Transcript: The Alzheimer’s Gene: Controlling ApoE
Back in the 1990’s, a major susceptibility gene was discovered for Alzheimer’s, called ApoE4. If we have one ApoE4 gene, either from our mom or dad, like about 15% of the U.S. population do, our risk of getting Alzheimer’s is tripled, and if we’re like the 1 in 50 folks who have ApoE4 genes from both parents, we may be at nine times the risk.
The highest frequency of ApoE4 in the world is in Nigeria, but they also have some of the lowest Alzheimer’s rates. To understand this paradox, one has to understand the role of ApoE. What does the ApoE gene do? ApoE is the principal cholesterol carrier in the brain. So, the Nigerians’ diet appeared to have trumped their genes, due to their low cholesterol levels from their low intake of animal fat, living off of mainly grains and vegetables.
High ApoE4, but Alzheimer’s a rarity, thanks perhaps to low cholesterol levels, which any of us can achieve eating healthfully. These findings suggest that long-term changes in plasma cholesterol can lead to changes in ApoE gene expression. Just because we may have been dealt some bad genetic cards doesn’t mean we can’t reshuffle the deck with diet.
We cannot change our genetic makeup, but we can reduce or prevent high cholesterol. In this study of a thousand people for over 20 years, ApoE4 doubled the odds of Alzheimer’s, but high cholesterol nearly tripled the threat; so, the risk for Alzheimer’s disease from treatable factors—elevated cholesterol and blood pressure—appears to be greater than that from the dreaded Alzheimer’s susceptibility gene. In fact, projecting from their data, controlling lifestyle factors could reduce a person’s risk for Alzheimer’s disease, even if they have the double Apoe4 gene, from nine or ten times the odds down to just two.
People tend to have a fatalistic view toward developing Alzheimer’s disease, like it’s going to happen if it’s going to happen, but studies like this undermine such a view. We just need to emphasize the need for preventing and treating high blood pressure and cholesterol in the first place to reduce our risks for heart disease, stroke, and Alzheimer’s disease and, as a result, potentially enhance quantity and quality of life. Of equal importance, these data should be comforting to anyone interested in attempting to reduce the risk for and future burden of Alzheimer’s disease.
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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