29 Nov 2025

Baby poo and long-term health

From Saturday Morning, 8:40 am on 29 November 2025
Image of a yawning baby wearing a knitted grey beanie hat tucked into cot with white teddy bear poking above the sheet.

Photo: Minnie Zhou for Unsplash

No one looks forward to a dirty nappy but poo samples collected by parents for the UK's Baby Biome Study are proving to be a valuable source of information.

Microbiome refers to the trillions of micro-organisms living inside you. 

The bacteria in a poo sample is an indicator of gut health and new evidence suggests that the first microbes you are exposed to as a baby could have lifelong consequences for your immune system.  

Professor Nigel Field is Director of the Centre of Molecular Epidemiology and Translational Research at University College London and Principal Investigator on the study. He talks to Mihi about what they can tell from a baby's first poo.  

Nigel Field. Dr Nigel Field is the Lead for the Centre of Molecular Epidemiology and Translational Research at the Institute for Global Health at UCL.

Professor Nigel Field Photo: © UCL Digital Media