Q30. Are there any steps I can take to lower my risk of developing Alzheimer disease? My mother was diagnosed with Alzheimer disease and both of her parents had dementia.
A30. The identification of what can be done to prevent Alzheimer disease is in its infancy. Such studies are very difficult to carry out because they require having thousands of people do a certain activity, follow a specific diet, take a specific medication, or follow a specific lifestyle for many years. There is, however, strong indirect evidence that the following actions can lessen risk:
Many of these have been proven to decrease stroke, heart attack, and vascular disease. This further supports the link between brain vascular disease and Alzheimer disease.
Q31. Do computer games, crossword puzzles, Sudoku, or cognitive training prevent Alzheimer disease?
A31. There is no evidence that such activities prevent the development of Alzheimer disease or dementia. A few studies have found that people can improve their performance on these specific activities with repeated practice, and that this benefit lasts for as long as 10 years. This training may lessen the cognitive changes that accompany normal aging.
Q32. Are there diets, vitamins, or other foods that can prevent dementia?
A32. Diets or diseases that cause deficiencies of vitamins B1, B6, and B12 can cause cognitive impairment. A well-balanced diet is enough to ensure adequate intake of B1 and B6, but some people develop an inability to absorb vitamin B12, and low levels of vitamin B12 can cause dementia. For that reason, anyone developing memory or cognitive decline should be tested for B12 deficiency, even though it is an uncommon cause of dementia.
There is some evidence that a “Mediterranean diet,” a diet in which red meat intake is low, vegetables, fruits, and nuts are eaten regularly, and olive oil replaces other fats, can lessen the cognitive declines that accompany normal aging. This does not mean that this diet lowers the risk of Alzheimer disease, however.
In my opinion there is no convincing evidence that antioxidant foods, omega-3 fatty acids, nuts, a ketogenic diet, a Mediterranean diet, supplements formulated to enhance memory, or a low-salt diet prevent Alzheimer disease. Some of these may have other health benefits, however. I also know of no evidence that ginkgo biloba, turmeric, jellyfish protein, or coconut oil prevent Alzheimer disease.
Some studies have shown that regular, modest intake of red wine is associated with a lower risk of dementia. However, a recent analysis of all studies that have examined potential health benefits of alcohol found no such association.
Q33. Does Alzheimer disease vary in frequency by country? Rural/urban populations? Gender?
A33. By and large, Alzheimer disease has been found to occur with the same frequency at any given age throughout the world. There are a few exceptions, but these tend to be in groups or places in which it is unusual to live to a late age. However, most studies comparing different populations rely on diagnoses made by researchers or doctors, not on autopsy-confirmed diagnoses. For this reason, I consider the final answer to your first 2 questions to be unknown.
Most experts now agree that women are at greater risk of developing Alzheimer disease than men, even after correcting for the fact that women have a longer life expectancy than men. The reason or reasons for this are not known.
Q34. What influence does diabetes have on developing Alzheimer disease?
A34. People with diabetes are at higher risk of developing dementia, but the specific cause or causes of this increase are not clear. One possibility is that diabetes increases the risk of developing vascular dementia. Another is that diabetes directly causes dysfunction and death of brain cells. So far, there is no evidence that better control of diabetes lowers the risk of developing dementia.
Q35. Do you really think it will be possible to prevent Alzheimer disease when it seems that everyone in their 90s has evidence of the disease in their brains? Doesn’t that imply that we will all get the disease if we live long enough?
A35. Yes, I do think it will be possible to prevent Alzheimer disease, or at least to significantly lower people’s risk for developing it. One strategy that could accomplish this is to delay its onset for so long that most people will die from some other cause before they develop Alzheimer disease.
Several pieces of data lead me to be optimistic. First is the finding that the abnormal proteins characteristic of Alzheimer disease are present in the brain years before the first symptoms of dementia appear. This suggests that the body has some innate ability to fight off the disease, but that these protective mechanisms become overwhelmed over time. It also raises the possibility that very early recognition of amyloid or tau deposition could indicate when to start treatment and thereby prevent symptoms from ever developing.
Second, several well-designed studies have found that the rate of onset of dementia (“incidence rate” is the technical term) has declined in the past decade. A combination of the following is thought to account for this decline: better treatment of high blood pressure and high blood lipids; declining rates of stroke; greater participation in exercise; lowered intake of red meat and other foods that increase the risk for arteriosclerosis; and the prevention of heart attacks and strokes by using stents and medications.
A third reason for optimism is that Alzheimer disease probably has multiple, interacting environmental and genetic causes. This raises the possibility that a combination of the following approaches might further lower the risk of developing the disease: additional small improvements in exercise, diet, and lowering of cardiovascular risk factors; the development of treatments that decrease the deposition of abnormal proteins in the brain; the stimulation of new connections among brain nerve cells and pathways; and the formation of new brain cells in areas vulnerable to cell death related to Alzheimer disease.
Finally, the identification of genetic risk factors raises the possibility that we will be able to target preventive treatments to those who are genetically at increased risk of Alzheimer disease, and, thus, improve the likelihood of an individual’s benefiting from a preventive intervention.
Q36. Why hasn’t more progress been made in coming up with a cure for Alzheimer disease?
A36. Several very challenging mysteries related to Alzheimer disease are yet to be solved. First, even though there is strong evidence that abnormal protein deposition begins 15 to 20 years before the first symptoms appear, it is not known what starts this process. Identifying this trigger would greatly aid the search for effective treatments.
Second, it is not yet clear how to detect these very early brain changes. This will be crucial, since any preventative or “curative” drug or drugs will need to be started when the brain degeneration first begins, if not before.
Third, most parts of the brain are not able to make new brain cells. As a result, even if the disease could be stopped in its tracks, replacement brain cells would not form on their own in most brain areas. One exception is the hippocampus, in which new brain cells do develop throughout life. Treatments that begin before the disease moves out of the hippocampus might allow new cells to form and replace those that have died. It will still be a challenge for these new cells to connect correctly to cells in other areas of the brain.