Your gut is home to trillions of bacteria, viruses and fungi—an ecosystem so active that it’s often called a second brain. These friendly microbes break down fibre, produce short-chain fatty acids and even synthesize vitamins B and K. They train your immune system (about 80% of immune cells live in the gut) and help keep you healthy from head to toe.

For men, a balanced gut microbiome can fuel energy, support hormone balance and boost mood, while an unhealthy gut (dysbiosis) has been linked to inflammation, obesity, and other chronic issues. In fact, men and women tend to harbour different gut bacteria. One large study found males were much more likely to carry high levels of Prevotella and lower Bacteroides than females, hinting that male-specific diet and hormones shape the gut.

Gut Health and Testosterone

Your gut isn’t just about digestion—it’s your body’s largest endocrine organ. Gut cells secrete hormones that regulate metabolism, hunger and satiety, and gut bacteria can even influence sex hormone levels.

Recent research shows a bidirectional link between gut flora and testosterone. For example, supplementing aging mice with the probiotic Limosilactobacillus reuteri restored their testosterone levels. In humans, higher gut microbial diversity often goes hand-in-hand with healthy testosterone: studies report that men with more diverse gut bacteria tend to have higher serum testosterone, and certain bacterial families correlate positively or negatively with androgen levels.

Although the science is still emerging, these findings suggest that nurturing your gut (“gut health and testosterone”) could help support natural hormone balance. (Tip: consider fermented foods or fermented dairy rich in Lactobacillus species, which in some studies have influenced testosterone levels. 

Dietary Habits: How Diet Affects Male Gut Bacteria

What you eat feeds both you and your microbes. Men’s diets—often high in protein and simple carbs—uniquely shape the gut microbiome. A high-protein diet (common among athletes and bodybuilders) can boost microbes that ferment protein. This can be beneficial (producing short-chain fatty acids) but also risky: excess undigested protein in the colon can generate harmful by-products like ammonia and sulphides linked to gut irritation. 

In contrast, fibre-rich plant foods feed healthy gut bugs. A diet rich in diverse fruits, vegetables and whole grains supplies the fibres that many beneficial bacteria crave. By fermenting fibre, they produce anti-inflammatory SCFAs that nourish gut cells and lower gut pH in ways that favour “good” bacteria. On the other hand, Western-style diets high in sugar, fat and ultra-processed foods tend to favour less helpful microbes.

A recent U.S. study found that men who ate more foods containing live microbes (like yogurt, kefir, and fermented veggies) had higher testosterone and lower risk of testosterone deficiency. The mechanism may involve improved gut diversity, reduced inflammation, and a friendlier gut environment for hormone production. In short, eating a gut-friendly diet matters: aim for lean proteins (fish, poultry, legumes) plus plenty of plant fibre and fermented foods. Avoid excessive red/processed meat and sugary snacks.

Exercise and Gut Health

Regular exercise is one of the best things you can do for your gut. Physical activity helps diversify the gut microbiome and boosts beneficial metabolites. In fact, studies have shown that moderate exercise improves energy balance and immune function in ways that “modify the gut microbiota” positively. Exercise can also sharpen gut transit and nutrient absorption. Over time, active people often have more SCFA-producing bacteria, which support gut barrier integrity and reduce inflammation. Exercise even lowers the risk of colitis and colon cancer, likely by enhancing antioxidants and anti-inflammatory signals in the gut. 

However, balance is key. While routine workouts help, very intense or prolonged exercise (like ultra-endurance events) can stress the gut. A recent review notes that “high-intensity exercise for a long duration can cause a leaky gut and consequent systemic inflammation,” potentially disrupting the microbial balance. In practice, most men benefit from a mix of cardio and strength training: it boosts bacterial diversity and supports metabolic health without overtaxing the gut. Listen to your body – if heavy workouts cause gut upset, back off and recover.

Stress, Mental Health and the Gut-Brain Axis

Your gut and brain are in constant “conversation.” Gut microbes make and release neurotransmitters (over 90% of the body’s serotonin is produced in the gut). They influence mood, stress levels and cognitive function. For example, certain gut bacteria can produce serotonin and dopamine, affecting signals sent along the vagus nerve. Researchers even say gut bacteria and their by-products “affect mood, cognition and behaviour”. In short, a happy gut helps keep your mind sharper and more resilient.

Stress and poor mental health can, in turn, harm the gut. Decades of research show that chronic stress (high cortisol) alters the gut microbiome and increases gut permeability. Anxiety or depression are often accompanied by gut dysbiosis. In men facing work or life stressors, gut symptoms (bloating, IBS-like pain) are common. That’s because stress hormones weaken gut defences and tip the bacterial balance. Managing stress (through sleep, relaxation or counselling) can therefore support gut health, and focusing on gut health (via diet, pre/probiotics) can improve mental wellness.

