Promoting Gastrointestinal Health and Reducing Subclinical Inflammation in Obese Individuals

Promoting Gastrointestinal Health and Reducing Subclinical Inflammation in Obese Individuals Through Intake of Whole Wheat Products in Comparison With Fruits and Vegetables

This study evaluates the impact of increased intake of fruits and vegetables and whole grains on markers of inflammation and gut microbial composition. The treatment groups are 3 servings of whole grain per day; 5 servings of fruits and vegetables per day; and a control (3 servings of refined grains per day provided).

Literature data suggests that fruits and vegetables and whole grains containing dietary fiber and other nutrients are important for maintaining beneficial microbes in the gut. The presence of beneficial microbes in the gut may mediate the subclinical inflammation experienced in metabolic disease. In this project, overweight or obese participants with low intakes of fruits and vegetables or whole grains will increase their intake of these foods to recommended levels. Changes in markers of inflammation and gut microbiota composition will be determined to assess and compare the potential impact of these foods on metabolic disease.

Plasma samples collected from participants at the beginning (week 0) and end of the study (week 8) will be analyzed for interleukin-6 concentrations using an enzyme linked immunosorbent assay. Changes in the concentrations of these inflammatory markers will be determined from week 0 to week 8.

Plasma samples collected from participants at the beginning (week 0) and end of the study (week 8) will be analyzed for tumor necrosis factor-α concentrations using an enzyme linked immunosorbent assay. Changes in the concentrations of these inflammatory markers will be determined from week 0 to week 8.

Plasma samples collected from participants at the beginning (week 0) and end of the study (week 8) will be analyzed for high sensitivity C-reactive protein concentrations using an enzyme linked immunosorbent assay. Changes in the concentrations of these inflammatory markers will be determined from week 0 to week 8.

Plasma samples collected from participants at the beginning (week 0) and end of the study (week 8) will be analyzed for lipopolysaccharide binding protein concentrations using an enzyme linked immunosorbent assay. Changes in the concentrations of these inflammatory markers will be determined from week 0 to week 8.

The Shannon Diversity Index is a quantitative measure that reflects how many different bacterial species there are in a sample. The greater the index, the more diverse the gut microbiota. A negative change indicates a decrease in diversity and a positive change indicates an increase in diversity.

Short-chain fatty acids (SCFAs) are the end products of fermentation of dietary fibers by the anaerobic intestinal microbiota. SCFAs have been shown to exert multiple beneficial effects on mammalian energy metabolism.

Branched chain fatty acids (BCFA) are mostly saturated fatty acids (SFA) with one or more methyl branches on the carbon chain. BCFAs were extracted from stool samples and measured using gas chromatography.

Body mass index will be measured on participants at the beginning (week 0) and end of the study (week 8). Changes in body mass index will be determined.

Inclusion Criteria: Obese or overweight men or women (body mass index, BMI, ≥25 kg/m2) Free of known gastrointestinal disease No supplements use (excluding multivitamin) Participate in less than 1 h of exercise per week Have not taken antibiotics in the last six months Exclusion Criteria: Men and women with fruits and vegetable intake exceeding 2 servings/day Men and women with whole grain intakes exceeding 1 serving/day Pregnant Do not fit the inclusion criteria

Kopf JC, Suhr MJ, Clarke J, Eyun SI, Riethoven JM, Ramer-Tait AE, Rose DJ. Role of whole grains versus fruits and vegetables in reducing subclinical inflammation and promoting gastrointestinal health in individuals affected by overweight and obesity: a randomized controlled trial. Nutr J. 2018 Jul 30;17(1):72. doi: 10.1186/s12937-018-0381-7.