Location: Small Grain and Food Crops Quality Research
Project Number: 3060-21650-002-041-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2022
End Date: Dec 31, 2025
Objective:
(1) Determine whether a nutritionally-balanced habitual low methionine, low trimethylamine-N-oxide diet, achieved by replacement of animal proteins with pulse-proteins, will improve system-biology markers of healthspan and maintain muscle fitness in adults 65 years or older at risk for chronic diseases and frailty; and (2) Determine whether daily consumption of dry peas, lentils, and chickpeas (combination) will result in beneficial alterations of the gut microbiota composition and function, assessed from microbiota-mediated healthful and harmful metabolites and their effects on the biomarkers of healthspan.
Approach:
A randomized, controlled, two-arm-crossover, all-food-provided, feeding trial requiring regular site visits and data collection at six-time points over an 18-week period will be conducted following the Institutional Review Board for Human Subject Research at the South Dakota State University (SDSU), and will be registered at clinicaltrials.gov before start of recruitment. Blinding will be implemented to the extent possible. Forty-two volunteers will be recruited from the Brookings county (SD) area. Isocaloric and eucaloric intervention diets will follow the energy and macronutrient guidance from 2020-2025 Dietary Guidelines for Americans (DGA) for individuals aged 65 years and older. A 7-day cyclical DGA menu will be developed in Nutritionist Pro software, which is connected to the USDA food composition and nutrition information databases. Intervention proteins divided between lunch and dinner menus will contribute to at least 50% of daily proteins: 156 g/day of fresh, lean meat or an equivalent (in terms of contributing protein amount) pulse-protein (pea protein based Beyond Meat products, lentils and chickpeas). Seafood, poultry, whole eggs as potential major protein sources will be excluded. Each diet will be consumed for 8 weeks separated by a 2-week washout. Food will be weighed out to the nearest gram and prepared using standardized recipes by trained researchers in SDSU metabolic kitchen laboratory. Volunteers will consume their first meal and thereafter 3 meals per work-week on-site in the presence of the research staff; all other meals, snacks, and beverages will be provided as takeaways with simple storage and reheating instructions. The investigators will maintain regular contact over the phone/email with participants to enhance the compliance throughout the study. Participants will complete a daily food-intake checklist and report consumption of non-study foods. Overnight-fasted blood will be collected using a venipuncture protocol at six-time points. For stool collection, participants will be provided with a collection hat, gloves, alcohol wipes, and an Omni-Gut DNA preservation kit. Muscle-fitness measures, body composition (DXA scans), anthropometrics, and blood pressure will be measured by research team members onsite at SDSU. Most assays will be run in-house except metabolomics (at the NIH metabolomics center of the University of California-Davis) and metagenomics sequencing (University of Minnesota Genomics Core) for which serum samples will be shipped on dry ice to these academic service labs. Muscle-fitness measures to assess strength will involve a series of standardized age-appropriate measures of muscle fitness to complement DXA skeletal muscle test: grip strength, chair rise and countermovement, isokinetic muscle test, and balance assessments.
