Isoleucine Addition Treatment Effects in a Controlled Diet Study

NCT ID: NCT07329088

Last Updated: 2026-01-16

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

NOT_YET_RECRUITING

Clinical Phase

NA

Total Enrollment

40 participants

Study Classification

INTERVENTIONAL

Study Start Date

2026-03-02

Study Completion Date

2029-01-31

Brief Summary

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The primary purpose of this study is to determine whether isoleucine repletion attenuates increases in insulin sensitivity typically observed when people with obesity follow a healthy, low-isoleucine diet.

Detailed Description

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Isoleucine restriction promotes insulin sensitivity in preclinical models and is a promising strategy for preventing type 2 diabetes. This project aims to identify clinical and molecular changes in skeletal muscle and adipose tissues when adults with obesity switch from a typical American style diet to a plant-based diet low in isoleucine with or without isoleucine repletion.

Conditions

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Prediabetes (Insulin Resistance, Impaired Glucose Tolerance) Metabolic Syndrome (MetS) Obesity & Overweight

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

PREVENTION

Blinding Strategy

TRIPLE

Participants Investigators Outcome Assessors

Study Groups

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Isoleucine group

Participants will be randomized to receive low-isoleucine diet and isoleucine supplement

Group Type EXPERIMENTAL

L-Isoleucine

Intervention Type DIETARY_SUPPLEMENT

Participants will follow a habitual American style diet. All participants transition to a healthy, low-isoleucine diet the study team provides, but only the isoleucine group receives isoleucine supplements to replete the overall diet to typical intake levels.

Low-isoleucine diet

Intervention Type OTHER

Healthy, weight-maintaining, low-isoleucine meals and snacks will be provided directly to participants for 4 weeks. Diets are formulated by registered dietitians to meet energy, protein, and amino-acid requirements while minimizing weight change; target macronutrient distribution ≈ 10% protein / 60% carbohydrate / 30% fat38. Isoleucine content will meet minimum needs of 23 mg/kg.

Placebo group

Participants will be randomized to receive low-isoleucine diet and placebo supplement

Group Type ACTIVE_COMPARATOR

Low-isoleucine diet

Intervention Type OTHER

Healthy, weight-maintaining, low-isoleucine meals and snacks will be provided directly to participants for 4 weeks. Diets are formulated by registered dietitians to meet energy, protein, and amino-acid requirements while minimizing weight change; target macronutrient distribution ≈ 10% protein / 60% carbohydrate / 30% fat38. Isoleucine content will meet minimum needs of 23 mg/kg.

Interventions

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L-Isoleucine

Participants will follow a habitual American style diet. All participants transition to a healthy, low-isoleucine diet the study team provides, but only the isoleucine group receives isoleucine supplements to replete the overall diet to typical intake levels.

Intervention Type DIETARY_SUPPLEMENT

Low-isoleucine diet

Healthy, weight-maintaining, low-isoleucine meals and snacks will be provided directly to participants for 4 weeks. Diets are formulated by registered dietitians to meet energy, protein, and amino-acid requirements while minimizing weight change; target macronutrient distribution ≈ 10% protein / 60% carbohydrate / 30% fat38. Isoleucine content will meet minimum needs of 23 mg/kg.

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

* BMI ≥ 30
* Meeting at least three metabolic syndrome criteria
* Follow an American style diet

Exclusion Criteria

* Type 1 or 2 Diabetes diagnosis
* Medical condition or medication that affects insulin sensitivity, weight, or metabolism
* More than 5% weight change in 3 previous months
* Restrictive dietary pattern
* History of bariatric surgery
* Food allergy more severe than grade 1 on the CoFAR Grading Scale for Systemic Allergic Reactions, Version 3.0
* Allergy to lidocaine.
Minimum Eligible Age

18 Years

Maximum Eligible Age

65 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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National Institute of General Medical Sciences (NIGMS)

NIH

Sponsor Role collaborator

Jean L. Fry

OTHER

Sponsor Role lead

Responsible Party

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Jean L. Fry

Associate Professor-PI

Responsibility Role SPONSOR_INVESTIGATOR

Principal Investigators

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Jean Fry, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Kentucky

Locations

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University of Kentucky

Lexington, Kentucky, United States

Site Status

Countries

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United States

Central Contacts

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Jean Fry, PhD

Role: CONTACT

859-562-2778

Kayla Anderson, MPH

Role: CONTACT

Facility Contacts

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Jean Fry, PhD

Role: primary

859-562-2778

Kayla Anderson, MPH

Role: backup

References

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Doi M, Yamaoka I, Fukunaga T, Nakayama M. Isoleucine, a potent plasma glucose-lowering amino acid, stimulates glucose uptake in C2C12 myotubes. Biochem Biophys Res Commun. 2003 Dec 26;312(4):1111-7. doi: 10.1016/j.bbrc.2003.11.039.

