Transcript: Preventing Alzheimer’s Disease with Diet
Up to half of Alzheimer’s cases may be attributable to just these 7 risk factors, and that’s not including diet, just because there are so many dietary factors that they couldn’t fit them into their model, but they acknowledged that diet might be another important modifiable risk factor for AD. In particular, there is growing evidence that dietary patterns, such as the Mediterranean diet, are associated with lower Azheimer’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 meat and dairy. When they tried to tease out the protective components, fish consumption showed no benefit, 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 correlated with the prevalence of Alzheimer’s disease, with the lowest fat intake and Alzheimer’s rates in China to the highest fat intake and Alzheimer’s rates in the United States. But this is grouping all fats together.
Harvard researchers examined the relationships of the major fat types to cognitive change over 4 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 60 to 70% greater odds of worst change on brain function. The magnitude of cognitive change associated with saturated fat consumption was equivalent to about 6 years of aging, meaning women with the lowest saturated fat intake had the brain function of women 6 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 a Mediterranean diet—or any diet for that matter—is associated with the subsequent course of the disease and outcomes had not been investigated, until now.
They found that adherence to the Mediterranean diet may affect not only risk for Alzheimer disease but also subsequent disease course: Higher adherence to the MeDi is associated with lower mortality. And the more they adhered to the healthier diet, the longer they lived. Within 5 years, only 20% of those with high adherence died, with twice as many deaths in the intermediate adherence group, and in the low diet adherence group, within 5 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 higher adherence to the healthier diet.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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