Junk Food and Alzheimer's - Yet Another Link to Diet

This very interesting article was recently passed on to me and I thought it was worth a share.  It explores the potential link between junk food (synonymous with high fructose corn syrup and unhealthy fats) and Alzheimer's Disease/dementia (AD). 

There has been a lot of research done in the area of insulin and AD, focusing on AD as primarily a metabolic disease.  These studies have shown that insulin and insulin-like growth factors are lower in the brains of people who died with AD compared to those that did not.  So why is insulin so important?  It is a hormone produced by the pancreas to prod the liver, muscles and fat tissues to absorb glucose (sugar) from the blood.  Following that logic, type 2 diabetes occurs in people who develop insulin resistance resulting in extremely high blood glucose levels that become toxic.  Researchers who examine AD as a metabolic disease believe AD may be the next type 3 diabetes.

The link between AD and insulin is still tenuous (it also begs the question, why does it manifest itself as dementia and why in people over the age of 65?).  Other research has shown abnormal cerebrospinal fluid insulin levels among people with the e4 protein variant of ApoE.  ApoE is a protein that helps carry lipids (fats) to the brain.  There are different variants of this protein (depending on the allele of the gene you carry) and people who carry the e4 variant are at a much higher risk of dementia.  In fact, ApoE4 is one of the few genetic risk factors linked to late-onset AD which is the form of AD that affects most people.

Research into AD as a metabolic disease is extremely complex, but there is clearly something to be said about diet and dementia.  There have been a plethora of articles about a healthy Mediterranean diet and lower risk of AD (see blog post Top Three Ways to Keep Your Brain Healthy).  This is true for most chronic diseases.  A diet high in saturated fats and trans fatty acid, as is the case with most junk food, has been linked to increased risk of diabetes, cardiovascular disease and potentially cancer.  So while there is no conclusive evidence that junk food causes dementia, there is certainly a link between unhealthy food and dementia.  The next ten to twenty years will be interesting  from a research perspective not only because of potential breakthroughs, but also because we can really start to see the long-term effects of our dietary decisions.