Alzheimer's disease and the insulin resistance

    For years it was hypotethised that there is a link between diabetes and Alzheimer's disease. But, as the latest researches point out, both illnesses got something in common: poor blood sugar management and insulin resistance. Despite the sugar being present in almost everything we eat or drink (yes, even bread, yogurts, cereals, you name it, it is there), our body tolerance for sugar is somewhere around 15-20 grams of single carbohydrates per day. Per day, i said, and keep in mind that just one energy drink with reduced sugar has 24 grams of it. There is also the not so well explained issue about high and low glycaemic index foods. Let's start with this first. 

    The higher the glycaemic index is (do not think only about sugar, the starch also has something to do with this - white bread, white rice, potatoes, baking goods) the larger amounts of insulin our pancreas will secrete into the bloodstream, to lower the blood sugar. If this happen too often, our cells will start to resist to the insulin signalling too much blood sugar, in the same way you got used in a very noisy environment (eventually). The noise is there (blood sugar in our case), but   you stop reacting too it. And a high level of blood sugar is damaging our body in so many ways. (Find more about this in this article).

    Well known effects of the insulin resistance are type 2 diabetes, fatty liver, metabolic syndrome, but also AD (Alzheimer's disease). There are many pathways that are affected by the insulin resistance. To start with the insulin binding to the insulin receptors, triggering the survival of the neurons, you can only imagine what will happen if this trigger is drastically decreased by the high insulin levels, present most of the time in our bloodstream. Another way to mess up with our nervous system is via the insulin-degrading enzyme (IDE) used to get rid on the insulin, but, surprise, also used to get rid of the amyloid beta (one of the main issues in AD). Because, as we know already, higher levels of amyloid-beta equals full blown AD. 

    As the insulin resistance is just a result, the cause being chronically high blood sugar levels, let's see how this is wreaking havoc in our body. The glucose can attack easily to many proteins, interfering with their usual functions. The common blood test to check diabetes called HbA1c is measuring one of these overused proteins - hemoglobins changed to produce advanced glycation end products (AGE). As these proteins trigger our immune system, raising inflammation (one of the risk factors in AD), they are also binding to their own receptor (AGE receptors of RAGE), triggering inflammation even further. Shall we add to the list? Yes, there is more, AGE molecules form free radicals, which in turn can damage almost anything they touch, even DNA and any cell membranes. The additionally damage the blood vessels (less nutrients to go to the brain) and negatively alter the blood-brain barrier. 

    The main blood tests to monitor these risk factors are fasting insulin level (ideally 4.5 microIU/ml or less), the HbA1c test (ideally under 5.6%) and the fasting glucose ( ideally between 70-90 mg/dl, but not more than that). 

    How you manage this? Learning about diabetes management is a good idea, as everything that is recommended for a type 2 diabetes, it will also work for healthy individuals or pre-diabetes condition. 

Next issue to tackle will be inflammation, as i started to explain a bit of its mechanisms today.