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International Journal of Livestock Research eISSN : 2277-1964 NAAS Score -5.36
Vol 8 (4) Apr ’18 DOI 10.5455/ijlr.20170810113426
Review Article
A1 versus A2 Milk: Impact on Human Health
Rajalaxmi Behera*, Adhikari Sahu1, Ajoy Mandal, Saroj Rai, M. Karunakaran and T. K.
ICAR-National Dairy Research Institute, ERS, Kalyani, West Bengal, INDIA
1Teaching Associate, Ranchi Veterinary College, Jharkhand, INDIA
*Corresponding author:
Rec. Date:
Aug 10, 2017 11:34
Accept Date:
Nov 11, 2017 15:07
Published Online:
February 21, 2018
Casein is the chief component of the milk proteins of which about 30-35 percent is beta-casein. The major
beta- casein variants are A1 and A2. A2 beta-casein possesses proline at 67th position of its 229 amino
acid chain while A1 beta casein has histidine at the respective position owing to a mutation that occurred
in due course of time. Breeds like Jerseys, Asian and African cows produce A2 milk while Holsteins and
Ayrshire predominantly produce A1 milk. Beta-casomorphin-7 (BCM-7) is a bioactive seven-amino
peptide released by digestive enzymes exclusively from the A1-beta-casein protein. Several researchers
have reported BCM-7 interacts with the human gastrointestinal tract, internal organs and brainstem.
BCM7 adversely affects the immune response and is also considered as a risk factor for type 1diabetes.
A2 milk is considered safe for human consumption. However, several other studies have found no
relationship between A1 milk and the etiology of these diseases. Hence the present picture on A1vs A2
milk in concern to their health impacts is still unclear.
Key words: A2 Milk, A1 Milk, BCM-7
How to cite: Behera, R., Sahu, A., Mandal, A., Rai, S., Karunakaran, M., & Dutta, T. (2018). A1 versus
A2 Milk- Impact on Human Health. International Journal of Livestock Research, 8(4), 1-7.
Since time immemorial milk has been considered as perfect food because it is an important source of
nutrients and micronutrients. Milk consists of about 87 percent water and 13 percent of milk solids
constituting fat, lactose, minerals and protein. Casein is the chief component of the milk proteins of which
about 30-35 percent is beta-casein. Beta- casein may be of different types based on genetic background
of the animals but the major types are A1 and A2 (Swinburn, 2004). Beta-casein consist a chain of 229
amino acids. Milk having proline at 67th position of beta- casein amino acid chain is regarded as A2 milk
International Journal of Livestock Research eISSN : 2277-1964 NAAS Score -5.36
Vol 8 (4) Apr ’18 DOI 10.5455/ijlr.20170810113426
and with histidine amino acid at this position is A1 milk (Cowan, 2009; Woodford, 2007). Cows
producing A2 milk are known as A2 cows while those producing A1 milk are called A1 cows. Cows like
Jerseys, Guernsey, Asian and African cows produce A2 milk while Holstein and Ayrshire cattle breeds
predominantly produce A1 milk (Woodford, 2007; Cowan, 2009; Sheep,
goat, yaks, buffalo, camels, donkeys and Asian cows naturally contain more A2 beta casein protein
(Briden, 2013).
Genetics behind A1 and A2 Milk
Production of A1 or A2 milk by cows is governed by beta casein gene which is located on chromosome
number 6. Since long back, cows have been producing A2 milk which is regarded as safe and nutritious.
Around five thousand years back beta-casein gene was mutated and 67th amino acid was changed from
proline (A2 allele) to histidine (A1 allele). A cow carries only two copies of the beta-casein gene. Hence,
possibly she can be of A2A2 homozygous genotype or A1A2 heterozygous genotype or A1A1
homozygous genotype. The alleles do not have dominant - recessive relationship i.e., both the alleles are
co-dominant in nature. Thus, an A1A2 cow will produce both A1 and A2 beta casein alleles in equal
proportion. An A2A2 genotype cow will only produce A2 beta-casein and an A1A1 cow will only
produce A1 beta-casein. A cow of A2A2 genotype will transmit the A2 allele to her progeny while an
A1A1 cow will pass on the A1 allele and for A1A2 cow there is an equal chance of transmitting either
allele. Breeding for A2A2 cows can be done by using semen from bulls of A2A2 genotype.
