High-Fat Diet Linked To Alzheimer's Disease

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- July 17, 2000

 

by Edward Edelson

HealthSCOUT Reporter

 

(HealthSCOUT) -- If you're already eating a low-fat, high-fiber diet to protect

your heart, there's a possible bonus, researchers say: It could be preventing

Alzheimer's disease.

The link between diet and the mind-sapping condition comes from a study of a

cholesterol-managing gene, Grace Petot, assistant professor emeritus of

nutrition at Case Western Reserve University School of Medicine, recently told

the World Alzheimer Congress 2000 in Washington, D.C.

 

In a study that looked at older people, her group found that people who carry a

specific version of the gene, called ApoE, and who ate a high-fat diet had a

much higher incidence of Alzheimer's disease.

 

And while the study included only a small number of subjects and does not

provide conclusive evidence, it is one more reason to follow what is now a

standard dietary recommendation, says Bill Thies, vice president of medical and

scientific affairs for the Alzheimer's Association.

 

" It fits in an emerging body of data that suggests that many of the traditional

cardiovascular risk factors are also risk factors for Alzheimer's disease, "

Thies says. " There is no guarantee that taking care of your blood vessels

prevents Alzheimer's disease, but it is a reasonable thing to do. "

 

The ApoE gene produces a protein that is involved in the transportation and

disposal of cholesterol. It comes in three versions, or alleles: e2, e3 and e4.

Each person has two ApoE genes.

 

" You can have one or two copies of the e4 allele, which predisposes to

Alzheimer's disease, " Petot explains. She and her colleagues ran a test for the

gene on 72 persons with Alzheimer's disease and 232 healthy people and came up

with some impressive numbers.

 

" People aged 40 to 59 with the e4 allele who ate diets in which more than 40

percent of the calories came from fat had a 29-fold increased risk of developing

Alzheimer's disease compared to people who ate high-fat diets and had no e4

allele, " she says. " People with the e4 allele whose diets included less than 35

percent of calories from fat had a fourfold risk compared to people without the

allele and who ate a low-fat diet. "

 

If 40 percent of calories from fat sounds excessive, " These people were living

in the 1940s and 1950s, when most Americans had diets high in fat, " Petot says.

" It was only in the 1960s that this diet was associated with heart disease. "

 

Her group is trying to verify the first finding by expanding the study. " We are

continually including more people in the study, " she says. " We now have about

250 cases in all. We haven't looked at the larger numbers yet. "

 

Some supporting evidence appears to be emerging from animal tests, Petot says.

Another study, done at the University of California, San Francisco and presented

at the conference said that transgenic mice given the ApoE e4 allele and fed a

high-fat diet appeared to have developed signs of brain deterioration, she says.

 

And scientists at the University of Wisconsin-Madison say another dietary

factor, the amount of food intake, could also affect brain function. In a mouse

study published in the July issue of the journal Nature Genetics, the Wisconsin

researchers say that a low-calorie diet lowers the activity of genes that

generate free radicals, chemicals that can damage brain cells.

 

Although tests for the ApoE gene are relatively easy to do, it's too early to

recommend their widespread use, Petot says. " There is a lot of controversy about

it, " she says. " And if you have a gene for a condition for which there is no

cure, why tell people to be tested for it? "

 

Whatever the genetics of Alzheimer's disease may be, says Thies, common sense

recommends a prudent lifestyle for just about everyone.

 

" There are some things that probably have consistent value, " he says. " Not

smoking, a lower-fat, high-vegetable diet, exercising, not letting weight get

too high, not drinking excessively, that is pretty good advice even if it

doesn't prevent Alzheimer's disease. "

 

Whatever your genetic makeup, following the basic principles of good diet, good

exercise and moderation in most things will pay off in better health over the

long run. The U.S. Department of Agriculture can help you plan. You can also try

the Alzheimer's Association to learn about the disease.

 

 

 

 

 

 

 

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