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Abstract Background A 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. Th...
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Context 1
... containing either A1 and A2 β-casein (conventional milk) or only A2 β-casein was provided by The a2 Milk Company (Shanghai, China). Both products were con- firmed to be identical (Table 1), except for the β-casein content. The ratio of A1 β-casein to A2 β-casein in con- ventional milk was 58:42. ...
Context 2
... were asked to complete food frequency question- naires (Additional file 1: Table S1) to document adherence to the dairy-free diet during the 3-day and 7-day washout periods. The questionnaires were conducted by the inves- tigators on days 1 and 8 at each study site. ...
Context 3
... were no significant effects of visit or age group on symptom scores (Additional file 1: Table S2). Therefore, data are grouped according to the intervention received. ...
Context 4
... also explored the possibility that age had an im- pact on gastrointestinal symptoms or the correlation be- tween lactose malabsorption and gastrointestinal symptoms. As indicated in Additional file 1: Tables S2, S5 and S6, age was not significantly associated with gastrointestinal symptoms. However, because the upper age range was limited to 50 years, it is possible that older subjects might experience more severe gastrointestinal symptoms after dairy intake. ...
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This study evaluated the influence of temperature and β-galactosidase concentration on lactose hydrolysis and on the composition of pasteurized goat milk. Goat milk was pasteurized at 75 °C/15 s and cooled to 10 °C and 30 °C, received 0 (control); 0.04%; 0.07%; 0.20% (v/v) β-galactosidase and was incubated for 5 h, followed by enzymatic inactivatio...
(1) Background: Lactose digestion depends on persistence genotypes (including rs4988235), the frequency of which exhibits broad geographical variability. However, little is known about the relationship between lactase (LCT) genotypes and intestinal expression of LCT. We aimed to investigate ileal expression of LCT depending on main genetic polymorp...
Background and Aims
There have been few reports on lactase deficiency (LD) and lactose intolerance (LI) in Malaysia, which has a peculiar mix of three distinct major Asian races—Malay, Chinese, and Indian. The aim of this study was to determine the prevalence of LD and LI in a young multiethnic Malaysian population.
Methods
Lactase activity was me...
Citations
... Several studies from developed and developing countries have shown GI improvement of A2 milk intake among adults [13][14][15][16]. However, only two studies with limited sample sizes (n ≤ 80) have assessed the health effects of A2 versus A1 β-casein among children and reported inconsistent results. ...
... Randomized controlled trials conducted among lactose-intolerant adults or children from the United States, Australia, and China, refs. [13][14][15]33], showed that milk containing only A2 β-casein improved GI symptoms and reduced digestive discomfort. ...
... Nutrients 2023,15, 1313 ...
Background: Emerging clinical evidence indicates the potential gastrointestinal (GI) benefits of milk containing only A2 β-casein, but data from randomized controlled trials is sparse among pediatric populations. We aimed to evaluate the effectiveness of growing-up milk (GUM) containing only A2 β-casein on GI tolerance in toddlers. Methods: A total of 387 toddlers aged 12–36 months were recruited in Beijing, China, and randomized in a 1:1:1 ratio to consume one of two commercially available A2 GUMs (combined in the analysis as A2 GUM) or continue their current feeding regimen of conventional milk for 14 days. The primary outcome was the total Gut Comfort Score (GCS) (range: 10–60; higher values indicate greater GI distress) derived from a 10-item (score range: 1–6 per item) parent-reported questionnaire, reflecting GI tolerance. Results: The GCS (mean ± SD) was comparable between the A2 GUM and conventional milk groups on day 7 (14.7 ± 5.0 vs. 15.0 ± 6.1, p = 0.54) and day 14 (14.0 ± 4.5 vs. 14.3 ± 5.5, p = 0.51). Parents reported less constipation in those consuming A2 GUM vs. conventional milk on day 14 (1.3 ± 0.6 vs. 1.4 ± 0.9, p = 0.020). Among 124 participants with minor GI distress at baseline (GCS ≥ 17, top tertile range 17–35), GCS was significantly lower in those consuming A2 GUM on day 7 (18.2 ± 5.1 vs. 21.2 ± 6.8, p = 0.004) and day 14 (17.1 ± 5.3 vs. 19.6 ± 6.3, p = 0.026), as were individual GI symptoms (all p < 0.05). In the toddlers without GI issues at baseline (GCS < 17), a low GCS was maintained throughout the study period after switching to A2 GUM (mean values range 10–13). Conclusions: Growing-up milk containing only A2 β-casein were well-tolerated and associated with lower parent-reported constipation scores after two weeks when compared to conventional milks. In healthy toddlers with minor GI distress, A2 GUM improved overall digestive comfort and GI-related symptoms within one week.