Table 1: Breeding designs and offspring genotype
Bull Genotype
Cow Genotype
(Woodford, 2007;;; Indian Dairymen, 2017)
With the continuous use of the European breeds in selective breeding to increase milk production,
improve reproduction gradually A1 allele have propagated through the breeding programme. It has been
shown by several surveys that A1 / A2 frequency is area-specific rather than breed-specific. Example, A1
gene frequency in Holstein Friesen of North America and North Europe cow is very high (above 90%)
but in German Holstein Frisian A2 gene frequency is very high (around 97 %). In other countries,
frequency of A1 in Holstein Friesian is in the range of 40 65%. Guernsey breed from USA or Europe
has high A2 frequency in cows and breeding bulls even more than 98 % which is almost equal to Indian
breeds. A2 gene frequency is usually higher in Jersey (60-80%) globally (Vet Helpline India, 2015,, Genotyping of bulls for A1 and A2 allele is a good
International Journal of Livestock Research eISSN : 2277-1964 NAAS Score -5.36
Vol 8 (4) Apr ’18 DOI 10.5455/ijlr.20170810113426
method for lowering the risk of A1 allele in human health and increase milk and protein yield (Olenski et
al., 2009)
The Devil in A1 Milk
Digestive enzymes act differently upon A1 and A2 beta-casein proteins during digestion process. Beta-
casomorphin-7 (BCM-7) is a bioactive seven-amino peptide is released by digestive enzymes from the
A1-beta-casein protein but these enzymes cannot split the A2 protein due to presence of proline at that
location. So BCM-7 is not released from A2 proteins digestion. BCM-7 interacts with the human
gastrointestinal tract, internal organs, and brainstem and is regarded as the “devil” in A1 milk
(, Trustwell, 2005).
Fig.1: A2 and A1 beta casein differ only by one amino acid at 67th position in 229 amino acid chain
Fig. 2: Release of BCM 7 from A1 beta casein during digestion (
Health Hazards of A1 Milk
Several research workers have reported about the health hazards associated with A1 milk consumption.
Elliot (1992) observed that children in Polynesian islands consuming only to A2 type milk were at lesser
risk to Diabetes type 1 than Polynesian children in Auckland who were accessing A1 type of milk. An in
vivo experiment on non-obese diabetic mice further scientifically authenticated the observation. Elliot et
International Journal of Livestock Research eISSN : 2277-1964 NAAS Score -5.36
Vol 8 (4) Apr ’18 DOI 10.5455/ijlr.20170810113426
al. (1999) found a positive correlation between consumption of the β-casein A1 variant and incidence of
diabetes mellitus. BCM-7 can affect many opioid receptors in the nervous, endocrine and immune system.
Infants are more vulnerable because they have more chance of absorption of BCM-7 because of
comparatively less developed gastro-intestinal tract than the adults. BCM-7 may act as an
immunosuppressant and may increase the risk of Type 1 Diabetes, Coronary Heart Disease,
Arteriosclerosis, and Sudden Infant Death Syndrome. It is also related with some neurological disorders
like Autism or Schizophrenia (Pattanayak, 2013).
Bovine BCM-7 has been associated with the possible risk of human ischemic heart diseases (McLachlan,
2001). Kamiński et al. (2007) claimed a probable linkage between consumption of beta-casein A1 and
occurrence of ischemic heart disease, sudden infant death syndrome, neurological disorders like autism
and schizophrenia in New Zealand. Beta-casein A1 is more atherogenic than beta-casein A2 (Tailford et
al., 2003). Moreover, Laugesen and Elliot (2003) also found a strong correlation between consumption of
A1 bovine milk and incidence of ischemic heart disease (IHD) and Type 1 Diabetes Mellitus. High intake
of milk with A1 β-casein increases the chance of different diseases likes Diabetes Mellitus-1, Ischemic
Heart Disease, Schizophrenia and Autism (Swinburn, 2004). Laugesen and Elliott analyzed food
consumption data from 19 ‘health care affluent’ developed countries to study correlations between food
consumption and the rates of Type 1 diabetes. Strong correlations (r = 0.92) were identified between the
consumption of A1 β-casein and the incidence of type 1 diabetes. Incidence was found to be highest in
Finland and Sweden (countries with the highest A1 β-casein consumption/per capita) and lowest in
Venezuela and Japan (countries with the lowest A1 β-casein consumption/per capita). Padberg et al.
