Britain’s hardships during World War II included weeks of bombing during the Blitz, the mass evacuation of children, and food rationing. That rationing, researchers report, holds cautionary lessons for today about the health consequences of consuming sugar at a young age.
Black and white photos from wartime to cope with long queues in the shops when the supply of meat, dairy, sugar and other foodstuffs was limited. Rationing began in 1940, but lasted long after peace was declared in 1945.
Restrictions on sugar ended in September 1953, a perfect turning point for a natural experiment in pre- and post-natal nutrition. Pregnant mothers and children had fewer sweet foods to eat before rationing ended, but almost immediately after restrictions ended, sugar consumption almost doubled, from 41 grams to 80 grams per day. The daily sugar ration was the equivalent of approximately 6 to 7 teaspoons of sugar, an amount comparable to current dietary guidelines from the World Health Organisationwho say that sugars should not exceed 10% of total calories.
Did the health of children conceived just before and just after that threshold differ later in life?
Decades later, researchers have used that moment, impossible to reproduce in a randomized clinical trial, to compare the impact of sugar during pregnancy and up to the first two years of life, before and after this turning point. Those 1,000 days revealed significant differences between the two groups, based on their health data in the UK Biobank.
The group of children who consumed less sugar in the womb or in toddlerhood had a 35% lower risk of type 2 diabetes and a 20% lower risk of hypertension than those who consumed more sugar before and after birth. If people in the earlier cohort developed these conditions, they did so at an older age: four years later for type 2 diabetes and two years later for hypertension. study published Thursday in Science found. Less exposure to sugar during pregnancy was associated with a third of the reduced risk of diabetes and hypertension, with a new decline in relative risk at six months of age, a time the authors linked to the first solid food of children.
Of the more than 60,000 people studied, almost 4,000 developed type 2 diabetes and almost 20,000 hypertension. The risk of these conditions increased with age, but not as rapidly for those who experienced sugar rationing. (Rationing for butter ended in May 1954 and for all foodstuffs in July 1954.) Obesity was 30% lower in the sugar rationed group. People who became pregnant after rationing ended continued to eat more sugar into their 60s, the study found.
What does this study, which happened to be published during the candy-filled holiday of Halloween, mean for children today?
“This is a very good and interesting study that exploits a natural history experiment in a very nice way. Because it is essentially an uncontrolled cohort study, I don’t think they conclusively demonstrate causality,” Bob Siegel, director of the Center for Better Health and Nutrition at Cincinnati Children’s Hospital, told STAT. He was not part of the investigation. “My own opinion is that limiting sugar is a good idea. It adds to the overwhelming evidence that sugar consumption is simply not good for you.”
Study author Tadeja Gracner, a health economist at the University of Southern California’s Center for Economic and Social Research, pointed out that the environment in the study — 1950s Britain — was not the extreme food deprivation you’d find in a famine. Sugar was not banned; it was rationed to what experts now consider a healthy amount. The onset of the disease was delayed, but not eliminated.
“We’re not saying, eat less sugar and you’ll never get sick again,” Gracner said in an interview. “We’re saying you’ll probably get a few extra years without it, which is pretty valuable.”
The researchers tried to take into account other factors that influenced the groups born within a few months of each other. For example, fruit and vegetable consumption remained flat before and after rationing. Diagnoses of type 1 diabetes, which are not related to diet, also remained stable. They also acknowledge that the Biobank cohort is not representative of the UK population, which is generally white, but also healthier and wealthier.
This study has inspired other research on when food preferences are formed and how they affect health, Gracner said. Her working paperposted by the National Bureau of Economic Research but not peer-reviewed, examines this issue. How much of a sweet tooth you develop can depend on your exposure, Gracner said, and that preference develops early.
“We find that a high-sugar diet early in life increases free sugar consumption across the lifespan, which is consistent with evidence that lifelong dietary preferences and habits emerge early and that sugar can be addictive,” the working paper said.
Caroline Apovian, an endocrinologist who co-directs the Center for Weight Management and Wellness at Brigham and Women’s Hospital, raised a similar theme, linking early preferences to the high prevalence of obesity among children in the US.
“This study really excites me because it basically says, my God, if you’re exposed to sugar in the womb, you’re more likely to develop diabetes years later,” she told STAT. She was not involved in the investigation. “We have so much more ultra-processed food now than we did then. If we acquire a taste for eating, say, foods with a high sugar content, then that can be indicative of all the cravings, not just for sugar, but for salty foods and all the ultra-processed foods that we eat.”
Apovian lamented the ubiquity of ultra-processed foods and who is most affected by their availability. It’s not so much about preference as it is about the environment, she said.
“The prevalence of obesity has particularly affected people in the United States in the lowest socioeconomic class,” she said. “We know there are food deserts. They can’t go to Whole Foods and get their fruits and vegetables because it’s too expensive, it’s not there. ”
While Gracner’s research highlights the importance of nutrition interventions in early life, she doesn’t want to blame pregnant women or parents.
“I want to emphasize that it is extremely difficult to eat healthy, with the abundance of added sugars,” she said. “This should not be about: pregnant women should no longer eat croissants.”
Amanda Adler, professor of diabetes medicine and health policy at the University of Oxford, called it “intriguing and entirely possible” that lower exposure to sugar before birth could lead to lifelong health benefits.
“This study is an open invitation to clinical subjects to clarify the ‘correct’ sugar levels to add to the diets of pregnant and lactating women, and for their infants,” she said in a statement from the Science Media Center .
Gracner hopes to explore the question in other ways: epigenetics, gut health and the microbiome, who is affected and when.
“There is so much to understand.”
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