The study does not specify how many grams constitute one serving of fruit or vegetables. However, according to recommendations from the World Health Organization, a standard serving of plant foods is about 80 grams. Thus, the high intake defined in the study as 2.1 servings of fruit and 2 servings of vegetables per day is equivalent to about 168 grams of fruit and 160 grams of vegetables, respectively.
Lead author Dr Annabel Mathieson said 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 were still well below the World Health Organization’s recommendation of at least 400 grams of these foods.
The study is unique in that it uses data from twins, which allows the influence of genetic and social factors to be excluded. Twins raised in the same environment have similar life experiences, but differences in their diets make it possible to assess the impact of nutrition on depression. Dr. Karen Mather, head of the CHeBA genomics group, noted that this approach helps to minimize the influence of factors such as childhood socioeconomic status or chronic diseases.
Scientists believe that the positive effects of fruits and vegetables are due to their high content of fiber, vitamins, and antioxidants. In addition, the diet affects the gut microbiome, which may reduce inflammation in the body and neuroinflammation associated with depression. However, more 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 uniform methods for collecting data and assessing mental health.
Based on the findings, the researchers recommend that healthcare professionals consider patients' diets when treating depression and provide advice on increasing fruit and vegetable consumption. The article with the results of the study was published in the journal Scientific Reports.