(1999) in one human study to investigate the differences in antibody responses to A1 and A2 β-
casein reported that the ratio of A1 to A2 β-casein antibodies was significantly higher in those with Type
1 diabetes than in controls (P<0.001).
Benefits of A2 Milk
A2 milk is free from the devil in milk BCM-7 and hence is safe for consumption (Pattanayak, 2013). The
populations consuming milk having more beta-casein A2 exhibit a lower occurrence of cardiovascular
disease and Type 1 diabetes (Sodhi et al., 2012). People consuming A2 milk had better stool consistency,
less incidence of bloating and less abdominal pain (Ho et al., 2014).
A2 Milk Production- Indian Context
In India, most of the native cows produce A2 milk which is very much safe for consumption. Several
research workers have attempted to study the A1 or A2 milk status in our indigenous breeds. Mishra et al.
(2009) examined 15 zebu cattle breeds (Kangayam, Nimari, Red Kandhari, Malnad Gidda, Kherigarh,
International Journal of Livestock Research eISSN : 2277-1964 NAAS Score -5.36
Vol 8 (4) Apr ’18 DOI 10.5455/ijlr.20170810113426
Malvi, Amrit Mahal, Kankrej, Gir, Sahiwal, Hariana, Tharparker, Rathi, Mewati and Red Sindhi) and 8
river buffalo breeds (Murrah, Mehsana, Marathwada, South Kanara, Manipur, Assamese Swamp, Nili
Ravi and Pandharpuri) and reported the absence of A1A1 genotype. A2 gene was nearly at fixation
(0.987) in zebu cattle. Indian cattle and buffalo breeds are reported to have 99 to 100% of the A2 /A2
genotype and A1 /A1 genotype is almost absent or very rare among them. Therefore, it can be said that
our native cows and buffaloes produce safer milk than European cattle breeds (Pattanayak, 2013).
Ganguly et al. (2013) reported genotypic frequency A1A1 (0.15), A1A2 (0.41) and A2A2 (0.44) in
Frieswal cattle and genotype frequency of A2A2 genotype (0.89), A1A1 (0.00) and A1A2 (0.11) in
Ongole cows. Malarmathi (2014) reported A2 gene frequency among Holstein Friesian crossbred to be
0.595 and 1.0 in pure Kangeyam cows.
Opportunity for Commercialization of A2 Milk
There is vast scope for commercialization of A2 milk worldwide since demand for safe A2 milk is ever-
increasing. In New Zealand, a company named A2 Corporation Ltd. (A2C) presently renamed as a2 Milk
Company Ltd has been launched to commercialize A2 milk. This company has started huge scale
marketing of A2 milk and milk products in the name of A2TM in New Zealand, Australia, United States
and Asia ( A subsidiary of A2 Corporation Limited known as A2 Milk
Uk (Ltd) produces and markets milk containing A2 protein in UK and Ireland (
Demand for Indian cattle (A2 milk) is rising globally in many countries like Australia, South America,
Africa, Brazil and Southeast Asia (De et al., 2015). So there is an opportunity to collect A2 milk from A2
genotyped herds separately and market at premium price. A2 milk can be used to prepare baby food.
Therefore, India has a prospect to become world leader in A2 infant food supply.
The Non-Conclusive Opinion on A1/A2 Milk
As stated above, there are many research reports reflecting the negative health impacts of A1 milk.
However, several other studies have found possible evidence of A1 milk as a factor for causing diabetes
and coronary heart disease. European food safety authority also could not find any relationship between
oral intake of BCM-7 and etiology of such diseases (Hills, 2009). The Australian and New Zealand food
safety Authorities have also reported no relation between A1 or A2 milk and diabetes and Coronary Heart
Disease incidence. Thus, there is no conclusive remark on A1 milk being the risk factor for these diseases.
