People who received little sugar in the womb and in their first years of life because of post-war rationing in the UK are less likely to suffer from dementia, Alzheimer's disease, depression and anxiety. The results of an analysis of UK Biobank data - a large long-term project on the health of UK residents - have been published in the journal npj Aging.
In the UK, sugar was rationed from 1942 to 1953. The ration corresponded to modern recommendations, and children under two were not given sugar at all. After rationing ended in September 1953, adults' sugar consumption almost immediately doubled, while other foods were eaten in roughly the same quantities. This allowed scientists to compare people conceived during rationing with those born after it ended.
The analysis included participants born between October 1951 and March 1956. Some of them were conceived during rationing, including those whose mothers followed the ration only during pregnancy. The rest formed the comparison group. Some participants without brain diseases had brain scans.
After adjusting for region and month of birth, socioeconomic status, education, family history and genetic risk factors, it emerged that those who were restricted in sugar both in the womb and after birth had a 27% lower risk of dementia, a 46% lower risk of Alzheimer's disease, an 11% lower risk of depression and a 20% lower risk of anxiety than the comparison group. Among those exposed to rationing only in the womb, the risk of anxiety was 10% lower, and no significant differences were found for the other conditions. No link was found with Parkinson's disease.
The longer a child lived under rationing after birth, the lower the risk of depression and anxiety. For example, among those restricted in sugar for 12 months after birth, the risk of depression was 23% lower and that of anxiety 28% lower. The lowest risks were observed among those who lived that way for 24 months. No such pattern was found for dementia and Alzheimer's disease.
The associations more often appeared in women: they had a lower risk of Alzheimer's disease, depression and anxiety. In men, only the reduction in anxiety risk was reliable.
On brain scans, people restricted in sugar after birth had brains that looked about 0.39 years (about five months) younger than their actual age, compared with the comparison group. They also had larger volumes of some deep brain structures, including the hippocampus, thalamus and putamen, and lower contrast between grey and white matter in many cortical areas. The authors warn that these data are preliminary.
The study did not measure individual sugar consumption: the scientists relied on dates of birth. In addition, the end of rationing coincided with a post-war economic boom, improved medical care for mothers and changes in infant feeding practices - all of which could have independently influenced brain development. Rationing of other products also ended by July 1954, although their consumption changed little. It therefore remains unclear what share of the differences is specifically linked to sugar.
Diagnoses of depression and anxiety were partly based on self-reports and primary care records. The participants grew up in a post-war environment, predominantly among the white population of Britain, which may not reflect the experience of today's children. The authors emphasise that the findings need to be replicated in modern cohorts with detailed nutrition data before they are used for clinical or public recommendations.