This week, our class discussed the detrimental effects of insulin resistance as seen in Type 2 diabetes mellitus. It has been established that Type 2 diabetes can be seen as a cofactor in the development of Alzheimer’s disease (AD). The defining characteristic of Type 2 diabetes is the body’s resistance to the effects of insulin. This differs from Type 1 diabetes mellitus in which insulin is simply not being produced, but can metabolized injected insulin without a problem. Insulin resistance makes it difficult for the body to perform insulin-mediated functions such as metabolism and regulation of other cellular processes. Like many people, I was unaware insulin played such a huge part in the brain. Recently, it has been established that insulin is involved in neuronal metabolism, cell survival, longevity, and learning and memory. This connection to learning and memory has led to research to determine insulin’s role in Alzheimer’s disease. The specific death of the cells in the brain’s memory center, called the hippocampus, leads to forgetfulness and inhibition of memory formation seen in Alzheimer’s disease. Insulin resistance facilitates this cell death through loss of intracellular transport of important nutrients, wastes, and other molecules.
The toxic β-amyloid plaques, typically seen in Alzheimer’s disease, can further decrease insulin activity by binding to insulin receptors. Neuronal insulin resistance contributes to the formation of these plaques as the enzyme that degrades both insulin and β-amyloid must work to degrade increased levels of both insulin resistance prevents the normal use and breakdown of insulin. This means that the same amount of enzyme would be responsible for the breakdown of an increasing amount of target molecules, which it is not intended to do.
So what does this mean for the population at large? Well, Type 2 diabetes can be caused by genetics, but also by poor diet (which causes obesity). With the obesity epidemic as of late, it is generally expected that frequency of Alzheimer’s disease will skyrocket in the coming years. As a society, the need for a quick fix has propagated and exacerbated the consumption of fast foods. This worsening in diet, along with people becoming more sedentary, has led to increasing obesity and also increased frequency of Type 2 diabetes. We should be concerned with this increased risk, per the previous discussion. It is difficult and expensive to maintain a healthy diet, but do a couple hours per day to make healthy food and exercise outweigh years of cognitive decline that will impact your family and your own quality of life? We, as a society, must change so as to be more conscious of our current health because it dictates our condition in the future. Stop spending so much on unnecessary things like multiple big televisions, movies you don’t need, or the up-and-coming Xbox One. Use your resources to enable your own well being as well as those for whom you are responsible. The benefits of a healthier lifestyle are plentiful and include more energy, more efficient cognition, and increased immune system function. The costs of not doing so are equally abundant and just as dire.