Gut Health: Is it a Thing or a Money Grab?

Gut health has become one of the latest health trends, with companies eager to analyze your gut and provide you with personalized supplements to address your problems. All of this is to help cure you of various ailments that have been linked to your faulty gut health. But is any of it true? What exactly is gut health? How do we find out if our gut is healthy? Can we change it if it isn’t? Is gut health actually a legitimate concern or is it just another health trend turned into a huge money grab? Let’s look at the evidence and see if we can answer these questions.

What is Gut Health?

According to the American Medical Association, gut health refers to the well-being of the digestive system, which is responsible for breaking down food, absorbing nutrients, and eliminating waste from the body. It is made up of trillions of bacteria, viruses, and fungi that are collectively referred to as the gut microbiome.¹ The gut microbiome is just part of the entire human microbiome, which encompasses microorganisms in other parts of our body and all over our skin.²

Our microbiomes are vast and unique.^3,4 Over 1000 bacterial species have been identified in the human microbiome, and approximately 160 of them are found in the gut of any individual.⁵ An individual’s microbiome starts during birth and is influenced by age, lifestyle, diet, ethnicity, geographic location, genetics, proximity to animals, and antibiotic use.^3,6,7  It stays pretty stable over time for most people.⁶ Good gut health is characterized by a balanced gut microbiome,³ while poor gut health refers to an imbalanced microbiome, known as dysbiosis.⁶ 

Functions of the Gut Microbiome

The microorganisms in our guts play several crucial roles.

1. Digestion of Foods. Our bodies do not produce the enzymes needed to break down certain plant carbohydrates and minerals or to synthesize certain vitamins.⁵ Our gut microorganisms do this work for us.
2. Metabolic Functions. In the digestion process, they produce specific short-chain fatty acids that may play a role in anticancer activity, glucose control, fat metabolism, and appetite regulation.^5,6
3. Immune System Support. In individuals with normal immune systems, our gut microbiome protects us from pathogenic organisms and helps our immune system function properly.⁶
4. Inflammation Regulation. Some data suggest states of dysbiosis may lead to inflammation.⁶

A Healthy versus Unhealthy Gut

Defining a “healthy” gut is problematic because no one knows what makes a “healthy” microbiome.^2,3 In 2007, the National Institutes of Health (NIH) launched the Human Microbiome Project to explore relationships between microbiota and human hosts.⁴ Before this initiative, approximately 300 studies had been published on the topic. After the project began, the number of studies nearly quadrupled.²

These studies have identified specific organisms that make up the microbiomes, attempted to link certain microbes to certain health states, and explored ways to modify microbiomes and their effects.^2,8 They suggest possible links between microbiota and conditions like lupus, obesity, diabetes, inflammatory bowel disease, irritable bowel syndrome, celiac disease, rheumatoid arthritis, multiple sclerosis, autism, colon cancer, mental health disorders, COVID-19, and nearly 130 other health issues.^5,6,8

Probiotics and Changing the Gut Microbiome

With all this talk about gut health, many people are turning to probiotics, prebiotics, and functional foods in an attempt to alter their gut microbiome for the better. Probiotics are living beneficial bacteria that can be ingested to promote “good” bacteria in the gut.^2,6 Prebiotics are nondigestible supplements that increase the growth and/or activity of preferred microbes.⁶ Functional foods are foods that include any of the following: probiotics, prebiotics, dietary supplements, vitamins, antioxidants, dietary fiber, and/or phytochemicals.⁹ They are also taken to boost overall gut health.

There are some reported benefits of both probiotics and prebiotics. Prebiotics are believed to decrease inflammation by promoting bacterial fermentation.⁶ Probiotics have demonstrated a decrease in irritable bowel syndrome symptoms in patients with celiac disease who are already following a strict gluten-free diet.⁷ They may decrease the recurrence of a dangerous, antibiotic-induced diarrheal illness called Clostridium difficile.⁶ They may also decrease the recurrence of  Helicobacter pylori, a type of bacteria known to cause stomach ulcers, when taken with the traditional treatments for the condition.⁷ There are also claims that probiotics boost the immune system, reduce the risk of cancers, prevent cardiovascular disease and diabetes, and may prevent some allergic reactions.⁹ However, not all of these claims are supported by strong evidence.⁶

Probiotics also have a few downsides. There is a question of how many of the organisms contained in capsules are alive or even make it to the gut.⁷ When they do make it to the gut, they do not colonize it permanently, so they must be taken regularly.⁶ Probiotic manufacturing is not standardized, so consumers cannot be guaranteed what they are getting.⁷ Many probiotic organisms are “generally recognized as safe” (GRAS),⁹ but carry risk with use in immunocompromised people and very young children.⁹ There’s also debate over the effectiveness and safety of foods supplemented with probiotics.²

There are two proven methods of changing a gut microbiome: diet and fecal transplants. In a study evaluating microbiome shifts with diet changes, researchers demonstrated that patients randomized to plant-based diets shifted their gut microbiome to one that was predominantly carbohydrate-fermenting bacteria. Patients randomized to the animal product diet shifted their microbiome to protein-degrading bacteria.⁶ A similar shift was demonstrated in a separate study evaluating the Mediterranean diet and a diet with high intakes of red meat.⁶

Fecal microbiota transplants involve transferring feces from a donor to a recipient to change the gut microbiome. This procedure has been successful in refractory C. diff infection and is currently being investigated in patients with inflammatory bowel disease such as Crohn’s disease. The process still has some challenges with regard to finding appropriate donors and determining proper dosing.⁶

Limitations of Current Evidence

I’ve used the words “may”, “claim”, and other cautious terms when discussing gut health because we are not sure if all the findings are accurate. One problem is the evidence is not strong. The studies cannot establish whether gut microbiomes are the cause of the issue or just correlated in some way. For example, the number of ice cream sales and drownings both increase during the summer. This is because it is hot during summer, so people eat more ice cream and swim more often. This is correlation, not causation. On the other hand, we have clinical evidence that directly links smoking to lung cancer – smoking is a direct cause of lung cancer. This is causation. Such a direct connection has not been made regarding the human microbiome and disease states.

