"What does your gut tell you?"
We’ve all pondered that question before. But the answer isn’t so simple. The intricate connection between a healthy gut and the brain underlies much of our overall well-being, both physical and psychological.
Studies have shown that the gastrointestinal system and the brain communicate with each other on the gut-brain axis through intestinal microorganisms that affect the body’s immune, endocrine, nervous and other organ systems, though these mechanisms are not fully understood.
For examples of the gut-brain dialogue we only have to look at how our emotions and mental distress affect our gut. Nervousness, sadness and anxiety can bring on gastrointestinal upset. Stress, lack of sleep, illness and certain medications can bring on digestive problems.
Conversely, doctors at the Johns Hopkins Center for Neurogastroenterology report in “The Brain-Gut Connection” that gastrointestinal issues may send a signal to the brain triggering mood changes.
“If you’ve ever gone with your gut to make a decision or felt butterflies in your stomach when nervous, you’re likely getting signals from an unexpected source: your second brain,” notes the report. “Hidden in the walls of the digestive system, this ‘brain in your gut’ is revolutionizing medicine’s understanding of the links between digestion, mood, health and even the way you think.”
Dubbed the enteric nervous system, it’s comprised of two thin layers of more than 100 million nerve cells lining your gastrointestinal tract from esophagus to rectum.
“Gut health, if disrupted, can have profoundly negative effects on the immune system and inflammation, and has been linked with changes in metabolism that can promote changes in weight,” says Sareen Gropper, a professor of nutrition at Florida Atlantic University’s Christine E. Lynn College of Nursing.
The entire digestive system plays a role in gut health, but when experts refer to “the gut,” what they really mean is the colon, says the registered dietitian/nutritionist.
She defines good gut health as “effective digestion of food, absorption of nutrients, and digestive processes such as motility; absence of GI tract illness and dysfunction; presence of sufficient quantities of healthy intestinal microorganisms; and good intestinal immune system function.”
That’s a lot to digest – but it’s important to note that healthy microorganisms are the good bacteria that fuel gut function and sustain its processes.
Yin And Yang
The buzz word in gut health is “microbiota” — the collection of good and bad bacteria, fungi, viruses and other microorganisms that live in the gut. “The research shows that your gut bacteria is pretty much established by two or three years old,” says Gropper, who places an emphasis on the role of nutrition in disease prevention and in healthy lifestyle habits.
So what do these good microorganisms that inhabit primarily the large intestine or colon, but also to a lesser degree the mouth, stomach and small intestine, actually do?
The good bacteria play many roles in gut health, Gropper explains. They enhance a person’s immune defense system, prevent bad bacteria from setting up shop, get rid of harmful substances that are ingested (such as the carcinogens on charred meat), and basically detoxify what comes in – along with promoting proper excretion.
When the good bacteria ferments fiber in the colon, it produces what are called short chain fatty acids, the main source of energy for colon cells. These fatty acids also create a beneficial environment for the absorption of nutrients and help the growth of more good bacteria.
Another job for the fatty acids is to stimulate the production of mucin, a substance that forms part of an intestinal barrier that prevents pathogens from getting in. Without tight intestinal barriers, you could develop leaky gut.
“Diet Is Crucial”
To optimize the good bacteria in the gut, “Diet is crucial,” explains Gropper, “but also getting enough sleep and physical activity and trying to reduce stress and anxiety. Microorganisms are affected by diet, medications, stress, illness, and antibiotics.”
We’ve heard a lot about prebiotics and probiotics, but what are they and how do they influence gut health?
While probiotic foods have live microorganisms, prebiotic foods feed the good bacteria that already live in your gut.
Part of a healthy diet, prebiotics include fructans, found in chicory root, asparagus, Brussels sprouts, onions, garlic, cabbage, and broccoli as well as wheat, barley and rye; and galactans, another type of fiber, found in peas, chickpeas, lentils and beans. Other examples of prebiotics are whole grain breads, cereals, seeds and legumes.
To be considered a probiotic, a product must contain 100 million live, active bacteria per gram, according to Gropper. Examples include yogurt with live cultures, fermented or cultured milk and milk products (such as buttermilk and kefir), miso, tempeh, kimchi and fermented vegetables like sauerkraut.
Gropper prefers food as the first line of defense for getting good bacteria rather than a supplement because, she says, probiotic manufacturing is not standardized.
If you have to take antibiotics, Gropper recommends increasing your intake of foods containing probiotics and prebiotics to restore good bacteria destroyed by the medication. “Even those who are lactose intolerant can often handle Greek yogurt or lactose free milk. Eat whole grains, fruits, vegetables and legumes, full of fiber, as often as you can get them in your diet,” she says.
But if you can’t tolerate dairy or certain foods, “Give probiotics a shot,” she says, “unless you have an immune disorder or a medical condition such as a leaky gut where intestinal cells are damaged, because harmful bacteria could get into the bloodstream.”
Food Sensitivities Have An Impact
Dr. Yihong Joy Hao, who practices family medicine and holistic integrative medicine in Boca Raton, says “For integrative and functional medicine, gut health is fundamental.” She explains: “When we talk about wellness, you have to start with gut health. In Chinese medicine, the gut is the middle section, and that is fundamental for life.”
Dr. Hao sees more and more patients complaining of GI symptoms across all age groups with varying symptoms of bloating, irritable bowel syndrome, acid reflux, gas and belching.
Those patients have normally seen another doctor and have had a colonoscopy or endoscopy, with normal test results. “It’s a functional problem,” Dr. Hao says of their conditions.
For gut issues, Dr. Hao uses a clinical specialty lab to conduct functional testing and a comprehensive analysis of a patient’s stool. The tests analyze things like gut flora, yeasts, parasites, absorption function, immunology in the gut and inflammation markers.
“It gives us a clear idea, function wise, how your gut works and we can treat accordingly,” Dr. Hao says.
Dr. Hao spends a lot of time with her patients exploring their habits, lifestyle and diet to discover the cause of their symptoms, and determine if they stem from frequent antibiotic use, which kills both good and bad bacteria, drinking too much coffee, not eating regular meals, alcohol abuse or other factors. If analysis warrants it, probiotics are recommended.
Another major factor in GI issues, she says, are food sensitivities, which make people chronically sick, as opposed to food allergies, in which people have an immediate adverse reaction to the food.
“The food industry actually contributes to lots of our GI problems with too many processed foods, GMOs, additives and colorings. More and more we see food sensitivities, even in young kids or college students,” says Dr. Hao.
In her practice Dr. Hao sees many people, including those with autoimmune diseases, who have an intolerance to gluten.
Unlike celiac disease, an autoimmune disease where the ingestion of gluten damages the small intestine, there is no test to confirm this intolerance. Patients with a food intolerance, like those with celiac disease, often respond positively after following a gluten-free diet.
Dr. Hao always starts with the basics, suggesting a simple diet with food choices patients can follow, and avoiding common triggers like gluten, milk, soy and corn to see the clinical results.
A Flourishing Future
Research into the gut-brain axis is a promising field of study. The development of psychobiotics to treat mental health through gut bacteria is underway.
Dr. Hao also points to research on patients with Parkinson’s disease who had chronic constipation for 10 years before their diagnosis. The possibility of diagnosing and treating patients through the gut microbiome before the onset of disease would have far-reaching results.
So much is beyond our control - such as genetics - when it comes to gut health, yet there’s something simple we can do to help keep the gut-brain signaling on track: incorporate a healthy diet with plenty of fruits and vegetables.
That’s more than a gut feeling.