Lifestyle Factors: Alcohol, Sleep and More

Daily habits play a big role in your gut ecology. Heavy alcohol use is especially hard on the gut. Alcohol shifts gut bacteria into dysbiosis: it suppresses beneficial strains and encourages harmful one. As the gut bacteria break down alcohol, they also produce toxic metabolites that damage the intestinal lining. Chronic drinking often leads to a “leaky gut,” letting toxins enter the bloodstream. These toxins circulate to the liver and beyond, increasing cancer and heart disease risk. In short, moderation is key – limit alcohol to keep your gut barrier strong.

Sleep is another overlooked factor. Sleep deprivation and poor sleep quality have been linked to gut imbalances. Studies report that even one or two sleepless nights can alter gut bacteria proportions. Getting 7–9 hours of quality sleep each night helps reset your gut; conversely, chronic sleep loss can fuel an unhealthy microbiome and “stack” onto other risk factors. Other lifestyle factors matter too. Smoking and environmental pollutants (car exhaust, chemicals) literally “poison” your microbiome. Many OTC drugs (especially antibiotics and acid blockers) can decimate gut flora if overused. By contrast, maintaining a healthy weight, avoiding chronic stress, and staying hydrated all give your gut a better shot. Remember: a garden thrives or fails by its soil and conditions. Treat your gut like a garden – give it clean inputs and good care.

Probiotics for Men’s Health: Best Strains and Foods

In recent years men have heard a lot about probiotics, but choosing the right ones can be tricky. The most common probiotic genera in foods and supplements are Lactobacillus and Bifidobacterium. (BIOME RESTORE) These friendly bacteria support digestion, immune function, and gut lining integrity. For men interested in hormone and gut health, one strain of note is Limosilactobacillus reuteri (formerly Lactobacillus reuteri), which in studies helped boost testosterone in older animals. Other popular strains in products (like L. acidophilus, L. rhamnosus, B. longum, B. infantis) have been associated with reduced inflammation and improved gut barrier, though research in men is still evolving.

You can naturally up your probiotics by eating fermented foods. Try to include Lactobacillus and Bifidobacterium-rich foods daily. For example:

• Live yogurt or kefir (look for “live and active cultures”) – these contain Lactobacillus species.
• Fermented vegetables: kimchi, sauerkraut, pickles (non-pasteurized).
• Miso or tempeh: fermented soy products from Asian cuisine.
• Kombucha tea or raw apple cider vinegar (with the “mother”) – contains acids and cultures.

By adding these foods to your diet, you feed your gut a variety of beneficial microbes. (Note: Don’t rely on one source or overdo it—variety and moderation are key.) 

Gut Health and Long-Term Men’s Wellness.

Gut health isn’t just about today’s digestion – it ties into many long-term outcomes that men care about. For heart health, gut bacteria play a surprising role. Certain microbes produce a compound called trimethylamine N-oxide (TMAO) from foods like red meat and eggs. TMAO tends to build up in arteries, promoting atherosclerosis and heart disease. In short, an unhealthy gut with too many of the “wrong” bacteria can raise cardiovascular risk. Keeping your microbiome balanced (through fibre, polyphenols and low red meat) helps reduce TMAO and inflammation in vessels.

Prostate health is another frontier. Scientists are finding that the gut microbiome influences prostate inflammation and hormone metabolism. Early research suggests that gut dysbiosis may contribute to prostatitis or benign prostate enlargement by driving systemic inflammation. Even prostate cancer treatments’ effectiveness may be linked to gut bacteria. As one review notes, understanding the gut-prostate connection “offers a fresh perspective on the aetiology and management of prostate disorders”. While we wait for more studies, a gut-healthy lifestyle (vegetable-rich diet, modest alcohol, regular exercise) can only help support prostate wellness.

Finally, gut health affects mood and mental resilience long-term. Chronic gut inflammation is associated with higher rates of depression and anxiety. By nurturing your microbiome (via diet, probiotics, sleep and stress management), you not only ease gut symptoms but also bolster your emotional health. In summary, a well-fed gut microbiome is a foundation for men’s lifelong health – from heart and hormones to mood and beyond.

Key Takeaways: A strong gut microbiome in men supports immunity, hormone balance, and even heart health. Eating diverse plants and fermented foods, exercising moderately, sleeping well, and reducing alcohol can keep your gut bacteria in balance. Doing so gives you more energy, better mood, and helps protect against chronic diseases that men face as they age.

Sources: Authoritative reviews and studies (e.g. Cleveland Clinic, Stanford Lifestyle Medicine, Nature Communications Biology, Nutrients, etc.) provide the basis for these recommendations. Each claim above is supported by recent research findings as cited.

Author: Dr Monika Stuczen, Medical Microbiologist