Hence, need of the present era is to carry forward for research to establish the association between A1 or
A2 milk with the etiology of the above said diseases (Indian Dairymen, 2017).
International Journal of Livestock Research eISSN : 2277-1964 NAAS Score -5.36
Vol 8 (4) Apr ’18 DOI 10.5455/ijlr.20170810113426
India is fortunately bestowed with a large number of dairy cattle and buffaloes producing the healthy A2
milk. Time has come to pay attention for improvement and conservation of our indigenous germplasm.
However, to establish the advantages and disadvantages of A1 vs A2 milk, more research should be
conducted to draw conclusion on the hypothesis.
1. Aparna Pallavi,
2. C.N.S. McLachlan Beta-casein A1, ischemic heart disease mortality, and other illnesses Med.
Hypotheses, 56 (2001):262272.
3. Elliott RB. (1992) Epidemiology and Etiology of Insulin-Dependent Diabetes in the Young eds Levy-
Marchal C & Czernichow P, Vol 21, pp 66−71 Basel: Karger.
4. Fact sheet, Present status of A1-A2 Milks by Indian Dairy Association (Gujarat State Chapter)
published in Indian Dairymen, May 2017 issue; pp 126-127.
5. Ho S1, Woodford K2, Kukuljan S3, Pal S1. Eur J Clin Nutr. (2014) Comparative effects of A1 versus
A2 beta-casein on gastrointestinal measures: a blinded randomised cross-over pilot study. 68(9):994-
8. Ganguly, I., Gaur, G K., Singh, U., Kumar, S., Kumar S and Mann S. (2013) Beta-casein (CSN2)
polymorphism in Ongole (Indian zebu) and Frieswal (HF × Sahiwal crossbred) cattle Indian Journal of
Biotechnology 12:195-198.
9. Ganguly, I., Kumar, S., Gaur, G K., Singh, U., Kumar, A., Kumar, S., Mann and Sharma A. (2013)
Status of β-casein (CSN2) Polymorphism in Frieswal (HF X Sahiwal Crossbred) Cattle. International
Journal of Biotechnology and Bioengineering Research 4 (3):249-256
10. Jim Cross, LAc, ND (
11. Kamiński S1, Cieslińska A, Kostyra E (2007) Polymorphism of bovine beta-casein and its potential
effect on human health. Journal of Appllied Genetics 48(3):189-98.
12. Knowledge based series by Suruchi Consultants Think Dairy. How to improve milk productivity in
India to meet vision 2022 as per National Dairy Plan? Interestingly India will be celebrating its 75th
year of independence at that time
13. Lara Briden - healthy hormone blogs, February 20, 2013.
14. Laugesen M, Elliott R (2003) Ischaemic heart disease, Type 1 diabetes, and cow milk A1 beta-casein.
N Z Med J. 2003 Jan 24; 116(1168):U295.
15. M. Malarmathi, M. Malarmathi, T. M. A. Senthil Kumar A. Senthil Kumar, M. Parthiban, M.
Parthiban, T. Muthuramalingam and . Muthuramalingam and A. Palanisammi. A. Palanisammi (2014)
Analysis of ß-Casein Gene for A1 and A2 Genotype Using Allele Specific PCR in Kangeyam and
Holstein Friesian Crossbred Cattle in Tamil Nadu. Indian Journal of Veterinary & Animal Sciences
Research 43 (4) 310 315.
16. Milk the way it used to be -
17. Mishra, B.P., M. Mukesh., B. Praksh., M. Sodhi., R. Kapila and A. Kishore (2009) Status of milk
protein, ß-casein variants among India milch animals, Indian J. Animal Sciences, 79(7):722 - 725.
18. Olenski K, Kamin’ ski S, Szyda J, et al. Polymorphism of the beta-casein gene and its associations
with breeding value for production traits of HolsteinFriesian bulls. Livestock Science. 2010; 131:
19. Pattanayak S. (2013). Human health impact of bovine Beta-casomorphin-7 of milk a question for
milk products or our breeding policy ? Explor.Anim.Med.Res. 3(2): 93-94.
