3 Tips to Support a Diverse Gut Microbiome

Did you know your gut is home to trillions of microorganisms that play a key role in influencing your health?

Research shows that a diverse gut microbiome is associated with better digestive, immune, metabolic, and mental health outcomes. What you eat is one of the most well studied modifiable factors influencing gut microbiome composition. This post covers what the gut microbiome is, why diversity matters, and the practical strategies that support it.

The Basics

What is the Gut Microbiome?

The gut microbiome refers to the trillions of microorganisms (bacteria, fungi, viruses, and other microbes) that live in your digestive tract, particularly the large intestine.

These microorganisms actively contribute to:¹

• Digesting food and absorbing nutrients
• Producing vitamins including B vitamins and vitamin K
• Regulating the immune system
• Protecting against harmful pathogens
• Communicating with the brain via the gut-brain axis
• Supporting hormone and metabolic health

Each person's microbiome is unique, shaped by genetics, birth method, early life feeding, diet, stress, medications, and environment.

Why does diversity matter?

A diverse microbiome (one with a wide variety of different microbial species) is consistently associated with better health outcomes.² Lower microbial diversity has been linked to increased risk of multiple chronic diseases. Think of it like a garden: the more varied the plant life, the more resilient the ecosystem.

Nutrition Strategy One

Plant Diversity: Aim for 30 Different Plants a Week

The American Gut Project, one of the largest microbiome studies to date, found that people who ate 30 or more different plant foods per week had significantly greater gut microbiome diversity than those who ate fewer than 10.⁴

What counts as a plant?

• Vegetables and salad leaves
• Fruits
• Wholegrains (oats, brown rice, quinoa, barley)
• Legumes (chickpeas, lentils, black beans)
• Nuts and seeds
• Herbs and spices
• Tea and coffee

Aim for mixed varieties when shopping. Try 2-3 different fruits, vegetables, and grains across the week, and don't forget herbs, nuts, and berries. They all count.

Nutrition Strategy Two

Prebiotic Foods: Feeding Your Gut Bacteria

Prebiotics are compounds (mostly fibre and polyphenols) that are not digested by the body but selectively feed and support the growth of beneficial gut bacteria.³

When gut bacteria ferment prebiotic fibre, they produce short-chain fatty acids (SCFAs) such as butyrate, propionate, and acetate. These support the gut lining, reduce inflammation, and help regulate immune function.³

Good sources of prebiotic foods

Garlic

Onion & leeks

Asparagus

Oats

Bananas

Legumes

Apples

Artichoke

Flaxseeds

Including a variety of these foods regularly across meals and snacks is a simple and effective way to fuel your gut bacteria.

Nutrition Strategy Three

Fermented Foods and Probiotics

Fermented foods contain live microorganisms that can transiently introduce new microbes to the gut. A Stanford University randomised controlled trial found that a diet high in fermented foods increased microbiome diversity and reduced markers of inflammation.⁵

Fermented foods to include regularly

• Yoghurt with live cultures
• Kefir — fermented milk with a wide range of bacterial strains
• Sauerkraut — choose unpasteurised for live bacteria
• Kimchi — fermented vegetables, also rich in fibre
• Miso — great in soups or dressings
• Tempeh — fermented soybeans and a great plant protein source

Probiotic supplements are not always necessary for gut health, nor are they indicated for everyone. If you are considering one, work with a dietitian to identify a strain and dose appropriate for your individual needs, as the evidence is highly strain-specific.

Beyond Nutrition

Lifestyle Factors That Support Gut Health

Nutrition is foundational, but several lifestyle factors also have a meaningful impact on gut microbiome diversity and function.

Sleep

Sleep deprivation has been associated with significantly reduced gut microbial diversity and altered microbiome composition.⁶ The gut microbiome follows its own circadian rhythm. Aim for 7-9 hours of quality sleep per night.

Stress management

Chronic stress can alter the gut microbiome composition and affect sensitivity of the gut via the gut-brain axis.⁷ Practices such as mindfulness, yoga, gentle movement, and adequate rest may help support a healthier gut environment.

Movement

Regular physical activity, particularly aerobic and resistance exercise, has been associated with greater microbiome diversity and increased production of beneficial SCFAs.⁸ Even regular walking makes a difference.

Be Mindful Of

Foods That May Reduce Gut Diversity

Overall dietary patterns matter most. Regularly consuming the following in excess may negatively affect gut microbiome composition:^1,2

• Ultra-processed foods — often low in fibre and linked with a less diverse microbiome
• Alcohol in excess — associated with reduced microbial diversity
• Very low fibre diets — can starve beneficial bacteria over time

Main Takeaway

Diversity is key when it comes to supporting a healthy gut microbiome. Aim for 30 different plant foods per week. Include prebiotic and fermented foods regularly. Prioritise sleep and moving your body in enjoyable ways.

Small, sustainable changes add up.

Please note: This blog post is for general educational purposes only and does not constitute personalised medical or dietetic advice. If you are experiencing persistent gut symptoms, always work with your doctor or a registered dietitian for personalised guidance.

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References

1. Valdes AM, et al. Role of the gut microbiota in nutrition and health. BMJ. 2018;361:k2179. PMID: 29899036

2. Lozupone CA, et al. Diversity, stability and resilience of the human gut microbiota. Nature. 2012;489(7415):220-230. PMID: 22972295

3. Deehan EC, Walter J. The prebiotic potential of dietary fibre and the gut microbiome. Cell Host Microbe. 2020;27(5):672-674. PMID: 32433949. See also: PMC12899272

4. McDonald D, et al. American Gut: an open platform for citizen science microbiome research. Cell Host Microbe. 2018;23(5):679-693. PMID: 29763717. PMC5954204

5. Wastyk HC, et al. Gut-microbiota-targeted diets modulate human immune status. Cell. 2021;184(16):4137-4153. PMID: 34256014

6. Supasitdikul S, et al. Sleep deprivation alters gut microbiome diversity and taxonomy: a systematic review and meta-analysis. J Sleep Res. 2025. PMID: 40562421

7. Karl JP, et al. Effects of psychological, environmental and physical stressors on the gut microbiota. Front Microbiol. 2018;9:2226. PMID: 30319571

8. Cullen JMA, et al. A systematic review on the effects of exercise on gut microbial diversity, taxonomic composition, and microbial metabolites. Front Physiol. 2023;14:1292673. PMID: 38148907. PMC10770260