Contributed by Dr. Amy Whittington, Trilogy’s Naturopathic Physician

Diabetes has become the most prevalent disease in this country. Chances are very good that you or a loved one have been diagnosed with this affliction (most commonly Type II), which often occurs as result of a combination of genetic predisposition and lifestyle. We have long associated diabetes with cardiovascular disease, neuropathy, and generalized inflammation, but more recent research has linked diabetes to a disease that is perhaps even more ominous… Alzheimer’s disease. Shockingly, Alzheimer’s is now the 6th leading cause of death in this country. This new association has been titled “Type III diabetes” and perhaps sheds light on the development of Alzheimer’s for many patients, but more importantly, it could eventually help us understand how we might prevent this horrible disease.

Historically, we have categorized diabetes into two general types. Type I generally begins in childhood or early adulthood and involves an autoimmune attack on the cells of the pancreas responsible for producing insulin. Type I diabetics must take insulin for the rest of their lives. Type II occurs with insulin resistance, a phenomenon where there is plenty of insulin in the bloodstream, but the cells will no longer take it in. This is usually due to years of overexposure: high sugar intake leads to high insulin output, and eventually the cells get so used to the high amount of insulin that they no longer respond to its request to enter. Type II diabetics are often prescribed medications to try to re-sensitize insulin receptors, like Metformin. We now also categorize a Type 1.5, which is also the result of an attack on the pancreas, but it occurs later in life. Type 1.5 diabetics often also require insulin. And now, it is proposed, we also have Type III.

Type III diabetes is most like Type II in that the primary issue is with insulin resistance. It is thought to occur when there is a lack of insulin in the brain. Remember that with insulin resistance there is more than enough insulin in the blood stream, but that insulin is not making it to the cells or tissues. In the case of the brain, insulin is unable to cross what is known as the blood/brain barrier due to a generalized resistance of the cells. (A recent article of mine was completely devoted to insulin and can be found in the archives of your community site.)

But, where does Alzheimer’s fit into this picture? In recent years, a neuropathologist at Brown University noticed that when she blocked the path of insulin to the brains of rats, their neurons deteriorated, they became physically disoriented, and their brains showed signs of Alzheimer’s. In fact, the rats developed deposits in their brain tissue very similar to the beta amyloid proteins which are often found in autopsies of Alzheimer’s victims. Although we have long associated the accumulation of these amyloid proteins in the brain with Alzheimer’s, the reason that they accumulate has always been a mystery.

And, although the link between a lack of insulin and amyloid production is still an enigma, it is easy to postulate what a decrease in insulin might do to the function of the brain. Like every organ, the brain needs insulin to carry glucose from the blood stream into the tissues so it has adequate fuel to perform its functions. Without fuel, our brains cannot produce the neurochemicals necessary for cell communication, because, in effect, the brain is starving. Furthermore, the high insulin levels on the inside of the bloodstream damage small blood vessels in the brain and lead to poor circulation, likely contributing to dementia-type symptoms.

It has been known for some time that people with Type II diabetes have about twice the likelihood of developing Alzheimer’s disease, but the idea that the association could be directly linked to insulin resistance is new. Furthering a possibility of a connection, it has also been shown that insulin given in an intranasal form to some Alzheimer’s patients can decrease dementia-type behavior and improve cognition. The intranasal route helps insulin get into the brain without having to penetrate the blood-brain barrier, by traveling through nerve channels connecting nasal passages to the brain. The result: when the brain is exposed once again to insulin, Alzheimer’s symptoms improve, which supports the theory of Type III diabetes.

There are still many unanswered questions, however, such as why some diabetics develop this complication and others don’t. Possible contributors are genetics, lifestyle, and environmental exposures. Conversely, there are also some Alzheimer’s patients that never show any other signs or symptoms of diabetes: are they somehow developing insulin resistance only in the brain, or are there additional causes of Alzheimer’s that are unrelated to insulin?

With the plethora of unknowns, it is clear that further research should occur to further associate these two afflictions. The bright side of the possibility of Type III diabetes is that it lends hope for treatment, or even better, prevention, of what has been the devastating and untreatable Alzheimer’s disease. The most obvious change that can be made in the healthcare industry, even as we wait for more information, is for those with symptoms and those at high risk for Alzheimer’s due to family history to begin preventive measures as if they are a Type II diabetic.

As with any disease of blood sugar disturbance, patients should be monitored for fasting blood sugar (glucose), fasting insulin, and the long-term blood sugar marker hemoglobin a1c, to ensure that no evidence of insulin resistance is mounting. Lifestyle adjustments including weight loss and exercise should be initiated. Diets should be low in sugar, and high in fiber (legumes, fruits and vegetables) and high in good fats (olive oil, avocados, salmon). Additives such as high fructose corn syrup (in soda, salad dressings, and sauces) and nitrosamines (in hot dogs and other processed meats) have been linked to the development of insulin resistance and should be avoided. And don’t make the mistake of adding sugar substitutes into your diet, as they too can increase insulin resistance. Many herbs and nutrients can also be prescribed to help re-sensitize insulin receptors and can slow, prevent, and sometimes reverse resistance. The possibility of Type III diabetes also signifies the importance of properly managing Type II with medications when necessary.

It is disconcerting that one of our most heartbreaking and incurable diseases could be associated with another affliction that is increasing quickly in numbers. But if there is a silver lining, it is the hope that for at least some people, we might eventually be able to prevent or treat Alzheimer’s.
Stay healthy & be well!

– Amy Whittington, NMD