New research is the latest to find that people who eat more highly-processed food are more at risk of depressive symptoms.

A study of 735 young adults aged under 35 in Italy found a “positive association” between ultra-processed food (UPFs) and depression.

It has led to researchers calling for further studies to try to further understand the link, saying: “The specific involvement of brain regions involved in behavioural disorders needs to be further investigated to better understand the impact of food additives on human mental health.”

The study found that even following a traditional Mediterranean diet, which centres around natural foods such as whole grains, nuts, legumes, fruit and vegetables, failed to compensate for the higher consumption of UPFs – rather it raised the risk of depressive symptoms.

Researchers say this suggests “that components of the diet other than nutritional quality may play a role on the reported association”.

The authors said: “The findings from this study do not necessarily imply that UPFs must necessarily cause depression, but that a mutual relation may exist, that UPFs might be consumed as comfort foods by an at-risk population (i.e., younger individuals with emerging mood disorders), and that it can establish a vicious cycle by further enhancing detrimental effects on brain health related to depression.”

UPFs contain few or no natural ingredients but instead contain chemical additives and preservatives to increase the shelf life of this type of food. They may also contain things like flavour enhancers and artificial sweeteners, making them more palatable.

The authors said: “In conclusion, a positive association between UPF consumption and likelihood of having depressive symptoms was found in younger southern Italian adults. Further studies are needed to corroborate this association, also among other populations.

“It is crucial to understand whether non-nutritional factors may also play a role in human neurobiology. ”

“The specific involvement of brain regions involved in behavioural disorders needs to be further investigated to better understand the impact of food additives on human mental health.”

UPFs are estimated to make up around a fifth of the daily energy intake in Mediterranean countries, while in more Westernised countries like the US and Australia, that figure may be as high as 80%.

Young people may be more at risk because their lifestyle – less free time, less disposable income and work pressures – could play a role in them opting for quick, cheap UPFs.

The study authors outlined how the make-up of UPFs, which includes a high concentration of refined sugars and saturated and trans fats, low fibre and food additives, may impact the body’s normal functioning.

Read the study in the journal Nutrients.

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