Impact of Diet on the Gut-Muscle Axis in Older Adults

Eligibility Criteria

• 1. Independently living older adults (\> 65y)
• 2. Sedentary (Godin-Shepard Leisure Time Physical Activity Questionnaire score \< 10)
• 3. Non-smoking
• 4. Not already consuming a high-fiber diet (\> 22, 28 g/day for women, men)
• 5. Free of gastrointestinal disease (gastrointestinal cancer, inflammatory bowel disease, bariatric surgery, irritable bowel syndrome)
• 6. Fluent in English
• 7. Willing to attend three study visits (enrollment, baseline, and week-13)
• 8. Willing to consume an abundance of fruits, vegetables, nuts/seeds
• 9. Willing to consume an abundance of soluble fiber-rich foods (broccoli, brussels sprouts, flaxseeds sweetened with dates, lima beans, butternut squash, carrots, collard greens)
• 10. Willing to tolerate mild gastrointestinal discomfort (bloating, belly grumbling, flatulence). Note that all attempts will be made to replace foods that may trigger these issues.
• 11. Willing to not consume antibiotics during the 13-week study
• 12. Willing to not schedule a colonoscopy during the 13-week study
• 1. Unwilling to visit the Tufts Human Nutrition Research Center on Aging (HNRCA) 3x/week to pick up the pre-prepared study diet
• 2. Unwilling to only consume the provided food (unsweetened tea and/or black coffee are allowed)
• 3. Food allergies related to foods that are included in the study
• 4. Chewing problems
• 5. Unwilling to wear a daily step counter (pedometer)
• 6. Unwilling to complete a daily questionnaire that will assess gastrointestinal comfort
• 7. Malnutrition (BMI \< 18.5 kg/m2)
• 8. Use of supplemental probiotics or antibiotics, participation in an investigational drug evaluation, or a recent change in habitual medication use within the 1 month-period prior to the screening visit
• 9. \> 5% weight loss or weight gain within the past 6-months
• 10. A recent history of alcohol abuse (within the past 5 years)
• 11. A history of any significant injury or surgery that currently affects physical functioning and ability to perform physical function testing
• 12. Treatment with immunosuppressive drugs
• 13. A prior diagnosis of organ failure (heart, liver, renal, respiratory)
• 14. Diabetes mellitus (type 1, or type 2 with insulin therapy)
• 15. Chronic kidney disease (eGFR ≤ 30 mL/min/1.73 m2)
• 16. Overt disease (cancer, dementia, cardiovascular disease)
• 17. Chronic use of anti-inflammatory medication (corticosteroids)
• 18. Already enrolled in another research study
• 19. Active infection, including Tuberculosis , HIV, malaria, hepatitis, shingles, Methicillin-Resistant Staphylococcus Aureus (MRSA), SARS-CoV-2
• 20. Any major illness or condition that may interfere with study outcomes at the discretion of the study physician
• 21. Won't remain in Boston for the 13-week study duration
• 22. Unwilling to complete a daily checklist aimed at quantifying the amount of food eaten on the study diet