Elsevier

Nutrition

Volume 32, Issue 5, May 2016, Pages 584-589
Nutrition

Applied nutritional investigation
Dietary fiber intake and depressive symptoms in Japanese employees: The Furukawa Nutrition and Health Study

https://doi.org/10.1016/j.nut.2015.11.014Get rights and content

Highlights

  • We examined the association between fiber intake and depressive symptoms.

  • Vegetable and fruit fiber was inversely associated with depressive status.

  • The associations were significant after adjusting for various confounders.

Abstract

Objective

Dietary fiber may play a favorable role in mood through gut microbiota, but epidemiologic evidence linking mood to dietary fiber intake is scarce in free-living populations. We investigated cross-sectionally the associations of dietary intakes of total, soluble, insoluble, and sources of fiber with depressive symptoms among Japanese workers.

Methods

Participants were 1977 employees ages 19–69 y. Dietary intake was assessed via a validated, brief self-administered diet history questionnaire. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. Logistic regression was used to estimate odds ratios of depressive symptoms adjusted for a range of dietary and non-dietary potential confounders.

Results

Dietary fiber intake from vegetables and fruits was significantly inversely associated with depressive symptoms. The multivariable-adjusted odds ratios (95% confidence intervals) for the lowest through the highest tertile of vegetable and fruit fiber were 1.00 (reference), 0.80 (0.60–1.05), and 0.65 (0.45–0.95), respectively (P for trend = 0.03). Dietary intake of total, soluble, insoluble, and cereal fiber was not associated with depressive symptoms.

Conclusions

Higher dietary fiber intake from vegetables and fruits may be associated with lower likelihood of having depressive symptoms.

Introduction

Depression is a highly prevalent mental disorder in the general population [1]. It is a major public health issue in terms of reduced productivity, lowers quality of life, and increases mortality [1]. Experimental and epidemiologic evidence suggests that dietary factors may play an important role in the development of depression [2], [3], [4], [5], [6]. Recent research suggests that the gut–brain axis, a bidirectional communication between the gut microbiota and the brain, functions as a pathway for the gut microbiota to modulate brain function, possibly through endocrine, immune, and neural pathway [7]; the hypothalamus–pituitary–adrenal axis regulates cortisol secretion and cortisol can affect immune cells, alter gut permeability and barrier function, and change gut microbiota composition [7]. Conversely, the gut microbiota and probiotics can alter the levels of cytokines, which may influence brain function [7]. In addition, the vagus nerve and tryptophan, the precursor of serotonin, are involved in relaying the influence of the gut microbiota to the brain [7]. Diet modification, especially fiber intake from fruits, vegetables, and other plants, can alter the profile of intestinal microbiota [8]. These findings draw attention to the need for further examination of the association between dietary fiber intake and depressive status.

There is a paucity of epidemiologic evidence for the association between dietary fiber intake and depressive symptoms in free-living people. Oishi et al. [9] found an inverse, albeit not statistically significant, association between fiber intake and depressive symptoms among older Japanese adults. Woo et al. [10] reported a statistically significant inverse association between fiber intake and depression score in an older Chinese population. These studies [9], [10], however, did not adjust for potentially important confounders including dietary intake of other nutrients, sleeping habits, and physical activity [2]. In addition, short-chain fatty acids (SCFAs), which are produced by fermentation of dietary fiber by intestinal microbiota, have been suggested to inhibit inflammation [11], a possible mediating factor for depression [12]. The fermentation of fiber by intestinal microbiota varies depending on its sources [13], [14], [15], [16] and types [16], [17]; vegetable and fruit or soluble fiber is more readily fermented than cereal or insoluble fiber [13], [14], [15], [16], [17]. Yet, no study has examined the association of depressive symptoms with sources (vegetables, fruits, and cereals) and types (soluble and insoluble) of fiber intake. To address these issues, we examined the association between dietary fiber intake and depressive symptoms in a Japanese working population.

Section snippets

Study design and participants

Data were derived from the Furukawa Nutrition and Health Study. Details of the study procedure were described elsewhere [6], [18], [19]. A nutritional epidemiologic survey was conducted undergoing periodic health examination in April 2012 (factory A) and May 2013 (factory B) among employees of a manufacturing company and its affiliates in the Kanto region of Japan. Of 2828 health examination attendants (women, 11%), 2162 (1930 men and 232 women aged 18–70 years) agreed to participate in the

Results

Participant characteristics by tertiles of energy-adjusted total fiber intake are presented in Table 1. Compared with participants with low total fiber intake, participants with higher total fiber intake were older and more likely to be women and physically active during leisure time, and drank green tea more frequently, but they were less likely to have job strain and be in low-ranking job positions, night or rotating shift workers, smokers, alcohol drinkers, and engaged in physical activity