... Several studies have shown that the consumption of milk containing A1 β-casein aggravates symptoms of lactose intolerance [9][10][11][12]. Our group previously conducted a double-blinded randomized study in lactose maldigesters and lactose intolerant subjects to study the effects of milk with varying compositions of A1 and A2 β-casein on intolerance and maldigestion. ...
... We found that significantly higher abdominal pain was associated with the consumption of milk containing 75% A1 β-casein and 25% A2 β-casein as compared to milk containing 100% A2 β-casein [13]. These results were consistent with others [9,11,14]. ...
Lactose maldigesters report an increase in abdominal pain due to the consumption of milk containing a mixture of A1 and A2 β-casein as compared to milk containing only A2 β-casein. Gastric transit affects gastrointestinal symptoms and rapid transit has been associated with an increase in abdominal pain. We conducted a double-blinded, randomized, crossover trial in 10 lactose maldigesters. Subjects consumed each of the two types of milk: conventional milk containing 75% A1 β-casein and 25% A2 β-casein and A2 milk containing 100% A2 β-casein. Magnetic resonance images were acquired, and abdominal pain was rated and recorded at 0, 10, 30, 60 and 120 min after milk consumption. The volume of milk in the stomach was calculated using FSL software. The volume of milk in the stomach after consuming milk with 75% A1 β-casein and 25% A2 β-casein was significantly lower at 30 (p = 0.01), 60 (p = 0.002) and 120 (p < 0.001) minutes as compared to milk with 100% A2 β-casein in the 10 lactose maldigesters. The transit of New-World milk containing A1 and A2 β-casein was more rapid as compared to Old-World milk containing only A2 β-casein. This difference in transit may mediate symptoms of lactose intolerance.
... The group which received A2 type and mixed milk (3:2 ratio) showed symptoms of gastrointestinal discomfort with increased gastrointestinal transit time; increased inflammatory serum marker level as well as retarded cognitive processing speed while none of these adverse effects were observed in group fed with A2 (A2A2) type milk. He et al. (2017) clearly revealed positive effects of A2 milk diet like attenuation of acute gastrointestinal symptoms of milk intolerance while A1 milk was reported to reduce lactase activity and increased gastrointestinal discomfort. Milan et al (2020) also showed improvement in digestive discomfort in individual having lactose intolerance or lactose malabsorption Impairment of functions including reduction in the frequency and amplitude of intestinal contractions by BCM7 is also well reported (Daniel et al. 1990;Mihatsch et al. 2005). ...
This e-book is designed to educate the field functionaries of the state animal husbandry departments of the country, extension workers, students, and research scholars, academicians related to veterinary science and animal husbandry about strategies for the characterization and conservation of indigenous animal genetic resources and appropriate policy interventions that are required to ensure their
sustainable utilization.
... Считается, что А2 является исходным бета-казеиновым белком, а А1 это результат мутации, произошедшей у европейского крупного рогатого скота несколько тысяч лет назад [6,7]. «Молоко А2», полученное от коров с генотипами А2А2, является перспективным продуктом для производства, так как в отличие от «молока А1» не вызывает негативных последствий для организма человека: воспаление кишечника, обострение желудочнокишечных симптомов [8,9,10,11,12]. ...
