Did you know your body carries more bacterial cells than human cells? Our bodies are home to about 40 trillion — yes, trillion —bacterial cells compared to only 30 trillion human cells! Even though they are tiny, bacteria account for about two to five pounds of our total body weight. You’ll also find fungi, viruses and other microscopic living entities in your body. As a group, these are called microorganisms, or microbes. You probably already know bacteria play an essential role in aiding digestion, but as we learn more, scientists are discovering a cornucopia of roles bacteria play in our health and wellbeing. In his post, we’re going to explore why our gut bacteria is vital to our mental and physical health.
Bacteria primarily live on our skin and in our intestines. Microbes in our intestines live in a part of the large intestine called the cecum — these are the microbes referred to as the gut microbiome. Up to 1,000 bacteria species live in the human microbiome — and each plays a different role in our bodies. Most are considered “helpful” and are extremely important to our overall health.
We’re first exposed to microbes in the womb and more so during the birth process. Recent research has found that babies delivered via Cesarean section don’t have as many microbes as babies born vaginally. Breastmilk contains a slew of necessary microbes and is one of the primary reasons why doctors recommend breastfeeding for a baby’s first year. As we grow and are exposed to more foods and the environment, our gut microbes diversify.Higher microbe diversity in our guts leads to better health. Researchers have found that those of us who eat a Western diet high in fried foods, sugary drinks, processed meats, refined sugars, and other highly processed foods containless gut microbe diversity than those who eat primarily fruits, vegetables, and unprocessed foods.
One type called gram-negative bacteria in our gut microbiome contains lipopolysaccharides, large molecules known as endotoxins. Endotoxins can cause allergic reactions and infections. They can also leak from our gut into our bloodstream. Our immune system sees these endotoxins as foreign invaders and attacks them, resulting in chronic inflammation throughout our body In fact, recent research has shown that endotoxins — and the inflammation they cause may be a driver for many chronic metabolic conditions such as Alzheimer’s, fibromyalgia, depression, Type 2 diabetes, metabolic syndrome, fatty liver disease, and many other diseases.
In addition to aiding digestion and the production of certain vitamins, new research has been finding several other important functions that our gut microbiome directly or indirectly influences, from obesity to the metabolic conditions we noted above to cancer to mental health to food allergies and even autism. In addition to a lack of gut microbiome diversity, an over or underpopulation of specific bacteria may impact our health. Two-thirds of our microbiome is unique to each person, influenced by what we’re exposed to as newborns and later by our environment, foods and possibly even our genes.
One surprising find in gut microbiome research is its link to obesity. Researchers from King’s College London and Cornell University conducted a 2014 study of identical and non-identical twins. They found that genetics plays a role in gut bacteria — but more significantly regarding weight gain, researchers discovered that a particular bacterial strain was more common in people who weighed less. Researchers introduced this strain calledChristensenellaceae minuta to mice and found they gained less weight than mice who were not given the bacteria. The study suggests that one possible way to reduce or prevent obesity is to increase the amount of Christensenellaceae minuta in people who lack sufficient levels.
Other studies have found links between certain strains of bacteria and weight gain. A strain called Escherichia coli Nissle 1917 produces a compound called N-acyl-phosphatidylethanolamine (NAPE). NAPE has been found to reduce food intake in mice. It’s highly likely new studies will find more definitive links and possibly ways to alter our gut microbiome to prevent or reduce obesity.
In a 2019 study, Canadian researchers identified 19 strains of gut bacteria which were higher or lower in numbers in fibromyalgia patients compared to those who did not have the condition. They found that the severity of patients’ symptoms directly correlated to an increase or decrease of specific bacteria. Researchers were quick to point out that the findings do not prove that altering fibromyalgia patients’ gut microbiome would alleviate symptoms or cure the disease, so further research is needed. Chronic inflammation is an underlying factor in fibromyalgia, so some patients find relief by taking supplements that can help reduce inflammation — click here to learn more.
Several studies in the U.S. and U.K. have found links between certain cancers and gut bacteria. A 2013 study found an intestinal bacteria called Lactobacillus johnsonii may play a role in the development of lymphoma, a cancer of the white blood cells. Other studies have found links between gut microbiome and stomach and colorectal cancer.
According to recent research, our gut microbiomes impact more than just our physical health — gut bacteria produce 95 percent of our body’s supply of the “feel good” hormone serotonin, as well as an array of other neurochemicals related to mood, memory, and learning. Doctors and researchers have known for years that people who experience anxiety and depression also frequently experience problems with their gut and digestion. One study found that adding prebiotics, carbohydrates that help increase healthy gut bacteria, to the diet of healthy adults lowered levels of the “stress hormone” cortisol — and participants reacted better to negative stimuli than the control group.
Exciting new research in the fields of autism and food allergies in children are finding links between gut bacteria and these conditions. An Arizona State University study found that children with autism processed lower levels of three bacterial strains compared to children without autism. Another study found different concentrations of chemicals called metabolites, which are produced by gut bacteria, in children with autism. Metabolites play a role in communication between the gut and the brain, so researchers theorized that the altered levels might be an underlying cause of autism.
Like autism, food allergy rates in children have increased exponentially over the past few decades. Now researchers are beginning to see links between children with food allergies and the absence of certain bacteria. One recent study suggests that replenishing the missing bacteria could treat food allergies.
In addition to the conditions we noted above, researchers are also looking at aging, gut health, and many other conditions. Given how much our gut flora impacts our health, the first question that comes to mind is — can we alter our gut bacteria? Yes, according to research — the no brainer answer is to eat more fruits and vegetables in their natural state and avoid processed foods. Exercise has also been shown to help with gut health. You can also consume fermented foods such as miso, sauerkraut, and kombucha, a type of fermented tea. We’re sure to see more exciting results from research on those tiny organisms in our intestinal tract and their impact on our health, but in the meantime, evidence indicates we should be paying attention to our gut health.