The study, published online in the journal 'Menopause', points out that more than 264 million people worldwide have depression, and the condition is two-times more common in women than in men, largely due to changes in hormone levels involved during perimenopausal and menopause.
Previous studies have already suggested the benefits of fiber for mental health, but this is the first known study to categorise the association in premenopausal and postmenopausal women.
In this new study involving more than 5,800 women of various ages, researchers specifically sought to investigate the relationship between dietary fiber intake and depression in women by menopause status.
The researchers used data from the Korea National Health and Nutritional Examination Survey from 2014, 2016, and 2018. This data included a broad range of ages in participants and involved women who underwent natural, as well as surgical, menopause.
Dietary fiber intake was calculated according to the 24-hour recall method and Patient Health Questionnaire-9 scores were used to assess depression.
The study confirmed an inverse association between dietary-fiber intake and depression in premenopausal women after adjusting for other variables, but no significant difference was documented in postmenopausal women.
Research has suggested that estrogen depletion may play a role in explaining why postmenopausal women don’t benefit as much from increased dietary fiber, because estrogen affects the balance of gut microorganisms found in premenopausal and postmenopausal women.
The authors note that the link between dietary fiber and depression may be partially explained by gut-brain interactions, because fiber improves the richness and diversity of gut microbiota and changes in gut-microbiota composition are suggested to affect neurotransmission.
Dr. Stephanie Faubion, North American Menopause Association (NAMS) medical director, points out that whilst it isn't possible to detect the cause and effect as this was an observational study, it still provides excellent new insights from a very large sample size.
“This study highlights an important link between dietary fiber intake and depression, but the direction of the association is unclear in this observational study, such that women with better mental health may have had a healthier diet and consumed more fiber, or a higher dietary fiber intake may have contributed to improved brain health by modulating the gut microbiome or some combination.
"Nonetheless, it has never been more true that ‘you are what you eat,’ given that what we eat has a profound effect on the gut microbiome which appears to play a key role in health and disease.”
Jung-ha. K., et al
"Inverse association between dietary fiber intake and depression in premenopausal women"