A diet high in cholesterol probably contributes to the onset of Alzheimer's. In a study conducted on rabbits, it became clear that when drinking water containing copper is added to it, the symptoms typical of Alzheimer's worsen
Cholesterol's involvement in arteriosclerosis and increasing the risk of cardiovascular diseases has been known for a long time. The market for drugs that lower cholesterol levels makes huge turnovers, reaching billions of dollars a year. In recent years, evidence has been accumulating that cholesterol also contributes to the development of Alzheimer's and that drugs that lower cholesterol levels may affect the progression of the disease.
This week new information was added. According to experiments in rabbits, a high-cholesterol diet and water containing tiny amounts of copper significantly worsen the accumulation of beta-amyloid deposits in the brain, similar to what happens in Alzheimer's disease. The study, which received early online publication, will appear in one of the upcoming issues of the journal The(PNAS) Sciences. National Academy of Proceedings of It is not yet clear whether the results in rabbits reflect what happens in humans. If the results are confirmed in humans, it may be possible to slow the progression of Alzheimer's disease by lowering blood cholesterol levels and reducing the amount of copper in drinking water.
The first to discover the link between cholesterol and Alzheimer's was the pathologist Larry Sparks from the University of Kentucky in the USA. About ten years ago he noticed that in 70% of the autopsies after death of patients who died of heart disease, aggregates of the protein beta amyloid were found in the brain. In patients who died of other diseases, no such findings were found. .
Additional studies have confirmed the link between cholesterol and Alzheimer's. Two years ago, epidemiological studies were published in which it was tested whether drugs called statins, which are used to lower the cholesterol level in heart patients, also affect the risk of Alzheimer's disease. The studies were conducted on different populations, in medical centers in the USA and the UK, and included information from many patients. They showed that the incidence of Alzheimer's disease in the patients who took statins decreased by 70% compared to control groups. Studies in cell cultures and animals confirmed that statins do protect against Alzheimer's, probably because They block the creation of cholesterol in the body.
Sparks continued to investigate and found that when he fed rabbits a high-cholesterol diet, they developed beta amyloid aggregates in the brain and other pathological symptoms similar to Alzheimer's disease. When Sparks lowered the cholesterol level in his diet, the number of beta amyloid aggregates also decreased. Other studies have also confirmed the findings in guinea pigs and transgenic laboratory mice that develop beta amyloid clusters in the brain similar to Alzheimer's disease in humans. Preliminary results in Alzheimer's patients suggest that statins lower the level of beta amyloid in the blood, but it is not yet clear how they affect the brain.
A strange thing happened last year. Two research groups that fed rabbits of the same strain the same high-cholesterol diet got different results. In both experiments, the high-cholesterol diet increased the accumulation of beta-amyloid deposits in the nerve cells in the rabbits' brains, creating deposits there similar to those that accumulate in the brains of Alzheimer's patients. But in one group the amount of sediment accumulated in the brains of the rabbits was immeasurably greater compared to the other group, led by Sparks.
An examination revealed that in Sparks' group the rats drank distilled water while in the other group they were watered with tap water. Several components in the tap water could have caused the difference between the two groups. Most of the "suspects" were metals, and Sparks decided to test the effects of one of them - copper. He added copper to distilled water, at a rate of one-tenth of the maximum amount allowed in drinking water in the United States, and gave this water to the rabbits that were fed a high-cholesterol diet. In addition to this group, two control groups participated in the experiment: in one of them, there were rabbits that were fed a high-cholesterol diet and drank distilled water that was not in which copper; in the second group there were rabbits that were fed a diet that did not include cholesterol and drank normal water, containing copper.
In the brains of the rabbits that were fed a cholesterol-free diet and drank plain water, no noteworthy change occurred. In the brains of the rabbits that were fed a high-cholesterol diet and drank distilled water without copper, deposits of the beta-amyloid protein appeared in many nerve cells. This also happened in rabbits that were fed a high-cholesterol diet and drank water that contained copper; However, in this group the number of nerve cells that produced beta amyloid was greater by 50%. Also, in the rabbits from the Sparks test group, the deposits were organized in structures similar to the beta amyloid clusters known in Alzheimer's disease and the affected areas were the areas involved in Alzheimer's. An even more significant finding was that in the rabbits that were fed a high cholesterol diet and drank water that contained copper, a sharp decrease in learning ability and the ability to perform complex functions was found. This decrease was not recorded in the rabbits from the control groups.
Analyzing the findings, the researchers write: "We hypothesize that in the rabbits that were fed a high-cholesterol diet, the cholesterol that entered the brain through the bloodstream stimulated the accumulation of beta-amyloid deposits, and the copper affects (preventing) the elimination of beta-amyloid from the brain..."
Alzheimer's researchers meanwhile are careful not to point out a certain connection between the findings and Alzheimer's disease. They emphasize that for this purpose the effect of copper must first be carefully tested in a special strain of mice that serves as a model for the human disease. "The findings make theoretical sense, but to verify this in humans, epidemiological studies must be conducted," says Prof. Danny Michaelson from Tel Aviv University, who studies Alzheimer's disease.
"The main importance of the research is in opening a new research direction, which may allow treatment of patients or assistance to them. It raises the idea that if we lower the level of copper in food or drink to a certain extent, we may be able to slow down the rate of Alzheimer's development. The challenge now is to prove in humans that such a thing can be effective."
