# Breastfeeding in Infancy and Adult Health: A Narrative Review

## TL;DR

Breastfeeding in infancy is linked to small long-term health benefits in adulthood, such as lower risk of heart disease and diabetes, but these effects are modest compared to other lifestyle factors.

## Contribution

The paper provides a narrative review showing that breastfeeding has small but consistent associations with better adult cardiometabolic and neurobehavioral outcomes.

## Key findings

- Breastfeeding is associated with modest reductions in adult cardiometabolic risk factors like adiposity and type 2 diabetes.
- Genetic studies suggest a protective association with coronary outcomes, but limited mediation via lipid pathways.
- Breastfeeding is linked to small improvements in cognitive performance and educational attainment.

## Abstract

What are the main findings?
Breastfeeding in infancy is consistently associated with small favourable shifts in adult cardiometabolic risk (adiposity, metabolic syndrome, type 2 diabetes) across large cohorts.Genetic epidemiology (including Mendelian randomisation) generally supports a modest protective association with coronary outcomes, but suggests limited mediation via lipids and substantial confounding in observational estimates.

Breastfeeding in infancy is consistently associated with small favourable shifts in adult cardiometabolic risk (adiposity, metabolic syndrome, type 2 diabetes) across large cohorts.

Genetic epidemiology (including Mendelian randomisation) generally supports a modest protective association with coronary outcomes, but suggests limited mediation via lipids and substantial confounding in observational estimates.

What are the implications of the main findings?
Breastfeeding should be promoted as a population-level prevention strategy with modest long-term benefits, while recognising that later-life behavioural and clinical risk factors dominate individual adult risk.Future studies should strengthen causal inference using triangulation (prospective cohorts, sibling/twin designs, and genetic approaches) and improve exposure ascertainment (duration, exclusivity, and neonatal intensive care feeding pathways).

Breastfeeding should be promoted as a population-level prevention strategy with modest long-term benefits, while recognising that later-life behavioural and clinical risk factors dominate individual adult risk.

Future studies should strengthen causal inference using triangulation (prospective cohorts, sibling/twin designs, and genetic approaches) and improve exposure ascertainment (duration, exclusivity, and neonatal intensive care feeding pathways).

Within the Developmental Origins of Health and Disease (DOHaD) framework, breast-feeding is a modifiable early postnatal exposure, but its long-term associations are difficult to separate from socioeconomic and family context. We conducted a structured literature search (PubMed/MEDLINE and Scopus; January 2015–December 2025) and prioritised large prospective/birth cohorts and genetic epidemiology studies reporting quantitative associations between breastfeeding in infancy (ever versus never, duration and, where available, exclusivity) and adult outcomes. Eighteen key primary studies were included in evidence tables across cardiometabolic, cancer, and neurocognitive domains. Overall, breastfeeding was associated with modestly lower all-cause and cardiovascular mortality, small reductions in cardiovascular disease and type 2 diabetes, and slightly more favour-able cardiometabolic profiles, including lower adiposity and higher HDL cholesterol. Where reported, effect sizes were generally small (e.g., hazard ratios typically close to 1.00), indicating limited clinical impact at the individual level but potential population relevance. Genetic analyses provide cautious support for a protective association with coronary outcomes, although lipid-mediated pathways appear to explain only a small proportion of the observed associations. Evidence for adult cancer outcomes remains mixed and largely inconclusive, while longer breastfeeding is associated with small ad-vantages in cognitive performance, educational attainment and selected psychological outcomes. Taken together, current evidence suggests that breastfeeding is associated with modestly more favourable adult cardiometabolic and neurobehavioural profiles, but its contribution to long-term health is small relative to the influence of later-life lifestyle and clinical risk factors and should therefore be interpreted cautiously.