Big Brains, Meat, Tuberculosis, And The Nicotinamide Switches Co Evolutionary Relationships With Modern Repercussions

This evolutionary research examines why humans developed larger brains compared to other primates and suggests that meat consumption played a crucial role in this development. The authors propose that two nutrients found abundantly in meat - nicotinamide (a form of vitamin B3) and tryptophan (an amino acid) - were limiting factors that previously prevented brain expansion in our ancestors.

The researchers explain that nicotinamide is essential for producing NAD, a molecule critical for cellular energy production and brain function. Without adequate amounts, the brain can actually shrink, as seen in pellagra (severe B3 deficiency). Tryptophan is equally important as it's used to make serotonin and other brain chemicals. Most primates eat very little meat and therefore have limited access to these nutrients, but humans evolved as omnivores with a strong drive to consume meat.

The study also presents an intriguing theory about tuberculosis (TB), suggesting it may have evolved alongside humans as a backup source of these nutrients during times when meat was scarce. This could explain why TB has unusual characteristics compared to other infectious diseases and why it produces nicotinamide.

From a metabolic health perspective, this research highlights the continued importance of adequate B3 and tryptophan intake for brain function and longevity. While we no longer face the evolutionary pressures our ancestors did, ensuring sufficient intake of these nutrients - whether through quality protein sources or appropriate supplementation - remains relevant for maintaining cognitive health and preventing age-related neurological decline.