October 21, 2024
5. Diet and Human Evolution
In this post let’s digress for a minute from Alzheimer’s and look at the brain development across evolution of humans.
How Food Scarcity Shaped Human Resilience
During evolution, individuals had to go through periods of no food in the day, or prolonged physical exertion or starvation sometimes. There was no reliable source of food so starvation was something that they had to get over and survive. The exertion side of this equation, we will address in a different post on the exercise effects. This resilience throughout their lifespan gave them better bodies and minds to cope with stress. This metabolic switch to ketones fueling the cells in the neuronal networks in the brain lead to increased resistance to stress, injury and disease
It also makes sense from this perspective, food is a number one survival intelligence needed for the self, protection from danger being the second which is needed more infrequently compared to food which is on an 8 hour cycle for humans. So food stress definitely has strong implications on brain and intelligence in early humans. So based on this, an intermittent diet or fasting builds that resistance and repairs inflammation and oxidative stress. A lot of the signaling is done by Gherlin, the hunger hormone released in gut cells and circulates in blood, acting at the hippocampus. Lab results on mice showed a 40% increase in lifespan for Alzheimer’s with intermittent fasting.
The Evolution of the Human Diet: From Fruit to Seafood, and Beyond
If we look at the diet evolution, apes and chimpanzees ate fruit. So we started out with a fruit diet, then added meat when we started making hunting tools. But all of these human-like tribes disappeared and homo sapiens sustained in South Africa where they depended on sea food. The theory is that the easy to digest sea food with abundant omega-3 oils could have played a role in brain development, as the brain is a massive cell membrane region needing high amounts of fat for the phospholipid layers as language and other faculties improved.
Cooking was used 800,000 years ago so that it allowed a variety of ingredients to become edible for humans, leading to complex diets that our brains demanded. The grain and vegetable diet came on only later when the nomadic lifestyle changed and cultivation started. Complex traits of language evolved around 100,000 years ago. Coordinated civilizations occurred 12,000 years ago. Only the highly adaptable homo-sapiens were able to survive showing that social and stress management is a higher order skill and therefore just diet alone is not sufficient to heal. In math this is called a necessary but not a sufficient condition.
Diet and Alzheimer's: The Challenge Isn't Knowledge, It's Implementation
We are concluding in this post the diet part of the lifestyle changes that can lead to reversal of or slow down Alzheimer’s progression. The central message is diet knowledge everyone may have, but putting it into daily practice is very difficult and creative psychological solutions are needed, the innovation is in this psychology and not in the diet. One example is why not make salad a compulsory part of food at parties and take away the sweets for once? Even vegetarians in Indian culture don’t have the habit of providing salads. Without such large-scale cultural changes, we cannot change our habits.