How trillions of organisms living in your digestive tract influence every aspect of your health
By Karen Dybis
The secret to your health lies deep within you. That’s not just some New Age-y slogan, it’s science: Every part of your body, from your brain and immune system to your skin, is influenced by the gut microbiome, a collection of over 100 trillion microorganisms (including bacteria, fungi, parasites and viruses) that live in your gastrointestinal tract.
When these microorganisms are in balance, your body tends to work better. But when they’re out of whack — something that depends on external factors, like what you eat, the amount of sleep you get or how much stress you’re under — it has implications for your health.
“The function of the human body is determined by the network of all of the body’s organs [including the microbiome] interacting with the individual’s environment, diet and lifestyle,” says Dr. M. Elizabeth Swenor, who heads the Functional Medicine program at the Henry Ford Center for Integrative Medicine in Detroit. (Functional medicine focuses on how bodily systems work together to promote health and wellness.)
In recent years doctors have discovered more about the microbiome and how, exactly, it influences our health — but the science is far from comprehensive. “There’s a lot that we have to learn about this in terms of how it impacts how our body works,” says Dr. Jay R. Levinson, a gastroenterologist at Beaumont and practitioner at Digestive Health Associates PLC in Farmington Hills.
But what do we know so far about how the microbiome affects different bodily systems, and how can you keep your own gut in check? Metro Detroit doctors share their insights.
“Eighty percent of your immunity comes from your gut health,” says Swenor. Indeed, research shows that the gut microbiome directly interacts with a body’s immune system, allowing for the development of healthy immune cells and functions. According to Swenor, disturbances in your gut microbiome may show up as autoimmune thyroid conditions such as low or high thyroid (known as hypo- or hyperthyroidism, respectively).
What’s more, your food choices can trigger immune-related symptoms (processed foods, we’re looking at you). “Food is a main contributor to the disruption of gut health,” says Swenor. Foods high in saturated fats, added sugars and artificial sweeteners “cause a cascade of inflammatory processes,” she says, which can spell trouble for your overall health.
More nutritious choices, however — think whole, plant-based foods — boost “healthier” bacterial species, says Swenor, as well as improved blood sugar and fat metabolism, and an overall improvement in immunity.
That said, no need to feel guilty about last night’s supersized burger and fries. “Within 72 hours, you can change the bacteria in your gut from a bad population of bacteria to a healthy population of bacteria” by eating fruits, vegetables and foods high in fiber, says Swenor. “Let food be your medicine.”
A poor diet can trigger inflammation, which then can circulate through the body and cause heart disease, says Swenor. How? Gut microorganisms are involved in the processes of atherosclerosis — i.e., hardening or plaque formation within the arterial walls. When your gut bacteria metabolizes foods like red meat and eggs, it can cause “a cascade of pro-inflammatory reactions that accelerate atherosclerosis,” she says. But the gut microbiome can also work in favor of your heart health: Research has found that it may play a key role in controlling body mass index and cholesterol.
Research has shown that the brain and the gut, which are connected by millions of nerves, are like you and your BFF — i.e., constantly in communication. (In other words, there’s a good reason why doctors call the gut microbiome your body’s “second brain.”)
“It may seem surprising that alterations in the gut microbiome can have an effect on mental health,” says Donald M. Kuhn, a professor in the Department of Psychiatry & Behavioral Neurosciences at Wayne State University who’s studying the communication network between the brain and the gut. He says that many psychiatric disorders, including depression and anxiety, as well as certain neurological conditions (like Parkinson’s disease and autism spectrum disorder) are now being linked to alterations in the gut microbiome.
The digestive system encompasses groups of microorganisms that live in the mouth, esophagus, stomach and the small and large intestines. The colon (the major section of the large intestine) is a key part of the gut microbiome — that’s where the majority of bacteria live — so it makes sense that what you eat affects the balance of bacteria in your body, and therefore impacts your digestive health.
Eat too many processed foods, for example, and you may see conditions such as acid reflux, constipation, irritable bowel syndrome and more. A healthy diet, however, “can help rebalance the gut microbiome and improve overall health,” says Kuhn.
Learn more about gut health and how it affects your entire body by signing up for our free virtual event, Gut Health & Your Whole Body on January 22. RSVP here!