Discussion

In this cross-sectional study, we found that higher intake of dietary fiber derived from vegetables and fruits was associated with a lower prevalence of depressive symptoms in Japanese workers, even after adjusting for a wide variety of potentially important dietary (including folate, vitamin B6, vitamin B12, n-3 polyunsaturated fatty acids, magnesium, zinc, coffee, and green tea) and non-dietary confounders. In contrast, dietary intake of total, soluble, insoluble, and cereal fiber was not

Conclusion

Higher intake of dietary fiber derived from vegetables and fruits was associated with significantly lower odds of depressive symptoms in Japanese employees even after adjustment for a variety of potential confounders including depression-related nutrients. The present finding based on cross-sectional observation requires confirmation in prospective studies. Further investigation into gut microbiota composition and SCFAs would contribute to the understanding of mechanisms whereby dietary fiber

References (55)

  • F.N. Jacka et al.

    Nutrient intakes and the common mental disorders in women

    J Affect Disord

    (2012)
  • K.P. Vashum et al.

    Dietary zinc is associated with a lower incidence of depression: Findings from two Australian cohorts

    J Affect Disord

    (2014)
  • G.R. Gibson et al.

    Selective stimulation of bifidobacteria in the human colon by oligofructose and inulin

    Gastroenterology

    (1995)
  • B. Kleessen et al.

    Effects of inulin and lactose on fecal microflora, microbial activity, and bowel habit in elderly constipated persons

    Am J Clin Nutr

    (1997)
  • B. Vitali et al.

    Novel probiotic candidates for humans isolated from raw fruits and vegetables

    Food Microbiol

    (2012)
  • M.B. Roberfroid

    Prebiotics and probiotics: Are they functional foods?

    Am J Clin Nutr

    (2000)
  • L. Desbonnet et al.

    Effects of the probiotic bifidobacterium infantis in the maternal separation model of depression

    Neuroscience

    (2010)
  • L. Desbonnet et al.

    The probiotic bifidobacteria infantis: An assessment of potential antidepressant properties in the rat

    J Psychiatr Res

    (2008)
  • A. Cuervo et al.

    Fiber from a regular diet is directly associated with fecal short-chain fatty acid concentrations in the elderly

    Nutr Res

    (2013)
  • H. Konttinen et al.

    Emotional eating, depressive symptoms and self-reported food consumption. A population-based study

    Appetite

    (2010)
  • J.S. Lai et al.

    A systematic review and meta-analysis of dietary patterns and depression in community-dwelling adults

    Am J Clin Nutr

    (2014)
  • S.M. O'Mahony et al.

    Serotonin, tryptophan metabolism and the brain-gut-microbiome axis

    Behav Brain Res

    (2015)
  • A.C. Logan et al.

    Major depressive disorder: Probiotics may be an adjuvant therapy

    Med Hypotheses

    (2005)
  • K. Murakami et al.

    Dietary intake and depressive symptoms: A systematic review of observational studies

    Mol Nutr Food Res

    (2010)
  • S. Gilbody et al.

    Is low folate a risk factor for depression? A meta-analysis and exploration of heterogeneity

    J Epidemiol Community Health

    (2007)
  • J.F. Cryan et al.

    Mind-altering microorganisms: The impact of the gut microbiota on brain and behaviour

    Nat Rev Neurosci

    (2012)
  • J. Oishi et al.

    Nutrition and depressive symptoms in community-dwelling elderly persons in Japan

    Acta Med Okayama

    (2009)
  • Cited by (0)

    T. Mizoue designed the research; M.E., K. Kurotani, T.K., K. Kuwahara, R. I., H.T., I. Kabe, and T. Mizoue conducted research; T. Miki performed statistical analysis, wrote the manuscript, and had primary responsibility for final content; and all authors were involved in revision and approved the final version of the manuscript. None of the authors had any conflicts of interest. M.E., T.K., R. I., H.T., and I. Kabe are health professionals at Furukawa Electric Corporation. The authors declare no conflicts of interest. T.K., M.E., H.T., R. I., and I. Kabe are health professionals at the Furukawa Electric Corporation. We thank Fumiko Zaizen (Furukawa Electric Corporation) and Ayami Kume, Sachiko Nishihara, Yuho Mizoue, Saeko Takagiwa, and Yuriko Yagi (National Center for Global Health and Medicine) for their help in data collection.

    This study was supported by JSPS KAKENHI Grant Numbers 25293146, 25702006 and Practical Research Project for Life-Style related Diseases including Cardiovascular Diseases and Diabetes Mellitus (15ek0210021h0002) from the Japan Agency for Medical Research and Development.

    View full text