Trial reportNutrition journal2017
Effects of cow's milk beta-casein variants on symptoms of milk intolerance in Chinese adults: a multicentre, randomised controlled study.
Trial report in Nutrition journal, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to 2 registered trials, which are not on this map. Cited by 47 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Incidence of Lactose Intolerance Among Self-reported Lactose Intolerant People
A Double-blind, Parallel Designed, Randomized Controlled Trial to Investigate Effects of Conventional Vs A2 Milk on Breastmilk Composition and Subsequent Infant Gut Health, Crying and Sleep Patterns in Healthy, Full-term Infants
Who cites it
47 citing papers in PubMed, 132 citations in OpenAlex.
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- Effect of A1 protein-free formula versus conventional formula on acute respiratory infections and diarrhea in toddlers: A Randomized Controlled Trial.Journal of pediatric gastroenterology and nutrition · 2025Trial
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- Trial
- Circulatory amino acid responses to milk consumption in dairy and lactose intolerant individuals.European journal of clinical nutrition · 2022Trial
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- Evaluation of breath, plasma, and urinary markers of lactose malabsorption to diagnose lactase non-persistence following lactose or milk ingestion.BMC gastroenterology · 2020Trial
- The combination of wheat peptides and fucoidan protects against chronic superficial gastritis and alters gut microbiota: a double-blinded, placebo-controlled study.European journal of nutrition · 2020Trial
- Effects of Conventional Milk Versus Milk Containing Only A2 β-Casein on Digestion in Chinese Children: A Randomized Study.Journal of pediatric gastroenterology and nutrition · 2019Trial
- Ex Vivo Immune Response of Casein-Sensitized Lymphocytes to Bovine Milk Protein Composite Genotypes: Beyond the β-Casein A1/A2 Paradigm.Nutrients · 2026Article
- KetoFLEX 12/3 Diet and Cognitive Health: A Precision-Nutrition Perspective on Mechanisms, Emerging Evidence, and Future Directions.Nutrients · 2026Review
- An ARMS-integrated high-resolution melting assay for reliable discrimination of the A1/A2 polymorphism in the bovineFood chemistry. Molecular sciences · 2026Article
- β-Casein Polymorphism as a Potential Evolutionary Trade-Off: The Rise of A1 Under Intensive Selection and Its Implications for Gastrointestinal Tolerance and Agroecological Resilience.Veterinary sciences · 2026Review
- β-casomorphin-7: a review of occurrence, identification, techno-functionality, and effects on human health.NPJ science of food · 2026Review
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- Rat models of lactose intolerance: sexually dimorphic comorbidities with neuropsychiatric disorders modulated by tryptophan hydroxylase and the dopaminergic system.Scientific reports · 2025Article
- Frequency of A1 and A2 alleles of the β-casein gene in cattle in the Cajamarca region of Peru.Open veterinary journal · 2025Article
- Cow milk protein allergy mimics in infancy.World journal of clinical pediatrics · 2025Review
- Is There a Potential Market for A2 Milk? Consumer Perception of Dairy Production and Consumption.Foods (Basel, Switzerland) · 2025Article
- Effect of Infant Formula Made With Milk Free of A1-Type β-Casein on Growth and Comfort: A Randomized Controlled Trial.Food science & nutrition · 2025Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors at 4 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundA major protein component of cow's milk is β-casein. The most frequent variants in dairy herds are A1 and A2. Recent studies showed that milk containing A1 β-casein promoted intestinal inflammation and exacerbated gastrointestinal symptoms. However, the acute gastrointestinal effects of A1 β-casein have not been investigated. This study compared the gastrointestinal effects of milk containing A1 and A2 β-casein versus A2 β-casein alone in Chinese adults with self-reported lactose intolerance.
methodsIn this randomised, crossover, double-blind trial, with a 3-day dairy washout period at baseline, subjects were randomised to consume 300 mL of milk containing A1 and A2 β-casein (ratio 58:42; conventional milk) or A2 β-casein alone; subjects consumed the alternative product after a 7-day washout period. Urine galactose was measured at baseline after a 15 g lactose load. Subjects completed 9-point visual analogue scales for gastrointestinal symptoms (borborygmus, flatulence, bloating, abdominal pain, stool frequency, and stool consistency) at baseline and at 1, 3, and 12 h after milk consumption.
resultsA total of 600 subjects were included. All six symptom scores at 1 and 3 h were significantly lower after consuming A2 β-casein versus conventional milk (all P<0.0001). At 12 h, significant differences remained for bloating, abdominal pain, stool frequency, and stool consistency (all P<0.0001). Symptom scores were consistently lower with A2 β-casein in both lactose absorbers (urinary galactose ≥0.27 mmol/L) and lactose malabsorbers (urinary galactose <0.27 mmol/L).
conclusionMilk containing A2 β-casein attenuated acute gastrointestinal symptoms of milk intolerance, while conventional milk containing A1 β-casein reduced lactase activity and increased gastrointestinal symptoms compared with milk containing A2 β-casein. Thus, milk-related gastrointestinal symptoms may result from the ingestion of A1 β-casein rather than lactose in some individuals.
trial registrationNCT02878876 , registered August 16, 2016. Retrospectively registered.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.