Recruiting

Lactose-Containing vs. Lactose-Free

Sponsor:

Albert Einstein College of Medicine

Code:

NCT06513026

Conditions

Lactose Intolerance

Lactose Intolerant

Lactase Persistence

Pre-Diabetes

Diabetes Mellitus, Type 2

Eligibility Criteria

Sex: All

Age: 18 - 70

Healthy Volunteers: Not accepted

Interventions

Lactose-Containing Milk

Lactose-Free Milk

Study Details

Brief summary:

Individuals with lactase non-persistence (LNP; determined by a functional variant in the LCT gene \[rs4988235, GG genotype\]) are susceptible to lactose intolerance in adulthood due to deficiency of lactase, the enzyme which digests milk lactose sugars. However, many LNP individuals still drink ≥1 cup of milk daily. Recent analysis in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) found that consumption of 1 serving (cup) of milk/day was associated with \~30% lower risk of type 2 diabetes among LNP individuals, but not among individuals with lactase persistence (LP). This beneficial effect might be partially explained by favorable alterations in gut microbiota and related metabolites associated with higher milk consumption among LNP individuals. Based on these observational study findings, the investigator team proposes to conduct a randomized, controlled trial of lactose-containing vs. lactose-free milk in LNP individuals with pre-diabetes, to comprehensively investigate the effects of milk intake on the gut microbiome and glycemic outcomes.

Conditions

Lactose Intolerance

Lactose Intolerant

Lactase Persistence

Pre-Diabetes

Diabetes Mellitus, Type 2

Study ID

NCT06513026

Start date

May 15, 2026

Status verified date

May, 2026

Completion date

Apr, 2028

Anticipated

Primary completion date

Apr, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 70

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • LNP genotype (LCT gene rs4988235, GG genotype)
  • History of pre-diabetes, defined as fasting blood glucose 100-125 mg/dL and/or hemoglobin A1c (HbA1c) 5.7-6.4% and have not been diagnosed with diabetes nor take diabetes medication (pre-diabetes determined at most recent study visit \[for HCHS/SOL participant\] or most recent medical chart or self-report \[for other participant\])
  • Drink ≤1 cup milk/day
  • Basic computer or smartphone skills
  • Can speak and read English fluently

Exclusion Criteria:

  • Diabetes diagnosis
  • Taking anti-diabetes medication
  • Cancer, cardiovascular disease (CVD), or life-threatening illness
  • Known milk allergy
  • Has severe GI symptoms after drinking milk
  • History of GI surgery
  • Had a double mastectomy
  • Smoking
  • More than 1 alcoholic beverage/day
  • Pregnant or breastfeeding
  • Colonoscopy in last 2 weeks
  • Antibiotics in last 3 months
  • Taking probiotics or fiber supplements (if taking, must be able to stop taking during study)
  • Taking laxatives, stool softeners, anti-diarrheal (if taking, must be able to stop taking during study)
  • Taking lactase pills (if taking, must be able to stop taking)
  • Participating in extreme dieting program
  • Planning extended travel that would prevent participation in study
  • Taking medication that must be taken separate from calcium or dairy products

Study Design

Enrollment

40 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Prevention

Interventions and Outcome Measures

Arms

active comparator: Lactose-Containing Milk

Participants will be randomized to lactose-containing milk in strata of age (<60, ≥60) and sex (female, male). Within each age and sex stratum, 10 participants will be randomized into two intervention groups in a 1:1 ratio

active comparator: Lactose-Free Milk

Participants will be randomized to lactose-free milk in strata of age (<60, ≥60) and sex (female, male). Within each age and sex stratum, 10 participants will be randomized into two intervention groups in a 1:1 ratio

Interventions

Lactose-Containing Milk

Participants will be asked to drink regular milk (1% or 2%) for 12 weeks as follows:

  • Weeks 1-4: ½ cup milk per day
  • Weeks 5-8: 1 cup milk per day
  • Weeks 9-12: 2 cups milk per day

Participants will continue drinking 2 cups milk/day for 2 weeks after the 12-week follow-up visit.

Lactose-Free Milk

Participants will be asked to drink 1% or 2% lactose-free milk for 12 weeks as follows:

  • Weeks 1-4: ½ cup milk per day
  • Weeks 5-8: 1 cup milk per day
  • Weeks 9-12: 2 cups milk per day

Participants will continue drinking 2 cups milk/day for 2 weeks after the 12-week follow-up visit.

Primary outcome measure

  • Gastrointestinal symptoms [ Time Frame: Daily From Screening visit to Week 12 ]
  • Change in Expired Breath Hydrogen [ Time Frame: From Baseline to Week 12 ]
  • Change in gut microbiome features - Relative Abundance of Species [ Time Frame: From Baseline to Week 12 ]
  • Change in gut microbiome features - Functional Pathway Relative Abundance [ Time Frame: From Baseline to Week 12 ]
  • Change in gut microbiome features - Metabolomics [ Time Frame: From Baseline to Week 12 ]
  • Change in glycemic outcomes - Fasting glucose [ Time Frame: From Baseline to Week 12 ]
  • Change in glycemic outcomes - Hemoglobin A1c (HbA1c) [ Time Frame: From Baseline to Week 12 ]
  • Change in glycemic outcomes - Continuous Glucose Monitoring (CGM) mean glucose [ Time Frame: From Screening visit to Week 14 visit ]
  • Change in glycemic outcomes - Continuous Glucose Monitoring (CGM) glycemic variability [ Time Frame: From Screening visit to Week 14 visit ]
  • Change in glycemic outcomes - Continuous Glucose Monitoring (CGM) time above range [ Time Frame: From Screening visit to Week 14 visit ]
  • Change in glycemic outcomes - Continuous Glucose Monitoring (CGM) time in range [ Time Frame: From Screening visit to Week 14 visit ]
  • Change in glycemic outcomes - Continuous Glucose Monitoring (CGM) time below range [ Time Frame: From Screening visit to Week 14 visit ]
  • Change in Flatulence [ Time Frame: From Screening to Week 1, from Week 1 to Week 10, and from Week 1 to Week 14 ]

Central Contacts and Locations

Central contacts

Brandilyn Peters-Samuelson, PhD

718-430-3281brandilyn.peterssamuelson@einsteinmed.edu

Qibin Qi, PhD

718-430-4203qibin.qi@einsteinmed.edu

Locations

HCHS/SOL Bronx Field Center

Recruiting

The Bronx, New York, United States, 10458

Contacts

718-584-1563milkstudy@einsteinmed.edu

More Information

Sponsor

Albert Einstein College of Medicine

Last update posted

May 26, 2026

Last verified

May, 2026

Keywords

  • Lactose
  • Lactose-free
  • Lactase Non Persistence

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Albert Einstein College of Medicine on 2026-05-26.