Introduction

 

Our gut microbiota — the collection of bacteria, fungi, and microorganisms in our intestines — plays a crucial role in our health. It affects our digestion, immunity, inflammation levels, and even our mental health. One of the most influential factors? Our diet.

In 2025, Nature Microbiology published one of the largest studies ever on the gut microbiome. Over 21,000 participants from various countries were examined to understand how vegan, vegetarian, and omnivorous eating shapes our gut microbiota.

The results are clear — and particularly relevant for anyone consciously engaged with nutrition and lifestyle.

 

What did the study investigate?

 

The researchers analyzed:

- Fecal samples via shotgun metagenomics

- Dietary patterns

- Cardiometabolic health markers

- Microbial functions such as short-chain fatty acid (SCFA) production

They compared three groups:

- Vegans

- Vegetarians

- Omnivores

 

Key Findings

 

1. Diet creates distinct microbial signatures

The gut microbiome of vegans, vegetarians, and omnivores was clearly distinguishable. With an accuracy of AUC 0.85, it was possible to predict to which group an individual belonged based on their gut microbiota.

Your gut microbiota reflects your dietary pattern.

2. Vegans have more beneficial bacterial strains

Vegan participants had:

- More bacteria that ferment fibers

- Higher production of SCFAs such as butyrate

- Lower levels of bacteria associated with inflammation

SCFAs are essential for:

- Repair of the intestinal wall

- Lower inflammation levels

- Better insulin sensitivity

- Protection against metabolic diseases

 

3. Omnivores have more bacteria linked to inflammation

Omnivores showed higher levels of microbes that are:

- Involved in meat digestion

- Associated with higher cardiometabolic risks

- Produce fewer SCFAs

Red meat was found to be a strong driver of this microbial signature.

4. Vegetarians fall between the two groups

Their microbiomes:

- Are more similar to vegans than to omnivores

- Contain both SCFA-producing bacteria and omnivore-typical strains

- Show a "hybrid" profile consistent with their mixed dietary pattern

5. Plant-based nutrition brings "soil microbes"

A striking finding: Vegans had more microbes also found in soil and plant-based foods.

Less processed, plant-based food increases the diversity of the microbiome.

 

What does this mean for your health?

 

Plant-based nutrition promotes a beneficial microbiome

More fiber → more SCFAs → less inflammation → better metabolic health.

Less red meat lowers inflammation markers

Even small reductions have measurable effects.

Flexitarian eating is a feasible middle ground

You don't have to go fully vegan to experience microbial benefits.

 

Practical tips (evidence-based)

1. Eat 30 different plants per week

Increases the diversity of your gut microbiota.

2. Add fermented foods

Kimchi, kefir, sauerkraut → more beneficial bacteria.

3. Reduce red meat

Even 50% less provides microbial benefits.

4. Choose fiber-rich supplements

Inulin, FOS, psyllium → support SCFA production.

5. Combine plant-based with omega-3

Vegan omega-3 (algae oil) supports anti-inflammation.

6. Support your gut health with SYL Vegan

SYL Vegan contains carefully selected nutrients that vegans and vegetarians often lack — such as B12, iron, and omega-3 — and helps balance your gut microbiome while eating plant-based.