Back in the 1990s, 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 percent of the U.S. population does, our risk of getting Alzheimer’s is tripled. If we’re like the 1-in-50 folks who have ApoE4 genes from both parents, we may be at nine times the risk. But there are ways to minimize that risk.
The highest frequency of ApoE4 in the world is in Nigeria, but Nigerians 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, with their low cholesterol levels from their low intake of animal fat from living off of mainly grains and vegetables.
Indeed, Nigerians have high ApoE4, but Alzheimer’s is a rarity, thanks, perhaps, to low cholesterol levels, which any of us can achieve by eating healthfully. These findings suggest that “long-term changes in plasma cholesterol…can lead to changes in brain ApoE 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 a study of a thousand people for more than 20 years, ApoE4 doubled the odds of Alzheimer’s, but high cholesterol nearly tripled the threat. So, the “risk for Alzheimer disease from treatable factors—elevated total cholesterol level 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 from nine or ten times the odds down to just two—even if they have the double ApoE4 gene from both parents.
“People tend to have a fatalistic view toward developing Alzheimer disease,” as though it’s going to happen if it’s going to happen, but such a view has been undermined. 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 disease.”
Michael Greger, M.D.
PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations—2015:Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not to Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.