Scientists also found that sugar intake during early life may influence brain development, with significant differences identified in 11 of the 80 brain regions examined.

The study investigated how exposure to sugar during early life affects mental health in adulthood, dietary preferences and neurodevelopment. Researchers found that the risk of developing anxiety was lowest among people who had the least exposure to sugar in the womb and during the first two years of life.

Dr Hana Navratilova of IPB University, Indonesia, who led the research while at the University of Surrey, said previous studies had shown that sugar exposure during the first 1,000 days of life may influence the risk of chronic diseases such as diabetes.

“Because we’ve seen in our previous work links between the liking of sugary foods and mental health issues, we were specifically interested in understanding if having sugar in early life could contribute to incidences of mental health issues such as depression and anxiety later in life,” she said.

“Knowing the full impact that sugar can have on our physical and mental health, across our lifespan, could help inform public health policy and reshape our diets.”

For the study, researchers analysed medical data from more than 45,000 UK Biobank participants born between 1951 and 1956, a period when sugar rationing in Britain was still in place before being gradually phased out.

Participants were divided into groups based on whether they experienced sugar rationing in the womb and during the first six, 12, 18 or 24 months of life. Researchers also examined participants who experienced rationing only in utero.

The study included a control group of people of a similar age who were born after sugar rationing had ended in the UK, as well as a separate group of children born in Ireland.

Researchers found that women who experienced no rationing or only a limited period of rationing were more likely to develop anxiety later in life.

An association between early-life sugar exposure and depression was also identified. However, the association became less significant after statistical adjustments, suggesting that depression may be more strongly influenced by dietary patterns later in adulthood.

The researchers also examined brain-imaging data in relation to exposure to sugar rationing. They found significant differences in grey matter volume across 80 of the 139 brain regions examined.

Further analysis identified significant differences in 11 of those 80 regions between most rationing groups and participants who had never experienced rationing. Some of the differences were observed in regions of the cerebellum.

The study also found that participants who experienced the longest period without exposure to excess sugar — from pregnancy through the first 24 months of life — reported a lower preference for sweet foods in adulthood.

Researchers identified differences in sweet-food preferences between some of the rationed groups and those who had never experienced rationing, suggesting that early-life sugar exposure may have lasting effects on dietary preferences.

Professor Nophar Geifman, Professor of Health and Biomedical Informatics at the University of Surrey and the study's senior author, said the UK Biobank provided researchers with a unique opportunity to examine the long-term effects of post-war sugar rationing.

“The UK Biobank is a treasure trove of data that allowed us to look at this post-war diet rationing, giving us unique insight into the impact of sugar exposure on our mental health,” Geifman said.

“It is highly unlikely that this sort of dataset would exist again, whereby so many people did not have excess sugar in their diets and then had it slowly phased in over a prolonged period of time.”

The researchers concluded that sugar rationing during early life was associated with reduced preference for sweet foods and a lower risk of anxiety in adulthood.