Goat vs. Cow Milk Digestive Tolerance (DIGIGOAT)

Digestive Tolerance and Nutrient Absorption Kinetics of Goat Milk Versus Cow Milk in Individuals With Reported Cow's Milk Intolerance : a Controlled Single-blinded Crossover Trial

The objective of this study is to assess to what extent goat's milk is better tolerated than cow's milk among individuals who report being intolerant to cow's milk, and, if so, to understand the underlying factors. To achieve this, digestive discomfort sensations and postprandial kinetics of nutrients after ingestion of cow's or goat's milk will be compared in two populations: individuals intolerant to cow's milk but not to goat's milk, and individuals who show no symptoms of intolerance to either cow's or goat's milk. For this purpose, approaches based on stable isotope labeling of milk will be employed.

Study Overview

• Status: Recruiting
• Conditions: Milk Hypersensitivity; Milk Intolerance; Cow Milk Protein Sensitivity
• Intervention / Treatment: Other: Cow milk; Other: Goat Milk

Detailed Description

Objective:

Although milk has many nutritional benefits, such as being rich in high-quality proteins and calcium, some people limit or exclude its consumption due to poor digestive tolerance. Lactose intolerance is a well-known cause, but other factors may occur, remaining poorly understood. Goat milk is perceived by consumers as causing fewer intestinal issues than cow milk, particularly for sensitive individuals. However, there is little scientific evidence to support this perception and to confirm the supposed health benefits of goat's milk over cow's milk. The objective of this study is to assess to what extent goat's milk is better tolerated than cow's milk among individuals who report being intolerant to cow's milk, and, if so, to understand the underlying factors.

Design:

This study is crossover study, randomized for the order of testing (goat milk or cow milk), conducted in a single-blind design (participants are not informed about the test meal, which is masked by aroma), involving two groups of at least ten volunteers: individuals intolerant to cow's milk but not to goat's milk, and individuals who show no symptoms of intolerance to either cow's or goat's milk. Each subject will have consumed both milks at the end of the two sessions, with a minimum one-month interval.

Postprandial Test Procedure:

Two days before the test, subjects must exclude consumption of the main dairy products (yogurt, cheese, milk, and custard creams). Volunteers arrive in a fasted state on the investigation day and are hospitalized for one day per session. On the first visit, volunteers bring a stool sample. Upon arrival, body composition is measured via bioelectrical impedance and a venous catheter is inserted. Blood samples are taken 30 minutes pre-meal, every 30 minutes for the first 4 hours, and hourly thereafter, totaling 291 mL. Urine is collected before the meal and every 2 hours post-meal. Respiratory is measured hourly using an indirect calorimeter. Digestive tolerance and hunger are assessed hourly using questionnaires. Volunteers remain semi-reclined for about 9 hours and fast until the experiment ends, receiving hourly water.

The test meal consists of aromatized 500 ml of cow's or goat's milk, labeled with stable isotopes: nitrogen-15 and deuterium. The incorporation rate is minimal and safe for human health, commonly used in clinical studies. The 15N enrichment is measured in collected biological samples (blood, urine) to track the digestive and metabolic fate of dietary amino acids, enabling precise evaluation of nutrient availability kinetics in the body. After the investigation day, volunteers can go home post-meal. A follow-up call the next day checks for digestive symptoms, with the doctor assessing the need for symptomatic treatment.

The protocol has been approved by the Ethical Committee and authorized by the French Agency of Drugs and Health. The personal data management will be in accordance with the regulation on personal data protection ("regulation n° 2018-493 du 20 juin 2018").

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Saviard; Phone Number: +33631312326; Email: tanguy.saviard@agroparistech.fr
• Study Contact Backup: Name: Maurinier; Phone Number: +33148957433; Email: suzette.maurinier@agroparistech.fr

Study Locations

• France
  • Bobigny, France, 93000
    • Recruiting
    • Hôpital Avicenne, 125 rue de Stalingrad
    • Contact: Benallaoua; Phone Number: +33148957433; Email: mourad.benallaoua@aphp.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Individuals who report being intolerant to cow milk but not to goat milk (one group) or tolerant to both cow milk and goat milk (another group)
• Good general health (WHO grade = 0)
• Affiliated with a social security scheme
• Free, informed, and express consent, in accordance with the public health code: 'No research mentioned in 2° of Article L. 1121-1 can be conducted on a person without their free, informed, and express consent.

Exclusion Criteria:

