3 Tips to support a diverse gut microbiome

The gut is home to trillions of microorganisms, and what you eat is one of the most powerful ways to influence them. Research consistently shows that a diverse gut microbiome is associated with better digestive, immune, metabolic, and mental health outcomes. This post covers what the gut microbiome is and three practical nutrition strategies that support it.

What is the gut microbiome?

The gut microbiome refers to the trillions of bacteria, fungi, viruses, and other microorganisms living in your digestive tract, particularly the large intestine. These microorganisms are far from passive. They actively contribute to digesting food, producing vitamins including B vitamins and vitamin K, regulating the immune system, and communicating with the brain via the gut-brain axis.¹

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

A diverse microbiome, one with a wide variety of microbial species, is consistently associated with better health outcomes. Think of it like a garden: the more varied the plant life, the more resilient the ecosystem.²

Strategy 1: eat a wide variety of plant foods

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 10.³

A plant food is broader than most people think. Vegetables, fruit, wholegrains, legumes, nuts, seeds, herbs, spices, tea, and coffee all count. Each variety contributes slightly different types of fibre and polyphenols, which feed a broader range of beneficial gut bacteria.

Some practical ways to build variety:

• Choose mixed varieties at the supermarket rather than the same type each week.
• Add lentils or chickpeas to mince dishes, soups, or salads.
• Season meals with a range of herbs and spices. Each one counts as a plant.
• Top oats or yoghurt with nuts, seeds, and fruit.
• Try one or two new plant foods each week to gradually build variety.

Strategy 2: include prebiotic foods

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. When bacteria ferment prebiotic fibre, they produce short-chain fatty acids such as butyrate. These support the gut lining, help reduce inflammation, and play a role in immune regulation.⁴

Good sources of prebiotic foods include:

• Garlic, onion, and leeks
• Asparagus and artichoke
• Oats
• Bananas and apples
• Legumes (chickpeas, lentils, black beans)
• Flaxseeds

Including a variety of these regularly across meals and snacks is one of the most effective ways to fuel your beneficial gut bacteria.

Strategy 3: eat fermented foods regularly

Fermented foods contain live microorganisms that can introduce new microbes to the gut and support overall microbiome diversity. A Stanford University randomised controlled trial found that a diet rich in fermented foods significantly increased gut microbiome diversity and reduced markers of inflammation compared to a high fibre diet over the same period.⁵

Examples of fermented foods:

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

Want personalised support for your gut health?

Gut health is individual, and a one size fits all approach rarely works. At Nula Nutrition, the approach is evidence based and tailored to you. Registered dietitian consultations are available for gut health and women's health in Calgary and online across Alberta, including Canmore, Banff, Edmonton, and Cochrane.

Ready to get personalised nutrition support?

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Please note: This post is intended for general educational purposes only and does not constitute personalised medical or dietetic advice. If you are experiencing persistent gut symptoms, please speak with your doctor or a registered dietitian for individualised assessment and support.

Written by Madison Hows RD APD

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

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

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