The aim of the study is to identify the frequency of occurrence of various allelic variants and genotypes of beta-casein in cows of the Kholmogory breed and their relationship with dairy productivity. The tasks of the research are genotyping of cattle of the Kholmogory breed by the beta-casein locus and establishing its connection with qualitative and quantitative indicators of dairy productivity. As the objects for the research there were taken 150 cows of the 1st, 2nd and 3rd lactation. An allele-specific variant of the PCR method (AS-PCR) was used to identify A1 and A2 beta-casein. As the result it had been established that in the studied part of the herd, 23 % of animals had the A2A2 genotype, 43 % of animals had the A1A1 genotype and 34 % of animals had the A1A2 genotype. For 100 days of the first lactation, animals with A1A2 genotype showed the highest value in milk yield. Animals with A2A2 genotype for 305 days of lactation had the highest milk yield and the amount of milk protein, however, the difference was not statistically significant compared to the animals with A1A2 genotype. Genotype A1A1 has lower indicators by all the parameters studied, with a significant difference relative to genotypes A1A2 and A2A2. Thus, the study of CSN2 is a promising area of scientific research, and the results of the study of beta-casein genotypes can be used as a marker selection in improving the herds of the Kholmogory breed.
... Digestive disorders after milk consumption are correlated not only with lactose intolerance, but also with the type of casein found in the consumed milk. Milan et al. conducted a study on a group of 40 women with self-reported varying dairy tolerance [127]. Participants ingested 750 mL of conventional milk (with A1 and A2 β-casein and lactose), A2 milk (with A2 β-casein and lactose), or lactose-free conventional milk (with A1 and A2 β-casein, but without lactose). ...
... The obtained results were the effect of a randomized, double-blind, crossover trial (a single-meal study), which was carried out on 25 participants (Ramakrishnan et al. 2020). A greater number of participants were included in the analysis performed by He et al. [127], who conducted a study with 600 patients randomly assigned to drink A1/A2 β-casein milk or A2 β-casein milk. Participants reported symptoms using 9-point visual analogue scales for gastrointestinal symptoms, and the following parameters were tested in the study: borborygmus, flatulence, bloating, abdominal pain, stool frequency, and stool consistency. ...
... The authors also noted that conventional milk containing β A1-casein reduced the activity of lactase and intensified dysfunctions in the digestive system. Therefore, one can conclude that in some individuals, gastrointestinal symptoms related to milk may be due to the ingestion of A1 β-casein, and this mechanism is not related to lactose intolerance [127]. ...
For over 20 years, bovine beta-casein has been a subject of increasing scientific interest because its genetic A1 variant during gastrointestinal digestion releases opioid-like peptide β-casomorphin-7 (β-CM-7). Since β-CM-7 is involved in the dysregulation of many physiological processes, there is a growing discussion of whether the consumption of the β-casein A1 variant has an influence on human health. In the last decade, the number of papers dealing with this problem has substantially increased. The newest clinical studies on humans showed a negative effect of variant A1 on serum glutathione level, digestive well-being, cognitive performance score in children, and mood score in women. Scientific reports in this field can affect the policies of dairy cattle breeders and the milk industry, leading to the elimination of allele A1 in dairy cattle populations and promoting milk products based on milk from cows with the A2A2 genotype. More scientific proof, especially in well-designed clinical studies, is necessary to determine whether a little difference in the β-casein amino acid sequence negatively affects the health of milk consumers.
... There is also a relationship between inflammatory bowel diseases (ulcerative colitis and Crohn's disease) and BCM7 (SIENKIEWICZ, SZYMANKA & FICHNA, 2021). On the other hand, milk with the variant A2 β-CN is safe and it decreases the incidence of health problems (BROOKE-TAYLOR et al., 2017;HE et al., 2017). And the exclusion of A1 β-CN in the diet would avoid digestive problems (BARNETT et al., 2014). ...
