The Addition of Whole Grains to the Diets of Adults: A Study of Digestive Health and Natural Defenses
- Conditions
- Digestive Health and Immune Function
- Interventions
- Other: Whole grainsOther: Refined grains
- Registration Number
- NCT01902394
- Lead Sponsor
- Tufts University
- Brief Summary
The purpose of this study is to determine if substituting whole grains for refined grains in the diets of healthy adults over a period of 6 weeks alters the composition of the bacteria in the gut, and has beneficial effects on immune function, digestive health, cardiovascular health, regulation of body weight and composition, and vitamin K status.
The investigators hypothesize that whole grain consumption over a period of 6 weeks will alter the gut microflora toward a more beneficial bacterial profile, improve the immune response while reducing oxidative stress and inflammatory markers, have favorable effects on factors influencing the regulation of body weight and composition,increase bacterial vitamin K synthesis, and beneficially effect surrogate markers of cholesterol synthesis/absorption, vitamin D concentrations, and whole genome DNA methylation patterns. In statin users it is hypothesized that, consumption of whole grains will alter statin pharmacokinetics by decreasing rate of statin absorption, resulting in more sustained plasma concentrations.
- Detailed Description
This study is a randomized parallel-arm trial using a six-week dietary intervention following a 2 week run-in period. Healthy volunteers will be randomized to two groups (n=40/group), and consume either a diet rich in whole grains or a diet rich in refined grains provided at estimated energy requirements for 6 weeks. Outcomes will be measured during the run-in period and at week 6 of the intervention. To control for variation in microbiota an additional 10 volunteers will serve as "negative controls" and not undergo any diet intervention.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 108
Not provided
Not provided
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Whole grain rich diet Whole grains Participants in the whole grain (WG) group will receive a diet providing 100% of energy requirements in a diet rich in whole grains. Refined grain rich diet Refined grains Participants in the refined grain (RG) group will receive a diet providing 100% of energy requirements in a diet rich in refined grains.
- Primary Outcome Measures
Name Time Method change in Lymphocyte proliferation week 2 of washout diet and week 6 of diet intervention Whole blood collected at baseline (week 2 of washout period) and at week-6 of the diet intervention will be investigated for the ability of lymphocytes to proliferate by quantifying the incorporation of tritium following mitogen stimulation.
change in T Cell-mediated immunity week 2 of washout diet and week 6 of diet intervention Delayed-type hypersensitivity (DTH) and lymphocyte proliferation will be measured at baseline (week 2 of washout period) and at week-6 of the diet intervention to assess adaptive immune function, specifically T cell-mediated immunity.
change in Natural Killer Function week 2 of washout diet and week 6 of diet intervention The ability of peripheral blood mononuclear cells to bind and kill leukemia cells will be measured at baseline (week 2 of washout period) and at week-6 of the diet intervention
change in Salivary immunoglobulin A (IgA) week 2 of washout diet and week 6 of intervention diet Salivary IgA will be analyzed at baseline (week 2 of washout period) and at week-6 of the diet intervention.
change in Cytokines week 2 of washout diet and week 6 of diet intervention Peripheral blood and stool samples will be analyzed at baseline (week 2 of washout diet) and week-6 of diet intervention for cytokines.
- Secondary Outcome Measures
Name Time Method change in vitamin K status week 2 of washout diet and week 6 of intervention diet Fecal menaquinones concentrations; Fasting serum phylloquinone and menaquinones concentration from 72-hour stool collected at baseline (week 2 of washout diet) and at week 6 of intervention diet
change in body composition week 2 of washout diet and week 6 of intervention diet Fat and fat free mass; waist and hip circumference
change in appetite Weekly for 8 weeks Visual analog scales to assess hunger, fullness and satisfaction while on the study diet
change in glycemic regulation week 2 of washout diet and week 6 of intervention diet 48 hr continuous glucose monitoring; fasting serum glucose; fasting serum insulin; HOMA-IR
change in quality of life week 2 of washout diet and week 6 of intervention diet Questionnaires will be administered at baseline (week 2 of washout diet) and week 6 of intervention diet
change in total stool anaerobic and aerobic bacterial counts week 2 of washout diet and week 6 of intervention diet Will be measured from 72-hour stool sample collected at baseline (week 2 of washout diet) and week 6 of intervention diet
change in stool energy content week 2 of washout diet and week 6 of intervention diet Will be measured from 72-hour stool sample collected at baseline (week 2 of washout diet) and week 6 of intervention diet
change in cardiovascular health risk factors week 2 of washout diet and week 6 of intervention diet Consumption of the whole grain (WG) diet will be beneficial for multiple outcomes of cardiovascular health including a favorable blood lipid profile (low density lipoprotein, very low-density lipoprotein, high density lipoprotein, total cholesterol and triglycerides), and a decrease in blood pressure, and in oxidative stress status (secondary hypothesis).
change in resting energy metabolism week 2 of washout diet and week 6 of intervention diet Resting energy expenditure; substrate oxidation at rest
change in breath hydrogen and methane week 2 of washout diet and week 6 of intervention diet change in stool pH week 2 of washout diet and week 6 of intervention diet Will be measured from 72-hour stool sample collected at baseline (week 2 of washout diet) and week 6 of intervention diet
change in 72hr fecal weight week 2 of washout diet and week 6 of intervention diet Will be measured from 72-hour stool sample collected at baseline (week 2 of washout diet) and week 6 of intervention diet
change in stool water content week 2 of washout diet and week 6 of intervention diet Will be measured from 72-hour stool sample collected at baseline (week 2 of washout diet) and week 6 of intervention diet
change in DNA methylation week 2 of washout diet and week 6 of intervention diet change in gut microbiota composition week 2 of washout diet and week 6 of intervention diet Phylogenetic composition and relative abundance of bacteria in stool will be analyzed from 24-hour fresh sample collected at baseline (week 2 of washout diet) and at week 6 of intervention diet
change in fasting gut hormone concentration week 2 of washout diet and week 6 of intervention diet Plasma glucagon-like peptide-1 and peptide-YY will be measured from blood samples collected at baseline (week 2 of washout diet) and week 6 of intervention diet
change in fasting serum leptin week 2 of washout diet and week 6 of intervention diet change in eating behaviors week 2 of washout diet and week 6 of intervention diet Questionnaires will be administered at baseline (week 2 of washout diet) and week 6 of intervention diet
change in concentrations of the cholesterol synthesis (squalene, desmosterol, lathosterol) and absorption (campesterol, sitosterol, cholestanol) markers week 2 of washout diet and week 6 of intervention diet Plasma squalene, desmosterol, lathosterol), campesterol, sitosterol, and cholestanol concentrations will be measured at baseline (week 2 of washout diet) and week 6 of intervention diet
change in serum vitamin D week 2 of washout diet and week 6 of intervention diet
Trial Locations
- Locations (1)
HNCRA at Tufts University
🇺🇸Boston, Massachusetts, United States