Early life sugar restriction reduces chronic disease risk for adults, new research flags

A low-sugar diet for babies in utero and in their first 1,000 days reduced diabetes risk by 35% and risk for hypertension by 20%, according to a new study. Sugar restriction delayed the onset of diabetes by four years and hypertension by two years. Mothers’ low sugar intake before birth lowered the risk, but sustained sugar restriction increased benefits.

The study in Science looked at how UK sugar rationing during World War II influenced long-term health conditions. The country introduced sugar distribution limits in 1942 in its food rationing program, which was lifted in September 1953. 

During rationing, sugar intake amounted to an average of 40 g or eight teaspoons daily, which skyrocketed to 80 g or 16 teaspoons daily when rationing was lifted. At the same time, rationing did not involve extreme food deprivation overall. 

“Studying the long-term effects of added sugar on health is challenging,” says co-author Tadeja Gracner, senior economist at the USC Dornsife Center for Economic and Social Research, US. 

“It is hard to find situations where people are randomly exposed to different nutritional environments early in life and follow them for 50 to 60 years. The end of rationing gave us a novel natural experiment to overcome these problems.” 

Natural experiment

Due to the sugar restrictions, people were exposed to varying sugar intake in early life, depending on whether they were conceived or born before or after September 1953. 

In the “natural experiment,” researchers identified 60,183 individuals born around this time in the UK Biobank data collected 50 years later. They used a tight birth window around the end of sugar rationing to compare midlife health outcomes of similar birth cohorts. The UK Biobank contains participants’ medical histories, genetics, lifestyle and other disease risk factors. 

During this time, diets were generally within current guidelines set by the US Department of Agriculture and WHO, which recommend no added sugars for children under two and less than 50 g or 12 teaspoons daily for adults. 

After World War II sugar rationing ended, intake went from an average 40 g daily to 80 g per day.Exposure to sugar restrictions in utero accounted for about a third of the risk reduction, which was reduced further with sugar restrictions after birth, especially after babies were six months old and solid foods likely began. 

However, Dr. Hilda Mulrooney, a nutrition and health reader at London Metropolitan University, UK, believes that the study cannot demonstrate causality due to its design. She was not involved in the research. 

“Nonetheless, it is a strong study, with several potential confounding factors taken into account and large numbers of participants — 38,155 exposed to rationing and 22,028 not exposed to rationing.”

“The groups were similar concerning gender, race, family history of diabetes and cardiovascular disease (for which hypertension is a strong risk factor) and genetic scores calculated for obesity (which could confound both type 2 diabetes and hypertension). In addition to sugar intakes immediately and markedly rising after rationing of sugar ended, risk of obesity was also significantly higher in those not exposed to rationing in utero and the first year of life, compared with those who were.”

Chronic disease impacts

The researchers highlight the impact of chronic diseases such as diabetes and cardiovascular diseases on health and healthcare costs. 

Scientists predict that 1.3 billion people will have diabetes by 2050. Early interventions that could delay or prevent diabetes are valuable, as research finds that earlier diagnosis means significantly shorter life expectancy. Every decade earlier that a diagnosis is made may cut three to four years of life expectancy. 

Exposure to sugar restrictions in utero accounted for about a third of the risk reduction for chronic diseases.Moreover, chronic diseases have a large impact on countries’ health expenses. For example, research indicates that US diabetes patients incur average annual medical expenses of around US$12,000. Last year, the European Society of Cardiology calculated that cardiovascular diseases comprised 11% of the EU health budget. 

Studies indicate various dietary interventions to reduce the risk of developing these diseases in adults. For example, moderate caffeine consumption may lower the risk of developing a cardiometabolic disease, while reducing ultra-processed food consumption could reduce diabetes risk. 

At the same time, experts underscore the importance of reducing sugar consumption for kids, especially in early life, a critical developmental period. However, the researchers caution that “added sugar is everywhere,” making it challenging to adjust child sugar consumption. For example, Nestlé was accused of adding sugar to infant nutrition sold in poorer countries earlier this year. 

“Parents need information about what works, and this study provides some of the first causal evidence that reducing added sugar early in life is a powerful step toward improving children’s health over their lifetimes,” says co-author Claire Boone of McGill University, Canada, and the University of Chicago, US. 

Commenting on the study, Jerusa Brignardello, lecturer in Dietetics and Nutrition at Oxford Brookes University, UK, adds: “Current evidence suggests that early exposure to sugar during pregnancy and early life may impact neonatal metabolism, obesity risk and taste perception, which may later influence food choices and the risk of other chronic diseases.” 

The authors call on food companies and legislators to reformulate infant and child nutrition with healthier options.Study limitations

Although the study authors accounted for confounding variables, Brignardello underscores that the UK Biobank cohort “is not nationally representative of the population and tends to represent a part of the population that was healthier and wealthy.”

She notes that the current food environment, lifestyle, dietary habits, obesity prevalence and physical activity are very different from the 1950s. Therefore, she warns that results should “be interpreted with caution.” 

Mulrooney also notes that the study has some inevitable weaknesses due to its type and reliance on historical data. “Changes to sugar intakes were unlikely to be the only changes that occurred to participants at that time.” 

“The authors took as many factors as they could into account, and the message is clear — exposure to high intakes of added sugar in utero and early childhood is a significant risk factor for chronic disease. This suggests that action to reduce the sugar content of foods and drinks aimed at or attractive to children is needed.” 

She cautions that this will not entirely reduce the risk, as diet during pregnancy enables in utero exposure. She calls for reductions in all foods and drinks high in added sugar. “However, this will have to be approached with care — simply replacing sugar with sweeteners will not enable the population to reduce their preference for sweet tastes.”

The current study is part of a larger research effort that explores how early life sugar restrictions affected a broader set of economic and health outcomes in adulthood, including education, wealth, chronic inflammation, cognitive function and dementia.