... The A2 milk causes fewer undesirable gastrointestinal effects, such as bloating, diarrhea, constipation, flatulence and abdominal pain (RAMAKRISHNAN et al.,2020). Even in lactose-intolerant people, the intake of A2 milk without the lactase enzyme, i.e. with lactose, presents less discomfort than lactose-free conventional A1/A2 milk (MILAN et al., 2020;RAMAKRISHNAN et al., 2020;HE et al., 2017). Researchers have stressed the importance of developing more research on the effect of A1/A2 milk on human health and the benefits of A2 milk, especially for children and for the development of infant nutritional formulas (DUARTE-VÁZQUEZ et al., 2017). ...
... Despite successful reports, researchers and the literature still recommend caution. Nobly, the cases are more related to digestive discomforts, an aspect in which the scientific literature already has more concrete results (HE et al., 2017;NGUYEN et al., 2018;BARBOSA et al., 2019;SHENG et al., 2019). ...
The objective of this study was to evaluate the potential of the A2 milk as an upgrading strategy for milk producers in Brazil. The primary data were obtained through semi-structured interviews with eight strategic actors of the A2 milk chain in September and October 2021. Five producers, two researchers and one member of the movements called the #bebamaisleite. The study was led by the theoretical framework of global value chain, focusing on the upgrading dimension. A2 milk is an upgrading opportunity for producers , following a global trend of food premiumization. However , caution is needed for producers to enter this chain because the market is incipient, the costs are significant, and the financial return is uncertain. Otherwise, there will be a reproduction of the inequalities and bottlenecks which are present in the conventional dairy chain. It was found that the A2 milk chain is not intended to replace the conventional one, but it aims to capture vegetable beverages consumers.
... Although BCM-7 was initially associated with several adverse effects, a review by the European Food Safety Authority [214] concluded that "a cause-effect relationship between the oral intake of BCM7 or related peptides and etiology or course of any suggested non-communicable diseases cannot be established." Recent studies have reported that consumption of A2 milk may be associated with attenuation of gastrointestinal symptoms of milk intolerance in self-reported lactose intolerant individuals [215][216][217]. Cows can be genetically selected to be homozygous for β-CN A2 (A2A2 genotype) and thereby produce milk that only contains β-CN of the A2 type (A2 milk), and dairy products manufactured from A2 milk have been on the market for many years. ...
Milk is newborn’s food and an emulsion full of all necessary components for neonatal growth. Its consumption is worldwide and is the base for all dairy products. Because of the latter, many new technologies are growing, among them proteomics; in order to give new insights in milk’s compounds and to maximize the beneficial potential for consumers’ health. In this review, we aimed to gather data of proteomics studies for the majority of dairy animals and elucidate the role of milk bioactive compounds. Furthermore, special reference was made to milk fat globule membrane (MFGM) peptides and the result of thermal treatment in milk proteins. Finally, the proteomic approach regarding adulterations was included in the review.
... To date many studies have focused on the effects of β-casein genetic polymorphism on animal and human health using in vitro, ex vivo and in vivo trials (Daniloski et al., 2021a(Daniloski et al., , 2021bHaq et al., 2014;He et al., 2017;Hockey et al., 2021;Ramakrishnan et al., 2022;Ramakrishnan et al., 2020;Yadav et al., 2020), with limited focus on the technical and functional properties of β-casein phenotype on milk products. Therefore, the main purpose of this review is to address the differences between the physicochemical properties of these β-casein phenotypes, but also the other caseins and their genetic variants. ...
