Type 2 diabetes causes a long list of complications. Research exploring the link between diet and dementia suggests that diabetes and Alzheimer’s disease may have the same root cause—eating too much sugar and refined carbohydrates. The connection has become so convincing that doctors are starting to call Alzheimer’s “type 3 diabetes.”
Insulin resistance in the brain
It’s not a reach to suggest that disrupting the function of insulin by eating processed foods with refined carbohydrates and added sugars can damage your brain, as well as your body. Cells need insulin to draw energy from sugar. Too much sugar results in too much insulin. Overwhelmed by insulin, cells change from being insulin receptive to insulin resistant and eventually you have type 2 diabetes. Can insulin resistance in the brain be type 3 diabetes?
Vicious synergy
Diabetes is a recognized risk factor for a condition called “vascular dementia.” Spurned by cells, excess insulin floods the bloodstream, where it damages blood vessels that supply the brain. According to the Mayo Clinic, many people with cognitive decline have brain changes that are hallmarks of both Alzheimer’s disease and vascular dementia.
Some researchers see a synergy between the two that makes each condition even worse. Healthy brain cells also depend on insulin to absorb glucose. Insulin resistance in these neurons impairs brain function. Eventually, insulin resistance in the brain can cause you to lose your memory, and your mind.
Diabetes and dementia
A recent Japanese study found that people with diabetes are twice as likely to develop Alzheimer’s. Using data from a long-term study of heart disease and stroke, researchers tracked 1,000 people for 15 years after a glucose tolerance test. Compared with those with normal glucose tolerance, people with diabetes were 74 percent more likely to be diagnosed with dementia.
People who were pre-diabetic (impaired glucose tolerance, rather than resistance) when the study started were 35 percent more likely to develop dementia. Alzheimer’s was the most common type of dementia diagnosed in the participants. The diabetics were twice as likely to develop Alzheimer’s. The pre-diabetics were 60 percent more likely to receive the diagnosis.
Insulin and Alzheimers
Alzheimer’s disease is diagnosed when a form of protein called beta amyloid plaque shows up where brain cells used to be. Research at Brown University links insulin resistance in the brain to the formation of beta amyloid plaque. Researchers there working with rats cut their brains off from insulin. The neurons degenerated, the plaque developed and the rodents staggered around, disoriented.
Choice, not fate
It should be good news that developing Alzheimer’s may depend somewhat on personal lifestyle choices, rather than the luck of the draw. It’s within anyone’s power to avoid type 2 diabetes with a healthy diet and regular exercise. The same strategy should work just as well for avoiding type 3 diabetes.
Source: New York Times, Los Angeles Times, Mayo Clinic