International Journal of Livestock Research eISSN : 2277-1964 NAAS Score -5.36
Vol 8 (4) Apr ’18 DOI 10.5455/ijlr.20170810113426
20. De, S., Paradkar,P and Vaidya A. (2nd September, 2015) Indian Breed Cow Milk - Powerhouse of
Health (
21. Swinburn B. (2004) Beta casein A1 and A2 in milk and human health Report to New Zealand Food
Safety Authority
22. Tailford KA, Berry CL, Thomas AC, Campbell JH. (2003)A casein variant in cow's milk is
23. Truswell, A.S. (2005), "The A2 milk case: a critical review", European Journal of Clinical Nutrition
59: 623631, doi:10.1038/sj.ejcn.1602104, retrieved 29 June 2014
24. Woodford, K. (2009). Illness, health and the politics of A1 and A2 Milk, In: Devil in the Milk, 1st
Edn, Chelsea Green Publishing, USA. pp 1-246. Forward by Tom Cowan
25. Woodford, Keith (2007) A2 Milk, Farmer Decisions, and Risk Management. Proceedings of the 16th
International Farm Management Association Congress, Peer Reviewed Papers Vol2:641-648.
26. Padberg S, Schumm-Draeger PM, Petzoldt R, Becker F, Federlin K. The significance of A1 and A2
antibodies against beta-casein in type-1 diabetes mellitus. Dtsch Med Wochenschr 1999; 124: 1518
27. Sodhi M., Mukesh M., Kataria R.S., Mishra B.P. and Joshi B.K. (2012) Indian J Endocrinol
Metab.16(5): 856.
28. Hills S (2009) European food safety authority also could not find any relationship between oral intake
of BCM-7 and etiology of such diseases. Newsletter- Food
... Both in vitro and in vivo studies have suggested the absorption and transport of BCM-7 across epithelial barrier of small intestine and its implication in different diseases, however, in the case of BCM-9, there are no studies suggesting the trans-epithelial movement. Genotypes with respect to A1/A2 allele of β-casein gene can be either of A2A2, A1A1 or A1A2 type with equal dominance of both the alleles in all the genotypes (Behera et al., 2018). ...
Background: Milk is essential part of diet across the globe and is a rich source of protein and calcium. Major protein component of milk is casein with beta-casein (β-casein) as the second most prevalent protein in cow milk. β-casein has 15 different genetic variants and of these A1 and A2 have gained research focus. All livestock as well as well human have proline at amino acid position 67 of β-casein, which is referred as A2 variant, but in cattle breeds, other genetic variant called A1 with histidine at amino acid position 67 is also present. This A1 type variant of â-casein or A1 type milk has been implicated as a potential etiological factor in several pathologies. Methods: The objective of the present study was to evaluate the A1and A2 β-casein variants of cow milk as factors affecting different hematological parameters and other parameters like glucose and insulin in streptozotocin (STZ)-induced diabetic C57/BL6 mice after the induction of diabetes. Diabetes was induced by injecting STZ intraperitoneally at dose of 45mg per kg of body weight for consecutive 5 days. Milk powder prepared from milk with A1A1 and A2A2 genotypes was used for feeding for three months. Result: After 3 months of feeding trial, it was observed that diabetic mice fed with A1A1 milk (STZ+A1A1) exhibited significantly elevated levels of glucose and insulin. Similarly, the levels of white blood cells, lymphocytes and neutrophils showed significant changes in STZ+A1A1 group compared to control and STZ+A2A2 group indicating the probable association A1A1 milk with inflammatory reaction. However, no significant changes were observed in parameters like red blood cells, hemoglobin, hematocrit or mean cell volume. In the mice group fed with A2A2 milk powder-based diet, no significant change was observed in the observed parameters except lymphocyte percentage which was lower compared to control group. In summary, our results show that A1 form of cow milk might have a proinflammatory effect.
... Milk is a highly evolved secretion of mammary glands of mammals [1].It serves as a complete nourishment as it contains nutrients such as proteins, fat and other essential micronutrients such as calcium, vitamin D, potassium, phosphorus which are required by the neonate animals and humans for their optimum growth and immunological protection [2,3].It contains 85% moisture and rest 15% is fat, protein, solid-not-fat(SNF), lactose and ash. The milk production in India has increased by three folds over the past 3 decades. ...
