According to the Alzheimer’s Association, alz.org, this is a question that continues to intrigue researchers and fuel new investigations. There are no clear-cut answers yet — partially due to the need for more large-scale studies in diverse populations — but promising research is under way. The Alzheimer’s Association® is leading the worldwide effort to find a treatment for Alzheimer’s, delay its onset and prevent it from developing.
What causes Alzheimer’s?
Experts agree that in the vast majority of cases, Alzheimer’s, like other common chronic conditions, probably develops as a result of complex interactions among multiple factors, including age, genetics, environment, lifestyle and coexisting medical conditions. Although some risk factors — such as age or genes — cannot be changed, other risk factors — such as high blood pressure and lack of exercise — usually can be changed to help reduce risk. Research in these areas may lead to new ways to detect those at highest risk.
Prevention studies
A small percentage of people with Alzheimer’s disease (less than 1 percent) have an early-onset type associated with genetic mutations. Individuals who have these genetic mutations are guaranteed to develop the disease. An ongoing clinical trial conducted by the Dominantly Inherited Alzheimer Network (DIAN), is testing whether antibodies to beta-amyloid can reduce the accumulation of beta-amyloid plaque in the brains of people with such genetic mutations and thereby reduce, delay or prevent symptoms. Participants in the trial are receiving antibodies (or placebo) before they develop symptoms, and the development of beta-amyloid plaques is being monitored by brain scans and other tests.
Another clinical trial, known as the A4 trial (Anti-Amyloid Treatment in Asymptomatic Alzheimer’s), is testing whether antibodies to beta-amyloid can reduce the risk of Alzheimer’s disease in older people (ages 65 to 85) at high risk for the disease. The A4 trial is being conducted by the Alzheimer’s Disease Cooperative Study.
Though research is still evolving, evidence is strong that people can reduce their risk by making key lifestyle changes, including participating in regular activity and maintaining good heart health. Based on this research, the Alzheimer’s Association offers 10 Ways to Love Your Brain — a collection of tips that can reduce the risk of cognitive decline.
Heart–head connection
Several conditions known to increase the risk of cardiovascular disease — such as high blood pressure, diabetes and high cholesterol — also increase the risk of developing Alzheimer’s. Some autopsy studies show that as many as 80 percent of individuals with Alzheimer’s disease also have cardiovascular disease.
A longstanding question is why some people develop hallmark Alzheimer’s plaques and tangles but do not develop the symptoms of Alzheimer’s. Vascular disease may help researchers eventually find an answer. Some autopsy studies suggest that plaques and tangles may be present in the brain without causing symptoms of cognitive decline unless the brain also shows evidence of vascular disease. More research is needed to better understand the link between vascular health and Alzheimer’s.
Physical exercise and diet
Regular physical exercise may be a beneficial strategy to lower the risk of Alzheimer’s and vascular dementia. Exercise may directly benefit brain cells by increasing blood and oxygen flow in the brain. Because of its known cardiovascular benefits, a medically approved exercise program is a valuable part of any overall wellness plan.
Current evidence suggests that heart-healthy eating may also help protect the brain. Heart-healthy eating includes limiting the intake of sugar and saturated fats and making sure to eat plenty of fruits, vegetables, and whole grains. No one diet is best. Two diets that have been studied and may be beneficial are the DASH (Dietary Approaches to Stop Hypertension) diet and the Mediterranean diet. The DASH diet emphasizes vegetables, fruits and fat-free or low-fat dairy products; includes whole grains, fish, poultry, beans, seeds, nuts and vegetable oils; and limits sodium, sweets, sugary beverages and red meats. A Mediterranean diet includes relatively little red meat and emphasizes whole grains, fruits and vegetables, fish and shellfish, and nuts, olive oil and other healthy fats.
Social connections and intellectual activity
A number of studies indicate that maintaining strong social connections and keeping mentally active as we age might lower the risk of cognitive decline and Alzheimer’s. Experts are not certain about the reason for this association. It may be due to direct mechanisms through which social and mental stimulation strengthen connections between nerve cells in the brain.
- What you can do now
- Physical exercise and diet
- Understanding prevention research