Banner by Amy Zhang

We've Got Guts

By Jessica Multani

How can one bacterium make a difference in your body? When working together, humans can accomplish a lot to greatly impact society, and similarly, when the bacteria in the gut work together, they can accomplish a lot for one’s overall well-being. There is a common misconception that all bacteria are bad, however, the gut of the human body hosts trillions of bacteria that all have various roles in maintaining our health. Therefore, it is important to care for these microscopic friends within our body. Neglecting gut health decreases metabolism, hinders digestion of nutrients from our diet, imbalances our gut microbiome, and suppresses the sense of feeling full, which can lead to weight gain. If this avoidable weight gain continues, it is also possible for someone to become obese from excess buildup of adipose tissue. Michelle Seguin is a family medicine and lifestyle medicine physician who passionately advocates for those suffering from food apartheid, or those who have low access to healthful, fresh foods. “Obesity typically is going to result from an imbalance in the amount of energy taken in through eating and drinking and the amount of energy spent on metabolism and physical activity,” Seguin explains. Since 1990, global adult obesity has more than doubled, with adolescent obesity having quadrupled. Given this rise of cases, we should pay attention to and care for our gut bacteria to aid our overall well-being by making gut-friendly dietary choices and keeping ourselves educated about gut health in the face of unhealthy influences around us.  

Healthy gut bacteria can have a great impact on overall health. Gut bacteria help us digest nutrients from our diet, such as fiber and antioxidants. A recipe for poor gut health consists of a decline in healthy bacteria and a rise in unhealthy bacteria, resulting in an imbalance of species in the gut. There are five main phyla of gut bacteria, Firmicutes, Bacteroidetes, Actinomycetes, Proteobacteria, and Verrucomicrobia. There is a lot scientists still do not understand about the relationship between gut microbiota and obesity. According to the NIH, altered ratios of Firmicutes to Bacteroidetes are more common in obese patients than non-obese patients. Given these are two of the major phyla our gut bacteria belong to, a drastic change in their abundance means a drastic change in the products they typically produce.  

One health-related impact of this dysbiosis, or imbalance, of the gut microbiome is weight gain. A contributing reason is due to a lack of energy. This exhaustion can result in someone being less motivated to do physical activity which can lead to weight gain. Decreased energy levels also result in consuming excess carbohydrates and protein for energy, leading to weight gain and potential obesity. Additionally, gut dysbiosis is shown to increase adipose (fat) tissue. In germ-free mice (whose gut bacteria were previously removed), their adipose tissue increased when given a transplant of various gut microbes from obese mice, even when they were fed less food.  

While an unhealthy gut microbiome can lead to weight gain, a healthy one is not enough for weight loss in obese populations. One would likely need additional support in attaining a healthier weight, such as physical activity, medication, and surgery. Exercise can be a very successful weight loss plan for many individuals, but may not be possible for someone who is disabled, does not have access to gyms, or does not have time for long periods of physical activity. Another option is prescription-based medications. However, these medications have a wide variety of side effects and purposes that may be irrelevant to someone simply trying to lose weight, including antidepressants, stimulants, or diabetes management. Surgery may be necessary for extreme cases, but there are still many health risks that follow these procedures, including nausea, loss of appetite, weakness, loose stool, and bowel obstruction.  

For low-income populations, following a gut-friendly diet may prove very difficult. In 2021—in relation to the COVID-19 pandemic—only 58% of the world’s population could afford a healthy diet. As the global population’s ability to eat healthily is decreasing over time, there is an increase in nutritional disorders over time as well, including obesity and type 2 diabetes, partially due to changes of the gut microbiota composition. Healthier foods are often more expensive or are sold in geographically farther locations from poor neighborhoods. Seguin has worked in a Federally Qualified Health Center with predominantly low-income patients. When following a gut-healthy diet is difficult or unattainable, things that she has seen to be beneficial for them are food assistance programs (e.g., SNAP dollars) that allow them to purchase at farmer’s markets. She has also worked towards providing transportation for low-income patients, especially seniors, since this can be another barrier for accessing fresh and healthy foods.  

What does it mean to “eat healthily” versus to “eat to improve gut health?” According to Seguin, they go hand in hand; “Diversity and variety in our gut is often fueled by diversity in our diets, so we want to try to have a great variety. We’re rotating through different fruits and vegetables on a regular basis because that helps improve the variety and diversity of the microbes in the gut.” She also notes the importance of fiber-rich and fermented foods, along with having diverse polyphenols, to feed our healthy gut microbiota: “Polyphenols are really just the very colorful pigments that we see in our fruits and vegetables, so I’m a very big fan of eating the rainbow… and they also help with the production of short-chain fatty acids which are helpful for maintaining a healthy lining in the gut.” 

Fiber-rich diets are important because while fiber is indigestible by our gastrointestinal tract, it instead travels down through our gut, feeding the gut bacteria that live there on its way. This sustains these bacteria, allowing them to live and continue doing their roles to help our overall health. When we do not eat enough fiber, some of our beneficial gut bacteria starve, and we are consequently deprived of their benefit. It has also been shown that people with high-fiber diets generally have lower weight than those with low-fiber diets, which could potentially be due to the gut bacteria that benefit from the fiber. The overflowing promotion of fast food, sugar-sweetened drinks, high-salt diets, and processed foods in popular Western culture has drastically decreased our fiber consumption. Seguin described a study that was done on the Hadza African tribe. This group—known for typically consuming 150g of fiber per day —was shown to have 40% more microbial diversity compared to Americans, who typically only consume around 15–20g of fiber per day.  

Overall, it is important to pursue a gut-healthy diet. Quality of diet is not always a choice, but rather a hope that depends on socioeconomic status, available resources, and education about this topic. In the future, it is hoped that audiences will be inspired to create or advocate for change in the American food industry, as well as for businesses and the government to continue pushing for more affordable healthy diets with a subsequently healthier society. There is progress towards the advertisement of health-conscious grocery stores and menu items on the rise, but not without additional costs. We have seen what one bacterium can do when working with other bacteria, but with all of this work remaining to be done by so many people, we now ponder: what can one person do? The answer may vary, but good suggestions are to self-educate through professional resources, such as doctors or dieticians, and spread the word to those around you to keep as many people healthy as possible! In the words of Seguin, “food is a conduit for connection…to the people who grew it, to the land that it comes from, connects us to our culture and heritage, and then when we share meals together, we’re able to connect with one another…the connection we’re making about food, it’s bigger than the calories; part of the healing components of food, I think, is connection.”