 The rates of dementia differ greatly around the world, from the lowest rates in Africa and India, South Asia, to the highest rates in Western Europe, and especially North America. Is it all just genetics? Well, the incidence of dementia in Alzheimer's disease is significantly lower for Africans in Nigeria than for African Americans in Indianapolis, for example, up to five times lower. Alzheimer's rates for Japanese Americans living in the US are closer to that of Americans than to Japanese. So when people of one ethnic group move from their homeland to the United States, Alzheimer's rates can increase dramatically. Therefore, when Africans or Asians live in the US and adopt a Western diet, their increase in Alzheimer's risk suggests that it's not the genetics. Unfortunately, one doesn't have to move to the West to adopt a Western diet. The prevalence of dementia in Japan has shot up over the last few decades. Mechanisms to explain this in Japan include increases in cholesterol, saturated fat, and iron from increases in the consumption of animal products. Traditional diets generally are weighted towards vegetable products such as grains and away from animal products. But since 1960, the diet in Japan has changed from a more traditional rice-based diet to one with a preponderance of meat. From 1961 to 2008, meat and animal fat increased considerably, whereas the rice supply dropped. The dietary factor most strongly associated with the rise in Alzheimer's disease in Japan was the increased consumption of animal fat. A similar analysis in China arrived at the same conclusion. On the basis of these findings, the rate of Alzheimer's disease in dementia will continue to rise unless dietary patterns change to those with less reliance on animal products. This is consistent with data showing that those who eat vegetarian appear two to three times less likely to become demented, and the longer one eats meat-free, the lower the associated risk of dementia. Globally, the lowest validated rates of Alzheimer's in the world are rural India, where they eat low meat, high grain, and high-bean, high-carb diets. Now it's possible the apparent protective association between rice and Alzheimer's is more likely due to the fact that the drop of rice consumption associated with increasing Alzheimer's was accompanied by a rise in meat consumption. But other population studies have found that dietary grains appear strongly protective in relation to Alzheimer's disease. In other words, perhaps, don't pass on the grain, pass the grain to spare the brain.