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A mother’s diet in pregnancy supports her child for life

A mother’s diet in pregnancy

Study shoes mother’s diet in pregnancy supports child for life.

25 October 2023

Post-war food rationing ended nearly 70 years ago in the UK. But, as research by the School of Economics’ Stephanie von Hinke shows, this era of food history left a surprising legacy that’s still with us today.

On the 24th of April 1949, the people of Britain rejoiced. After seven long years, the government had finally abolished rationing on chocolates and sweets.

From early that morning, queues of customers stretched from kiosks across the country, desperate to indulge in 2lb boxes of chocolates and armfuls of boiled sweets. Retailers feared their stock would soon run dry.

Over the coming weeks, customers each bought an average of 8-10 ounces (227-283 grams) of sweets and chocolates every week. This was roughly three times more than they’d been allowed under rationing (around 3 ounces each).

The confectionery industry could not keep up with the demand. Some shops even had to close. And so, less than four months later, in August 1949, the government decided to bring the rations back.

The lifelong effects of sugar

We’re all used to hearing that too much sugar is bad for us. So what did that intense burst of sugar consumption do to the nation’s health? Seven decades on, the four months of derationing in 1949 have helped Stephanie von Hinke, Professor of Economics at the University of Bristol, overcome a major barrier in her research.

Von Hinke researches the economics of health and diet. A big challenge for researchers like her, who want to understand the impacts of particular foods, is that we all eat different diets. What’s more, if one food becomes unavailable, people often substitute it with something else. Isolating sugar’s effects from everything else is tough.

But thanks to the wartime and post-war rations of 1940-1954, everyone in the UK – rich or poor – ate pretty similarly. By rationing almost all major foods to ensure equal access for all, the government inadvertently created excellent conditions for von Hinke’s future ‘experiment.’

Her study is one of few to explore an important question: how does our consumption of sugar when we are still in the womb, via our mothers’ diet, affect us throughout our lives?

Conducted with Gerard van den Berg and Adele Wang, the study was funded by the European Research Council and NORFACE DIAL.

It combines the disciplines of economics and genetics. The team used micro-econometric tools to estimate the health and educational impact of babies’ exposure to the four-month sugar high whilst they were in utero. They applied these statistical tools to data from the UK Biobank for between 36,000 and 84,000 people – depending on the health or educational outcome in question – who were aged 56–63 in 2006-2010 (the study period).

A clear impact of prenatal sugar

The spike in chocolate and sweet consumption had, indeed, left a long-term mark on the babies’ lives.

But here’s the twist. The high-sugar pregnancy diets had been good for their health in older age. Specifically, and on average, their BMIs were 0.08 units lower than for people whose time in the womb fell outside (but within two years) of the four-month derationing period. The mothers of all these babies had eaten similar diets under post-war rations. And, save for the sugary binging of April–August 1949, their diets changed little.

The derationing babies also ate 0.9% less sugar in later life. Looking at their earlier lives, they had performed better at school too – completing an extra 1.8 months of education, on average. On other long-term measures considered – including cardiovascular disease, type-2 diabetes and fat consumption – their mothers’ chocolate and sweet binges had had no obvious effect, good or bad.

On top of that, people who were genetically predisposed to a sweet tooth benefited more from derationing, as it had an even bigger effect on lowering their sugar consumption in their 50s and 60s.

Explaining the results

The research team cannot be sure why the derationing had these effects. But they have some good theories.

First is the idea that your pregnancy diet prepares your baby for the world it will enter. In medical research, this is known as ‘foetal programming’ or the ‘developmental origins’ framework.

The biological processes behind it are unclear. But, as von Hinke explains: “We know that babies who were in utero during famines, for example, are more likely to become obese and suffer heart disease and type 2 diabetes when they’re older. It’s as if their body can’t cope with all this food now.”

And so, maybe pregnant women’s high-sugar diet of 1949 helped their post-war babies cope with the high-sugar world in which we now live. For the babies who were genetically predisposed to enjoy more sugar, this priming may have been even more important.

Another possibility is that the sweet treats helped the mums de-stress. An absence of these stress relievers could have signalled to the baby that it was about to enter a stressful world – and triggered a taste for more sugar. Or, perhaps, the happiness brought by the treats meant mothers could bond better with their newborns. This would have supported the babies’ development, paving the way for stronger health and educational success.

No dietary advice – but an important message

“The results certainly made me feel better about my own diet during pregnancy,” confesses von Hinke. “There was a lot of chocolate.”

Any pregnant readers of this blog should think twice before reaching for yet another triple chocolate chip cookie, however. This study does not support a high-sugar diet in pregnancy.

“We can’t give any dietary recommendations,” she confirms. “It’s still important to eat as healthily as you can during pregnancy.”

Thanks to the rationing, diets were generally better and more nutritionally balanced after the war than they are now. The mothers in the study only temporarily upped their chocolate and sweet intake.

“That might have made them happier, it might have reduced their cravings,” elaborates von Hinke. “But it’s very hard to extrapolate those findings to today’s world. Nowadays, we can easily replace or complement one food with another and, in general, we eat less healthily. The effects of suddenly eating lots more sugar could be different now.”

She does draw one important conclusion from the study, however. And that is that it provides clear evidence that what we do during pregnancy affects our children for life.

“People used to think that the foetus is completely protected by the placenta. We now realise that, actually, it’s very vulnerable,” she warns.

It might seem a little scary, but “what a mother does during pregnancy – what she eats, how much she smokes, how much she drinks, how happy she is  – can affect the child when they are 50, 60 or 70 years old.”

The effects may not be obvious at birth – or even at age 20 or 30. “Diseases like heart disease and type 2 diabetes only appear later in life. But they could be driven by very early-life conditions.”

The impacts of the four-month derationing on the babies’ long-term health and education might sound small, although the researchers wouldn’t expect anything major in response to the relatively mild dietary change.

But: “Our study does show the importance of the prenatal period in shaping life outcomes. And knowing that early-life conditions affect adults as they grow older is vastly important for public policy.”

Further information

Read the study in full here.

This study was conducted under the GEIGHEI (Gene-Environment Interplay in the Generation of Health and Education Inequalities) and DONNI (Developmental Origins: exploring the Nature-Nurture Interplay) projects.

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