The mouse study, published in the British Journal of Pharmacology, investigated the link between diet, diabetes and depression by testing the influence of type 2 diabetes on emotionality.
Led by senior author, Dr Bruno Guiard, the research team reported that increased body weight, hyperglycaemia and impaired glucose tolerance in response to a high fat diet (HFD) are correlated with anxiogenic/depressive-like symptoms in mice, while the beneficial effects of an antidepressant were also found to be blunted in mice fed a high-fat diet.
“On the contrary, HFD withdrawal completely reversed metabolic impairments and positively impacted anxious symptoms, although some behavioural anomalies persisted,” said the team – adding that the data provides “clear-cut evidence that both pathologies are finely correlated and associated with impaired hippocampal serotonergic neurotransmission.”
Guiard said the evidence that removing a HFD and reversing the metabolic impacts of diabetes can also lead to positive changes on anxiety and depression reinforces an existing idea that the normalisation of metabolic parameters may give a better chance of achieving remission for people with depression, and particularly in depressed patients with type 2 diabetes.
The results set the tone for future investigations on potential mechanisms that may link metabolic and psychiatric disorders.