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Over the years milk has become an important part of our diets and is consumed by people of all ages ranging from infants to elderly. Numerous studies have been carried out to determine the benefits as well as the detrimental aspects of milk on human health. However, from the past few decades the focus of research has shifted towards the effect of consuming A1 milk. A1 milk is an allele of milk which is obtained from certain high yielding varieties of cows namely Holstein, Jersey and their hybrids. The amino acid sequencing of A1 milk established proline on the 67th position of amino acid while histidine at this position for the A2 milk. They further differ in the mode of digestion as A1 milk produces a μ-opioid BCM-7(betacasomorphin-7). In many studies, this BCM-7 production has been linked with various health problems such as ischemic heart disease, diabetes type-1, sudden infant death syndrome, and certain mental disorders i.e. autism, schizophrenia, etc. On the other hand, A2 milk has been suggested as an apt substitute to A1 milk. However, A2 milk has certain limitations as it is much more expensive in comparison to A1 milk owing to its lesser yield and production by some indigenous breeds only. Also, due to no reliable quick detection methods being currently available it leaves room for adulteration.
... A seven-amino peptide, β-casomorphin-7 (BCM 7) is released by digestion of A 1 milk whereas digestion of A 2 milk releases BCM-9 (Farrell et al. 2001). A correlation was observed between the prevalence of milk with A 1 β-casein proteins and various chronic diseases like Type 1 Diabetes, coronary heart disease (CHD) and, possibly, schizophrenia and autism in people with immune deficiencies (Elliott 1992(Elliott , 1999Truswell 2005, De Noni et al. 2009, Elsik et al. 2009, Lacroix and Li-Chan 2013, Ho et al. 2014, Jianqin et al. 2015, Chia et al. 2017, Duarte-Vázquez et al. 2017, Behera et al. 2018. ...
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Around 35% of the total caseins are β-caseins, which are further classified as A 1 β-caseins and A 2 β-caseins, based on differences in the amino acid composition of both. A 2 is the wild type genetic variant of β-casein while A1 is the mutant. The present study aimed at the isolation of A 1 and A 2 casein from different cow milk sources and its characterization by using simple chemical techniques, viz. FTIR and spectrofluorimetry. The commercial milk sample from Bos indicus (Gir) (A 2) was obtained from Bombay Panjrapole, Mumbai and two commercially available packaged cow milk samples (pasteurized, skimmed) namely from Gokul and Mother Dairy (A 1) were also obtained for comparison analysis from the local market. The isolation of casein was performed by standard method and analyzed using SDS-PAGE, FTIR and spectrofluorimetry. There was evidence that the A 2 milk lacked histidine and rich in aromatic amino acids like tryptophan using FTIR and spectrofluorimetry techniques.
... The A1 and A2 variants of beta casein differ at amino acid position 67 with histidine in A1 and proline in A2 milk as a result of single nucleotide difference [2]. Cows producing A1 milk are exotic cows (Taurine type) like Holstein, Friesian and Ayrshire whereas indigenous cows (Zebu type) like Gir, Red Sindhi and Sahiwal produce A2 milk [3]. Population consuming A2 milk are not prone to various diseases such as coronary heart diseases, Type -1 diabetes, sudden infant death syndrome and autism and had many health benefits such as better stool consistency and less incidence of bloating etc., [4] because it does not contain beta casomorphin-7 (BCM7), which is present in A1 milk due to its histidine position. ...
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Now-a-days almost all trending milk start-ups were following the principles and practices of age-old people. Indians were known to consume the desi milk since ages which is categorized as A2 milk. The concept of A2 milk has again trended when people started realizing the benefits of A2 milk, so market for A2 milk is also increasing rapidly. Around 10 A2 milk firms have emerged over the last 5 years in Hyderabad city, The study revealed that majority of the consumers are well educated, middle aged people having more than 8 lakhs annual income. Majority of the consumers were aware about A2 milk consumption increases brain function and A2 milk is a good measure for Type-I diabetes majorly through word-of-mouth and social media. Product quality, product attributes, health benefits, easy accessibility and word of mouth are the five factors which influencing the consumers to purchase A2 milk. Majority of the consumers were purchasing 3-7 litres/week of A2 milk on alternate day and depended upon home delivery for their regular purchase of A2 milk. Family size and annual income of the family had a significant association in determining the quantity of purchase of A2 milk.
