Date of Award

2014

Degree Type

Thesis

Degree Name

Master of Science in Nutrition and Food Science

Specialization

Nutrition

Department

Nutrition and Food Sciences

First Advisor

Kathleen J. Melanson

Abstract

Objective: Irritable Bowel Syndrome (IBS) is the most commonly diagnosed Gastrointestinal (GI) condition in the United States affecting 30 million (10%) people. Symptoms include abdominal pain, bloating, distension, excessive wind and altered bowel habits when anatomical abnormalities and inflammation have been excluded. A low-FODMAP diet is now considered as an effective strategy for managing symptoms of IBS in Australia, with interest expanding across the world. Several limitations of a low-FODMAP diet pertaining to dietary quality and health benefits have been suggested. Malabsorbed FODMAPs provide multiple benefits which include a natural laxative effect due to their osmotic effects, a prebiotic effect with beneficial fermentation by-products and production of a low glycemic response compared to other carbohydrates. Additionally, Dietary adherence is crucial to the success of a low-FODMAP diet, however most people do not find the diet easy to incorporate into their life. Not one study has looked exclusively at healthy adults or looked at changes in FODMAP intake and diet quality as compared to established guidelines. A study is needed looking at dietary quality of low- vs. high-FODMAP diets and should consider how adherence and other factors that may influence efficacy of the diet.

Design: This study used a single-blinded crossover design. Subjects (n=16) were instructed about following a low-FODMAP and a high-FODMAP diet for three days each, presented in a random order and separated by an 11-day wash out period. The study was entitled “The Carb Study” and diets labeled “diet 1” and “diet 2” without reference to FODMAP. No food was provided. Dietary instruction was provided for each diet along with a dietary booklet. Dietary assessment consisted of four 24-hour recalls using NDS-R. Recalls assessed the day prior to each intervention period (2 baselines) and assessed day 3 of each intervention period (2 interventions). FODMAP intake was estimated based on the sum of fructose, lactose and polyol intake and dietary quality was calculated based on the Healthy Eating Index 2010 (HEI-2010).

Setting: Free living subjects recruited from a northeastern university.

Subjects: Participants were healthy adults without gastrointestinal disorders (n=16, 63% female, 20.47±1.77 years).

Results: There was no effect of diet order. There was a non-significant trend for a between treatment difference in FODMAP intake (F(1,14df)=4.27, p=.058) and a significant difference between groups in HEI-2010 total score (F(1,14df)=10.45, p=.001). Within the low-FODMAP treatment, FODMAP intake decreased from 36.30±22.62 grams to 19.29±15.79 grams (-t=2.84, p=.01) and HEI-2010 scores increased from 53.60±17.16 to 63.09±17.23 (t=2.20, p=.04); Energy intake also significantly decreased from 2259±1325 kcals to 1510±795 kcals (-t=2.68, p=.017). Within the high-FODMAP treatment, there was no change in FODMAP intake (t=.35, p=.731) but HEI-2010 scores decreased from 60.83±12.76 to 52.04±11.27 (-t=2.45, p=.027); There was no difference in energy intake (1993±962 to 2251± 864, -t=1.57, p=.14)

Conclusions: This study suggests that reducing FODMAP is feasible in healthy, free-living young adults and that this reduction is associated with an increase in dietary quality. However, the high-FODMAP intervention in this study was not effective in increasing FODMAP intake. Future research with larger samples is needed to develop interventions for increasing healthy FODMAP intake in young adults. In addition, future research is needed to assess long-term effects of these dietary modifications in healthy individuals.

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