Eating ultra-processed foods significantly increases the risk of depression, according to a large-scale study.
These foods have long been linked to conditions such as heart disease, cancer, diabetes and Alzheimer’s.
But now researchers at Tehran University of Medical Sciences in Iran have concluded that regularly eating junk food increases the risk of depression by 15 percent.
Diets that include prepared meals, sugary cereals and soft drinks tend to be high in fat, salt and sugar and low in vitamins and fibre.
The researchers used data from clinical trials and studies involving 160,000 men and women from around the world to explore the link between mental illness and unhealthy eating habits.
Results showed that consuming large amounts of nutrient-poor food also increased the risk of anxiety by 16 percent.
Scientists suggest that ultra-processed foods (UPF) could cause brain inflammation, which could lead to mental health problems.
Britons consume more UPF than any other European country, with it making up around 57 per cent of the national diet.
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The Iranian study, the largest to date of how diet affects mental health, also suggests that these foods may lower the body’s levels of a protein called brain-derived neurotrophic factor, which is essential for healthy mental function.
However, some experts argue that ultra-processed foods don’t necessarily cause depression.
Instead, they argue, depressed people are more likely to make poor dietary choices.
“When people are feeling down, they often make less effort to cook and turn to ready-made meals,” says Gunter Kuhnle, professor of nutrition and food science at the University of Reading.
“We’ve known for some time that there’s a strong connection between diet and mental health, but it’s hard to say definitively that poor diet causes depression.”
Earlier this year, the world’s largest study on UPF found that taking large amounts increases the risk of harm to various parts of the body.
A study published in the British Medical Journal found that a diet high in UPF foods increased the risk of death from heart attack or stroke by 50%.
