Interrelationship of Diet, Visceral Adipose Tissue and Cortisol in Pre-menopausal Female Runners
Year: 2015
Type: article
Abstract: Background: The interaction of diet and serum cortisol has been researched in endurance athletes, producing conflicting results.Higher serum cortisol levels have also been well documented in several disease states, but the data is not available for a more physically active, healthy population.Objective: This project was a secondary analysis of a female runner study to assess dietary macronutrients, as well as visceral adipose tissue, in relation to morning serum cortisol values.Participants/Setting: Final analysis included 100 premenopausal recreational female runners between the ages of 18 -50 who had been running at least 15 miles per week for the immediate 6 weeks preceding data collection.A standard three-day food diary was used to collect dietary data and the Bouchard physical activity grid was used to estimate energy expenditure.Fasting serum cortisol was collected between 7am and 9am to reflect typical early morning levels.In order to allow a more relevant view of carbohydrate, values in grams/kilogram were stratified into two groups based on activity level 1 : "Carbohydrate Inadequate" (n = 52) and "Carbohydrate Adequate" (n = 48).Energy availability was defined as energy intake minus energy expended in exercise normalized for fat free mass. 2 Full body GE Lunar iDXA 3 scans, with additional analysis using the GE CoreScan version 15 software 4 were used to estimate visceral adipose tissue. Statistical Analyses:Final data was collated from the parent study, and the data and variables of interest were compared using quantitative analysis.An independent iii samples t-test was performed to on serum cortisol in relation to carbohydrate adequacy groups.Univariate analyses, with linear and quadratic models, were used to analyze serum cortisol in relation to carbohydrate, protein and fat, respectively.Similarly, a univariate analysis, with a linear and quadratic model, was performed on serum cortisol in relation to visceral adipose tissue.Finally, a regression was performed to on serum cortisol in relation to visceral adipose tissue and energy availability.A priori statistical significance for all tests was set at p ≤ 0.05.Results: The results show that the carbohydrate inadequate group had a significantly lower serum cortisol than the carbohydrate adequate group.Both group means were within the normal range.5 Macronutrient analysis for carbohydrate, protein and fat failed to demonstrate significance as predictors for serum cortisol.However, visceral adipose tissue proved to be a significant predictor for serum cortisol.The correlation was the opposite of what was expected in that serum cortisol increased as visceral adipose tissue decreased.Analysis of visceral adipose tissue, controlled for energy availability, was not a significant predictor for serum cortisol.Future research should examine diet, serum cortisol and visceral adipose tissue among a more active population with a wider range of visceral adipose tissue.iv
Author: Jordan Marie Jennewine
Institution: The Ohio State University
Language: English
Subfield: Endocrine and Autonomic Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2895289584