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Dietary guidelines say that babies from conception to age two should not consume added sugars. However, pregnant women typically consume twice the recommended amount of sugar, and most babies consume some type of sweetened food or drink every day. Some critics say that such recommendations are based on studies that are of poor quality or are not detailed enough. To overcome these limitations, a team led by Tadeja Gracner of the University of Southern California used information generated by a natural experiment that took place shortly after World War II, when rationing eliminated sugar from the diets of British people, including children and pregnant women, from the end of the war in 1945 until 1953.
The team used data from a biobank of 60,183 individuals born between October 1951 and March 1956, comparing the health outcomes of those conceived before and after sugar rationing ended in 1953. During rationing, adults were allowed up to 40 grams, half the current average consumption, and children aged under two received nothing. In a study published on November 1 in the journal Science, they found that over the years, restricting sugar during the first 1,000 days of life reduced the risk of developing diabetes and hypertension later by about 35% and 20%, respectively, and delayed the onset of these diseases by about four and two years. The protective effect was strongest for those whose exposure to sugar was restricted both in utero and in the months after birth. The authors estimate that 30% of the reduction in disease risk should be attributed to whether or not there was exposure during pregnancy.
Although the study does not prove a causality between sugar consumption during the first months of life and protection from disease, the observation of the link strengthens the reasons for recommending limiting sugar consumption. The authors of the study offer possible explanations for their results. On the one hand, as suggested by the hypothesis of the fetal origin of adult diseases, the consumption or not of sugar by the mother can change the physiological programming of the baby from the womb. “Our findings on the effect of sugar in the womb coincide with the results of animal studies, which show that high-sugar diets during pregnancy increase the risk factors for type 2 diabetes and hypertension […] or studies in humans that show an association between a high-sugar diet during pregnancy and lactation and the risk of obesity in the child,” write Gracner and her colleagues. A second possibility is that tasting sugar early in life permanently conditions our desire for sweets, as some studies suggest. If this were the case, we should consider the effects of around 70% of children’s products containing added sugars, whether they are drinks, milk formula, or other foods.
One of the difficulties in reaching definitive conclusions about the effects of single dietary measures is that you can’t keep hundreds or thousands of humans in a controlled environment for decades, feeding them only what the experimenters want. So methods are used to get closer to reality, comparing the results of observational studies in humans with more controlled ones in animals. In this regard, the effect of consuming less sugar in the first months of life was greater in reducing the risk of type 2 diabetes in women than in men, a difference between the sexes that has also appeared in several animal studies. In addition, sugar rationing reduced the risk of obesity, which increases the risk of heart and metabolic diseases and suggests a possible biological explanation for the problems caused by sugar.
Gracner believes that “as discussions intensify around policies such as sugar or sugary drink taxes, or regulation of added sugars in infant and toddler foods and their marketing, understanding the direct relationship between sugar consumption in early life and chronic disease is critical […] Our results contribute to this debate by linking sugar to health and highlighting the importance of early-life diet to manage the risk of metabolic diseases in the long term,” she concludes.
The natural experiment of rationing after World War II has similarities with one that took place in Cuba between 1991 and 1995. Then, during the so-called “Special Period,” the lack of Soviet assistance after the fall of the USSR left the Caribbean island in a deep crisis. It is said that bathtubs in Havana were used to raise pigs, in order to hide them. From consuming 3,000 calories per person per day, Cubans went on to consume about 2,200. Against their will, they began to walk more or use bicycles because there was no fuel to propel cars. The island’s inhabitants remember that period with the same fondness as the British remember the post-war period, but, according to a study published in the British Medical Journal, that radical diet and exercise plan improved Cubans’ health and life expectancy.
That result showed that the important changes in habits that have the greatest effects on health cannot be a sum of correct individual decisions. “It must happen in the environment, so that I don’t have to make the decision to choose between a food with a lot of salt and one with little salt every time I go to eat, because that is not going to work,” explained Manuel Franco, author of the study. Some epidemiologists like Franco argue that it is necessary to have policies that ensure, at least to a certain extent, that these decisions are made, as happened with sugar rationing. Another dilemma is whether, just as we are prohibited from consuming heroin or driving at 200 mph without a seatbelt, it is legitimate for the state to force us to eat healthily.
