World Hepatitis Day: What Your Gut and Liver Are Quietly Telling Each Other

World Hepatitis Day falls on 28 July, a fitting moment to remember that the liver doesn't work alone. The gut and liver are closely connected anatomically, making the gut-liver axis an active area of research.

What Is the Gut-Liver Axis?

The gut-liver axis describes the two-way relationship between the gut and the liver. Blood leaving the intestines flows through the portal vein directly into the liver, carrying nutrients absorbed during digestion along with bacteria, bacterial byproducts and other compounds picked up along the way.

The liver filters and processes this blood before it reaches the rest of the body. In practical terms, the liver is exposed to whatever is happening in the gut more directly, and more often, than almost any other organ.

Why World Hepatitis Day Matters Beyond the Liver Itself

World Hepatitis Day is marked on 28 July each year, a date chosen because it's the birthday of Dr Baruch Blumberg, the scientist who discovered the hepatitis B virus and developed the first vaccine against it [2]. The World Health Organization estimated that 240 million people were living with chronic hepatitis B in 2024, with around 1.1 million deaths that year, mostly from cirrhosis and liver cancer [1].

The NHS lists three main causes of liver disease: obesity, undiagnosed hepatitis infection and alcohol misuse [3]. None of these start in the gut on paper, but many processes in the gut have the potential to influence the liver through the gut-liver axis.

What the Gut May Have to Do With Liver Health

Non-alcoholic fatty liver disease (NAFLD), now also known as MASLD, is a common condition where fat builds up in the liver, most often linked to being overweight, inactive, or living with conditions like type 2 diabetes [4]. It usually causes no symptoms early on, which is part of why it's often only found when people have tests for something else [4].

Researchers are increasingly interested in whether gut bacteria and the substances they produce, delivered straight to the liver via the portal vein, play a role in liver fat and inflammation. Much of this research is still at an early stage, drawing heavily on animal studies and small human samples, so it's best treated as an emerging area rather than a settled one, and it isn't a basis for self-diagnosis.

What is established is the anatomical route: because blood from the intestines passes through the liver first, changes in the gut can influence what the liver is exposed to.

Hepatitis at a Glance

Hepatitis B and C together account for the majority of hepatitis-related deaths globally, which is largely why the WHO's elimination targets focus on closing the testing and treatment gap for these two strains [1][2].

Most check-ins on organ health, including liver health, happen occasionally: a blood test once a year, a GP visit when something feels wrong. Gut health has traditionally worked the same way.

Ongoing gut health monitoring is a newer idea: tracking bathroom patterns over time rather than relying on a single snapshot. This isn't a diagnostic tool and it can't detect liver disease, but it may help build a fuller gut health baseline of what's normal for you, which is a useful habit alongside, not instead of, medical care.

Building that baseline starts with knowing what's actually living in your gut and understanding what a healthy gut microbiome looks like in general terms, then learning how to measure your own gut health over time.

A few habits are associated with supporting both digestive and liver health: staying within recommended alcohol limits, keeping a healthy weight, eating a fibre-rich diet, and getting vaccinated against hepatitis A and B if you're at risk [3][4].

Beyond that, simply noticing your own gut patterns, what's normal, what's changed, is a low-effort way to stay tuned into a system that's quietly in touch with your liver every day.

Curious about your own gut patterns? Gutsi's Gut Quiz may be a good place to start.

References

[1] World Health Organization. Hepatitis B. Fact sheet, updated 10 June 2026. who.int/news-room/fact-sheets/detail/hepatitis-b
[2] World Health Organization. World Hepatitis Day. who.int/campaigns/world-hepatitis-day
[3] NHS. Liver disease. Page last reviewed 9 August 2023. nhs.uk/conditions/liver-disease
[4] NHS. Non-alcoholic fatty liver disease (NAFLD). Page last reviewed 31 July 2025. nhs.uk/conditions/non-alcoholic-fatty-liver-disease

This content is for informational purposes only and does not constitute medical advice. If you have concerns about your digestive health, please speak to a healthcare professional.