Sad but true: the older we get, the greater our chances of developing dementia. Alzheimer’s disease (AD) is the most common form of dementia. In the United States, about 6 million people suffer from the condition and experts expect that number to triple in less than 30 years.
We don’t develop dementia just by racking up the years. Some people remain as sharp as the proverbial tack well into old age.
That raises a question: does your genome set the stage for cognitive decline?
We’ve learned valuable lessons about disease development from studying identical twins. Because they have identical genomes, it’s reasonable to assume twins would develop the same illnesses. Surprisingly, a wide body of research shows this isn’t the case. As twins grow older, their lives change and their differing experiences influence their health.
We know that AD has a strong genetic component. But thanks to the science of epigenetics, we also know that genes are constantly engaged with their environment, busily reacting to influences like diet, physical activity, stress and exposure to toxins. Environmental impacts affect how genes express themselves and differential gene expression plays a big role in whether you develop AD.
Consider one 2006 study published in the Archives of General Psychiatry which found that when one twin of an identical pair develops AD, the other develops the condition just 45% of the time. We now know that lifestyle modifications can slow the progression of AD in part by improving gene expression. Here are six strategies for harnessing the power of epigenetics to keep AD at bay.
Eat an Anti-Inflammatory Diet. Chronic inflammation is strongly linked with AD development. Numerous studies have identified the Mediterranean Diet (MD), which is rich in plant foods, as being anti-inflammatory and positively affecting gene expression. Extra-virgin olive oil, a key component of the diet, has specifically been shown to improve the expression of certain genes associated with age-related conditions like dementia.
Nurture Your Gut. Certain foods associated with the MD (for instance, walnuts and olive oil) support brain health, in part because they are rich in polyphenols. These phytonutrients (found in herbs, berries and dark chocolate, among other foods) encourage the growth of beneficial gut bacteria, which in turn produce substances that improve gene expression and help to keep your brain healthy. Consuming a significant quantity of flavonols, a type of polyphenol, has been shown to reduce the risk of developing AD by almost 50 percent.
Research also links certain types of unhealthy gut bacteria with the accumulation of amyloid plaques, a marker for AD. One study showed that when elderly patients with AD consumed certain probiotics, their cognitive function improved. Probiotics work their magic in part by improving the expression of certain genes.
Watch Your Weight. Obesity is a risk factor for AD. One study concluded that the more belly fat you have, the more your brain will shrink as you age. Studies of obese people who undergo gastric by-pass surgery suggest that gut bacteria are involved. Obese people have fewer “good” bacteria, which produce inflammation-fighting compounds such as short-chain fatty acids. After gastric bypass surgery, it’s been shown that their bacterial communities shift and the expression of genes related to AD development as well as others associated with keeping inflammation under control improve.
Manage Your Blood Sugar. The links between diabetes and AD are so strong that AD has been called “type 3 diabetes.” Scientists are exploring the connections between certain genes linked with diabetes, how they are expressed and their impact on AD development. Research is in the early stages, but keeping blood sugar in check has been shown to benefit gene expression in ways that support healthy insulin production, possibly helping to ward off dementia.
Watch the Toxins. Numerous bad habits that promote inflammation like cigarette smoking, heavy drinking and a sedentary lifestyle have been linked with AD. All have been shown to negatively affect gene expression, as has exposure to air pollution, which has been linked to the development of dementia through a specific gene. Living within 100 meters of a green space has been shown to mitigate the negative effects of polluted air.
Flex Your Muscles. We’ve known for years that exercise helps to keep your brain healthy and reduces your risk of developing AD. Basically, physical exercise increases blood flow to the brain, altering gene expression in ways that help to protect against AD.
More and more research suggests that AD (and dementia in general) may be a degenerative inflammatory disease linked with long-term nutritional deficiencies and poor lifestyle choices. We don’t have a treatment that will cure or stop the progression of dementia but we do know that a healthy diet and lifestyle can help to delay its onset by positively influencing gene expression.
King’s College London. Department of Twin Research and Genetic Epidemiology. https://twinsuk.ac.uk
Marquez et al. Changes in Neuropsychological Tests and Brain Metabolism After Bariatric Surgery. https://doi.org/10.1210/jc.2014-2068
Gatz, Margaret et al. Role of Genes and Environments for Explaining Alzheimer Disease. DOI: 10.1001/archpsyc.63.2.168
Joven, Jorge. Polyphenols and the Modulation of Gene Expression Pathways: Can We eat Our Way Out of the Danger of Chronic Disease. https://doi.org/10.1080/10408398.2011.621772
Van Praag. Henriette. Exercise and the Brain: Something to Chew On.. doi: 10.1016/j.tins.2008.12.007