In the not-so-distant past the term “gut health” equated with digestion. Today it references the trillions of microbes residing in your gastrointestinal tract. Collectively these microbial settlers are known as your gut microbiome and their effect is systemic.
Basically, an ailing microbiome houses too many pathogenic bacteria. Current research links this state (dysbiosis) with a wide range of diseases, meaning your gut bacteria play an outsized role in keeping you well.
Here are some ways your microbiome is pulling strings on your health and well-being.
1. Microbes Shape Your Mood
A gut that harbors too many hostile bacteria makes you more vulnerable to stress.
One laboratory study identified a link between the onset of stress, a loss of beneficial Lactobacillus bacteria and depression. The condition improved with a probiotic supplement providing the deficient bacteria.
Neurotransmitters connect gut health with depression. About 90 percent of your body’s supply of serotonin (known as the happy hormone) is generated by your gut bacteria, which also regulate other neurotransmitters, like dopamine, glutamate and GABA.
One 2022 study linked depressive symptoms with the presence of 13 types of unfriendly gut bacteria. On the other hand, high ratios of beneficial bacteria have been shown to support mental health, from helping to manage everyday stress to avoiding postpartum depression.
The best way to bulk up your microbial troops and build resilience to stress is by eating an abundance of plant foods. The Mediterranean diet (rich in plant-based foods like whole grains, fruits, vegetables, legumes and nuts, plus healthy fats obtained mainly from fish and olive oil) raises the ratio of mood-supporting bacteria.
The SMILES trial studied the Mediterranean Diet as a treatment for people medically diagnosed with depression. After 12 weeks, participants who adhered to the diet felt significantly better. One third (32 %) achieved full remission and were no longer depressed.
2. Your Gut May Be Making You Sneeze
Runny nose? Weepy eyes? Emerging evidence suggests that the more robust and diverse your microbiome the less likely you are to suffer from seasonal allergies and asthma. Data from the American Gut Project links allergies provoked by seasonal pollen with low bacterial diversity.
About 70 percent of your immune system is in your gut. Research suggests that our increasingly sterile environments shortchange exposure to bacteria that support immune system development. One study found that children raised on small, traditional farms had richer and more diverse microbiomes and significantly lower rates of asthma compared to a control group raised in more industrialized environments.
To help children develop strong immune systems experts recommend a nutritious fiber-rich diet that includes fermented foods. Other strategies include limiting the use of antibiotics, using standard (as opposed to anti-bacterial) detergents and cleaning products, and having a family pet. Children who grow up with a dog have have fewer allergies.
3. Friendly Flora Support Beautiful Skin
Common wisdom suggests that what goes into your stomach comes out on your skin. Today, research links conditions like acne, rosacea, eczema, psoriasis and even skin that ages before its time with a dysbiotic gut. Scientists now speak of the “gut-skin axis,” the interaction between your microbiome and disease states in your skin.
Unsurprisingly, the so-called Standard American Diet (high in calories and low in nutrients like gut-friendly fiber) has been linked with both gut dysbiosis and inflammatory skin conditions. We’re not there yet, but scientists envision the day when tweaking the gut microbiome will be a routine treatment for skin care. Studies already show the benefits of probiotic supplementation in numerous conditions, like acne, psoriasis and atopic dermatitis.
4. Bacteria Influence How Well You Sleep
Good sleep is vital to long-term health, influencing whether you develop conditions like type 2 diabetes, heart disease and even how much you weigh. Now we’re learning that your microbiome regulates how well you sleep.
Basically, people with healthy microbiomes (bacterially diverse) tend to sleep better. This partnership has a spillover effect. Older people with robust microbiomes who regularly sleep well are less likely to experience age-related cognitive decline.
On the other hand, people who aren’t good sleepers tend to have lower ratios of friendly bacteria and a higher proportion of pathogenic species. Scientists don’t fully understand the mechanisms, but unhealthy guts appear to throw neurotransmitter production out of whack. One result is a deficiency of serotonin, which undermines sleep quality.
Tailored therapies using prebiotics appear to improve sleep quality, as do dietary interventions like the Mediterranean diet, which boost the body’s ability to produce serotonin.
Give Your Microbes Credit
Essentially, your gut microbes are much smarter than you might think. They can communicate with organs well beyond your gut, triggering changes throughout your body. It’s a reciprocal relationship. If you look after them, they will likely take good care of you.
Judith Finlayson is a journalist and bestselling author with a longstanding interest in health and nutrition. Her most recent book, You Are What Your Grandparents Ate: What You Need to Know About Nutrition, Experience, Epigenetics, and the Origins of Chronic Disease, was published in 2019. It has been translated into 7 foreign-language editions, including French, German, Spahis and Japanese. Visit her at www.judithfinlayson.com.