Unravelling the Link Between Healthy Habits and Depression

In a recent publication in Nature Mental Health, an international research team, including members from the University of Cambridge and Fudan University, delves into the intricate relationship between factors such as lifestyle, genetics, brain structure, and immune/metabolic systems concerning depression. With depression affecting approximately one in 20 adults globally, the study aims to unravel the complexities surrounding its onset, encompassing biological and lifestyle elements.

The researchers turned to the UK Biobank, a comprehensive biomedical database containing anonymized genetic, lifestyle, and health information from nearly 290,000 participants. Over nine years, with 13,000 individuals experiencing depression, the team identified seven healthy lifestyle factors associated with a lower risk of depression. These factors included:

• Moderate alcohol consumption
• A nutritious diet
• Regular physical activity
• Adequate sleep
• Never smoking
• Low-to-moderate sedentary behavior
• Frequent social connections.

Among these factors, the most impactful was a good night’s sleep( between seven and nine hours a night), reducing the risk of depression by 22%. Frequent social connections were most protective against recurrent depressive disorder, lowering the risk by 18%. Moderate alcohol consumption, healthy diet, regular physical activity, never smoking, and low-to-moderate sedentary behavior contributed to risk reduction by 11%, 6%, 14%, 20%, and 13%, respectively.

Participants were categorized into three lifestyle groups based on adherence to these factors—unfavorable, intermediate, and favorable. Individuals in the intermediate group exhibited a 41% lower likelihood of developing depression than those in the unfavorable lifestyle group. Those in the favorable lifestyle group demonstrated a 57% lower possibility.

Additionally, the researchers analyzed the participants’ DNA, assigning a genetic risk score based on known genetic variants linked to depression. Individuals with the lowest genetic risk score were 25% less likely to develop depression than those with the highest score. This highlights the significant impact of lifestyle, irrespective of genetic predisposition.

Reason of link between lifestyle and depression.

Further investigation involved studying MRI brain scans of nearly 33,000 participants, revealing brain regions with larger volumes linked to a healthy lifestyle. These regions included the pallidum, thalamus, amygdala, and hippocampus. The study also explored blood markers related to immune and metabolic functions, such as C-reactive protein and triglycerides, finding links between these markers and lifestyle.

The researchers emphasized that the pathway from lifestyle to immune and metabolic functions was crucial. A less healthy lifestyle was shown to impact the immune system and metabolism, subsequently increasing the risk of depression.

Dr. Christelle Langley from the University of Cambridge stressed the importance of a healthy lifestyle for mental health, stating that it not only benefits brain health and cognition but also indirectly promotes a healthier immune system and better metabolism.

Professor Jianfeng Feng from Fudan University and Warwick University highlighted the early onset of depression and suggested educating young people on the significance of a healthy lifestyle for mental health starting in schools.

In conclusion, the study underscores the importance of a healthy lifestyle in preventing depression, demonstrating its significant impact on mental health, cognition, immune system function, and metabolism.