When I was a kid growing up in suburban New Jersey, I remember walking through fields or on the path to school and having to dodge grasshoppers with nearly every step. There were so many grasshoppers that it was impossible to walk without being bombarded by dozens, if not hundreds, over just a one-mile walk to Lake Hiawatha Elementary School.
I also remember that it was common that, after a rain, there would be huge numbers of earthworms that had come to the surface, scattered across the driveway, street, and lawn, making it difficult to not squash them underfoot just by taking a few steps.
There were also great swarms of fireflies in the yard, casting a glow bright enough to light up bushes, trees, and grass. Remember when you could see butterflies and hummingbirds everywhere? And remember the dense flocks of birds that could sometimes darken the sky due to their great numbers?
No longer. Sure, you might spot some grasshoppers or hummingbirds in rural areas or forests. But they have been largely lost from most urban and suburban locations.
I am not the only one to have made such observations, as scientists have indeed been studying this phenomenon, what some label an “insect apocalypse.” Increasing urbanization, widespread use of pesticides and herbicides, and global climate change have contributed to widespread decimation of various species. (Recall that birds live largely on earthworms and insects.)
If humans are capable of introducing dramatic changes into the earth’s macroenvironment, could we have introduced parallel changes into the human microenvironment, i.e., the populations of bacteria, fungi, archaea, and viruses that inhabit the human gastrointestinal (GI) tract? I believe that it is not only likely, but assured: We have introduced devastating changes into the human GI microbiome, changes that come with considerable health consequences.
Just as in the macroenvironment in which loss of some species, especially keystone species that support other species, such as plankton in the ocean serving as food for filter-feeding species higher up the food chain such as jellyfish and whales, or loss of various insect species leads to decline of several species of birds. So it goes in the microenvironment ecosystem: Lose one keystone species and several other species follow, having lost metabolites or other factors that previously came from the keystone species. Just as we have to look long and hard to see a grasshopper (I’ve seen only one in the last 20 years) or firefly, so we can look long and hard for numerous species of the human GI tract that have either been dramatically reduced or have disappeared. And the list of species in the latter category—species that have disappeared—is getting bigger all the time.
Just as I do not have all the answers to the destructive changes we’ve inflicted on the macroenvironment, I don’t have all the answers on how to manage the altered species of our personal microenvironments. But there are a few clear and readily accessible strategies you can adopt right away to begin to effect change in your intestinal microbiome. Among them:
- Avoid food additives—Good evidence suggests that common food additives such as emulsifying agents polysorbate 80 and carboxymethylcellulose, as well as maltodextrin, bisphenol A, and carrageenan, adversely impact the composition of the gut microbiome. The list is sure to grow longer, especially since food manufacturers are unrestrained in their enthusiasm in adding such ingredients to processed food. The solution? Eat foods unchanged by the food industry whenever possible: eggs, avocados, vegetables, etc., foods that require no label, no nutrition panel, and are the least likely to have such added ingredients.
- Fermented foods—Ever since the advent of affordable home refrigeration in the 1920s, Americans have developed disdain for fermented foods. The soupy, cloudy mix that develops in a jar of fermented vegetables, for instance, would be regarded as rotten by most people and tossed in the trash, even though it is actually a healthier food with the presence of fermenting microbes. Some of the superstars in the microbial world can be obtained via fermented foods, species such as Pediococcus pentosaceous and Leuconostoc mesenteroides.
- Avoid sugars—Sugars, such as that in a can of soda or a slice of pie, are an open invitation to disruptions of intestinal bacterial species and overgrowth of fungal species. All it takes is a few margaritas over three or four days on an all-inclusive Caribbean vacation and you have altered the composition of your intestinal microbiome.
- Minimize or avoid prescription medications—It is becoming clear that prescription drugs, even agents often thought of as benign, exert deleterious effects on the intestinal microbiome. Non-steroidal anti-inflammatory agents such as ibuprofen and naproxen, stomach acid-blocking drugs such as ranitidine, Prilosec, and Protonix, statin drug like Lipitor and Crestor, all alter the composition of bowel flora, shifting away from beneficial species and towards over-proliferation of unhealthy stool species. There are undoubtedly thousands of other agents that have microbiome-altering effects, but testing for this phenomenon is not a component of testing for a drug’s FDA approval. We therefore do not appreciate just how common or widespread these effects are—but they are likely common. In fact, it is hazardous to not factor in microbiome changes when considering the effects of any pharmaceutical agent.
- Filter drinking water—Just as it would be beneficial to the environment if we all restrained our reliance on herbicides and pesticides, so it would be beneficial if we reduced the ingestion of antimicrobial chlorine and chloramine. The full range of consequences of chlorine products on bowel flora has not been fully charted, but they at the very least disrupt the mucus barrier of the upper gastrointestinal tract, a disruption that likely cascades into alterations in bacterial populations and increased endotoxemia.
As an individual, there is a limit to how much we can achieve in backpedaling on global climate change of the macroenvironment. But there is a ton you can achieve in undoing the harm we’ve inflicted on our personal microenvironments. Our L. reuteri yogurt is just one example of the extraordinary effects that can occur when you begin the process of restoring microbes lost from your intestinal microbiome.