The impact of a single amino acid mutation within the peptide structure of bovine milk protein is important to understand as it can effect processability and subsequently effect its physiological properties. Genetic polymorphisms of bovine caseins can influence the chemical, structural, and technological properties, including casein micelle morphology, calcium distribution, network creation upon gelation, and surface activity. The A1 and A2 genetic variants of β-casein have recently acquired growing attention from both academia and industry, prompting new developments in the area. The difference between these two genetic variants is the inclusion of either proline in β-casein A2 or histidine in β-casein A1 at position 67 in the peptide chain. The aim of this review was to examine the extent to which milk and ingredient functionality is influenced by β-casein phenotype. One of the main findings of this review was although β-casein A1 was found to be the dominant variant in milks with superior acid gelation and rennet coagulation properties, milks comprised of β-casein A2 possessed greater emulsion and foam formation capabilities. The difference in the casein micelle assembly, hydrophobicity, and chaperone activity of caseins may explain the contrast in the functionality of milks containing β-casein from either A1 or A2 families. This review provides new insights into the subtle variations in the physicochemical properties of bovine milks, which could potentially support dairy producers in the development of new dairy products with different functional properties.
... Namun dari hasil jumlah penggumpalan atau curd yang didapatkan berbeda-beda dari ketiga jenis susu. Hal ini disebabkan oleh kandungan protein dari masing-masing susu berbeda, terlebih pada kandungan protein kasein yang terkandung pada susu sekitar 75 -80% dari total protein susu (He et al., 2017;Bhat et al., 2016). Protein kasein memiliki peranan penting dalam proses penggumpalan susu, karena mampu menghasilkan jaringan gel untuk mempertahankan misel protein kasein yang satu dengan yang lainnya sehingga dapat membentuk gumpalan pada susu (Beux et al., 2017). ...
... There is also a relationship between inflammatory bowel diseases (ulcerative colitis and Crohn's disease) and BCM7 (SIENKIEWICZ, SZYMANKA & FICHNA, 2021). On the other hand, milk with the variant A2 β-CN is safe and it decreases the incidence of health problems (BROOKE-TAYLOR et al., 2017;HE et al., 2017). And the exclusion of A1 β-CN in the diet would avoid digestive problems (BARNETT et al., 2014). ...
... The A2 milk causes fewer undesirable gastrointestinal effects, such as bloating, diarrhea, constipation, flatulence and abdominal pain (RAMAKRISHNAN et al.,2020). Even in lactose-intolerant people, the intake of A2 milk without the lactase enzyme, i.e. with lactose, presents less discomfort than lactose-free conventional A1/A2 milk (MILAN et al., 2020;RAMAKRISHNAN et al., 2020;HE et al., 2017). Researchers have stressed the importance of developing more research on the effect of A1/A2 milk on human health and the benefits of A2 milk, especially for children and for the development of infant nutritional formulas (DUARTE-VÁZQUEZ et al., 2017). ...
... Despite successful reports, researchers and the literature still recommend caution. Nobly, the cases are more related to digestive discomforts, an aspect in which the scientific literature already has more concrete results (HE et al., 2017;NGUYEN et al., 2018;BARBOSA et al., 2019;SHENG et al., 2019). ...
The objective of this study was to evaluate the potential of the
A2 milk as an upgrading strategy for milk producers in Brazil. The
primary data were obtained through semi-structured interviews
with eight strategic actors of the A2 milk chain in September and
October 2021. Five producers, two researchers and one member
of the movements called the #bebamaisleite. The study was led by
the theoretical framework of global value chain, focusing on the
upgrading dimension. A2 milk is an upgrading opportunity for pro�ducers, following a global trend of food premiumization. Howe�ver, caution is needed for producers to enter this chain because
the market is incipient, the costs are significant, and the financial
return is uncertain. Otherwise, there will be a reproduction of the
inequalities and bottlenecks which are present in the conventional
dairy chain. It was found that the A2 milk chain is not intended
to replace the conventional one, but it aims to capture vegetable
beverages consumers.
