THey, they were born into a Britain still recovering from the hardships of war. Even though the air warning sirens have gone silent, many daily foods remain rationed, including sugar. Adults were limited to about 3 tablespoons (40g) per day to stretch between cups of tea, pastries and desserts; children were limited to less than one tablespoon. Babies and very young children were supposed to have little or no added sugar.
Then, in 1953, the brakes failed. Separate restrictions on sweets and chocolate were lifted in February, followed by sugar in September. By the second half of 1954, average sugar consumption had almost doubled.
The lifting of sugar rationing after the war inadvertently created a natural experiment, the consequences of which scientists are only beginning to understand. A series of recent studies suggest that spending the first 1,000 days of life on sugar rationing may have left its mark on people’s health more than seven decades later.
“What makes the end of sugar rationing particularly interesting is the nature of the exposure,” said Dr Jiazhen Zheng of the Hong Kong University of Science and Technology in Guangzhou, China, who has worked on several recent studies. “In September 1953, the availability of sugar changed quite abruptly at the population level, largely due to policies rather than individual choices. In a sense, history created an experiment that we could never deliberately carry out in a human lifetime.”
The first in this recent wave of studies on sugar rationing was published in the journal Science two years ago. Dr Tadeja Gračner from the University of Southern California and colleagues used data from the UK Biobank to compare the health of people born shortly before and after the end of sugar rationing in the UK. Some had only been exposed to this low-sugar environment during their time in the womb; others remained exposed for months or years, while those designed after rationing ended were not exposed at all.
Gračner found that the longer people stayed on rationing, the lower their risk of developing type 2 diabetes and high blood pressure in mid-to-late life: those exposed in their first 1,000 days had a 35% lower risk of type 2 diabetes and a 20% lower risk of high blood pressure than those who had never been rationed.
The results prompted Zheng and others to wonder whether these effects might extend to other organ systems. In recent months, other studies drawing on UK Biobank data by his group and others have linked reduced sugar exposure to lower risks of a growing list of health problems.
“I was more struck by the consistency between different organ systems than by a single effect estimate,” Zheng said. “In our work, we have seen associations with cardiovascular disease, liver disease, respiratory health, dementia, and, more recently, with broader measures of aging. Our study of aging, for example, found an overall lower incidence of diseases linked to characteristics of aging and slightly younger biological and organic ages among those exposed to rationing early in life.”
Gračner is not entirely surprised. “A lot of these results are related,” she said. “Diabetes, hypertension and obesity are major risk factors for cardiovascular disease, cognitive decline and several other conditions. Thus, if early life sugar restriction affects these upstream risks, the associations across a wide range of related outcomes are what one would expect.”
What is perhaps more surprising is the suggestion that the effects could extend beyond physical health. In August, Professor Nophar Geifman of the University of Surrey and colleagues reported that people who spent the first 1,000 days of their lives on sugar rationing had a 33% lower risk of being diagnosed with anxiety than those born after rationing ended.
They were also less likely to report a preference for sweet foods decades later. “Despite the increase in sugar consumption after rationing, early nutritional environments appear to have lasting relevance for mental health,” Geifman said.
How a relatively brief difference in sugar exposure might leave detectable traces decades later remains unclear. Gračner said: “We can demonstrate that growing up with less sugar has a protective effect decades later, but we don’t know how: whether through sugar itself, through taste preferences formed early, or through a metabolic response set early in life.
His team’s latest research, now undergoing peer review, suggests that growing up under rationing conditions could weaken the influence of genes that predispose people to higher body weight.
“Importantly, while we observe that people exposed to rationing consume less free sugar as adults, we find that dietary differences are similar across genetic risk groups,” Gračner said. “This indicates a response that is not purely behavioral: early nutrition can act on physiological pathways such as metabolic programming, insulin sensitivity, regulation of appetite and satiety or the development of adipose tissue.”
Explaining the result of anxiety is a little trickier. Geifman says the brain undergoes rapid development in the womb and during the first years of life, which could make it particularly sensitive to its nutritional environment. Diets high in sugar have also been linked to inflammation and altered gut microbiome – two possible pathways by which sugar could affect brain function.
Zheng’s study on aging offers another potential clue. People exposed to rationing were found to score about a year younger on several measures of biological age. The researchers also detected differences in proteins involved in pathways that help cells respond to nutrients and have been implicated in aging. “So I view biological aging as a possible shared upstream pathway, rather than necessarily as a completely separate phenomenon,” Zheng said.
The idea that early nutrition can have lasting effects is not new. Since the 1970s, researchers have used famines as natural experiments to study the consequences of severe nutritional deficiency early in life.
Much of this research has focused on the Dutch “hunger winter” of 1944-45, when German restrictions on food transportation left millions of people in the western Netherlands facing severe shortages. Because this famine began and ended abruptly in a previously well-fed population, and because food rations were recorded and detailed birth records survived, researchers were able to compare those exposed during different stages of pregnancy with those born before the famine or conceived after its end.
“The most reliable findings are an increased risk of overweight, obesity and type 2 diabetes,” said Professor LH Lumey, professor emeritus of epidemiology at the Columbia Mailman School of Public Health in New York. “People are likely to be more overweight starting at age 20 or 30, and they are more likely to have diabetes at age 50 or 60. »
Although British studies of rationing might seem to point in the opposite direction, the conditions were very different. “Sugar rationing in Britain was not a famine, and it did not involve severe overall caloric deprivation. Rather, it selectively limited sugar consumption while the diet as a whole remained relatively adequate,” Zheng said.
So the lesson is not simply that less nutrition is better. “This suggests that the quality and timing of nutrition during early development may have consequences that extend throughout life,” Zheng said.
So where does this leave us? As fascinating as these findings are, they do not prove that differences in sugar consumption early in life cause later differences in health. “There is no causality implied,” Geifman said. “It’s an association.”
Many recent studies also rely on overlapping groups of UK Biobank participants, meaning they cannot be considered independent replications. “The strongest evidence will ultimately come from triangulating independent data sets and research models,” Gračner said.
Lumey said the findings represented “a big first step, not the last word. They should be examined in more detail, without answering the question: Is there an association or not? But is the risk really 30% or 50% higher, and is it in the first 1,000 days, or just the gestation period?”
Even if the associations ultimately prove causal, these current studies cannot tell parents exactly how much sugar is excess. They also cannot identify a single critical window. The data available so far suggests that exposure during pregnancy is important, but some associations become stronger when rationing continues beyond about six months of age – around the time babies start eating solid foods.
“The emerging picture is that the entire first 1,000 days may be important, with pregnancy and the transition to solid foods representing potentially important windows,” Zheng said. “While these findings support existing recommendations to limit unnecessary free or added sugars, they should not be interpreted as…
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