Dietary Risk Factors for Alzheimer’s Disease

 

The incidence rates of Alzheimer’s disease are rising across the world. One Alzheimer’s disease risk factor that is readily being studied is diet. In 1985 the Japanese population was eating a traditional Japanese diet and had a population incidence rate of 1% for Alzheimer’s disease. By 2008 the incidence of Alzheimer’s disease had increased to 7%, and the population had begun to transition from the traditional Japanese diet to the Western diet.^{1, 2}

 

Foods that are believed to be protective against Alzheimer’s disease include fruits, vegetables, grains, low-fat dairy products, legumes, and fish. Foods associated with an increased risk for Alzheimer’s disease include meat, sweets, and high-fat dairy products. The evidence for these guidelines comes from ecological and observational studies as well as investigations of how dietary factors affect risk.

 

The research described in this article was from an ecological study conducted using Alzheimer’s disease prevalence from 10 countries (Brazil, Chile, Cuba, Egypt, India, Mongolia, Nigeria, Republic of Korea, Sri Lanka, and the United States). They also evaluated dietary supply data 5, 10, and 15 years before the Alzheimer’s disease prevalence data. They found that a dietary supply of meat, fish eggs, and animal product (less milk) 5 years before Alzheimer’s disease prevalence had the highest correlations with the Alzheimer’s disease prevalence.³

Dietary intake of animal products increases the production of insulin-like growth factor, which has been associated with an increased risk of Alzheimer’s disease.⁴ Thus, reducing meat consumption may reduce the risk of Alzheimer’s disease. Meat consumption is a risk factor for several other conditions, including type 2 diabetes mellitus, stroke, and, chronic kidney disease. Consumption of red and processed meat is also associated with obesity. Several leading Alzheimer’s disease researchers created a set of dietary and lifestyle guidelines for the prevention of Alzheimer’s disease. Their dietary guidelines were to minimize intake of saturated fats and trans fats and to make vegetables, fruits, and whole grains the main components of the diet.⁵ It is important to note that changes in the brain begin to occur many years before the development of Alzheimer’s disease, and as such the dietary changes should likely begin mid-life to be most effective.

1. Grant WB. Trends in diet and Alzheimer’s disease during the nutrition transition in Japan and developing countries. J Alzheimers Dis.2014;38:611–620.
2. Dodge HH, Buracchio TJ, Fisher GG, Kiyohara Y, Meguro K, Tanizaki Y, et al. Trends in the prevalence of dementia in Japan. International Journal of Alzheimers Disease.2012;2012:956354.   doi: 10.1155/2012/956354. Epub 2012 Oct 3.
3. Grant WB. Using Multicountry Ecological and Observational Studies to Determine Dietary Risk Factors for Alzheimer’s Disease. Journal of the American College of Nutrition. 2016;35(5) 476-489.
4. Barnard ND, Bush AI, Ceccarelli A, et al. Dietary and lifestyle guidelines for the prevention of Alzheimer’s disease. Neurobiology of Aging. 2014;35(Suppl 2):S74–S78.
5. de Bruijn RF, Janssen JA, Brugts MP, et al. Insulin-like growth factor-I receptor stimulating activity is associated with dementia. Journal of Alzheimers Disease. 2014;42:13