Researchers around the globe are exploring how to prevent Alzheimer's. While Alzheimer's prevention has no definitive answers at this time, research has shown that we can take action to reduce our risk of developing it.
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.
A small percentage of people with Alzheimer’s disease (less than 1%) 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 Alzheimer's 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.
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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% 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 to lowering the risk of Alzheimer's are the DASH (Dietary Approaches to Stop Hypertension) diet and the Mediterranean diet.
- The DASH diet emphasizes vegetables, fruits, fat-free or low-fat dairy products, whole grains, fish, poultry, beans, seeds, nuts and vegetable oils. The DASH diet limits sodium, sweets, sugary beverages and red meats.
- A Mediterranean diet includes relatively little red meat. It emphasizes whole grains, fruits and vegetables, fish and shellfish, and healthy fats like nuts and olive oil.
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.
There appears to be a strong link between future risk of cognitive decline and serious head trauma, especially when injury involves loss of consciousness. You can help reduce your risk of Alzheimer's and protect your head by:
- Wearing a seat belt.
- Using a helmet when participating in sports.
- "Fall-proofing" your home by minimizing clutter, loose rugs and poor lighting.
What you can do now
While research is not yet conclusive — partially due to the need for more large-scale studies in diverse populations — certain lifestyle choices, such as physical activity and diet, may help support brain health and prevent Alzheimer's. Many of these lifestyle changes have been shown to lower the risk of other diseases, like heart disease and diabetes, which have been linked to Alzheimer's. With few drawbacks and plenty of known benefits, healthy lifestyle choices can improve your health and possibly protect your brain.
In addition, taking care of your health now may help improve your outcomes in the long term, such as reducing your risk for Alzheimer's and dementia. Research released at the Alzheimer's Association International Conference 2020 suggests flu and pneumonia vaccination—especially multiple vaccinations over time—is associated with a lower risk of Alzheimer’s in later life. While it is too early to tell if getting a flu vaccination on its own can reduce risk of Alzheimer’s, this paves the way for future studies to explore why vaccinations may be protective.
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You can help increase our knowledge by considering participation in a clinical study. Our free clinical trial matching services, TrialMatch®, can help you find clinical trials in your area that are seeking volunteers.
Understanding prevention research
Here are some things to keep in mind about the research underlying much of our current knowledge about possible prevention:
- Insights about potentially modifiable risk factors apply to large population groups, not to individuals. Studies can show that factor X is associated with outcome Y, but cannot guarantee that any specific person will have that outcome. As a result, you can "do everything right" and still have a serious health problem or "do everything wrong" and live to be 100.
- Much of our current evidence comes from large epidemiological studies such as the Honolulu-Asia Aging Study, the Nurses' Health Study, the Adult Changes in Thought Study and the Kungsholmen Project. These studies explore pre-existing behaviors and use statistical methods to relate those behaviors to health outcomes. This type of study can show an "association" between a factor and an outcome but cannot "prove" cause and effect. This is why we describe evidence based on these studies with such language as "suggests," "may show," "might protect," and "is associated with."
- The gold standard for showing cause and effect is a clinical trial in which participants are randomly assigned to a prevention or risk management strategy or a control group. Researchers follow the two groups over time to see if their outcomes differ significantly.
- It is unlikely that some prevention or risk management strategies will ever be tested in randomized trials for ethical or practical reasons. One example is exercise. Definitively testing the impact of exercise on Alzheimer's risk would require a huge trial enrolling thousands of people and following them for many years. The expense and logistics of such a trial would be prohibitive, and it would require some people to go without exercise, a known health benefit.