People with diabetes have a higher risk of dementia. But could dementia actually be a type of diabetes?
Some researchers say yes. The disease affecting millions of Americans -- Alzheimer's -- is actually "type 3" diabetes, not a separate condition, some say.
In clinical practice today, there are three types of diabetes: type 1, which has no known cause or cure and is typically diagnosed in childhood; type 2, called the "lifestyle" diabetes, though it is also caused by ethnicity and family history; and gestational, which strikes pregnant women and in 90% of cases goes away after women give birth.
But as food writer and health advocate Mark Bittman writes in a recent New York Times op-ed, the idea that Alzheimer's is actually just another form of diet-induced diabetes was introduced in '05 by neuropathologist and professor at Brown Medical School, Suzanne de la Monte, MD, MPH. In her research, de la Monte demonstrated levels of insulin and its receptors diminish significantly in the brain during early Alzheimer's -- and this trend continues as the disease progresses.
And many of the unexplained features of Alzheimer's, such as cell death and tangles in the brain, appear to be linked to abnormalities in insulin signaling. This demonstrates the disease is most likely a neuroendocrine disorder, or another type of diabetes," she wrote in a press release when the study was published in the Journal of Alzheimer's Disease.
The "why" makes sense once you know how insulin works. Insulin is how your body regulates blood sugar -- it prompts cells to pick up sugar from your blood and use that sugar as energy. When you eat a high-fat, high-sugar diet (as many Americans do), the cells are overwhelmed by all the sugar and stop reacting well to insulin. This is called insulin resistance, a condition that if left untreated, leads to type 2 diabetes.
All the sugar that's left in your blood stream by insulin resistance then wreaks havoc over the rest of your body, causing heart disease, nerve damage, eye damage, and more. When this damage reaches your brain cells, you lose memory function and become disoriented. Or in other words, some researchers say, you develop Alzheimer's.
Alzheimer's and diabetes rates are both on the rise. And as the population ages, Alzheimer's disease rates will "escalate rapidly in coming years," the Alzheimer's Association reports. It's believed that Alzheimer's is brought on by a combination of genetics, environmental, and lifestyle factors -- but the type 3 diabetes idea adds new credence to the suggestion that diet and exercise, more than any other factor, can prevent Alzheimer's.
The omega-3 fatty acids found in fish, walnuts, and flaxseed have been shown to decrease risk of cognitive decline, as have the antioxidants in fruits, vegetables, and tea -- foods that have all been shown to help prevent type 2 diabetes. The answer, healthy eating advocates like Bittman say, is adopting a "sane" diet full of plants, and low in saturated fat and sugar to head off cognitive decline, diabetes, and the host of negative side effects that come with.