New research using international studies of twins suggests that eating more fruit and vegetables could help reduce depression. Previous studies have indicated the benefits of fruit and vegetable intake, but limited studies focus on those 45 plus or twins.
The study, led by UNSW Sydney’s Centre for Healthy Brain and Ageing (CHeBA), assessed the associations between fruit and vegetable intake and depressive symptoms over 11 years in 3,483 twins from Australia, Denmark, Sweden and the USA.
Lead author and Postdoctoral Fellow Dr Annabel Matison said, “The findings present another argument for increasing fruit and vegetable intake in adults over 45 years of age.”
Co-author of the research and Leader of CHeBA’s Genomics and Epigenomics Group, Dr Karen Mather, says that twin studies provide a unique opportunity to address some of the limitations of previous observational studies.
“Twin pairs share 50-100 per cent of their genetic background and, when raised together, share the same family environment. One of the advantages of the twin design is that it can help address the issue of unwanted factors, such as socioeconomic status early in life, influencing the results,” said Dr Mather.
In this research, low fruit intake was, on average, 0.3 servings per day, and low vegetable intake was 0.5 servings per day, whereas high fruit intake was 2.1 servings per day and high vegetable intake was 2.0 servings per day. Interestingly, total fruit and vegetable consumption in the high category still fell notably below the dietary recommendations of most countries.
“We found that fruit and vegetable consumption in the two large Scandinavian studies were particularly low, with the average for both being less than half the World Health Organisation recommended intake of at least five serves per day,” said Dr Matison.
“We are unclear what the reduction in depression scores would be if intakes were increased to recommended levels.”
According to the researchers, the beneficial relationship between fruit and vegetable intake and depression is most likely due to high levels of dietary fibre, vitamins and micronutrients. Consumption of fruit and vegetables also appears to positively impact the composition of the gut microbiome and protect against oxidative damage to the brain.
“The importance of the gut microbiome and its potential influence on depression as a result of inflammation, both systemic and neuroinflammation, is becoming increasingly well understood,” said Dr Matison.
Dr Matison said consideration should be given to healthcare providers monitoring their patients’ fruit and vegetable intakes and providing behavioural counselling to help people increase their consumption.