Reference Type BACKGROUND
PMID: 14651987 (View on PubMed)

Zhang S, Yang Q, Ren M, Qiao S, He P, Li D, Zeng X. Effects of isoleucine on glucose uptake through the enhancement of muscular membrane concentrations of GLUT1 and GLUT4 and intestinal membrane concentrations of Na+/glucose co-transporter 1 (SGLT-1) and GLUT2. Br J Nutr. 2016 Aug;116(4):593-602. doi: 10.1017/S0007114516002439.

Reference Type BACKGROUND
PMID: 27464458 (View on PubMed)

Woo SL, Yang J, Hsu M, Yang A, Zhang L, Lee RP, Gilbuena I, Thames G, Huang J, Rasmussen A, Carpenter CL, Henning SM, Heber D, Wang Y, Li Z. Effects of branched-chain amino acids on glucose metabolism in obese, prediabetic men and women: a randomized, crossover study. Am J Clin Nutr. 2019 Jun 1;109(6):1569-1577. doi: 10.1093/ajcn/nqz024.

Reference Type BACKGROUND
PMID: 31005973 (View on PubMed)

Drummond MJ, Bell JA, Fujita S, Dreyer HC, Glynn EL, Volpi E, Rasmussen BB. Amino acids are necessary for the insulin-induced activation of mTOR/S6K1 signaling and protein synthesis in healthy and insulin resistant human skeletal muscle. Clin Nutr. 2008 Jun;27(3):447-56. doi: 10.1016/j.clnu.2008.01.012. Epub 2008 Mar 14.

Reference Type BACKGROUND
PMID: 18342407 (View on PubMed)

Yu D, Richardson NE, Green CL, Spicer AB, Murphy ME, Flores V, Jang C, Kasza I, Nikodemova M, Wakai MH, Tomasiewicz JL, Yang SE, Miller BR, Pak HH, Brinkman JA, Rojas JM, Quinn WJ 3rd, Cheng EP, Konon EN, Haider LR, Finke M, Sonsalla M, Alexander CM, Rabinowitz JD, Baur JA, Malecki KC, Lamming DW. The adverse metabolic effects of branched-chain amino acids are mediated by isoleucine and valine. Cell Metab. 2021 May 4;33(5):905-922.e6. doi: 10.1016/j.cmet.2021.03.025. Epub 2021 Apr 21.

Reference Type BACKGROUND
PMID: 33887198 (View on PubMed)

Yeh CY, Chini LCS, Davidson JW, Garcia GG, Gallagher MS, Freichels IT, Calubag MF, Rodgers AC, Green CL, Babygirija R, Sonsalla MM, Pak HH, Trautman M, Hacker TA, Miller RA, Simcox J, Lamming DW. Late-life isoleucine restriction promotes physiological and molecular signatures of healthy aging. bioRxiv [Preprint]. 2024 Jan 9:2023.02.06.527311. doi: 10.1101/2023.02.06.527311.

Reference Type BACKGROUND
PMID: 36798157 (View on PubMed)

Trautman ME, Richardson NE, Lamming DW. Protein restriction and branched-chain amino acid restriction promote geroprotective shifts in metabolism. Aging Cell. 2022 Jun;21(6):e13626. doi: 10.1111/acel.13626. Epub 2022 May 8.

Reference Type BACKGROUND
PMID: 35526271 (View on PubMed)

Green CL, Trautman ME, Chaiyakul K, Jain R, Alam YH, Babygirija R, Pak HH, Sonsalla MM, Calubag MF, Yeh CY, Bleicher A, Novak G, Liu TT, Newman S, Ricke WA, Matkowskyj KA, Ong IM, Jang C, Simcox J, Lamming DW. Dietary restriction of isoleucine increases healthspan and lifespan of genetically heterogeneous mice. Cell Metab. 2023 Nov 7;35(11):1976-1995.e6. doi: 10.1016/j.cmet.2023.10.005.

Reference Type BACKGROUND
PMID: 37939658 (View on PubMed)

Fontana L, Cummings NE, Arriola Apelo SI, Neuman JC, Kasza I, Schmidt BA, Cava E, Spelta F, Tosti V, Syed FA, Baar EL, Veronese N, Cottrell SE, Fenske RJ, Bertozzi B, Brar HK, Pietka T, Bullock AD, Figenshau RS, Andriole GL, Merrins MJ, Alexander CM, Kimple ME, Lamming DW. Decreased Consumption of Branched-Chain Amino Acids Improves Metabolic Health. Cell Rep. 2016 Jul 12;16(2):520-530. doi: 10.1016/j.celrep.2016.05.092. Epub 2016 Jun 23.

Reference Type BACKGROUND
PMID: 27346343 (View on PubMed)

Other Identifiers

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P20GM156679

Identifier Type: NIH

Identifier Source: secondary_id

View Link

108059

Identifier Type: -

Identifier Source: org_study_id

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