Association Between Microbe Accessible Carbohydrates (MACs) Intake and Healthy Eating Index (HEI-2015) in the College Students

OBJECTIVES: Young adults tend to consume western diets with low microbe-accessible carbohydrates (MACs), which are fermentable carbohydrates that may reduce the risk of developing non-communicable diseases. The importance of dietary fiber (only one type of MAC) in the prevention of chronic diseases led to recommendations for increasing fiber intake. However, a reference to other MACs such as resistant starches, non-starch polysaccharides, polyols (lactitol, sorbitol, etc.), and oligosaccharides (fructo-oligosaccharides, etc.) is still lacking and their relationship with diet quality is far less understood. The healthy eating index (HEI) score is a measure of diet quality, independent of quantity, and is useful to assess compliance with U.S. Dietary Guidelines for Americans. The primary aim of this study was to determine the MACs consumption in healthy US college students and their association with dietary quality as indicated by the HEI-2015. METHODS: For this cross-sectional study, data were collected from consenting students (≥ 18years old) in an introductory nutrition course (n = 592, age (mean ± standard deviation) 19.5 ± 3.5; 83.7% white; 78.4% female). Dietary intake was measured via a web-based dietary history questionnaire (DHQ-II), which is able to quantify the consumption of MAC's and subclasses such as polyols and soluble dietary fibers. DHQ website provided step by step instructions to calculate HEI in SAS (SAS enterprise guide 7.4). Linear regression was run to determine the association between the average daily intake of MACs and the HEI-2015 score. RESULTS: Average MAC intake was 7.7 ± 4.4 grams with most of the amounts coming from soluble dietary fibers (6.6 ± 3.8). The mean HEI-score of this population was 64.9 ± 10.8. Average daily consumption of MAC was significantly associated with HEI score, F(1,590) = 65.22, P = 0.000, accounting for 10% of the variation in HEI-score with adjusted R(2) = 9.8%, a medium-size effect according to Cohen (1988). An extra gram of daily average intake of MAC led to a 0.78 (95% CI, 0.59 to 0.97) increase in HEI-score. CONCLUSIONS: MAC intake was associated with an increase in HEI-2015 score; however, the total MAC intake was low in this population of college students. Therefore, more efforts are needed to increase the consumption of MACs not just dietary fibers in college students. FUNDING SOURCES: None.