Study points to dietary influence on Alzheimer's risk


First the bad news. When I began preparing to write this article I Googled dementia.

One website mentioned that there were 50 kinds of dementia or loss of brain function but that most of them were rare. The most common type is Alzheimer's disease. That website stated that folks over 80 had a 50 percent chance of getting Alzheimer's.

Now for the good news. In the last two years several scientific studies have indicated that diet plays a role in causing Alzheimer's.

If this is true then we may be able to prevent it. Here is list of some of the journals that have had those studies: Archives of Neurology, 2009; Journal of the American Medical Association, 2009; Journal of Alzheimer's Disease-2010, Progress in Lipid Research-2010, Archives of Neurology, 2010; and Physiology and Behavior, 2011.

These studies all served as an encouragement and background for an article that appeared in the June 2011 Archives of Neurology.

For me this was an exciting article because of its novel approach and how it confirmed what I had suspected for years -- that diet had to play a role in the development of Alzheimer's. Part of the reason for my excitement was the author's statement that "to our knowledge, no study has examined the effects of dietary intervention on cerebrospinal fluid (CSF) AD biomarkers."

From my own knowledge of the medical scientific literature I have to agree with the authors.

It appeared the authors felt strongly about their findings also because their conclusion was as follows:

"Our results suggest that diet may be a powerful environmental factor that modulates Alzheimer disease risk through its effects on central nervous system concentrations of AB42, lipoproteins, oxidative stress, and insulin."

This study was done at the Seattle VA Hospital by staff from that hospital and the University of Washington. In this study they took 20 people who were in good health and 29 people with amnestic mild cognitive impairment which has been considered an early symptom of the onset of Alzheimer's.

These folks were fed two different diets. One was a high saturated fat diet with an elevated glycemic index, called the HIGH diet. The second diet was a low saturated fat diet with a low glycemic index, called the LOW diet. The glycemic index is a way to measure how fast certain foods are digested and release glucose (blood sugar) into the bloodstream.

Twenty-four people received the HIGH diet and 25 the LOW diet. Each person had blood tests and a spinal tap to check the CSF before starting the diet. These were repeated in the fourth week of the study. The memory performance of each group was also measured before and after the study.

So what were the results? In the normal individuals the HIGH diet produced substances in the CSF similar to the substances that are found in the CSF of the aCMI people who appear to be headed to full-blown Alzheimer's. The LOW diet, on the other hand, showed beneficial effects in their CSF. The healthy people and the aMCI group showed improved memory with the LOW diet.

Saturated fat comes primarily from animal sources, especially cheese, red meat, butter and whole milk.

In 1970 the average consumption of cheese in the U.S. was 11.7 pounds per year. By 2009 it had gone up to 32.9 pounds per year. In 1950, the total average consumption of chicken, turkey, veal, lamb, pork and beef was 144 pounds. By 2007 it was 222 pounds. In 1850 the average consumption of sugar per person was 5-10 pounds. By 2006 it has risen to about 150 pounds per person per year.

A large portion of that is in pop of one kind or another. And then there are all the sweet deserts and the foods, such as tomato juice, that now come with sugar in them.

However we need to point out there may be other factors that play a role in causing Alzheimer's, although no one seems to know what that they are.

No doubt some folks will want more information about the glycemic index. There are three groups, and here are some examples: low -- 55 or less -- fruits and vegetables, legumes, nuts whole grains; medium -- 56-69 -- whole wheat products, sweet potatos, sucrose (table sugar); and high -- 70 and above -- baked potato, white bread, watermelon, dates.

More complete tables can be found online or obtained from a dietitian or books.

The Alzheimer's study looked at two separate issues dietwise: the effect of levels of saturated fat in the diet and the effect of the levels of the glycemic index.

Most of the articles mentioned above focused on saturated fats, which in my opinion are more important to focus on, in part because of their role in increased risks of other health problems.

Obviously more studies need to be done. Some folks may wonder if Alzheimer's could be reversed by a change in diet. Given the nature of the disease I think that is highly unlikely.

However it may be that if a person with aMCI was fed the low saturated fat-low glycemic index diet it might stop the progression of the disease. You may be sure that if I had a close relative with that condition I would want him or her to try the LOW diet.

Two or three people to whom I had mentioned this exciting news mentioned they had a relative or acquaintance who had "lost their minds" even though they had been raised on a good diet. I reminded them that there are other causes for dementia and perhaps they were in that category.

The folks who conceived and performed this study need to be congratulated. It represents a real step forward. Also the people who consented to be in the study group need to be complimented.

Dr. Don Casebolt of College Place is a retired physician who is passionate about preventive medicine. He spent 4 years as a medical officer in the U.S. Navy, the last 21/2 years as a flight surgeon. He also worked on the Navajo Reservation for 22 years.


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