Introduction,
The gut-brain axis, a concept once relegated to fringe science, is now recognized as a powerful influencer of our mental and physical health. The gut and brain communicate through a complex network of biochemical signals, and this connection affects everything from mood to memory and immune function. But many common habits could be undermining this critical link.
In her new book, Genius Gut: The Life-Changing Science of Eating for Your Second Brain, microbiome scientist Dr. Emily Leeming explores how lifestyle choices shape the gut-brain axis and why certain habits may be harming it. Based on her research and insights, here are seven surprising ways we may be sabotaging this connection—and how to turn things around for better gut and brain health.
- Living with Chronic Stress
Stress is an unavoidable part of life, but chronic, long-term stress can wreak havoc on the gut-brain axis. When stress levels are high, the body’s “fight-or-flight” response kicks in, causing changes to the nervous system and impacting the vagus nerve, a major communication pathway between the gut and brain. This stress response disrupts gut bacteria, reduces nutrient absorption, and even impairs the gut lining, which can lead to digestive issues and impact mood regulation.
“Chronic stress is one of the most damaging influences on our gut-brain health,” says Dr. Leeming. Studies have shown that heightened stress alters the diversity and function of gut bacteria, potentially leading to an increase in inflammation, which is linked to mental health issues like anxiety and depression.
Solution, Incorporate stress management techniques, such as mindfulness meditation, regular exercise, and deep breathing exercises, which can help modulate the body’s stress response and support a balanced gut-brain axis.
- Overusing Antibiotics
Antibiotics are powerful tools for fighting bacterial infections, but their overuse can disrupt the delicate balance of the gut microbiome. These medications don’t discriminate—they wipe out both harmful and beneficial bacteria, leading to a reduction in microbial diversity, which is essential for gut-brain health. Studies indicate that antibiotics can disrupt gut flora for up to six months, impairing the gut’s ability to produce essential neurotransmitters like serotonin, which affects mood and cognition.
“Antibiotics should only be used when absolutely necessary,” advises Dr. Leeming. “Taking them for viral infections, for example, is ineffective and can take a toll on your gut microbiome.” To help restore balance, consider incorporating probiotic-rich foods and prebiotic fibres, which provide beneficial bacteria with the fuel they need to thrive.
Solution, Only take antibiotics when prescribed by a doctor for bacterial infections, and follow the full prescribed course. Eating fermented foods or taking a probiotic supplement after a course of antibiotics can also help replenish the gut’s beneficial bacteria.
- Skimping on Omega-3 Fatty Acids
Omega-3 fatty acids, commonly found in fish, walnuts, and flaxseeds, play a vital role in supporting brain health and the gut-brain connection. These fatty acids help form the brain cell membranes necessary for cognitive function and mood regulation. Unfortunately, many people don’t get enough omega-3s in their diet, which can affect both brain and gut health, as omega-3s also influence gut microbiota composition.
“Omega-3s are critical for brain function and have anti-inflammatory properties that benefit gut health as well,” explains Dr. Leeming. Studies suggest that omega-3s can help reduce symptoms of depression and anxiety, potentially by impacting gut bacteria.
Solution, Add more omega-3-rich foods to your diet, like fatty fish, walnuts, chia seeds, and flaxseeds, or consider an omega-3 supplement if dietary sources are limited.
- Drinking Alcohol Regularly
While the occasional glass of red wine may have some benefits, frequent alcohol consumption can disrupt gut bacteria and lead to inflammation, both in the gut and the brain. Alcohol has been shown to alter the diversity of gut bacteria, impairing gut barrier function and increasing the risk of “leaky gut,” a condition where toxins and bacteria can pass into the bloodstream. This inflammation can reach the brain, affecting mood and cognitive health.
“Regular alcohol intake is one of the most disruptive factors for the gut-brain axis,” Dr. Leeming says. While social drinking is a part of life for many, moderation is essential for preserving gut health and mental well-being.