... The A1 β-casein content of milk differs between breeds and herds of cows, such that milk produced by pure Asian or African breeds [40] (including Jersey and Guernsey [66]) are usually free from A1 β-casein (like A2M), unlike European breeds [40] including Holstein Friesian [66] (which are more like CON milk with both A1 and A2 β-casein). Although A2 gene frequency is higher in Jersey cows (more than 50%) [67] this may vary between herds [66]. Depending on the region, breed, or even the herd that milk is sourced from, these types of protein variability may impact the cut-off required for accurate diagnosis. ...
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Abstract Background Adult lactase non-persistence (LNP) is due to low lactase expression, resulting in lactose malabsorption (LM). LNP is a genetic trait, but is typically determined by LM markers including breath H2, blood glucose, and urinary galactose after a lactose tolerance test. Known validity of these markers using milk is limited, despite being common practice. Compositional variation, such as β-casein variants, in milk may impact diagnostic efficacy. This study aimed to evaluate the diagnostic accuracy to detect LNP using these commonly measured LM markers after both lactose and milk challenges. Methods Fourty healthy young women were challenged with 50 g lactose then randomized for separate cross-over visits to ingest 750 mL milk (37.5 g lactose) as conventional (both A1 and A2 β-casein) and A1 β-casein-free (a2 Milk™) milk. Blood, breath and urine were collected prior to and up to 3 h following each challenge. The presence of C/T13910 and G/A22018 polymorphisms, determined by restriction fragment length polymorphism, was used as the diagnostic reference for LNP. Results Genetic testing identified 14 out of 40 subjects as having LNP (C/C13910 and G/G22018). All three LM markers (breath H2, plasma glucose and urinary galactose/creatinine) discriminated between lactase persistence (LP) and LNP following lactose challenge with an area under the receiver operating characteristic (ROC) curve (AUC) of 1.00, 0.75 and 0.73, respectively. Plasma glucose and urinary galactose/creatinine were unreliable (AUC
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A balanced diet is a blend of quantity and quality of foods eaten to support an individual’s health and well-being. This narrative review aims to deliver a simplified version of the 2020 dietary guidelines by the Indian Council of Medical Research and the National Institute of Nutrition (ICMR-NIN). The review comprehensively analyses the latest ICMR-NIN 2020 dietary guidelines for healthy adults. The approach to achieving a balanced diet is focused on the inclusion of a plant-based diet with special significance placed on dietary fibre and antioxidants. The review presents the updated macronutrient and micronutrient requirements, with the spotlight has been on the types of food to be taken or the food-based approach. This review also highlights food groups and gut nutrition and provides dietary tips on wholesome meals to promote optimal health.
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Milk is the one of the most important protein diet to the human population. However, in last few decades, presence of A1 b casein in milk was associated with important issues associated with range of illnesses in human being. In this study a total of 85 cattle blood samples (Kangeyam and HF crossbred) were analysed for A1 b casein gene based on AS-PCR. A1/A2 genotype frequency data indicated that 37% were A2 homozygous (A2A2), 17% were A1 homozygous (A1A1) and 46% heterozygous (A1A2) in HF cross bred cattle. The pure Kangeyam (Bos indicus) cattle breed had only A2 gene and showed only A2A2 genotype, which produce safer A2 milk for the human consumption. The Holstein Friesian cross breed animal also showed mostly of A2 gene (0.595).
