Mental health is associated with numerous lifestyle factors including physical activity, sleep, alcohol intake and the quality of the diet. Fibre is just one of many dietary components to be investigated. This study found that an intake of ≥21g fibre daily and specifically fibre from fruit and vegetables was significantly associated with reduced depression scores.(1) The study used data from over 16,500 participants from the US National Health and Nutrition Examination Survey. Depressive symptoms were measured using the validated screening tool - Patient Health Questionnaire (PHQ)-9 - and dietary fibre intakes were assessed via 24-hour recall questionnaires. Higher fibre intakes from all plant sources was significantly associated with reduced depressive symptoms, but only total, fruit and vegetable fibre intakes remained significant once all other confounding factors were accounted for.
The mechanism of action is poorly understood, however, current theories centre on the gut barrier and microbiota. Fibre is known to stimulate the gut microbiota and produce SCFA, both of which impact on inflammatory regulation, one of the underlying mediating pathway in depression.
What does this mean for the UK? Total fibre intakes for adults are 19g per day whilst 11-18 year olds consume around 15g per day.(2) This is significantly below the recommendations of 25-30g per day.(3) More importantly, fruit and vegetable intakes, which were most correlated with improving depressive symptoms, remain low with only 1/3rd of adults and 8% of 11-18 year olds achieving their 5-a-day.(2)
- Xu H, Li S, Song X et al. Exploration of the association between dietary fiber intake and depressive symptoms in adults. Nutrition.. 2018;54:48-53.
- FSA, PHE. The National Diet and Nutrition Survey: results from years 7 and 8 (combined): rolling programme for 2014 to 2015 and 2015 to 2016 [Internet]. 2018 [cited 7/13/2018]. Available from: https://www.gov.uk/government/statistics/ndns-results-from-years-7-and-8-combined
- SACN. Carbohydrates and Health Report [Internet]. 2015 [cited Apr 2018]. Available from: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/445503/SACN_Carbohydrates_and_Health.pdf