Another issue is the quality of the research. A large portion of the studies are done on animal models.² Mice are not people, so the results are not directly applicable. Many studies done on humans are unblinded observational studies, which means they are subject to bias and can’t determine which factors contribute to the results or outcomes. Lastly, the effects of the interventions were often self-reported surveys. This means people participated in the study and they filled out a survey on what they think is happening in their bodies, which is subjective rather than objective.

Another issue with defining a healthy gut biome is the action and presence of microbes are contextual. For example, the same bacteria that are protective in a full-term baby can cause serious illness in a premature baby.³ These same issues exist when discussing probiotics, prebiotics, and some functional foods as well. The bottom line is clinical data on the prevention or treatment of many of these disorders and the causal links to the gut health are lacking.^2,7,10,11

The Gut Health Industry

There are numerous microbiome-related products for consumer purchase. These include gut makeovers, gut health diets, cleanses, microbiome reboots, probiotic products, and skin regimens. There are also disease “cures” and “treatments” such as colonic hydrotherapy.⁸ As of 2024, the global probiotics market is valued at approximately $78.9 billion and expected to grow to nearly $113.4 billion by 2029.¹² As we discussed in Buyer Beware, you must always be skeptical of different health claims when someone is making billions of dollars off you as a consumer. I looked up a few websites and found several companies willing to charge $100-$600 from you for a detailed report of your gut microbiome. They then offer you a customized list of supplements to “fix” your microbiome for an additional cost.

The media plays a role in this hype as well. They often report inflated conclusions of poorly done studies which mislead the public.^2,8 In an effort to feel better or treat medical conditions, people turn to unproven treatments which could be harmful. For example, there are reports of a Canadian naturopath performing fecal microbiota transplants on children to treat autism.⁸

Putting it All Together

Gut health is indeed an integral part of our digestive system and overall health. The microbes in our gut play essential roles in digestion, metabolism, and immune function. However, the science behind manipulating our gut microbiome for health benefits is still evolving, and more robust research is needed to draw definitive conclusions. While companies are eager to sell tests and supplements, the evidence supporting their effectiveness in conditions outside of the gastrointestinal system is not strong.

So, is gut health a legitimate concern or just another health trend turned into a money grab? The answer is somewhere in between. Gut health is important, but our current understanding and ability to manipulate it are limited. Instead of relying on expensive tests and supplements, focusing on a balanced diet, regular exercise, and a healthy lifestyle may be the best way to support your gut and overall health.

References

1.             American Medical Association. What doctors wish patients knew about improving gut health. Updated September 12, 2023. Accessed October 17, 2024. https://www.ama-assn.org/delivering-care/public-health/what-doctors-wish-patients-knew-about-improving-gut-health#:~:text=Gut%20health%20refers%20to%20the,known%20as%20the%20gut%20microbiome.

2.             Ma Y, Chen H, Lan C, Ren J. Help, hope and hype: ethical considerations of human microbiome research and applications. Protein & cell. 2018;9(5):404-415.

3.             Shanahan F, Ghosh TS, O’Toole PW. The healthy microbiome—what is the definition of a healthy gut microbiome? Gastroenterology. 2021;160(2):483-494.

4.             Rhodes R. Ethical issues in microbiome research and medicine. BMC medicine. 2016;14(1):156.

5.             Rowland I, Gibson G, Heinken A, et al. Gut microbiota functions: metabolism of nutrients and other food components. European journal of nutrition. 2018;57:1-24.

6.             Clemente JC, Manasson J, Scher JU. The role of the gut microbiome in systemic inflammatory disease. Bmj. 2018;360

7.             Smieško G, Gusman V, Banović P, Mikov M. Probiotics and fecal bacteriotherapy: the line between deception and treatment. Vojnosanitetski pregled. 2021;78(9):994-999.

8.             Marcon AR, Turvey S, Caulfield T. ‘Gut health’and the microbiome in the popular press: a content analysis. BMJ open. 2021;11(7):e052446.

9.             Koirala S, Anal AK. Probiotics-based foods and beverages as future foods and their overall safety and regulatory claims. Future Foods. 2021;3:100013.

10.          Kazemian N, Mahmoudi M, Halperin F, Wu JC, Pakpour S. Gut microbiota and cardiovascular disease: opportunities and challenges. Microbiome. 2020;8:1-17.

11.          Martin CR, Osadchiy V, Kalani A, Mayer EA. The brain-gut-microbiome axis. Cellular and molecular gastroenterology and hepatology. 2018;6(2):133-148.

12.          Grand View Research. Probiotics Market Size, Share & Trends Analysis Report By Product (Food & Beverages, Dietary Supplements), By End User, By Distribution Channel, By Region, And Segment Forecasts, 2023 – 2030. Grand View Research,. Updated March 2023. Accessed October 17, 2024. https://www.grandviewresearch.com/industry-analysis/probiotics-market

13.          Fleerackers A, Moorhead LL, Maggio LA, Fagan K, Alperin JP. Science in motion: A qualitative analysis of journalists’ use and perception of preprints. Plos one. 2022;17(11):e0277769.