Five Symptoms of an Unhealthy Gut, and What to Do About It

Brett SmithApril 15, 2022

Your gut is home to trillions of microorganisms, which have garnered tremendous interest from both the general public and scientists over the past few decades.

Most people think of bloating, constipation, diarrhea, and abdominal pain as the primary markers of suboptimal gut health. While gastrointestinal symptoms can certainly indicate a gut in disrepair, they aren’t the only signs to look out for. Here are five surprising symptoms that might indicate an unhealthy gut, and what to do about it.

1. Excessive Sugar Cravings

It’s no secret that sugar has addictive qualities. In fact, excessive sugar cravings may be partially caused by the types of microorganisms in your gut. According to a review published in the journal Bioessays, since our bodies are composed of a number of organisms competing for nutritional resources, cravings may be the result of an evolutionary conflict between the person and their own microbiota gut microbes may manipulate our eating behaviors to benefit their survival.

If you have a particularly stubborn sweet tooth, the best way to discourage sugar-loving gut microbes from taking over is to progressively decrease your intake of added sugars.

For example, replace sugar-sweetened beverages with herbal teas and water infused with citrus fruit. Instead of reaching for a candy bar, opt for dark chocolate and nuts. If you typically add sugar to oatmeal, tea, or coffee, instead try adding cinnamon, a naturally sweet flavoring agent.

It’s also good to read nutrition labels and ingredient lists to minimize consumption of unnecessary added sugars hiding in foods you wouldn’t expect, like pasta sauces, nut butters, condiments, and breads. Over time, these seemingly small adjustments will help restore balance to your gut microbiome.

2. Food Intolerances

Food allergies are immune reactions to proteins in foods we eat, whereas food intolerances occur when you have difficulty digesting a certain food or food component. Food allergies may cause shortness of breath, swelling of the tongue or mouth, itching, or hives.

Food intolerances do not create allergic reactions, but instead lead to gastrointestinal symptoms like diarrhea, abdominal cramping, bloating, and gas. Unlike food allergies, those with food intolerances may be able to tolerate small quantities of a food they are intolerant to, according to Mayo Clinic. Food intolerances affect an estimated 20 percent of the population, according to research published July 19 in the journal Nutrients, and although they are not life threatening, they can be highly disruptive.

While there are different types of food intolerances and a number of reasons why one might develop, research suggests that many food intolerances may result from changes in the gut microbiome that may be corrected through dietary adjustments. Research published in Case Reports in Clinical Nutrition in July 2021 described a case in which fecal microbiota transplantation (FMT) effectively treated a woman with food intolerances to dairy, gluten, eggs, and soy. By altering the ecosystem of microbes living in her gut, she experienced significant improvements in her gastrointestinal symptoms, and was able to reincorporate gluten and dairy into her diet.

To identify food intolerances, it’s helpful to keep a food and symptom journal, to pinpoint the offending food. Once identified, eliminate that food from your diet for several weeks. If your symptoms dissipate, consider reintroducing the food in small quantities, slowly increasing portions as tolerated. Gradual reintroduction allows your gut bacteria to shift and adjust to become more adept at breaking down this food, potentially increasing your tolerance. Working with a registered dietitian can be particularly helpful in guiding you through this process.

3. Unintentional Weight Gain

If you experience unintentional weight gain that cannot be attributed to a medical condition or lifestyle changes, your gut microbiome may be the culprit. According to a study published in Cancer Epidemiology, Biomarkers, & Prevention in November 2020, gut bacteria affect energy expenditure and the amount of calories a person extracts from food. After researchers sequenced the gut microbiomes of over 500 participants, they found that as diversity of participants’ gut microbiomes decreased, Body mass index (BMI) increased. Another study, published in the Journal of Internal Medicine in July 2020, demonstrated that researchers can predict who is living with obesity by analyzing the composition of a person’s gut microbiome.

A potential explanation for these findings is that some gut bacteria are more efficient at breaking down food than others, allowing us to absorb more calories from eating the same exact foods, as suggested by a review published in the journal Nutrients in November 2020. Additionally, as outlined in research published in the journal Frontiers in Immunology in October 2020, certain gut bacteria promote inflammation, which contributes to insulin resistance, indirectly affecting weight.

The link between weight and the gut microbiome is so well established that new proposed strategies to treat and prevent obesity target the gut microbiome. A review published in March 2019 in the journal Nutrients noted a handful of clinical trials examining the effects different probiotic formulations have on weight loss. While the research is promising, it is too preliminary to recommend specific probiotic supplements or protocols. In the meantime, it’s best to stick to a diet high in plant fibers from fruits, vegetables, legumes, and whole grains, to promote a healthy gut microbiome. According to research published in Preventive Nutrition and Food Science in June 2020, this type of dietary pattern is associated with reduced weight gain independent of calories consumed.

4. Moodiness, Anxiety, and Depression

It’s no wonder many phrases in our vernacular associate the gut with our emotions — if you’ve ever had “butterflies in your stomach,” a “gut feeling” about something, or felt “sick to your stomach,” you’re likely familiar with the gut-brain connection. In fact, the gut is often referred to as the second brain, and for good reason. According to a review published in May 2018 in Frontiers in Psychiatry, gut microbes communicate with the nervous system, endocrine system, and immune system, influencing mood.

Individuals diagnosed with anxiety and depression are thought to have abnormal intestinal function, and a handful of studies suggest that supplementation of prebiotics and specific probiotic strains may improve symptoms. A Frontiers in Neurology meta-analysis published in May 2020 found probiotic supplementation to be associated with reduced depressive symptoms. That said, the ability of a probiotic supplement to improve mood is likely dependent on the specific probiotic strains and formulation.

Short of specific probiotic supplementation, adopting a diet rich in whole, plant-based foods, such as the Mediterranean diet, may promote a gut microbiome conducive to optimal mental health. According to a review published in Advances in Nutrition in July 2020, this type of dietary pattern promotes gut microbial diversity and reduces gut inflammation, benefiting mental health. Increasing dietary omega-3 fatty acids from certain fish or micro-algae may also have a positive effect on gut microbiome composition, and reduce risk for depression.

5. Skin Irritation

If you have ever found certain foods to exacerbate skin ailments, your gut bacteria may be part of the problem. Eating foods high in saturated fat and refined sugar promotes an unhealthy balance of gut bacteria, according to research published in the journal Microorganisms in February 2021. This state of dysbiosis is associated with abnormal immune function, contributing to inflammatory skin conditions like eczema, psoriasis, acne, rosacea, and dandruff.

The research also demonstrated that those with inflammatory skin conditions have different gut bacteria compared with those without these conditions. Those with rosacea also have a higher prevalence of gastrointestinal conditions, and an estimated 7 to 11 percent of inflammatory bowel disease (IBD) patients also have psoriasis, further validating the gut-skin connection.

To support skin health, following the same anti-inflammatory dietary guidance for optimal gut microbiome health is recommended. According to a study published in the journal Gut in April 2021, this means consuming a diet rich in whole plant foods and incorporating omega-3 fatty acid sources like fish while limiting processed and animal-derived foods.