Depression risk? Steve Prezant/Getty

Watch the sugar, boys. Men who consume high levels of sugar from sweet drinks and snacks have been found to be 23 per cent more likely to develop depression or anxiety.

Excessive sugar consumption has been linked with a range of health problems, including diabetes, obesity, and dementia. There also seems to be a link between sugar and depression and anxiety, but whether sugar contributes to these conditions, or if these disorders instead make people eat more sugar, has been unclear.

To find out, Anika Knüppel at the University College London and her team studied data from over 8,000 adults in the UK who had regularly answered questionnaires about their health and lifestyles since the 1980s. The questionnaires included questions like “how often do you eat a piece of cake”, and the participants also completed mental health surveys and attended clinical appointments that assessed their weight and height.


Analysing this dataset, and controlling for a range of factors like health and socio-economic status, the team found that, when men were ranked among the top third of the group for sugar consumption from items like fizzy drinks, cakes and sugary tea, they were 23 per cent more likely to experience a bout of depression or anxiety over the following five years. There was no sign that mood disorders themselves boosted sugar intake, and the pattern seen in the men was not seen in women.

Too much cake?

“I had a feeling we’d see the ‘Bridget Jones-like women eat chocolate’ idea,” says Knüppel. “But it turns out people underestimate that men’s sugar intake is super high.” However, women only made up one third of the people included in the study, so it is possible sugar may have a similar effect for women that wasn’t picked up due to the smaller sample size.

Knüppel thinks there may be several explanations for how sugar could affect mental health. For example, eating something very high in sugar can cause a person’s blood sugar to drop to a low level later on, and it’s possible that high sugar intake may have longer-term effects similar to this phenomenon.

Alternatively, sugar may affect the development of nerve cells. High-fat, high-sugar diets have previously been found to reduce the levels of a protein that influences neuron growth in the brain and is thought to be involved in depression and anxiety. High-sugar diets also increase inflammation in the body, and inflammation has been implicated in depression.

The health effects of high sugar intake aren’t likely to be limited to only those eating the very highest amounts. Adults in the UK consume, on average, twice the recommended amount of sugar, while the average US adult consumes triple the guideline amount.

Journal reference: Scientific Reports, DOI: 10.1038/s41598-017-05649-7

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