Solution, Limit alcohol intake to moderate levels, as defined by health guidelines, and focus on non-alcoholic alternatives. If you do drink, opt for red wine in moderation, as it contains polyphenols, which may have a protective effect on gut bacteria.
- Skipping Fiber-Rich Foods
Fiber is crucial for gut health, feeding beneficial bacteria and promoting the production of short-chain fatty acids (SCFAs) that support the gut lining and immune system. However, many diets are low in fibre, which can starve the gut microbiome and reduce microbial diversity. A low-fibre diet impairs the gut-brain axis by limiting the production of SCFAs, which influence brain health and help regulate inflammation.
“Fiber is essential fuel for gut bacteria, yet many people don’t get enough,” Dr. Leeming explains. Research shows that low fibre intake is associated with increased inflammation and a higher risk of mood disorders.
Solution, Increase fibre intake by eating more fruits, vegetables, whole grains, legumes, and nuts. Aiming for a variety of fibre sources supports diverse gut bacteria, promoting both gut and brain health.
- Avoiding Fermented Foods
Fermented foods like yogurt, kefir, sauerkraut, and kimchi contain live bacteria that can help populate the gut microbiome with beneficial species. Emerging research suggests that consuming fermented foods may have benefits for mental health as well, potentially enhancing memory and reducing stress responses. Dr. Leeming notes that two studies found that regular kefir consumption was linked to improved relational memory and stress resilience.
“Fermented foods can be an incredibly powerful addition to the diet,” Dr. Leeming says. “These foods support a diverse microbiome, which is linked to better brain health.”
Solution: Incorporate a small serving of fermented foods into your diet daily. Fermented foods are widely available and easy to add to meals, making them a simple but impactful way to support the gut-brain connection.
- Poor Sleep Habits
Sleep and the gut-brain connection are deeply intertwined. Poor sleep quality disrupts gut bacteria, which can impact mood, cognitive function, and stress regulation. Studies have shown that disrupted sleep can reduce microbial diversity and increase levels of inflammation in the body, making it harder for the gut-brain axis to function optimally. Lack of sleep also reduces the body’s ability to recover, further stressing the gut and brain.
“Good sleep hygiene is often overlooked in gut-brain health,” says Dr. Leeming. Ensuring regular, quality sleep helps stabilize the gut microbiome, which in turn supports mental clarity and emotional balance.
Solution, Prioritize sleep by setting a regular bedtime, limiting screen time before bed, and creating a calming evening routine. Aim for 7-9 hours of quality sleep each night to support gut-brain health.
A Balanced Approach for a Healthier Gut and Mind
Dr. Leeming’s research underscores the importance of caring for both the gut and the brain. The gut-brain axis is a two-way street, where gut health impacts mental well-being, and brain health influences gut function. By addressing these seven habits, individuals can take meaningful steps to support this intricate system, benefiting not only their mental health but also their immune function, digestion, and overall quality of life.
As Dr. Leeming puts it, “These are simple but powerful changes that can make a real difference.” For those looking to learn more, her book Genius Gut provides a deeper dive into the science of the gut-brain axis, along with practical tips for optimizing both gut and brain health.
With just a few tweaks to our daily routines, we can work toward a more balanced, resilient body and mind, starting from the gut.
References
- Leeming, E. Genius Gut: The Life-Changing Science of Eating for Your Second Brain. Penguin, 2024.
- “Impact of Stress on Gut Health.” Neuroscience Research Reviews, 2023.
- “Antibiotics and Microbiome Diversity.” Journal of Clinical Gastroenterology, 2022.
- “Omega-3 Fatty Acids and Cognitive Function.” Nutritional Neuroscience, 2021.
- “Effects of Alcohol on Gut Barrier Function.” Gastroenterology Journal, 2022.
- “Role of Dietary Fiber in Mental Health.” American Journal of Clinical Nutrition, 2023.
- “Fermented Foods and Brain Health.” Journal of Psychobiology, 2024.
- “Sleep and Gut Microbiome Interactions.” Frontiers in Behavioural Neuroscience, 2022.