Alzheimer’s disease is a leading cause of death worldwide, garnering billions of dollars annually for research for new pharmacological targets. Yet unlike the other chronic diseases of aging for which decent pharmacological treatments exist, the research for finding a drug to make a substantial impact on the burden of Alzheimer’s disease and dementia has been an abject failure. The reason for this lack of success is likely multi-faceted. However, a multi-disciplinary approach is needed to prevent and treat Alzheimer’s disease successfully. Based on the wealth of literature available, that multi-disciplinary approach, without question, must include nutritional intervention.
It’s estimated that only about 3% of Alzheimer’s cases are attributed purely to genetics. That means that in the overwhelming majority of cases, including those when someone carries the genetic variant ApoE4, environmental and lifestyle factors play a major role in the development of Alzheimer’s. Perhaps the most influential of these modifiable lifestyle factors is nutrition. Through a process known as nutritional epigenetics, we have the ability to express or downregulate various genes. Thus, even for those susceptible to Alzheimer’s disease through genes with incomplete penetrance such as ApoE4, our dietary choices can sway the odds for us or against us. People typically eat three times a day, meaning we have three times each day when we can drive the disease process or promote health and longevity.
The link between dietary patterns and Alzheimer’s disease has been well-researched. The Mediterranean diet has been shown countless times to preserve brain function. The Mediterranean diet is characterized by high amounts of whole grains, legumes, vegetables, fruits, olive oil, fish, nuts, and seeds; moderate consumption of unsweetened yogurt, cheese, and wine; limited amounts of meat, eggs, and animal products; and avoidance of added sugars and ultra-processed hyper-palatable foods. Results of studies investigating the Mediterranean diet find increased cognitive performance and decreased risk of Alzheimer’s and dementia (among other chronic diseases). One likely mechanism for this outcome is that the Mediterranean diet decreases biomarkers of inflammation, and neuroinflammation is a primary component in neurodegenerative processes. In recent years, the MIND diet has been studied as a therapeutic intervention for cognitive decline. The MIND diet is a combination of the Mediterranean diet and the DASH diet (Dietary Approach to Stop Hypertension). The MIND diet is similar to the Mediterranean diet, but more specific as it includes serving recommendations by food group for better adherence. Epidemiologic data show that greater adherence to the MIND diet was independently associated with better cognitive function and lower risk of cognitive impairment in older adults. The observational evidence is overwhelming and the available clinical trials also support that dietary modification to more plant-centric, whole foods diets, such as the Mediterranean or MIND diet preserves cognitive health, reduces risk of dementia, and improves overall health outcomes.
One might think that given the enormity of evidence showing benefits for such a devastating disease, we would see more attention given to the importance of our dietary pattern. Yet human outcomes nutrition research is rarely given the attention it warrants because the insight it provides requires that we make changes to our dietary habits. As anyone who has ever tried to change their diet will tell you, making dietary changes is hard. Beyond the difficulty of changing habits, people have an emotional connection to food, so unlike some other areas of health, adjusting one’s diet can be emotionally difficult as well. However, if we want to truly make an impact in the silver tsunami that is Alzheimer’s and dementia, we have to trust the evidence and we have to be willing to put in the work to make changes to our dietary habits, personally and systematically.
