The other day I had a conversation with a friend, and the topic of Alzheimer’s disease (AD) came up. My friend’s opinion was basically why would I want to know I have a disease that results in steady decline in function, and lacks any disease modifying treatments? This is in large part true, there have been multiple clinical trials of both symptomatic and disease modifying drugs that failed to produce adequate results. However, this is a very limitted view and neglects the benefits of focusing on modifiable risk factors and primary prevention. We know approximately 1/3rd of AD cases are due to modifiable risk factors, and the implementation of lifestyle modification early may prevent or delay the onset of AD.
Modifiable Risk Factors
Common modifiable risk factors for AD include hypertension, hyperlipidemia, diabetes, obesity and smoking. Management of these risk factors as early as possible may offer a preventative approach for AD. Equally important are lifestyle modifications such as physical exercise, diet, mediation/mindfulness, and social activity.
Physical inactivity has a significant influence on the development of AD. Twenty-one percent of AD cases are attributable to physical inactivity. There is a significant number of studies in the literature that indicate physical activity is neuroprotective. We know one of the areas in the brain affected by physical activity is the hippocampus which is involved in memory. Exercise leads to increased neurogenesis and neuroplasticity in the hippocampus. Other benefits of exercise on the brain include increased blood flow, modulation of inflammatory markers, and increased brain-derived neurotrophic factor (BDNF). The exact definition of adequate exercise varies in the literature. Any activity that is sufficient to increase heart rate and can be sustained for 30-60 minutes is my definition. A basic example would be brisk walking for 30-60 minutes. Physical activity two times a week beginning in middle age is associated with reduced risk of AD. Aerobic exercise is associated with additional cognitive benefits including improved processing speed, attention, and memory in adults with mild cognitive impairment. This recommendation is especially important for ApoE4 carriers, as exercise is associated with reduced amyloid deposits.
Physical activity should be a recommendation for all patients without major health concerns preventing physical activity. The earlier in life a patient begins an exercise routine the better. Some of these studies have looked specifically at starting exercise routines in middle age, but there is no reason to wait. The physical and cognitive benefits of exercise are beneficial regardless of age. It’s much easier to begin training when you are young and healthy. If you build healthy lifestyle habits earlier in life, they are likely to last as you age. Guidelines for regular exercise can be found on the American Heart Association or American College of Sports Medicine websites.
Meditation or mindfulness is a topic that is beginning to get more attention in the medical literature. Chronic stress is believed to effect brain structures involved in memory and may contribute to AD. Psychological stress increases oxidative stress and telomere shortening which could contribute to the neuronal loss seen in AD. Meditation has emerged as a possible way to reduce the stress associated with daily life. The techniques of mindfulness involve directing one’s attention to the present moment to reduce the stress associated with constant thinking and worrying. Randomized controlled trials (RCTs) have shown significant improvements in overall well-being and attention. Improved executive function and reduced inflammatory processes implicated in AD. Additional research and larger RCTs are needed to improve the evidence base. Given the data we currently have there is no reason to not begin mindfulness practices. The techniques are relatively simple and can be learned from a variety of sources. If you are looking for low cost options for learning mindfulness, YouTube has a variety of guided mediations available. I personally like Headspace for beginners because it provides a solid foundation, has a variety of meditation courses, and allows you to track your progress. There is a fee for access to all the courses, but the first 10 sessions are free. Whichever route you choose, spending 10-15 minutes per day practicing mindfulness will lead to a happier and healthier brain.
A great deal of research has been conducted over the last several years on the role of diet with respect to cognition. People with high calorie diets, specifically those high in fat are at higher risk for AD. Traditional western diets high in processed carbohydrates, simple sugars, and saturated fatty acids can impact the hippocampus and memory. When Japan transitioned to western diet the incidence of AD increased. Lower calorie diets with lower saturated fat content are linked to lower oxidative stress, decreased Beta amyloid burden, and decreased inflammation. One diet with proven benefits for preventing AD is the Mediterranean diet. This diet is rich in fruits, vegetables, whole grains, olive oil, and fish. There is moderate intake of low-fat dairy products and low intake of red meat, saturated fats, and sugar. Most of the data supporting the reduce risk of AD with this diet comes from epidemiological studies. Studies have shown combining this diet with exercise further reduces the risk of AD. The Mediterranean diet is associated with better cognitive function and reduced cognitive decline. This is one specific example, but the basic principles can be applied without the need to adhere to one specific named diet.
Some specific foods you may want to add to your diet to prevent AD include fresh berries which have the highest amounts of antioxidants among the fruits. They are also low in calories and work well in diets where weight loss is a goal. Green leafy vegetables and tomatoes have the highest nutritional value when it comes to brain health amongst the vegetables. Foods high in omega-3 fatty acids are considered to be helpful in supporting brain function. The omega-3 fatty acid most important in brain function is docosahexaenoic acid (DHA), which is mostly found in fish. The anti-inflammatory and antioxidant properties of DHA are thought to be responsible for its role in preventing AD. Patients with diagnosed AD are known to have low levels of DHA. Omega-3 fatty acids recommendations from the American Heart association for adults is to eat fish rich in omega-3s two or more times per week. If using a supplement 1-3 grams per day is an adequate dose. Over 3 grams per day, you should consult with your doctor before moving above 3 grams per day.
Finally, curcumin which is derived from turmeric has anti-inflammatory, antioxidant, and anti-amyloid properties. There is low bioavailability of the curcumin lead to mixed results in the initial trials. A new more bioavailable form called Theracumin demonstrated positive results in a randomized double-blind placebo-controlled study on memory, attention, and amyloid plaques in older adults without dementia.
While there is no guarantee that lifestyle modification alone will prevent AD, there are some promising studies indicating it plays a role in the development of this disorder. Most of these interventions are things patients can implement in their lives immediately. They will not only improve cognitive function and lower the risk of developing AD, but it will improve and potential reverse other diseases of lifestyle.