ReviewNutrients2015
Milk Intolerance, Beta-Casein and Lactose.
Review in Nutrients, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 61 papers, 1 of them a synthesis that pooled it.
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.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
61 citing papers in PubMed, 1 synthesis or guideline pooled it, 179 citations in OpenAlex.
- Systematic Review of the Gastrointestinal Effects of A1 Compared with A2 β-Casein.Advances in nutrition (Bethesda, Md.) · 2017Pooled it
- Trial
- 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
- Trial
- Trial
- Circulatory amino acid responses to milk consumption in dairy and lactose intolerant individuals.European journal of clinical nutrition · 2022Trial
- Evaluation of breath, plasma, and urinary markers of lactose malabsorption to diagnose lactase non-persistence following lactose or milk ingestion.BMC gastroenterology · 2020Trial
- Effects ofNutrients · 2019Trial
- A2 Milk Enhances Dynamic Muscle Function Following Repeated Sprint Exercise, a Possible Ergogenic Aid for A1-Protein Intolerant Athletes?Nutrients · 2017Trial
- A Sensitive LC-MS/MS Method for Quantifying Beta-Casomorphin 5 in Pasteurized Milk.Food science & nutrition · 2026Article
- The Diagnostic Elimination Diet and Challenge Protocol for Management of Patients with Food Intolerance-Purpose and Development.Nutrients · 2026Article
- Differential Release of β-Casomorphins from A1 and A2 Milk During Standardized Gastrointestinal Digestion Quantified by CE-MS.Foods (Basel, Switzerland) · 2026Article
- β-casomorphin-7: a review of occurrence, identification, techno-functionality, and effects on human health.NPJ science of food · 2026Review
- Exploratory identification of coding and splicing-related SNV variants in A1A1 and A2A2 β-casein Holstein dairy cows.Journal of animal science · 2026Article
- Article
- Frequency of A1 and A2 alleles of the β-casein gene in cattle in the Cajamarca region of Peru.Open veterinary journal · 2025Article
- Transcriptomic profiling of milk fat globules in cows with different β-casein genotypes.Scientific reports · 2025Article
- Cow milk protein allergy mimics in infancy.World journal of clinical pediatrics · 2025Review
- 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
- Influence of the Casein Genotype on Goat Milk Bioactivity: An In Silico Analysis of the Casein Peptidome.Molecules (Basel, Switzerland) · 2025Article
1 more citing papers are in PubMed but not listed here.
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 3 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
True lactose intolerance (symptoms stemming from lactose malabsorption) is less common than is widely perceived, and should be viewed as just one potential cause of cows' milk intolerance. There is increasing evidence that A1 beta-casein, a protein produced by a major proportion of European-origin cattle but not purebred Asian or African cattle, is also associated with cows' milk intolerance. In humans, digestion of bovine A1 beta-casein, but not the alternative A2 beta-casein, releases beta-casomorphin-7, which activates μ-opioid receptors expressed throughout the gastrointestinal tract and body. Studies in rodents show that milk containing A1 beta-casein significantly increases gastrointestinal transit time, production of dipeptidyl peptidase-4 and the inflammatory marker myeloperoxidase compared with milk containing A2 beta-casein. Co-administration of the opioid receptor antagonist naloxone blocks the myeloperoxidase and gastrointestinal motility effects, indicating opioid signaling pathway involvement. In humans, a double-blind, randomized cross-over study showed that participants consuming A1 beta-casein type cows' milk experienced statistically significantly higher Bristol stool values compared with those receiving A2 beta-casein milk. Additionally, a statistically significant positive association between abdominal pain and stool consistency was observed when participants consumed the A1 but not the A2 diet. Further studies of the role of A1 beta-casein in milk intolerance are needed.
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What OpenQuestion holds
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.