Phenolic Dependent And Independent Effects Of Whole Grain Sorghum On Immunometabolism

Whole grain sorghum is a nutrient-dense, climate-resilient cereal grain that contains dietary fiber, protein, and bioactive compounds such as phenolics, which may beneficially influence gut microbiota and host immunometabolism. However, evidence from well-controlled human randomized controlled trials (RCTs) remains limited, particularly regarding how sorghum varieties with distinct phenolic profiles differentially affect metabolic health and the gut microbiome.

This study is a randomized, three-phase crossover dietary intervention trial designed to evaluate the phenolic-dependent and independent effects of whole grain sorghum consumption in adults with excess body weight. Participants will consume foods made from (1) whole grain sumac sorghum (high phenolic profile), (2) whole grain white sorghum (low phenolic profile), and (3) white rice (control), in random order.

The study consists of a baseline phase of up to two weeks, followed by three 4-week intervention phases separated by washout periods of at least three weeks. During each intervention phase, participants will consume three study foods daily: ready-to-eat cereal, crispy breadsticks, and pre-cooked grain pouches, providing approximately 84 g/day of the study grain. Clinical, metabolic, and microbiome-related outcomes will be assessed through repeated biospecimen collection and questionnaires.

Inclusion criteria

• Between the age of 19 and 64 years.
• Not currently pregnant or planning to become pregnant (females only).
• Stable body mass index above or equal to 26 kg/m² (rounded up) for the last month.
• Body fat above or equal to 36% (female) or 25% (male) (rounded up).
• No major diet changes in the last month.
• Ability to eat provided study foods each day and avoid eating sorghum except for the study foods.
• Ability to wear a continuous glucose monitor for 10 days.
• Ability to have blood drawn after ~12 hours of fasting.
• Have a bowel movement at least every third day.
• Ability to collect and deliver your stool samples to the study site within 4 hours of collection.
• No known allergies or intolerance to sorghum or rice.
• No known allergies to wheat or soy (study foods may contain wheat or soy)
• Able to read and speak English.
• Requires no legally authorized representative (LAR).
• Not institutionalized (e.g., prison, psychological treatment center, etc.).

Exclusion criteria

• Has cardiac device or history of organ transplant.
• History of cancer within the last year (excludes skin cancer).
• History of gastrointestinal surgery or disease diagnosed by a physician that involves the stomach, small, and large intestines.
• Current use of tobacco.
• Excessing alcohol use (≥8 drinks [female] or ≥15 drinks [male] per week).
• Taken antibiotics in the last 2 months.
• Current long-term use of anti-diabetic, anti-inflammatory, or cholesterol-lowering medications.
• Medication regimen or dosage changed within the last 2 months.
• Use of digestive enzymes, laxatives, dietary fiber, prebiotic, or probiotic supplements within the last 3 weeks.
• Supplement regimen or dosage changed within the last 3 weeks