The findings support the recommendation to minimize added sugars in the diets of pregnant women and infants.

A new study published in The BMJ has found that limiting sugar intake during early life is associated with a reduced likelihood of developing major heart conditions later on, including heart attack, heart failure, and stroke. The research drew on historical data from the period following the end of sugar rationing in the United Kingdom in 1953.

The most significant protection against heart disease, as well as the longest delay in the onset of such conditions, was observed in individuals whose sugar consumption was limited from conception (“in utero”) through roughly the first two years of life.

Previous evidence indicates that the first 1,000 days of life (from conception to about two years of age) represent a critical window in which nutrition can influence lifelong health. Health authorities recommend avoiding sugary drinks and ultra-processed foods (which often contain large amounts of added sugar) as infants and toddlers begin transitioning to solid foods.

Building on this understanding, the researchers set out to explore whether restricting sugar during this early developmental period could lower the risk of cardiovascular disease in adulthood.

A Natural Experiment: The End of UK Sugar Rationing

Using the end of UK sugar rationing in September 1953 as a natural experiment, they drew on data from 63,433 UK Biobank participants (average age 55 years) born between October 1951 and March 1956 with no history of heart disease.

In total, the study included 40,063 participants exposed to sugar rationing and 23,370 who were not.

Linked health records were then used to track rates of cardiovascular disease (CVD), heart attack, heart failure, irregular heart rhythm (atrial fibrillation), stroke, and cardiovascular death, adjusting for a range of genetic, environmental, and lifestyle factors.

An external control group of non-UK-born adults who did not experience sugar rationing or similar policy changes around 1953 were also assessed for more reliable comparisons.

The results show that longer exposure to sugar rationing was associated with progressively lower cardiovascular risks in adulthood, partly due to reduced risks of diabetes and high blood pressure.

Compared with people never exposed to rationing, those exposed in utero plus 1–2 years had a 20% reduced risk of CVD, as well as reduced risks of heart attack (25%), heart failure (26%), atrial fibrillation (24%), stroke (31%), and cardiovascular death (27%).

People exposed to rationing in utero and during early life also showed progressively longer delays (up to two and a half years) in the age of onset of cardiovascular outcomes compared with those not exposed to rationing.

Sugar rationing was also associated with small yet meaningful increases in healthy heart function compared with those who never rationed.

Historical Context and Modern Relevance

The authors point out that during the rationing period, sugar allowances for everyone, including pregnant women and children, were limited to under 40 g per day – and no added sugars were permitted for infants under 2 years old – restrictions consistent with modern dietary recommendations.

This is an observational study, so no firm conclusions can be drawn about cause and effect, and the authors acknowledge several limitations, including a lack of detailed individual dietary data and potential recall bias that could have affected their results.

However, they say this large, well-designed study allowed them to separately assess the effects of different exposure periods and explore the potential pathways linking sugar rationing and cardiovascular outcomes.

As such, they conclude: “Our results underscore the cardiac benefit of early life policies focused on sugar rationing. Further studies should investigate individual-level dietary exposures and consider the interplay between genetic, environmental, and lifestyle factors to develop more personalized prevention strategies.”