Elucidating the Effect of Dietary Stearic Acid on the Regional Heterogeneity of the Gut Microbiome and Metabolome: Focus on Bile Acid Metabolism (SAMPill Study)

Conditions

• CVD Risk

Eligibility Criteria

Sex

FEMALE

Age

50 Years - N/A

Healthy Volunteers

Not accepted

Interventions

• High Palmitic Acid Diet — OTHER
  The main source of palmitic acid that will be used to prepare the meals will include blends of palm oil and safflower oil, which are commercially available. These blends will be incorporated into foods such as muffins, cookies, sauces, and mixed dishes (e.g., casseroles).
• High Stearic Acid Diet — OTHER
  The main source of stearic acid that will be used to prepare the meals will include blends of cocoa butter, fully hydrogenated soybean and safflower oil, all of which are commercially available. These blends will be incorporated into foods such as muffins, cookies, sauces, and mixed dishes (e.g., casseroles).

Study Details

Stearic acid and palmitic acid are two common consumed saturated fatty acids found in foods. Palmitic acid is associated with increases in blood cholesterol, whereas stearic acid is generally considered neutral with respect to blood cholesterol. However, the mechanisms underlying these different effects are not fully understood. The goal of this clinical trial is to determine how replacing dietary palmitic acid with stearic acid affects microorganisms living in the gastrointestinal tract (gut microbiome) and the metabolites they produce, including secondary bile acids, and whether these changes influence heart and metabolic health in postmenopausal women. The main question it aims to answer is whether the cholesterol lowering effect of dietary stearic acid, compared to dietary palmitic acid is due to changes in the composition and function of the gut microbiome and bile acid metabolism. Participants will consume a controlled diet high in palmitic acid for a 10-day run-in period, followed by a controlled diet high in stearic acid for 28 days. During the study, participants will provide biological samples, including blood samples collected in both fasting and non-fasting states, for assessment of cardiometabolic outcomes. Participants will also swallow mini-pills designed to collect samples from different regions of the gastrointestinal tract to assess the gut microbiome and related metabolites. Results will contribute to understanding the relationship between stearic acid mediated microbiota effects on cardiometabolic heath.

Key Dates

First listed

Aug 17, 2026

Start date

Sep 30, 2026

Status verified

Aug 2026

Primary completion

Dec 31, 2027

Completion

Aug 31, 2029

Study Design

Enrollment

20 participants (estimated)

Allocation

NA

Intervention model

SINGLE_GROUP

Primary purpose

BASIC_SCIENCE

Arms

• Experimental: Palmitic Acid Run-In Followed by Stearic Acid Diet
  A controlled 38-day intervention with a10 day run-in phase with a diet high in palmitic acid to stabilize baseline variables, followed by a 28 diet phase with a diet high in stearic acid

Primary Outcome Measure

Relative Abundance of Gut Microbial Taxa (%) [ Time Frame: End of the 10-day palmitic acid run-in period and end of the 28-day stearic acid intervention period. ]

Central Contacts

• Nirupa R Matthan, PhD
  6175563114
  [email protected]

Locations (1)

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