Lactose-containing versus lactose-free milk for diabetes prevention in people with lactase non-persistence

Milk for Diabetes Prevention

Not applicable Interventional Albert Einstein College of Medicine · NCT06513026

This trial will test whether drinking lactose-containing milk instead of lactose-free milk for 12 weeks changes gut bacteria and improves blood sugar in people with lactase non-persistence and prediabetes.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment40 (estimated)
Ages18 Years to 70 Years
SexAll
SponsorAlbert Einstein College of Medicine Academic / other
Locations1 site (The Bronx, New York)
Trial IDNCT06513026 on ClinicalTrials.gov

What this trial studies

After a 2-week milk washout, participants with the LCT rs4988235 GG genotype and prediabetes are randomized 1:1 to lactose-containing or lactose-free milk for 12 weeks, with dose escalation of ½ cup, 1 cup, and 2 cups each for four weeks. Clinic visits before and after the intervention include lactose hydrogen breath tests and blood draws for fasting glucose, HbA1c, and metabolomics, while stool samples and continuous glucose monitoring are collected at home. The trial aims to test feasibility and tolerability and to measure changes in gut microbiome species, microbial functions, metabolites, and short-term glycemic outcomes. Randomization and controlled milk formulations are used to isolate the effect of lactose in a real-world consumption pattern.

Who should consider this trial

Good fit: Adults with prediabetes who carry the lactase non-persistence genotype (LCT rs4988235 GG), drink one cup of milk or less per day, and can read and speak English are the ideal candidates.

Not a fit: People already diagnosed with diabetes, taking diabetes medications, with known milk allergy or severe gastrointestinal reactions to milk, or who cannot tolerate milk are unlikely to benefit from this intervention.

Why it matters

Potential benefit: If successful, this could point to a simple dietary approach that lowers diabetes risk or improves blood sugar control in people with lactase non-persistence.

How similar studies have performed: Observational data from the HCHS/SOL found about a 30% lower diabetes risk with daily milk intake in LNP individuals, but randomized trials testing lactose-containing versus lactose-free milk are novel.

Eligibility criteria

Show full inclusion / exclusion criteria
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

Where this trial is running

The Bronx, New York

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Lactose IntoleranceLactose IntolerantLactase PersistencePre-DiabetesDiabetes Mellitus, Type 2LactoseLactose-freeLactase Non Persistence
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.