The study does not specify how many grams constitute a serving of fruit or vegetables. However, according to World Health Organization recommendations, a standard serving of plant foods is approximately 80 grams. Therefore, a high intake, defined in the study as 2.1 servings of fruit and 2 servings of vegetables per day, is equivalent to approximately 168 grams of fruit and 160 grams of vegetables, respectively.
According to the study's lead author, Dr. Annabel Mathison, the findings support the importance of increasing fruit and vegetable consumption for improving mental health in adults over 45. The researchers also noted that even the "high" intake figures remain significantly below the World Health Organization's recommendations for at least 400 grams of these foods.
A unique feature of the study is its use of twin data, which allows it to exclude the influence of genetic and social factors. Twins raised in the same environments have similar life experiences, but differences in their diets make it possible to assess the impact of diet on depression. Dr. Karen Mather, head of the CHeBA genomics group, noted that this approach helps minimize the influence of factors such as childhood socioeconomic status or chronic illnesses.
Scientists believe the beneficial effects of fruits and vegetables are due to their high fiber, vitamin, and antioxidant content. Furthermore, diet influences the gut microbiome, which may reduce inflammation and neuroinflammation associated with depression. However, further research is needed to fully understand the mechanism of action.
Limitations of the study include the lack of data on participants' physical activity, the use of different methods for self-reporting diet and depressive symptoms, and the lack of clinical diagnoses. In the future, the researchers plan to use more specific and consistent methods for collecting data and assessing mental health.
Based on their findings, the researchers recommend that healthcare professionals consider patients' diets when treating depression and provide counseling on increasing fruit and vegetable consumption. A paper describing the study's findings was published in the journal Scientific Reports.
