Fiber and Calcium Absorption in Older Men

NCT06519877 | Recruiting Phase 2

• 2 other identifiers: ENDB-009-23F24-41270
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

Osteoporotic fractures are a major but underrecognized problem in men. There is growing evidence that low dietary fiber intake is a modifiable risk factor for age-related bone loss in men. Preclinical and human studies in adolescents and postmenopausal women suggest that dietary fiber intake influences bone metabolism by modulating the gut microbiome to augment intestinal calcium absorption, but it is unclear through what molecular mechanism and whether dietary fiber has the same effects in older men. In this crossover intervention study, the investigators will enroll and follow 30 older male Veterans to evaluate the effects of soluble corn fiber on intestinal calcium absorption and explore the contribution of the gut microbiome.

Conditions

Aging

Outcome Measures

Primary Outcomes (1)

• Intestinal fractional calcium absorption

  Dual stable calcium isotopic tracer method

  At week 4 and week 12 of study participation (at the end of each treatment phase x2)

Secondary Outcomes (4)

• Biochemical markers of bone turnover

  At week 4 and week 12 of study participation (at the end of each treatment phase x2)

• Calciotropic hormones

  At week 4 and week 12 of study participation (at the end of each treatment phase x2)

• Gut microbial profiling

  At week 4 and week 12 of study participation (at the end of each treatment phase x2)

• Adherence, tolerability, and acceptability

  Throughout study period, an average of 12 weeks

Study Arms (2)

Group 1

EXPERIMENTAL

Soluble corn fiber 20g/day x 4 weeks, washout period for 4 weeks, and placebo (maltodextrin) x 4 weeks.

Dietary Supplement: Soluble corn fiber

Group 2

EXPERIMENTAL

Placebo (maltodextrin) 20g/day x 4 weeks, washout period for 4 weeks, and soluble corn fiber x 4 weeks.

Dietary Supplement: Soluble corn fiber

Interventions

Soluble corn fiber DIETARY_SUPPLEMENT

Soluble corn fiber, also referred to resistant maltodextrin, is a type of dietary fiber made from corn starch. Soluble corn fiber is typically used to thicken processed foods and has been marketed as a prebiotic to improve digestive health.

Group 1; Group 2

Eligibility Criteria

• Age: 60 Years+
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Male Veterans 60 years of age

You may not qualify if:

• History of malabsorption
• Hypercalcemia (corrected Ca \> 10.2 mg/dL)
• Vitamin D insufficiency (25OHD \< 30 ng/mL)
• Chronic kidney disease stage 3B or worse (CrCl \< 45 mL/min)
• Severe hypogonadism (AM fasting serum total testosterone \< 150 ng/dL)
• Daily use of proton pump inhibitor
• Use of medication(s) known to affect calcium metabolism
• Use of medications or supplements that could impact gut microbiota in the previous 3 months (antibiotics or commercially available probiotics or prebiotics.
• Presence of a condition or abnormality that in the opinion of the Investigator that would compromise the safety of the patient or the quality of the data.

Sponsors & Collaborators

• VA Office of Research and Development: lead
• San Francisco VA Health Care System: collaborator

Study Sites (1)

San Francisco VA Medical Center, San Francisco, CA

San Francisco, California, 94121-1563, United States

RECRUITING

Study Officials

• Karin C Wu, MD

  San Francisco VA Medical Center, San Francisco, CA

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Karin C Wu, MD

CONTACT

(415) 221-4810; karin.Wu@va.gov

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Sachets of soluble corn fiber and placebo will be prepared and assigned randomization numbers by the investigational pharmacist at the San Francisco VA Health Care System. Participants, study staff, and those involved in outcome assessment will be blinded to the group assignment throughout the study.
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: FED
• Responsible Party: SPONSOR

Model Details: Participants will be randomized into one of two groups at a 1:1 ratio in random permutated blocks of size 6. Each group will undergo 2 phases of intervention with soluble corn fiber 20g/day for 4 weeks and placebo (maltodextrin) for 4 weeks, with 4-weeks of washout in between. Group 1 will receive soluble corn fiber first followed by placebo, whereas group 2 will receive placebo first followed by soluble corn fiber. Outcomes will be assessed at the end of each intervention phase.

Study Record Dates

• First Submitted: June 20, 2024
• First Posted: July 25, 2024
• Study Start: January 1, 2025
• Primary Completion (Estimated): January 1, 2029
• Study Completion (Estimated): January 1, 2029
• Last Updated: February 17, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)