The Sexual Dimorphic Relationship Between Dietary Fiber Intake and Visceral Adipose Tissue

Abstract

Accumulation of visceral adipose tissue (VAT) has been mechanistically implicated in compromised metabolic health and increased risk for cardiovascular disease. However, sex is an important determinant of fat tissue compartmentalization or distribution. Substantial differences in VAT between males and females emerge early in life and are sustained throughout adulthood. These differences are thought to contribute to the disproportionate prevalence and incidence rates of cardiovascular diseases between males and females. Thus, it is plausible that relationships between dietary behaviors and VAT are influenced by sex as well. Specifically, meeting dietary guidelines for fiber intake remains a prominent feature of public health policy towards obesity prevention. Although the recommendations for fiber intake are greater among males (38g/d) compared to females (25g/d), the extent to which meeting the sex‐specific dietary fiber recommendations protects against VAT remains unclear. This study aimed to elucidate the differential association between dietary fiber intake and VAT among male and female adults. Healthy adults (N=318; 155 females, aged 18–44 y) underwent Dual Energy X‐ray Absorptiometry (DXA) to estimate VAT. 3‐day food records were used to assess daily fiber intake. The proportion of daily sex‐specific fiber recommendation met (%Fiber) was used as the primary dietary variable. Physical activity was recorded among a subsample of participants (n=269) and was assessed as steps/day using an accelerometer (Actigraph GT3X+) worn for at least 4 days (minimum 8 hours/day). As expected, VAT was significantly greater among males (P<0.01). Total fiber intake was not different between males and females (P=0.62). However, only 6% of participants met their recommended fiber intake. Nevertheless, %Fiber intake was greater among females (P<0.01) by 23%, indicating that males consumed significantly less fiber, relative to their daily recommended intake. Among males, VAT was inversely related to %Fiber (r=−0.18, P=0.01) intake. This relationship persisted even following adjustment of age and physical activity using partial correlations. However, no significant associations between fiber intake and VAT (r=0.06, P=0.23) were observed among females. In conclusion, these results suggest that fiber was independently and inversely related to visceral fat accumulation in a sexually dimorphic manner. These findings have important public health implications because they suggest that chronically lower fiber intake or failure to meet fiber recommendations may disproportionately compromise metabolic health among adult men. Future research is needed to determine the source of these differential associations and whether interventions targeted at meeting dietary fiber intake recommendations provide adequate protective effects against visceral fat accumulation.Support or Funding InformationThe research is based upon work supported by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), via Contract 2014‐13121700004 to the University of Illinois at Urbana‐Champaign. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the ODNI, IARPA, or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes notwithstanding any copyright annotation thereon.