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Background/objectives: At present, there is debate about the gastrointestinal effects of A1-type beta-casein protein in cows' milk compared with the progenitor A2 type. In vitro and animal studies suggest that digestion of A1 but not A2 beta-casein affects gastrointestinal motility and inflammation through the release of beta-casomorphin-7. We aimed to evaluate differences in gastrointestinal effects in a human adult population between milk containing A1 versus A2 beta-casein. Subjects/methods: Forty-one females and males were recruited into this double-blinded, randomised 8-week cross-over study. Participants underwent a 2-week dairy washout (rice milk replaced dairy), followed by 2 weeks of milk (750 ml/day) that contained beta-casein of either A1 or A2 type before undergoing a second washout followed by a final 2 weeks of the alternative A1 or A2 type milk. Results: The A1 beta-casein milk led to significantly higher stool consistency values (Bristol Stool Scale) compared with the A2 beta-casein milk. There was also a significant positive association between abdominal pain and stool consistency on the A1 diet (r=0.520, P=0.001), but not the A2 diet (r=-0.13, P=0.43). The difference between these two correlations (0.52 versus -0.13) was highly significant (P<0.001). Furthermore, some individuals may be susceptible to A1 beta-casein, as evidenced by higher faecal calprotectin values and associated intolerance measures. Conclusions: These preliminary results suggest differences in gastrointestinal responses in some adult humans consuming milk containing beta-casein of either the A1 or the A2 beta-casein type, but require confirmation in a larger study of participants with perceived intolerance to ordinary A1 beta-casein-containing milk.
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Health of Beta Casomorphin- 7 of A 2 milk of cow is discussed in the article.
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The role of A1 and A2 beta casein milk variants and human health is a matter of concern for scientific investigations. The status of A1/A2 beta casein variants in Bos taurus cattle breeds from different countries have been shown presence of A1 variant in European cattle which has been linked to a range of illness. However, no data on beta casein A1/A2 frequency is available on diverse Indian cattle (Bos indicus) breeds. Also no report is available on river buffalo breeds which contribute more than 55 percent of total milk produced in the country. In this study we report the frequency of beta casein variants among 618 animals of 15 zebu cattle breeds and 231 buffaloes of 8 river buffalo breeds. The beta casein A1/A2 frequency data indicated the predominance of A2 variant (0.987) in zebu cattle breeds while the river buffalo indicated only A2 milk type. The results point towards the origin of A2 variant in Bos indicus cattle. This is the first report of A1/A2 milk variant majority of Indian zebu cattle and riverine buffalo breeds.
Beta-casein A1 protein variant might be one of the risk factors in the etiology of human disorders like diabetes and ischemic heart disease. However, from the practical perspective selecting for the A2 allele in dairy cattle requires knowledge of whether the A1/A2 polymorphism is associated with breeding values for production traits. A DNA fragment containing A1/A2 polymorphic region was amplified and genotyped using the PCR-ACRS (Amplification Created Restriction Site) technique in 478 Holstein–Friesian bulls yielding the allele frequencies of 0.35 and 0.65 for the A1 and the A2 variants, respectively. A linear regression model was used for testing the association between the polymorphism and breeding values for production traits and showed that the allele coding the A2 protein variant increases breeding values for milk and protein yield and decreases breeding values for fat percentage in milk. Genotyping A.I. bulls at beta-casein locus and preferring A2 allele may lead to two benefits: increasing breeding value for protein yield and decreasing frequency of A1 protein variant, being considered as risk factor for human health.
The hypothesis that cow's milk components may constitute environmental factors in the pathogenesis of insulin-dependent diabetes mellitus (IDDM) is increasingly gaining in importance. This study for the first time determined, in a family study, antibodies against the most common variants of the beta-casein (A1 and A2). A total of 1,257 sera--from 287 patients with IDDM, 386 siblings, 477 individual parents and 107 healthy controls--were tested by enzyme-linked immunosorbent assay (ELISA) for anti-beta casein A1- and A2-IgG antibodies. Antibodies against casein were present in all four groups, highest titres being found in diabetics. In all four groups there was an inverse correlation between A1 and A2 antibodies and age (p < 0.001). Increased amounts of anti-casein A1 antibodies were found among patients with IDDM and their siblings. On the other hand, the serum samples from parents and control persons contained antibodies against the A2 variant. The preferential binding of sera to the one or other casein variant was in all four groups statistically significant (p < 0.001). Because the A1 variant of beta-casein correlates with the onset of IDDM, but can also occur in normal controls, this may confirm the hypothesis of a defective oral immunotolerance to cow's milk antigens in IDDM.