A Western diet of sweet and fatty junk food increases your risk of Alzheimer's disease, a new study warns.
Americans have a higher average risk than most other nationalities of developing the degenerative brain disorder, and have done for years.
That is likely due to their dietary pattern, which drives up cholesterol and Alzheimer's-influencing proteins that create blockages in the brain.
This is according to Dr William Grant, the lead author of a landmark review of international data tracking Alzheimer's disease and its causes.
He said: 'Mounting evidence from ecological and observational studies indicates that the Western dietary pattern—especially the large amount of meat in that diet—is strongly associated with risk of developing Alzheimer's disease.
'Although the traditional Mediterranean diet is associated with about half the risk for Alzheimer's disease of the Western diet, the traditional diets of countries such as India, Japan, and Nigeria, with very low meat consumption, are associated with an additional 50 per cent reduction in risk of Alzheimer's disease.'
Dr Grant, of San Francisco's Sunlight, Nutrition, and Health Research Center, looked at a host of peer-reviewed studies to draw his conclusion, which is published in the Journal of the American College of Nutrition.
He also conducted an investigation into how changing global diets affected rates of Alzheimer's disease.
First, he looked at Alzheimer's disease prevalence from 10 countries (Brazil, Chile, Cuba, Egypt, India, Mongolia, Nigeria, Republic of Korea, Sri Lanka, and the United States).
Then he cross-referenced those findings with official dietary guidelines.
For example, he would see that Japan's Alzheimer's rate in 1985 was 1 per cent, then he would look at dietary guidelines five, 10, and 15 years before 1985 to track the influence.
Then he would see that Japan's Alzheimer's rate in 2008 was 7 per cent, so he would look at dietary guidelines five, 10 and 15 years before that date.
In every country, a swing towards Western dietary lifestyles coincided with an increased rate in Alzheimer's disease.
Dr Grant warns that the most important dietary link to Alzheimer's appears to be meat consumption, with eggs and high-fat dairy also contributing.
Diets high in grains, fruits, vegetables, and fish are associated with reduced risk of the disease.
Higher amounts of vitamin D is also associated with reduced risk of the disease.
But these factors cannot counter the effects of meat, eggs, and high-fat dairy, he warns.