New research out of Sweden is zeroing in on the link between diet and genetic risk for Alzheimer’s disease.
The findings, published last month in the Journal of the American Medical Association (JAMA) discovered people with a certain genetic risk factor for Alzheimer’s disease who consumed more meat –particularly unprocessed meat like steak or ground beef – had a lower risk of developing dementia.
The Findings
At the center of it all is a gene everyone carries, the APOE gene, which comes in different variants. Some variants dramatically increase a person’s likelihood for developing Alzheimer’s.
On Friday’s AM Update, the scientists behind the study, Dr. Sara Garcia-Ptacek and Dr. Jakob Norgren of the Karolinska Institutet, explained the results. First, Dr. Norgren broke down the significance of the APOE gene:
“We can say that everybody has the APOE gene, and it comes in three different variants – the APOE2, APOE3, and APOE4 – and you get one from each of your parents, meaning that there are six possible combinations, which we call genotypes… If you have the APOE4 gene, your Alzheimer’s risk is higher compared to the APOE3/APOE3, particularly if you have a double four. So in this study, we studied the APOE3/4 and the APOE4/4 compared to the other genotypes. These risky genotypes make up approximately a quarter of the population, but they account for the majority of Alzheimer’s cases.”
Actress Gwyneth Paltrow says she has the APOE4 gene, while actor Chirs Hemsworth has two copies of it, dramatically raising his risk of Alzheimer’s.
The science isn’t settled on why APOE4 carriers face a higher risk of Alzheimer’s, but research has linked the variant to higher cholesterol levels, with evidence suggesting buildup in the brain may interfere with neuron function and contribute to the plaque formation seen in Alzheimer’s disease, according to The Wall Street Journal.
APOE4 carriers who consumed more unprocessed meat saw lower mortality and lower cholesterol than those with the same variant who ate less meat. The study showed eating meat everyday can lower the risk APOE4 carriers have to that of non-carriers, and Dr. Norgren said there may be an evolutionary explanation for this:
“What we know is that APOE4 is the oldest genotype. APOE3 is contemporary with modern humans. It’s about 200,000 or 300,000 years old, and APOE2 is even more recent, but the APOE4 gene occurred for probably a few million years ago, and it might have been that our ancestors at that time consumed a more animal-based diet and could possibly be adapted to a different diet than modern humans.”
The researchers suggest APOE4 carriers may absorb more key nutrients from meat than they do from plant-based foods, including nutrients like vitamin B12, iron, and zinc that are linked to brain health.
Public Health Guidelines
These findings also raise bigger questions about how we think about diet more broadly. Many public health guidelines take a one-size-fits-all approach, but Dr. Garcia-Ptacek said this research underscores the role genetics plays in determining the proper diet:
“I think what one of the things our study shows is that brain health needs to be considered when we’re writing dietary guidelines. We need to do more research on the cognitive effects of diet and. in particular, look at this effect of APOE and see if we can replicate it in other cohorts. We have to remind everyone that this is a relatively small cohort in Sweden, and we need to make sure that this transfers to other populations. In future, if we can replicate this across cohorts or even do a clinical trial and understand the mechanisms behind this, this would open the door for more of a precision nutrition or precision recommendations that are tailored to people’s genotype.”
So, how does one determine if they are an APOE4 gene carrier? Dr. Garcia-Ptacek explained:
“There’s a number of ways to get genotyped. It can be a blood test or other kinds of genetic tests. Some companies offer cheek swabs. It’s not particularly complicated, but it’s not usually done in routine clinical practice, at least not in Sweden. We do do it for individuals who are getting a workup for a suspicion of dementia.”
To those who say they’d rather not know, Megyn noted that this is “real actionable data that may help prevent the onset of Alzheimer’s, so maybe consider it.”
You can get all the day’s headlines by tuning into the AM Update with Megyn Kelly on YouTube, Apple Podcasts, or wherever you like to listen. And don’t forget that you can catch AM Update on SiriusXM’s The Megyn Kelly Channel (channel 111).