 Up to half of Alzheimer's cases may be attributable to just these seven risk factors, and that's not including diet, just because there's so many dietary factors they couldn't fit them into their model. But they acknowledge that diet might be another important modifiable risk factor for Alzheimer's disease. In particular, there's growing evidence that dietary patterns, such as the Mediterranean diet, are associated with lower Alzheimer's risk, as well as slower cognitive decline. But which constituents of the Mediterranean diet are responsible? The traditional Mediterranean diet is a diet high in intake of vegetables, beans, fruit, and nuts, and low in meats and dairy. When they tried to tease out the protective components, fish consumption showed no benefit, and neither did moderate alcohol consumption. The two critical pieces appeared to be vegetable consumption and the ratio between unsaturated fats and saturated fats, essentially plant fats to animal fats. In studies across 11 countries, fat consumption appeared to be most closely associated with the prevalence of Alzheimer's disease, with the lowest fat intake in Alzheimer's rates in China, to the highest fat in Alzheimer's rates in the United States. But this is grouping all fats together. Harvard researchers examined the relationship between major fat types to cognitive change over four years, among 6,000 healthy older women, and found that higher saturated fat intake was associated with a poorer trajectory of cognition and memory. Women with the highest saturated fat intake had 67% greater odds of worse change on brain function. The magnitude of cognitive change associated with saturated fat consumption was equivalent to about six years of aging, meaning women with the lowest saturated fat intake had the brain function of women six years younger. What if one already has Alzheimer's, though? Previously, this group of Columbia University researchers reported that eating a Mediterranean-style diet was related to lower risk for Alzheimer's disease. But whether Mediterranean diet or any diet, for that matter, associated with subsequent course of the disease and outcomes had yet to be investigated until now. They found that adherence to the Mediterranean diet may affect not only risk for Alzheimer's disease, but also subsequent disease course. Higher adherence to the Mediterranean diet was associated with lower mortality, and the more they adhered to the healthier diet, the longer they lived. Within five years, only 20% of those with high adherence died, with twice as many deaths in the intermediate adherence group, and the low diet adherence group, within five years, more than half were dead. And by 10 years, 90% were gone, 80% were gone, or less than half. And by the end of the study, the only people still alive were those with high adherence to the healthier diet.