One third of the world’s population is infected with tuberculosis (TB) but the vast majority of those people are asymptomatic. The relatively small number of deaths occur mostly in impoverished regions where meat is unaffordable.
A new study published in the International Journal of Tryptophan Research hypothesizes that TB co-evolved with humans to provide a buffer against meat shortages. Mycobacterium tuberculosis acts less like a pathogen and more like symboitic organism similar to the beneficial bacteria found in the gut. It produces nicotinamide (B3) a vitamin found in meat that the body converts into nicotinamide adenine dinucleotide plus hydrogen (NADH) to fuel metabolism and brain function. In fact, the immune system encourages the growth of the bacteria with defensive walls known as granulomas that typically wall off infections to suppress them. It’s only when the host becomes malnourished that TB is intolerable.
TB has co-evolved with humans for at least 70,000 years, yet there’s no evidence of it acting as a disease until 10,000 years ago. It was at that time that the our diet changed from meat to cereal after the advent of agriculture.
The data shows a clear correlation between the increase in meat consumption and the decrease in TB deaths in the U.K. from 1840 to 1960.
1841 saw a dramatic drop in deaths coinciding with a 300-fold rise in meat consumption due to improvements in refrigeration and transportation.
The downward trend reversed during World War II. Historically, there have been increased incidences of tuberculosis during wars when food shortages are common.
“It is not a conventional pathogen in an ‘Arms Race’ to avoid detection with us that became adept at evading our immune system,” the researchers reiterated. “Otherwise, as pointed out recently by others would it not have caused its and our own extinction 70,000 years ago?”