Three Weeks to a Clouded Mind: BelSU Geneticists Part of Global Team Link Western Diet to Depression

Researchers from Belgorod National Research University (BelSU) have joined colleagues from Russia, China, the Netherlands, France, and Germany to demonstrate that a diet high in saturated fats, cholesterol, and simple carbohydrates – the so-called Western diet – does not merely trigger metabolic disorders but can directly worsen mental health. The study, covered by the Russian news agency RIA Novosti, focused especially on ageing females, a group the authors believe holds clear parallels for humans.

BelSU’s principal contribution lay in genetic analysis and data interpretation, coordinated by Alexey Deykin, Head of the Laboratory of Genetic Technologies and Gene Editing for Biomedicine and Veterinary Science.

“The Western diet is unfortunately widespread throughout the world today, and it is already known to lead to serious endocrine and cardiovascular diseases. We were interested in a subtler mechanism: how such a diet affects serotonin reuptake, a process directly linked to mood and anxiety,” Deykin told RIA Novosti.

At the centre of the investigation was the serotonin transporter (SERT), a protein that controls serotonin levels in the brain’s intercellular space. When reuptake happens too rapidly, serotonin concentrations fall – a hallmark of depressive states and the very target of many modern antidepressants.

The findings were striking. After just three weeks on a high-fat, high-sugar diet, elderly female mice showed decreased exploratory activity, heightened impulsivity, signs of helplessness, and memory impairment. They explored new spaces less often, froze in forced swim tests, and struggled with cognitive tasks. At the same time, they developed impaired glucose tolerance and altered expression of genes that regulate both metabolism and emotional state.

According to Deykin, a matching genetic mechanism means the results are relevant to humans. In people, a polymorphism in the SLC6A4 gene (known as 5-HTTLPR) reduces the efficiency of the serotonin transporter. Carriers of the “short” allele of this gene – like the mice with partial SERT deficiency – are objectively more susceptible to anxiety and depression.

“The practical conclusion is clear,” Deykin said. “An unhealthy diet oversaturated with animal fats and simple carbohydrates can not only disrupt metabolism but also provoke anxious and depressive behaviour and impair memory. Monitoring your diet is not simply about looking after your figure or your heart – it is a real tool for preventing mental disorders, especially in vulnerable populations.”

The researchers stressed that the study deliberately targeted ageing females: menopausal women represent the group at highest risk for both metabolic and mental disorders. Because the basic biochemical mechanisms are shared across mammals, the findings are highly likely to apply to humans.

The international team, including the BelSU geneticists, now aims to identify molecular targets for personalised prevention and treatment of metabolically driven mental conditions. Full details of the study have been published in the international journal Metabolites (MDPI).