What to Eat for a Healthier Microbiome—and a Longer Life

Gut health is a cornerstone of longevity, resilience, and well-being.

Researchers have come up with a simple way to measure how your diet supports your gut. One science-backed framework being studied right now is the Dietary Index for Gut Microbiota (DIGM). It’s designed to help people (and researchers) better understand the connection between diet and gut microbial health.

Developed by a team from the University of South Carolina, the DIGM pulls together two decades of research linking specific foods and food groups with positive or negative impacts on gut microbiome diversity, richness, and functionality.

Here’s what you need to know.

What Is the Dietary Index for Gut Microbiota?

The DIGM is a research-based scoring system that evaluates diet quality based on how well it supports the gut microbiome.

The premise is simple: Foods that have been repeatedly shown to benefit gut microbial diversity and produce favorable metabolites like short-chain fatty acids (SCFAs) earn positive scores. Foods that have been associated with reduced microbiome diversity, inflammation, or harmful microbial changes earn negative scores.

The higher your DIGM score, the more your diet is thought to promote a thriving, diverse, and health-supportive microbiota.

How A Healthy Gut May Slow Aging

Recent research is already connecting DIGM scores to broader health outcomes. A 2025 study published in Frontiers in Nutrition found that individuals with higher DIGM scores, meaning more gut-friendly diets, had a lower prevalence of diabetes. The researchers also found that for every 1-point increase in DIGM score, biological (or phenotypic) age decreased by 0.14 years, and body mass index (BMI) was also lower.

This suggests that building a gut-supportive diet today may actively help you age more slowly, build and sustain muscle mass, and reduce your risk of metabolic diseases like diabetes.

Which Foods Benefit Your Gut Microbiome?

According to the Dietary Index for Gut Microbiota (DIGM), these foods have the strongest evidence supporting positive effects on gut health:

• Fermented Dairy: Yogurt and kefir with live cultures that deliver beneficial probiotics.
  
• Chickpeas: A rich source of fiber and resistant starch, fueling short-chain fatty acid production.
  
• Soybeans: Including edamame, tofu, and tempeh, high in prebiotics and isoflavones that support microbiota diversity.
  
• Whole Grains: Oats, quinoa, barley, and brown rice provide fermentable fibers that nourish gut bacteria.
  
• Cranberries: Rich in polyphenols, cranberries may support beneficial bacteria while suppressing harmful strains.
  
• Avocados: High in fiber and healthy fats, avocados have been shown to positively alter gut microbiota composition.
  
• Broccoli: A cruciferous vegetable linked to improved gut barrier function and a healthier microbial profile.
  
• Coffee: Particularly black coffee, rich in polyphenols and prebiotics that feed beneficial microbes.
  
• Green Tea: Contains catechins, powerful polyphenols that can support gut health and modulate inflammation.
  
• Fiber (Total Intake): Diets higher in overall fiber consistently promote microbial richness and short-chain fatty acid (SCFA) production.
  

Key Mechanism:
These foods feed beneficial bacteria, boost the production of short-chain fatty acids like butyrate (which strengthens the gut lining), and reduce gut inflammation.

The Foods That May Harm Your Gut Microbiota

The DIGM also identifies foods and dietary patterns consistently linked to reduced gut health:

• Red Meat: Especially processed or high-fat red meats, which can encourage harmful microbial shifts.
  
• Processed Meats: Such as bacon, sausage, and deli meats, often high in nitrates and pro-inflammatory compounds.
  
• Refined Grains: White bread, white rice, and other ultra-processed grains lacking fiber and prebiotics.
  
• High-Fat Diets: Diets where 40% or more of total calories come from fat (especially saturated fat) are associated with an imbalance in the gut’s microbial ecosystem and increased gut permeability.
  

Key Mechanism:
These foods can starve beneficial bacteria, fuel pro-inflammatory species, and damage the intestinal barrier, setting the stage for systemic inflammation and chronic disease.

Building a Gut-Friendly Plate

Gut microbial health isn’t just about digestion.

A healthy microbiota is now linked to better immune regulation, lower risk of chronic diseases like obesity and diabetes, improved cognitive function, and even healthier aging. “Dietary interventions aimed at modifying gut microbiota composition are emerging as a key strategy for improving human health,” the researchers note.

Right now, the DIGM provides a structured way to assess dietary patterns in research. Eventually, it could be adapted for practical tools that help individuals track and optimize their own gut-supportive eating habits.

According to the DIGM, the recipe for a thriving microbiome is simple:

• Pile your plate with fruits, vegetables, legumes, and whole grains.
  
• Include fermented foods like yogurt and kefir.
  
• Favor olive oil, nuts, and seeds as primary fat sources.
  
• Minimize processed meats, sugary drinks, refined carbs, and fried foods.
  

In other words: Feed your gut and it will feed your health for years to come.