Alzheimer’s and Eggs

Functions in the brain such as memory occur by large groups of neurons or nerve cells sending messages to each other.  They do this by sending a chemical signal called a neurotransmitter across the gap between each pair of neurons.  The neurotransmitter in the brain’s pathways that are affected first in Alzheimer’s Disease is acetylcholine and the levels of it begin to drop early or even prior to the disease process resulting in the onset of symptoms.

One of only two drugs approved to treat the disease, Aricept, attempts to delay the progression of the disease by propping up acetylcholine levels.  It does so by inhibiting the enzyme cholinesterase which eventually breaks unused acetylcholine down. 

An important question should be, why is too little acetylcholine present in the first place?  It seems that a growing deficiency of one of the primary ingredients, choline, is often the problem.  The predominant source of choline in the western diet had always been eggs.  The same eggs that became “evil” in the 1960’s as the cause of heart disease was an idea now known to have been based on some highly biased research. Two eggs, the breakfast of many up until that time, provided about 300 mgs of choline.  This is in contrast to other high choline sources such as chicken and meat which supply about 150 mgs.

The recommended daily intake of choline is 450-550 mgs/day so dropping out the important source of 300 mgs of it is problematic.  More problematic was that the rationale for avoiding those “dangerous eggs” has proven to be in error. 

Dr. Steven Nissen, chairman of cardiovascular medicine at the Cleveland Clinic, told CNN announcing the major cardiology professional associations new stance on dietary cholesterol: “The idea we need to limit saturated fat and cholesterol shifted Americans from a well-balanced diet to high-sugar diets, which made people eat more and get fatter.”  What he did not comment on, perhaps because it was out of his research area, was that this same cholesterol phobia may have contributed a piece to the growing epidemic of Alzheimer’s disease over that 60-year period.

So how could we have gotten so far off the accurate course with cholesterol?  It all goes back to a biased study published by a scientist, Ansil Keys.  Dr. Keys published a study in which he claimed to look at all of the previous epidemiological studies that looked at diet content and the relationship to heart disease risk.  Specifically, he compared the low-fat/high-carbohydrate diet to the higher-fat/low-carbohydrate diet.  His conclusion was that the 6 studies found all supported the risk reduction with the low-fat/high-carbohydrate diet as more cardio-protective.

Over 50 years later after several new studies fairly uniformly demonstrated that the lower carbohydrate diet actually reduced cardiovascular risk factors more so than the commonly used low-fat diet, another researcher decided to go back and revisit Dr. Keys’ data.

While Keys reported that all 6 available studies led to his conclusion, there were actually 21 studies available in his review.  He selectively used only the 6 that supported his preconceived conclusion.  When the total 21 studies were included in the re-analysis, the opposite conclusion was obvious.

This kind of study bias rarely occurs today as many safeguards have been built into the pre-publication review process, safeguards that did not exist 60 some years ago.

If the above is not enough to make you regret that Dr. Keys ever got involved in food science, he contributed another piece of our current food problems, inventing processed food.  The first was the K-ration, a highly processed meal that could be stored and transported over a longtime interval without spoiling. 

Once WW II ended this new technology was without a user so the natural thing to do was to roll it into everyday food production.  In fairness to Dr. Keys on this one, he was just doing his job for the DOD probably not knowing it would become the basis of the production of some of our least nutritious food today.

Back to our original discussion, eggs have appeared to always play a role in our brain health given their potent choline content.  A key component of the Bredesen Protocol for Alzheimer’s disease is that it removes the added sugars and highly processed carbohydrates from the diet that so many “enjoy”.  If there is a trade-off it may be that one could get 2 things in exchange, their eggs back and a healthier, better functioning brain.