Sugar restrictions in utero and early childhood reduces risk of chronic disease, study finds

A toddler gets her hands on some candy at a Halloween event in Ashland, Ky. (Kevin Goldy/The Daily Independent via AP)

A low-sugar diet in utero and in the first two years of life can meaningfully reduce the risk of chronic diseases in adulthood, according to a study published today in the journal Science. The researchers used contemporary data from the U.K. Biobank to study the effect of exposure to sugar restrictions early in life on health outcomes of adults conceived just before and after the end of wartime sugar rationing in the United Kingdom in September 1953.

The study, published on Halloween, finds that children exposed to sugar restrictions during their first 1,000 days—including in utero—had up to a 35% lower risk of developing Type 2 diabetes and up to 20% lower risk of hypertension as adults. In-utero exposure alone was enough to lower risks, but disease protection increased with length of exposure after birth.

The study—a collaboration by researchers Tadeja Gracner from the University of Southern California, Claire Boone of McGill University, and Paul Gertler of the University of California Berkeley’s Haas School of Business—provides compelling new evidence of the lifelong health effects of early-life sugar exposure.

“Studying the long-term effects of added sugar on health is challenging because it is hard to find situations where people are as-if randomly exposed to different nutritional environments early in life and follow them for 50 to 60 years,” said Gracner (PhD 15, Economics). “The end of rationing provided us with a novel natural experiment to overcome these problems.”

Wartime sugar rationing

The study exploits a natural experiment: the end of sweets and sugar wartime rationing in the U.K. during World War II. Rationing was in effect during the war and ended in September 1953. Sugar intake during that time was about half (around 40 grams per day) the level immediately following rationing. The rationing was not one of extreme food deprivation—in fact, diets generally appeared to have been within today’s USDA/WHO dietary guidelines.  WHO,  as well as Dietary Guidelines for America adopted in 2020, recommend that children under two should consume no added sugars, and adults should aim to limit their added sugar intake to 7 teaspoons per day and consume no more than 12 teaspoons (50g).

When rationing ended, sugar and sweets consumption skyrocketed–doubling to about 80 grams per day on average. Other foods, like butter, cheese, cereals, and meat were also rationed, but there was little if any change in their consumption after rationing ended. Almost all of the sharp increase in total calorie intake post-rationing was explained by the rise in sugar calorie intake.

The end of WWII rationing therefore created a natural experiment in which children born just before the end of rationing were exposed to sugar-scarce conditions compared to those born just after who were born into a sugar-rich environment. The researchers then identified those born around this time in the UK Biobank data collected more than 50 years later. Enough time has passed since then for chronic diseases to develop and using a very tight birth window around the end of WWII sugar rationing allowed the authors to compare midlife health outcomes of otherwise similar birth cohorts.

Less diabetes, hypertension

The authors found that exposure to sugar restrictions in utero and during the first 1,000 days substantially lowered the risk of developing Type 2 diabetes and hypertension. If diagnosed, reduced early-life sugar intake delayed onset of diabetes by four years and hypertension by two years, respectively. In-utero exposure alone was enough to lower risks, but disease protection increased with the length of time babies had limited exposure to added sugar.

The magnitude of this effect is meaningful as it can save costs, extend life expectancy and, perhaps more importantly, improve quality of life. In the U.S., people with diabetes incur annual medical expenditures of about $12,000 on average. Every decade of earlier diagnosis of diabetes is associated with three-to-four years lower life expectancy, underscoring the value of early interventions that could delay or prevent this disease.

Policy implications

Today, there is a growing concern about children’s long-term health as they are consuming excessive amounts of added sugars during this critical early period. Added sugar is everywhere—even in baby and toddler foods—and children are bombarded with TV ads for sugary snacks. Adjusting sugar consumption is not easy, the researchers acknowledge, but information is key. “Parents need information about what works, and this study provides some of the first casual evidence that reducing added sugar early in life is a powerful step towards improving children’s health over their lifetimes,” said Boone (PhD 22, Public Health).

Gertler adds, “Sugar early in life is the new tobacco, and we should treat it as such by holding food companies accountable to reformulate baby foods with healthier options. We should also tax and regulate the marketing of sugary foods targeted at kids.”

This is the first study out of a larger research effort exploring how early-life sugar restrictions affect a broader set of economic and health outcomes including education, wealth, chronic inflammation, cognitive function, and dementia in later adulthood.

The study was supported by the U.S. National Institutes on Aging, part of the National Institutes of Health.

About the study

“Exposure to Sugar Rationing in the First 1000 Days of Life Protected Against Chronic Disease”
by Tadeja Gracner, Claire Boone and Paul J. Gertler
Science, October 31, 2024

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