Back in high school, two of my closest friends decided to try being vegetarian for a few months. I was curious and wanted to join them, but I only managed to stick with it for about a week. Looking back, there may have been a reason why it didn’t suit me.
Over millions of years of human evolution, our brains grew dramatically — by roughly 300%. Many scientists believe that the inclusion of meat in early human diets played a major role in that development. In simple terms, humans likely evolved to thrive on an omnivorous diet rather than a strictly plant-based one.
According to research discussed by National Geographic, early humans began replacing high-fiber plant foods with more calorie-dense sources like meat and bone marrow. This dietary shift may have led to smaller digestive systems, which required less energy to maintain. The saved energy could then be used to support brain growth, allowing for more complex thinking, imagination, and the development of language.
Because of this evolutionary background, scientists are now studying how meat consumption might affect brain health today—and the findings are quite interesting.
Recent research suggests that diets rich in meat could potentially help protect against serious cognitive conditions such as dementia. Dementia is a condition that affects memory, behavior, and thinking ability, often linked to diseases like Alzheimer’s. It currently affects a significant portion of older adults.
However, this potential benefit may only apply to certain individuals. Specifically, people who carry particular genetic variants (APOE 3/4 or 4/4), which are associated with a higher risk of Alzheimer’s disease, might respond differently to diet.
The study, led by Jakob Norgren from Sweden’s Karolinska Institute, followed more than 2,100 adults aged 60 and above over a period of up to 15 years. Participants were initially free of dementia, and researchers tracked their eating habits alongside regular cognitive assessments.
The results showed that individuals with these higher-risk genes who consumed less meat were more than twice as likely to develop dementia compared to those without the genetic variants.
While the exact reason for this link is still unclear, researchers suggest it could be related to human evolutionary history. The APOE4 variant is considered one of the oldest forms of the gene and may have developed during a time when human diets were more heavily based on animal foods.
It’s important to note that not all types of meat are equal—processed meats are unlikely to provide the same potential benefits. Additionally, the study is observational, meaning it shows a connection but does not prove direct cause and effect.
Researchers emphasize that more clinical trials are needed before making firm dietary recommendations. Still, the findings open the door to the possibility of personalized nutrition plans based on genetic makeup, which could help reduce the risk of cognitive decline.
