A healthy gut isn’t just necessary for good digestion. Scientists are discovering more about how the bacteria in your gut may play a role in your overall health, including your mental well-being.

Gut Bacteria

While infection is commonly associated with bacteria, it’s essential to note that the majority of bacteria in the gut are actually beneficial.

The gut microbiome, comprising approximately 100 trillion microorganisms, including bacteria, yeasts, fungi, and viruses, is primarily situated in the colon. With approximately 1,000 species of bacteria, the unique combination varies from person to person and evolves throughout life.

Research indicates that maintaining a balance between more and less helpful bacteria is crucial for a healthy gut.

In addition to their role in digesting food, gut bacteria perform various vital functions. They aid in the absorption of minerals from food, synthesize vitamins such as vitamin K (essential for blood clotting), and break down dietary fiber, releasing molecules like butyrate, which reinforces the gut barrier, and propionate, which assists the liver in regulating blood sugar levels and appetite.

Not Just About The Gut

Individuals with inflammatory bowel conditions such as Crohn’s disease and ulcerative colitis exhibit a reduced number of species and a lower proportion of beneficial gut bacteria.

Similarly, studies have identified lower diversity in individuals with obesity, diabetes, as well as certain forms of eczema and arthritis.

The presence of dysbiosis, an imbalance in the gut microbiome, has been linked to contributing factors in metabolic syndrome, allergies, colorectal cancer, and Alzheimer’s disease.

A robust immune system is supported by a healthy gut, with approximately 70 percent of immunity-related cells located there. Friendly bacteria play a crucial role in interacting with the intestinal lining, preventing the leakage of harmful molecules into the body, and aiding in the activation of new immune cells.

Healthy Gut, Healthy Mind

While we commonly understand that the brain can influence the gut, as evidenced by experiencing stress or excitement in our stomachs, we now recognize that diet can also impact the brain.

Scientists have recently delved into the mechanisms through which gut bacteria may affect the brain, shedding light on how gut health might influence mood.

Numerous studies have revealed disparities in the microbial composition of individuals with depression compared to others. In 2019, researchers identified two specific types of gut bacteria, Coprococcus and Dialister, consistently lacking in the microbiomes of individuals with depression.

The Gut-Brain Axis

Scientists currently understand that there is ongoing, bidirectional communication between the gut and the brain, facilitated through various pathways. These pathways include the vagus nerve, cells of the immune system, and the release of chemicals into the bloodstream.

How To Improve The Microbiome

Maintaining a healthy and functional gut relies on the diversity of bacteria residing within it.

The formation of our gut microbiome takes place predominantly from birth to approximately three years old. During this critical period, most microbes are inherited either from the mother’s birth canal in vaginal deliveries or from the hospital environment in the case of caesarean sections.

Additionally, the microbiome can be influenced by whether an infant is breast or bottle-fed. Subsequently, infants continue to acquire bacteria from their environment, interactions with nearby individuals, and their diet.

While the initial composition of the gut microbiome is established early in life, ongoing factors such as lifestyle, stress levels, and diet can still induce shifts that either support or undermine overall health.

Notably, certain strains from the Bifidobacteria and Lactobacillus families have been identified for their ability to prevent the overgrowth of potentially harmful gut bacteria.

Improve Microbiome Diversity

An international study, analyzing data from thousands of volunteers, has correlated bacterial diversity in the gut with the variety of plant species consumed.

The research suggests that the consumption of 30 or more types of plants per week is associated with the production of various short-chain fatty acids, contributing to the protection of both gut health and immunity.

It has also been demonstrated that increasing the intake of indigestible fiber enhances the richness of the gut microbiome, while an overall low-fiber diet diminishes bacterial

Besides vegetables, whole grains such as oats, brown rice, beans, and lentils, as well as nuts and seeds, are excellent sources of fiber.

UK health guidelines recommend that healthy adults consume 30g of fiber daily from diverse food sources. Many of these foods have a “prebiotic” effect, nourishing beneficial bacteria.

Additionally, naturally fermented “probiotic” foods like kefir can be beneficial, with various species of Lactobacillus commonly found in fermented foods.

In contrast, studies have shown that a typical Western diet, characterized by high animal protein and fat content and low fiber, leads to a significant decrease in total bacterial numbers and beneficial Bifidobacteria.

It’s worth noting that a short-term change in diet can rapidly influence microbiome balance. But, substantial shifts in bacterial diversity typically require a long-term change in eating habits.

Why is Fiber Important in Your Diet?

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Medications

The excessive use of medications, especially antibiotics, can lead to a reduction in the abundance of beneficial gut bacteria.

A study examining 900 antibiotic medications found that over a quarter of them had the potential to harm the growth of microbes.

Probiotics offer a solution by promoting the increase of beneficial bacteria. Taking them after a course of antibiotics most effectively supports their efficacy, helping prevent antibiotic-associated diarrhea.

Feeding your microbiome

Research shows that eating 30-plus different plant foods each week supports the gut’s bacterial diversity and barrier strength. It provides varying combinations of vitamins, minerals, and phyto (plant) chemicals.

Fecal transplant

A fecal transplant is a form of bacteriotherapy that involves the transplantation of stool from a healthy donor. Healthcare professionals perform this procedure to rebalance the gut bacteria in unwell individuals, especially in cases of specific gastrointestinal disorders.
Ongoing research suggests that fecal transplants may be an effective treatment for recurrent C. difficile infections.

Reference: Lambert, R. (2022). The Science of Nutrition: Debunk the diet myths and learn how to eat responsibly for Health and Happiness. DK Publishing (Dorling Kindersley).