Lifestyle can ward off depression and even counteract an unfavorable genetic profile for this disease, according to a study with data from 290,000 people.
By Sonia Moreno
Lifestyle guidelines that reduce the risk of depression can be summarized as eating a healthy diet (moderate alcohol consumption and not smoking) , engaging in regular physical activity , getting enough sleep , and maintaining a rich social life . Nothing surprising, but a new study of a large population sample has not only confirmed this but also revealed some key reasons why these factors benefit mental health.
The study has just been published in Nature Mental Health . It was carried out by an international group of researchers, including those from the University of Cambridge (UK) and Fudan University in Shanghai (China).
Scientists have analyzed genetic traits, brain structure, and elements of the immune and metabolic systems to explain the link between certain lifestyles and protection against depression.
“We tend to think that a healthy lifestyle is important for our physical health, but it’s equally important for our mental health . It’s good for brain health and cognition, but it’s also good indirectly by promoting a healthier immune system and better metabolism,” says Christelle Langley , from the Department of Psychiatry at the University of Cambridge, and a researcher on the study.
The findings are based on an analysis of approximately 290,000 people , 13,000 of whom had depression, and who were followed for nine years. The data analyzed came from the UK Biobank , a database of anonymous citizens' health information.
The benefits of sleeping well and…
Among the factors found, sleeping seven to nine hours a night was the most influential , reducing the risk of depression (including treatment-resistant depression) by 22%. A rich social life reduced the risk by 18% (and was the most protective factor against recurrent depression). Not smoking reduced the likelihood of the disorder by 20%; regular physical activity, by 14%; moderate alcohol consumption, by 11%; and a healthy diet, by 6%.
In the study, individuals classified as having the healthiest lifestyle were 57% less likely to experience depression than those grouped with the least protective lifestyle. In comparison, those with a genetic profile showing fewer traits known to be linked to the illness—that is, with a lower genetic predisposition to developing it—had a 25% lower risk compared to those with the least favorable profile. Genetics, therefore, scored lower than lifestyle in terms of protection.
"Although our DNA - the genetic lot we've been dealt - may increase our risk of depression, we have shown that a healthy lifestyle is potentially more important ," says another of the authors, Barbara Sahakian , also a psychiatrist at the University of Cambridge.
…those of having a hobby
Mental well-being is the subject of another study, this time in an older population, whose results also confirm certain lifestyle habits as a protective factor.
A meta-analysis also published in today's issue of Nature Medicine concludes that people over 65 who have hobbies and leisure activities report better health and mental well-being compared to those who do not have any hobbies .
The results are based on five studies that examined leisure patterns in 93,263 people from 16 countries (including the United States, China, Japan and several European countries, including Spain).
The average age of the participants ranged from 71.7 to 75.9 years. Countries with a high happiness index (measured according to international standards) and a high life expectancy , such as Denmark, Sweden, and Switzerland, also showed greater participation in hobbies.
The research collected all kinds of hobbies , practiced alone or in groups: from art and crafts and reading to sports, gardening, volunteering, participation in clubs or societies, as long as they were not considered domestic tasks or work-related activities.
Overall, the association between practicing a hobby and mental well-being was relatively universal across all countries, according to the authors of the study, coordinated by Daisy Fancourt , from the Institute of Epidemiology and Health Care at University College London.
Why does it affect health?
The methodology of this work does not demonstrate causality - that having a hobby necessarily ensures a certain mental well-being - although it does establish the relationship.
In contrast, lifestyle analysis does offer an explanation for how certain habits can protect against depression. Specifically, brain MRI scans of approximately 33,000 participants revealed greater volume (and therefore more neural connections and better functioning) in regions such as the globus pallidus, thalamus, amygdala, and hippocampus among those with a healthy lifestyle.
It also found blood markers , such as C-reactive protein, which is associated with the stress response and the functioning of the immune system, or triglycerides, which indicate metabolic health, and which have better values in people who sleep well and perform physical activity.
These and other biomarkers, according to researchers, trace a path from lifestyle to the proper functioning of the body and, therefore, to a lower risk of disease.