A Season for Every Microbiome

At any given time, our bodies carry about 10-30 trillion bacteria that belong to thousands of different species. Depending on the person, these populations can fluctuate from day to day and even from morning to afternoon! Scientists studying the human gut microbiome have been evaluating those populations to find trends, keystones, and troublemakers to identify a possible “key” to good gut health. Our diet plays a large role in the types of bacteria that reside in our gut.

In 2020, you can eat crepes for breakfast, sushi for lunch, and street tacos for dinner, followed by a completely different worldly spread the next day. For most of human history, up until the industrial revolution and the boom of the rapid import of non-native foods, humans ate what was available and in season in their region. Studies following traditional hunter-gatherer tribes in Tanzania showed seasonal trends in their gut microbiomes. Wet season diets relied more heavily on foraged foods, vegetables, and berries that boost the population of fiber-loving bacteria in the gut. During the dry season, hunting was more common. So, the more meat consumed by humans, the more protein-craving bacteria that dominated the microbiome. Scientists leading the study were surprised to see the pattern repeat year after year with the same seasonal trends, interestingly with the “off-season” bacteria almost disappearing each time.

Similar seasonality is seen in Western societies but is more pronounced in areas that eat seasonal produce and experience true seasonal changes. The so-called “American lifestyle” of eating our favorite fruits and vegetables and spending all our time in climate-controlled homes and offices may be taking away from our natural microbiome swings. Our microbiome is a dynamic and ever-changing system. If we don’t give our gut the chance to have a seasonal recovery, it can lead to microbial depletion.

Gut-friendly options for embracing the seasonality of your microbiome:

  1. Getting a good night’s rest – avoid sleep deprivation that adds stress to your body and use Circadian rhythms to moderate your sleep patterns
  2. Eat seasonal produce – it’s not just in your head that watermelons taste better in the summer and apples are so much more delicious in the fall – when produce is in season, they have more nutrients and need fewer pesticides and chemicals to have them ripen
  3. Feed your microbiome – not only fueling your own body, but your gut microbiome’s most beneficial members also thrive on fiber. You can get your daily fiber in by eating lots of fruits and vegetables, or with prebiotic supplements
  4. Spending time outdoors – being around nature helps to stimulate your immune system (looking at you, pollen), increase the diversity in your microbiome, and decreasing your stress levels