• Individuals under guardianship or curatorship
• Individuals under legal protection
• Any known food allergies
• Anemia: hemoglobin levels below 13 g/dL for men and 12 g/dL for women
• Pregnant women or those likely to be (based on a positive urine pregnancy test at the time of inclusion)
• Excessive alcohol consumption (>2 drinks/day). Harmful alcohol consumption is assessed by the investigator at the time of inclusion.
• Hypertension, diabetes, digestive tract diseases (except for irritable bowel syndrome, IBS), liver or kidney diseases, severe heart disease. The presence of these conditions will be assessed by the investigator based on usual clinical criteria and the volunteers' declarations during inclusion. Hypertension: Significant arterial hypertension as determined by the investigator or systolic blood pressure greater than or equal to 140 mmHg and/or diastolic blood pressure greater than or equal to 90 mmHg on the day of inclusion. Diabetes: Type 1 or Type 2 diabetes or any fasting blood glucose level > 1.25 g/l. Digestive tract disease: Gastrointestinal disorders deemed by the investigator as clinically significant (bleeding, vomiting, constipation/diarrhea grade >1), any inflammatory bowel disease, acute gastroenteritis in the month preceding the intervention. Liver disease: Any significant liver disorder as determined by the investigator or any AST/ALT > 2.5 times the upper normal limit.
• Elite athletes (> 8 hours per week)
• Blood donation in the 3 months preceding the start of the study
• Participation in a clinical study in the 3 months preceding the study
• Lack of free, informed, and express consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cow milk intolerant; Individuals who report being intolerant to cow's milk but not to goat's milk	Other: Cow milk; Consuption of 500 ml of aromatized cow milk, labeled with stable isotopes: nitrogen-15 and deuterium. Body composition is measured via bioelectrical impedance. A venous catheter is inserted. Blood, urine and breath samples are taken pre-meal, and regularly during 8 hours. Digestive tolerance and hunger are assessed using questionnaires.; Other: Goat Milk; Consuption of 500 ml of aromatized goat milk, labeled with stable isotopes: nitrogen-15 and deuterium. Body composition is measured via bioelectrical impedance. A venous catheter is inserted. Blood, urine and breath samples are taken pre-meal, and regularly during 8 hours. Digestive tolerance and hunger are assessed using questionnaires.
Experimental: Control; Individuals who report being tolerant to both cow's milk and goat's milk.	Other: Cow milk; Consuption of 500 ml of aromatized cow milk, labeled with stable isotopes: nitrogen-15 and deuterium. Body composition is measured via bioelectrical impedance. A venous catheter is inserted. Blood, urine and breath samples are taken pre-meal, and regularly during 8 hours. Digestive tolerance and hunger are assessed using questionnaires.; Other: Goat Milk; Consuption of 500 ml of aromatized goat milk, labeled with stable isotopes: nitrogen-15 and deuterium. Body composition is measured via bioelectrical impedance. A venous catheter is inserted. Blood, urine and breath samples are taken pre-meal, and regularly during 8 hours. Digestive tolerance and hunger are assessed using questionnaires.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Digestive discomfort score from 0 to 8 hours post-meal	A digestive tolerance questionnaire (Casellas, 2009) and a hunger sensation questionnaire using visual analog scales are administered hourly. These are based on scales from 1 to 10 to assess feelings of : flatulence, nausea, diarrhea, bloating, and abdominal pain.	0, 1, 2, 3, 4, 5, 6, 7, 8 hours post-meal

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
15N enrichment of plasma and urine fractions from 0 to 8 hours post-meal	The measurement of isotopic enrichment of nitrogenous compounds in plasma and urine, in response to the ingestion of 15N-labeled milk proteins, provides an estimate of proteins absorption kinetic.	0, 1, 2, 3, 4, 5, 6, 7, 8 hours post-meal
2H enrichment of plasma fatty acids from 0 to 8 hours post-meal	The measurement of isotopic enrichment of fatty acids in plasma, in response to the ingestion of 2H-labeled milk lipids, provides an estimate of fatty acid absorption kinetics.	0, 1, 2, 3, 4, 5, 6, 7, 8 hours post-meal
2H enrichment of plasma glucose from 0 to 8 hours post-meal	The measurement of isotopic enrichment of glucose in plasma, in response to the ingestion of 2H-labeled milk lactose, provides an estimate of lactose absorption kinetics.	0, 1, 2, 3, 4, 5, 6, 7, 8 hours post-meal
Blood metabolites concentrations from 0 to 8 hours post-meal	Analysis of the amino acid, urea, glucose, triglyceride, free fatty acid, cholesterol, and insulin concentrations in blood	0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8 hours post-meal
Exhaled breath gas concentrations from 0 to 8 hours post-meal	Hydrogen (H2), methane (CH4), and carbon dioxide (CO2) concentration from exhaled air	0, 1, 2, 3, 4, 5, 6, 7, 8 hours post-meal
Substrate oxidation rates from 0 to 8 hours post-meal	Fat and glucose oxidation are assessed by measuring respiratory exchanges using indirect calorimetry	0, 1, 2, 3, 4, 5, 6, 7, 8 hours post-meal
Intestinal microbiota composition	Volunteers must bring a stool sample in the container previously provided to them. The samples will be analyzed using the 16S rRNA method to assess gamma and beta diversity.	Once at the beginning of enrollement

Collaborators and Investigators

• Sponsor: Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

Study record dates

Study Major Dates

• Study Start (Actual): September 25, 2025
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): February 1, 2027

Study Registration Dates

• First Submitted: September 11, 2025
• First Submitted That Met QC Criteria: November 18, 2025
• First Posted (Actual): November 20, 2025

Study Record Updates

• Last Update Posted (Actual): November 20, 2025
• Last Update Submitted That Met QC Criteria: November 18, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: Stable isotopes; Milk intolerance; Milk hypersensitivity; Digestion; Digestive confort; Goat milk; Cow milk
• Additional Relevant MeSH Terms: Metabolism, Inborn Errors; Genetic Diseases, Inborn; Metabolic Diseases; Intestinal Diseases; Immune System Diseases; Digestive System Diseases; Gastrointestinal Diseases; Hypersensitivity, Immediate; Hypersensitivity; Malabsorption Syndromes; Carbohydrate Metabolism, Inborn Errors; Food Hypersensitivity; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Nutritional and Metabolic Diseases; Milk Hypersensitivity; Lactose Intolerance; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Beverages; Dairy Products; Milk
• Other Study ID Numbers: DIGIGOAT

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No