A Gut Feeling

Over the past few years, research on the gut biome has produced a number of increasingly startling conclusions about how the human body actually works. We learned that Alzheimer's disease, indeed, many immune related diseases appear to be closely linked to the bacteria that dwells in our guts, and many other syndromes afflicting large numbers of people also trace their origins to imbalances of our bacterial composition. A more recent revelation gives new meaning to the expression "you are what you eat".

Researchers at Northwestern University conducted an experiment with a group of mice that had been raised without exposure to any foreign microbial matter. They introduced a sample of gut biome from large brained primates, monkeys and humans, as well as a control from smaller brained macaques and were stunned to find a connection they had only theorized. The brains of the mice who were exposed to gut bacteria from large brained primates began to change. The mice began to display behavior uncharacteristic of their own biology and more like us.

If this sounds like science fiction rather than science it nevertheless suggests that our own evolution was influenced by the food stock early humans ingested and, therefore the bacterial composition that evolved along with them as they moved from hunter gatherers to cultivators. It is not a leap too far to observe that our diets--and more precisely the bacteria which occupy our bodies, far outnumbering our own cells, have a lot more to do with our overall health and well being than scientists have previously assumed.

I don't want to be accused of a breezy exposition that gets the science fundamentally wrong so let me be sure to characterize these recent findings carefully. Changing their diet won't turn mice into men, and certainly not in any time frame we might measure in our lifetimes. The signs of primate tendencies researchers found in the inoculated mice were measurable changes in metabolic activity and brain function. Equally important, no such signs were found in the mice that received bacteria from small brained primates.

So, what does this all mean to us? Well it confirms the idea that diet is about more than just our weight or general health. It supports the theory that over time, changes to the gut biome may have played a much larger part in influencing development and diet across human populations contributing to fundamental differences in how we are impacted by environmental and genetic factors.

Not to be too pointed, but this research also strongly cautions us against making sweeping changes in our diet without fully understanding the consequences. Just a few days before I wrote this post, the FDA revised its dietary recommendations, inverting the so-called food pyramid most of us learned eons ago in grade school. Meat and dairy have ascended to the top, and grains fell to the bottom. There are a lot of arguments for and against this change, and there is little dispute that any movement away from processed foods is a positive one. But the science on which the new guidelines are based is not only sketchy and unproven, it risks a multi-generational impact on health which cannot be accurately predicted.

With tongue pressed against cheek, it may not matter. We've been ignoring the FDA's recommendations for generations already, filling our guts with fast food and all manner of chemicals and additives we don't even bother to note; generally acting as if there is no relation between what we eat and how we think and act. I don't blame anyone for skepticism, but you don't need a degree in nutrition to see the effect of diet on the overall population of our country. We are overweight, we are unhealthy, and we may be eating our way generation by generation in the wrong direction. If the findings of the Northwestern experiment prove consistent in the future we may just be eating our way to devolution.