which some scientists have dubbed "type 3 diabetes" or "brain diabetes." The findings suggest that the risk of developing Alzheimer's can potentially be reduced by managing diabetes well or avoiding it in the first place, according to the researchers.
Study leader Narendra Kumar, an associate professor at Texas A&M University in College Station, stated, "We believe that diabetes and Alzheimer's are strongly linked, and by taking preventive or mitigative measures for diabetes, we can prevent or at least slow the onset of dementia symptoms in Alzheimer's." Both diabetes and Alzheimer's are rapidly growing health concerns worldwide, with diabetes affecting the body’s ability to convert food into energy, while Alzheimer's is defined as a form of dementia that causes a gradual decline in memory and thinking skills.
It is known that diet impacts the development of diabetes as well as the severity of its health effects. To understand how diet may affect the development of Alzheimer's in diabetic patients, researchers tracked how a specific protein in the gut affected the brain. They found that a high-fat diet suppressed the expression of a protein named Jak3 (an enzyme crucial in how cells communicate, particularly within the immune system), and mice lacking this protein experienced a series of inflammation that started in the gut, traveled through the liver to the brain. Ultimately, the mice showed symptoms resembling Alzheimer's disease in the brain, including increased beta-amyloid secretion and hyperphosphorylated tau, along with evidence of cognitive impairment.
Kumar noted, "Since the liver is the metabolizer of everything we eat, we believe that the pathway from the gut to the brain goes through the liver." He added that his lab has been studying Jak3 functionalities for a long time, and they now know that the impact of food on changes in Jak3 expression leads to leaky gut (a condition where the lining of the small intestine is damaged), which in turn results in chronic low-grade inflammation, diabetes, and a reduced brain ability to clear toxins leading to dementia-like symptoms seen in Alzheimer's.
The good news, according to Kumar, is that it may be possible to halt this inflammatory pathway by adopting a healthy diet and controlling blood sugar levels as early as possible. In particular, individuals with prediabetes may benefit from lifestyle changes to prevent the progression to type 2 diabetes, potentially reducing the risk of developing Alzheimer's.
