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Body System

Digestive

Gut health, the microbiome, and nutrient absorption.

Last reviewed
July 2026
Version
1.0
Review cadence
Annually

Overview

The digestive system breaks down food, absorbs nutrients, and hosts the gut microbiome — a community of microbes that influences metabolism, immunity, and even mood.

Why it matters

Digestive health affects nutrition, immune function, and metabolic health, and the liver's status (via markers like ALT) is an early window on whole-body metabolic health.

Start Here

New to this? Read these first

  1. FoundationGut Health & The MicrobiomeWhat actually improves gut health — and why fibre beats the supplements people buy.
  2. ConditionIrritable Bowel SyndromeA disorder of gut–brain interaction
  3. BiomarkerTriglyceridesA window on metabolic health
  4. Signal RecordNSAIDsIbuprofen, naproxen, diclofenac — and why there is no safe one
  5. Body SystemMetabolism
Typical Journey

How this usually unfolds

  1. Understand the system
  2. Know the key biomarkers
  3. Learn the common conditions
  4. Apply evidence-based interventions

An orientation to how this topic is typically approached — not medical advice.

Major functions

  • Digestion and nutrient absorption
  • Microbiome-driven fermentation
  • Barrier and immune interface
  • Liver-based metabolism and detoxification

Common conditions

Evidence-based

Prevention

  • Eat adequate fiber and varied plants
  • Maintain a healthy weight (liver)
  • Limit alcohol
  • Age-appropriate cancer screening
Evidence-based

Improvement strategies

  • Fiber for regularity and metabolic health
  • Weight loss for fatty liver
  • Treating the underlying condition
  • Reducing alcohol
Explore

Explore this system across BioSignal

Related body systems

Related lifestyle interventions

  • Adequate dietary fiber
  • Minimally processed, varied diet
  • Hydration
  • Limiting alcohol
  • Regular activity

Related diagnostics

  • ALT / AST (liver)
  • (Colonoscopy and endoscopy — clinician-directed)
  • Ferritin (absorption/loss context)

Frequently asked questions

Do I need a probiotic?

For most healthy people, a fiber-rich, varied diet supports the microbiome more reliably than a supplement. Specific probiotics help specific conditions — the evidence is strain- and situation-specific.

What does a high ALT mean?

Most often fatty liver linked to weight and insulin resistance, which is frequently improvable with weight loss and activity. New or marked elevations should be evaluated.

Educational information — not medical advice

Body System hubs orient you across the evidence; they don't diagnose or treat. Interpret your own health with a qualified clinician. See our Medical Disclaimer.

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