How High Blood Sugar Shortens Your Life: Part Three: Alzheimer’s disease

James Meschino DC, MS, ROHP
There is a great deal of evidence to show that high blood sugar is a major contributing factor to the development of Alzheimer’s disease. Although it’s not the only factor that causes Alzheimer’s disease, the increasing number of individuals with high blood sugar is now making it a very prevalent cause of the problem. The good news is that, unlike genetic inheritance, high blood sugar is a modifiable risk factor, which means there is something we can do for ourselves to eliminate the risk. This of course, involves more prudent diet, physical activity, remaining at one’s ideal body weight and minimizing the impact of stress (see two previous High Blood Sugar articles for details)

How Do We Know High Blood Sugar Causes Alzheimer’s disease?
It is well established that individuals with type 2 diabetes have twice the risk of developing Alzheimer’s than non diabetic patients.Insulin-dependent diabetics have four times the risk.One reason for this is explained by the fact that there is an enzyme in the brain that breaks down both insulin and amyloid plaque – a hallmark feature of Alzheimer’s disease. Thus, in cases where insulin levels are high, which occurs when blood sugar is too high, the brain enzyme is so busy breaking down insulin that it allows amyloid plaque to build up. High levels of amyloid plaque (a protein known also as beta-amyloid protein) sort of strangles brain cells from the outside and generates copious amounts of free radicals – which further damages brain cell structure and function.

High blood sugar also increases brain inflammation, which contributes to Alzheimer’s disease development (2). As well, Alzheimer’s brains demonstrate insulin resistance, which is triggered by sustained high blood sugar levels (3).

Evidence shows that hyperglycemia (high blood sugar) speeds up aging in general, including brain aging. In fact, structural brain differences often occur in patients with both type I and II diabetes that resemble those of non-diabetic patients, who are over 80 years of age. So, having high blood sugar is a good way to develop an 85-year old brain at a young age. Common structural brain changes include shrinkage (atrophy) of the hippocampus and the amygdala – two important brain areas that shrink in Alzheimer’s disease.

We also know that patients with uncontrolled type II diabetes have worse cognitiveand memory functions, as do patients exhibiting more diabetic complications (indicating poorer blood sugar control). Alzheimer’s disease is also the cause of dementia in 82.5-91% of type II diabetics – which is greater than the general population (1).

It’s also worth noting that you don’t have to be a diabetic to have brain damage and risk of Alzheimer’s disease,from high blood sugar. Studies show that simply being  aprediabetic is sufficient to damage your brain and increase your risk. This involves having a fasting blood sugar above 5.6 mmol/L (100 mg/dL) (2).

The bottom line is that blood sugar control is an important part of preventing Alzheimer’s disease. From the standpoint of longevity and a disease-free, highly functional life, the best fasting blood sugar to achieve is a reading at or below 5 mmol/L (90 mg/dL). Make that one of your life long goals, and have your physician track your fasting blood sugar (glucose) as part of your annual physical exam (and ask to see the number).

References:

1. http://www.psychologytoday.com/blog/evolutionary-psychiatry/201109/alzheimers-and-high-blood-sugar
2. http://www.alz.org/national/documents/latino_brochure_diabetes.pdf
3. http://www.jci.org/articles/view/59903