PRebiotic to IMprovE Calcium Absorption

NCT ID: NCT03272542

Last Updated: 2020-10-22

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE2
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2017-11-21
• Study Completion Date: 2020-01-31

Brief Summary

Gastric bypass surgery is a highly effective treatment for obesity, but it has negative effects on skeletal health, due in part to a dramatic decline in intestinal calcium absorption capacity. Animal and human studies suggest that non-digestible fibers termed prebiotics, such as soluble corn fiber (SCF), augment calcium absorption in the lower intestine as they act as substrates for beneficial gut microbiota. This is a pilot randomized controlled trial of the effects of SCF vs. placebo on intestinal calcium absorption, bone turnover marker levels, and the gut microbiome in postmenopausal women who have previously undergone gastric bypass surgery.

Detailed Description

The study is a pilot randomized control trial (RCT) of the effects of the prebiotic SCF vs. placebo in 20 postmenopausal women who underwent Roux-en-Y gastric bypass surgery 2-6 years previously and thus have completed the postoperative period of rapid weight loss and metabolic and dietary change. A 24 g/day dose of SCF85 (which is approximately 20 g/day fiber) will be tested, as that dose was proven effective for calcium absorption/retention in healthy postmenopausal women and adolescents. The SCF and the maltodextrin placebo will be mixed in water and consumed in divided doses twice daily for 2 months, a duration exceeding other SCF trials but remaining feasible for a pilot. The primary outcome will be change in intestinal calcium absorption, which is the efficacy outcome about which the study must collect preliminary data and from which the investigators must refine power calculations for the anticipated future trial. Because the investigators hypothesize that an increase in calcium absorption will decrease bone turnover and ultimately increase bone mineral density (BMD), the study will measure biochemical markers of bone turnover in this pilot. Secondary outcomes will be gastrointestinal tolerability and acceptability. On an exploratory basis, the study will determine effects of the prebiotic on the gut microbiome. This pilot will yield critical experience about feasibility of recruitment and adherence to the intervention and measurements.

Conditions

Obesity

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: OTHER
• Blinding Strategy: QUADRUPLE

Study Groups

Prebiotic: soluble corn fiber

SCF (PromotorTM Soluble Corn Fiber 85, provided by manufacturer Tate \& Lyle) will be dispensed to participants as a dry powder in sachets of 12 g SCF85 product (which is approximately 10 g fiber). Participants will mix the powder into 250 mL water and consume two such beverages daily, ≥1 hour apart. (For the first week, all participants will consume one beverage daily, and subsequently increase to one beverage twice daily.) Participants will be asked to substitute these for 500 mL of their usual daily water intake but to make no other dietary changes.

Group Type: EXPERIMENTAL

Prebiotic: soluble corn fiber

Intervention Type: DIETARY_SUPPLEMENT

prebiotic

Placebo

The placebo control will be maltodextrin powder in identical sachets. Participants will mix the powder into 250 mL water and consume two such beverages daily, ≥1 hour apart. (For the first week, all participants will consume one beverage daily, and subsequently increase to one beverage twice daily.) Participants will be requested to substitute these for 500 mL of their usual daily water intake but to make no other dietary changes.

Group Type: PLACEBO_COMPARATOR

Placebo: maltodextrin

Intervention Type: DIETARY_SUPPLEMENT

placebo

Interventions

Prebiotic: soluble corn fiber

prebiotic

Intervention Type: DIETARY_SUPPLEMENT

Placebo: maltodextrin

placebo

Intervention Type: DIETARY_SUPPLEMENT

Other Intervention Names

PROMOTOR 85

Eligibility Criteria

Inclusion Criteria

1. Postmenopausal women (no menses for ≥4 yrs)

2. ≤ 75 yrs old,

3. Underwent Roux-en-Y gastric bypass surgery for weight loss 2-6 years prior

Exclusion Criteria

1. Serum 25(OH)vitamin D level <30 ng/mL (to remove the effect of vitamin D insufficiency/deficiency)*

2. History of >1 bariatric surgical procedure

3. Antibiotic therapy in the last 3 months

4. Regular pre- or probiotic use in the last 3 months

5. Regain of >50% of weight loss post-bypass

6. Calculated creatinine clearance <30 mL/min

7. Serum calcium >10.2 mg/dL

8. Use of hormone therapy, osteoporosis pharmacotherapy, glucocorticoids, or other medications impacting calcium metabolism

9. Thyroid stimulating hormone (TSH) <0.01 milli-international units per liter (mIU/L)

A potential participant may be excluded if she has a condition or abnormality that in the opinion of the Investigator would compromise the safety of the participant or the quality of the data.

*Women excluded due to 25(OH)D level will be offered re-screening after vitamin D supplementation.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 75 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: No

Sponsors

University of California, San Francisco

OTHER

Sponsor Role: collaborator

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

NIH

Sponsor Role: collaborator

San Francisco Veterans Affairs Medical Center

FED

Sponsor Role: lead

Responsible Party

Anne Schafer

Assistant Professor of Medicine and of Epidemiology and Biostatistics; Staff Physician

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Anne Schafer, MD

Role: PRINCIPAL_INVESTIGATOR

UCSF & SFVAMC

Locations

UCSF

San Francisco, California, United States

Countries

United States

References

Wu KC, Cao S, Weaver CM, King NJ, Patel S, Kingman H, Sellmeyer DE, McCauley K, Li D, Lynch SV, Kim TY, Black DM, Shafer MM, Ozcam M, Lin DL, Rogers SJ, Stewart L, Carter JT, Posselt AM, Schafer AL. Prebiotic to Improve Calcium Absorption in Postmenopausal Women After Gastric Bypass: A Randomized Controlled Trial. J Clin Endocrinol Metab. 2022 Mar 24;107(4):1053-1064. doi: 10.1210/clinem/dgab883.

Reference Type: DERIVED

PMID: 34888663 (View on PubMed)

Other Identifiers

R21DK112126

Identifier Type: NIH

Identifier Source: secondary_id

View Link

17-22618

Identifier Type: -

Identifier Source: org_study_id