Medically reviewed on September 16, 2022 by Morgan Spicer, Medical Communications Manager. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
With hashtags like “#guthealth” garnering more than 2.2 billion views on TikTok, it’s safe to say gut health is having a moment in the wellness space. And beyond viral user-created videos of “hacks to heal your gut,” studies show people are leaning into digestive health now more than ever. According to a 2021 survey by the International Food Information Council, nearly one in four people consider digestive health as the most important aspect of their overall health and one-third of respondents reported that they actively try to consume gut-supporting probiotics daily.
The downside of gut health’s seat in the spotlight? There’s a lot of misinformation floating around. So to help cut through the clutter of information out there, we spoke with two digestive health experts — Dr. Hugh Humphery, a psychiatrist and MD who specializes in gut health, and registered dietitian, Nicole Lindel — to answer your questions on all things gut health. Here’s what they said:
Dr. Humphrey: In medicine, the mind and body have traditionally been treated as separate entities by doctors. However, research in recent years on the gut microbiota has shown gut health not only plays a role in physical health but in mental health, too. The gut-brain axis is a two-way route of communication between the central nervous system and the enteric (the gut) nervous system, which links the brain’s emotional and cognitive centers with intestinal functions.  We feel this connection when we have a “gut feeling” or when stress or anger causes the stomach to be “tied in knots.” Several human and animal studies have shown that when the subject consumes beneficial microbes — probiotics from supplements or food —there’s reduced inflammation, anxiety, and signs of distress].
Dr. Humphrey: Research shows that gut microbes influence the release of neurotransmitters such as serotonin, noradrenaline, dopamine, and acetylcholine and, although they do not cross the blood brain barrier, they do indirectly affect brain function. Serotonin, for example, is mainly produced in the enterochromaffin cells of the intestine and communicates directly or indirectly with all areas of the intestines, the brain, the nervous system, and the immune system. Serotonin plays an important role in gut homeostasis, sensory motor function, brain control of stress, immune cell function, and blood coagulation. In other words, in order for the body to produce adequate amounts of serotonin, leading to a stable and happy mental state, it’s essential to have a healthy gut.
Dr. Humphrey: Research shows that stress-related disorders typically manifest in a breakdown of the gut barrier and increased intestinal permeability. This disruption of a healthy gut-brain axis influences not only energy and digestion, but also emotions and behaviors. Roughly 50% of irritable bowel syndrome (IBS) patients have comorbid depression or anxiety disorders. This suggests there is a strong correlation between the gut-brain axis and mood issues. Additionally, it is well known that stress activates the hypopituitary (HPA) axis, which in turn secretes more stress related hormones such as cortisol. Cortisol is a substance that prepares our bodies for a “fight or flight” reaction. In adequate amounts it prepares muscles for intense activity, increases brain functioning, and helps the body produce more energy. However, in excessive amounts—due to severe or prolonged stress—cortisol will have significant negative effects on the body and the mind. Excess cortisol breaks down muscle, zaps the body of energy, causes brain fog, and leads to the breakdown of the intestinal barrier, further disrupting the gut-brain axis.
Dr. Humphrey: The foundation of good gut health sounds like the age-old advice from our grandmothers: Eat a balanced diet, maintain low stress levels, get good sleep, and exercise frequently. In addition, eating the right amount of pre- and probiotics (obtained from food or supplements), having adequate levels of vitamins in our systems, and maintaining a healthy microbiome are now also considered part of the foundation of good gut health. In fact, a disruption of any of these factors can lead to worsening gut health. To achieve optimal gut health, one must try to improve each factor individually. Since this could be a daunting task, I recommend working on one factor at a time while adding prebiotics, probiotics and key vitamins to one’s diet. Studies show that consuming pre- and probiotics help in improving digestive tract function, support a healthy immune system, and reduce colic symptoms, antibiotic associated diarrhea, eczema, and upper respiratory tract infections. Research also indicates that adding vitamins C, B, and D to our supplementation regimen may help modulate the human gut microbiome, impacting metabolic activity and bacterial composition. These vitamins have a particular impact on preventing and treating dysbiotic microbiota related to human diseases.
Dr. Humphrey: While the mechanisms underlying food sensitivity are still unclear to researchers, several studies suggest that gut microorganisms along with other predisposing Factors — such as genetics — dictate the development of food sensitivities. Researchers have also linked food sensitivities to various microbial signals that are possibly food-induced by gut infections or alterations in the gut microbiota.
While research is still ongoing about the specific mechanisms that connect gut health and food sensitivities, what is clear at this time is that gut health influences the creation of food sensitivities, as well as the overall health of our bodies and our minds. So paying attention to what we eat and how it makes us feel is a smart choice.
Lindel: Fruits, vegetables, nuts, legumes, and whole grains are all rich in fiber and can benefit gut health. Eating fermented foods like Greek yogurt, kimchi, or kefir help boost microbiome diversity and improve the body’s immune response.[7,8] It’s important to remember that it’s less about a specific food and more about adding a variety to the diet to promote gut health. Eat a rainbow of colors! Each color in fruits and vegetables indicates an abundance of specific nutrients. For example, carrots and oranges are rich in vitamin C and other antioxidants that have been shown to enhance vision, promote a healthy heart, and stimulate our body’s natural defense system.
Lindel: Yes, we are learning more and more about how gut health impacts overall health but on the flipside — it means there’s a lot of misinformation online. That’s why it’s important to find sources that are backed by science, too.
1. IFIC Survey: Consumer Insights on Gut Health and Probiotics. Food Insight. URL. Accessed September 7, 2022.
2. The Gut-Brain Axis: Influence of Microbiota on Mood and Mental Health. NIH. URL. Accessed September 7, 2022.
3. The Microbiota-Gut-Brain Axis. NIH. URL. Accessed September 7, 2022.
4. The Gut-Brain Axis. NIH. URL. Accessed September 7, 2022.
5. The Intervention of Prebiotics on Depression via the Gut-Brain Axis. NIH. URL. Accessed September 7, 2022. 6. Mechanisms Underlying Food-Triggered Symptoms in Disorders of Gut-Brain Interactions. NIH. URL. Accessed September 7, 2022.
7. Hills RD Jr, Pontefract BA, Mishcon HR, Black CA, Sutton SC, Theberge CR. Gut Microbiome: Profound Implications for Diet and Disease. Nutrients. 2019 Jul 16;11(7):1613. doi: 10.3390/nu11071613. PMID: 31315227; PMCID: PMC6682904. 8. Bischoff, S.C. 'Gut health': a new objective in medicine?. BMC Med 9, 24 (2011). https://doi.org/10.1186/1741-7015-9-24