Diet has a major impact on risk of Alzheimer’s disease

4 December 2023


San Francisco, CA - In a detailed study, Diet’s Role in Modifying Risk of Alzheimer’s Disease: History and Present Understanding published in the Journal of Alzheimer’s Disease, we can finally see which diets are helpful in reducing the risk of developing Alzheimer’s disease. The role of diet in modifying the risk of Alzheimer’s disease is discussed in detail. Diets that are more plant based, like the Mediterranean diet and traditional diets in China, Japan, and India, are shown to reduce risk, especially when compared to the Western diet.

Alzheimer’s disease rates rise in these countries as they make the nutrition transition to the Western diet. This study identifies dementia risk factors including higher consumption of saturated fats, meat, especially red meat such as hamburgers and barbeque as well as processed meats such as hot dogs, and ultra processed foods high in sugar and refined grains.

This review also lets us know why certain foods increase or reduce risk of Alzheimer’s disease. For example, meat raised risk of dementia the most by increasing risk factors such as inflammation, insulin resistance, oxidative stress, saturated fat, advanced glycation end products, and trimethylamine N-oxide. This study also outlines several foods that are protective against Alzheimer’s disease, such as green leafy vegetables, colorful fruits and vegetables, legumes (like beans), nuts, omega-3 fatty acids, and whole grains.

Ultra processed foods can increase the risk of obesity and diabetes, themselves risk factors for Alzheimer’s disease. Ultra processed foods often lack the very ingredients found in whole plant foods that keep dementia away, such as anti-inflammatory components and antioxidants.

Poverty is an important driver of Alzheimer’s disease in the US since ultra processed foods and meat are cheaper sources of energy than fruits, vegetables, whole grains, and other more nutritious foods, thus promoting obesity.

The paper also suggests that Alzheimer’s disease rates in the US are projected to increase by 50% from 2018 levels by 2038. This calculation is based on comparing trends of obesity in the US with Alzheimer’s disease trends. This comparison shows a 20-year lag between obesity rates and Alzheimer’s disease rates. This estimate is very close to the estimate published by the Alzheimer’s Association in 2018, an estimate of a 56% increase. Our estimate suggests that the rising trend of obesity, due to consumption of meat and ultra processed foods, is the force driving dementia. Although our personal risk of Alzheimer’s disease can be reduced with diet, it is expected that those who continue to eat the Western diet will continue to have a higher risk.

Effects of specific dietary food groups and factors on risk of Alzheimer's disease. Credit: Steve Blake 2023

“Grant and Blake comprehensively review and synthesize the role of dietary factors in Alzheimer’s disease. Evidence from diverse perspectives support that a diet that emphasizes fruits, vegetables, legumes, nuts, whole grains, and…de-emphasizes meat, especially red meat, saturated fats, and ultra-processed foods is associated with lower risk of Alzheimer’s disease. Physical inactivity and obesity also contribute to higher risk. In addition, the dietary and lifestyle patterns associated with higher risk of Alzheimer’s disease are known to affect the constellation of mechanisms believed to increase risk, including inflammation, insulin resistance and oxidative stress, among others. Grant and Blake make a strong case that, while further research is needed to better understand the mechanisms, diet and lifestyle factors linked to diabetes, cardiovascular disease and some cancers are likely to influence risk of Alzheimer’s disease.”
Edward Giovannucci, MD, ScD, Professor of Nutrition and Epidemiology, Harvard University.

“Grant and Blake provide a comprehensive review on the dietary and other factors that affect the risk of Alzheimer's disease (AD). Apart from the particular type of diet they demonstrate that the consumption of red meat, insulin resistance, obesity, reactive oxygen species, and oxidative stress, phytochemicals and homocysteine amongst other factors interact with neuroinflammation and play a major role in the aetiology of AD. This treatise provides an excellent overview of modifiable risk factors for AD.”
Paul Marik, MD, Chairman and Co-Founder, FLCCC (Front Line COVID-19 Critical Care Alliance).

Article: Diet’s Role in Modifying Risk of Alzheimer’s Disease: History and Present Understanding
DOI: 10.3233/JAD-230418
Volume 96 Issue 4
Journal: Journal of Alzheimer's Disease

Contact: William B. Grant, PhD, Director, Sunlight, Nutrition and Health Research Center, San Francisco, CA, USA.

Steven M. Blake, ScD, Nutritional Biochemistry. Director Nutritional Neuroscience, Maui Memory Clinic, Wailuku, HI, USA.

William B. Grant published the first paper identifying diet as a major risk factor for Alzheimer’s disease in 1997 while he was working as an atmospheric scientist with NASA. He retired from NASA in 2004 and formed Sunlight, Nutrition and Health Research Center to continue his health studies. He has published over 500 articles, reviews, and letters to the editor including 325 regarding vitamin D and 50 regarding diet including landmark papers on solar UVB/vitamin D and risk of cancer and vitamin D and risk of COVID-19.

Steven M. Blake designed and ran the Hawaii Dementia Prevention Trial at the Hawaii Alzheimer Disease Center. He is lead author of the paper published in 2018: Hawaii Dementia Prevention Trial: A Randomized Trial Evaluating A Multifaceted Nutritional Intervention To Slow Cognitive Decline In Mild Cognitive Impairment Patients, published in the Journal of Brain Sciences.

About the Journal of Alzheimer’s Disease
Now in its 26th year of publication, the Journal of Alzheimer’s Disease (JAD) is an international multidisciplinary journal to facilitate progress in understanding the etiology, pathogenesis, epidemiology, genetics, behavior, treatment, and psychology of Alzheimer’s disease. The journal publishes research reports, reviews, short communications, book reviews, and letters-to-the-editor. Groundbreaking research that has appeared in the journal includes novel therapeutic targets, mechanisms of disease, and clinical trial outcomes. JAD has a Journal Impact Factor of 4 according to Journal Citation Reports (Clarivate, 2023). The journal is published by IOS Press.

About IOS Press
IOS Press is an international scientific, technical, medical (STM) publishing house established in 1987 in Amsterdam. We produce around 90 journals and 70 books annually in a broad range of subject categories, primarily specializing in health and life sciences (including neurosciences, medical informatics, cancer research, and rehabilitation) and computer sciences (including artificial intelligence, data science, and semantic web). In addition, we offer specialized services that support scientific advancement.