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Ramakrishnan M, Mysore Saiprasad S, Savaiano DA. Prolonged Consumption of A2 β-Casein Milk Reduces Symptoms Compared to A1 and A2 β-Casein Milk in Lactose Maldigesters: A Two-Week Adaptation Study. Nutrients 2024; 16:1963. [PMID: 38931316 PMCID: PMC11206509 DOI: 10.3390/nu16121963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2024] [Revised: 06/08/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
Approximately 30% of milk protein is β-casein. We aimed to determine whether lactose maldigesters who chronically consumed two cups of A1/A2 milk (containing 75% A1 β-casein and 25% A2 β-casein) would adapt to have fewer intolerance symptoms, lower serum inflammatory markers, and/or altered glutathione levels similar to those consuming A2 milk (containing 100% A2 β-casein). A double-blinded, randomized, crossover trial was conducted. Sixteen confirmed lactose maldigesters consumed 250 mL of A1/A2 milk and A2 milk twice daily with meals for two weeks. At the end of the adaptation period on day 15, lactose maldigestion was measured after a challenge with the same milk used for adaptation (0.5 g of lactose per kg of body weight) with a hydrogen breath test. Fecal urgency was higher during the two-week consumption of A1/A2 milk compared to A2 milk (p = 0.04, n = 16). Bloating (p = 0.03, n = 16) and flatulence (p = 0.02, n = 16) were also higher on the 15th day with A1/A2 milk compared to A2 milk challenge. However, day-to-day symptoms, hydrogen, serum inflammatory markers, and antioxidant concentrations were not different after A1/A2 and A2 milk consumption adaptation periods. Adaptation over two weeks did not improve lactose digestion or tolerance of A1/A2 milk to match that of A2 milk.
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Affiliation(s)
- Monica Ramakrishnan
- Department of Nutrition Science, College of Health and Human Sciences, Purdue University, West Lafayette, IN 47907, USA; (S.M.S.); (D.A.S.)
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Sun Y, Ding Y, Liu B, Guo J, Su Y, Yang X, Man C, Zhang Y, Jiang Y. Recent advances in the bovine β-casein gene mutants on functional characteristics and nutritional health of dairy products: Status, challenges, and prospects. Food Chem 2024; 443:138510. [PMID: 38281416 DOI: 10.1016/j.foodchem.2024.138510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/04/2024] [Accepted: 01/17/2024] [Indexed: 01/30/2024]
Abstract
β-casein is the second most abundant form of casein in milk. Changes in amino acid sequence at specific positions in the primary structure of β-casein in milk will produce gene mutations that affect the physicochemical properties of dairy products and the hydrolysis site of digestive enzymes. The screening method of β-casein allele frequency detection in dairy products also has attracted the extensive attention of scientists and farmers. The A1 and A2 β-casein is the two usual mutation types, distinguished by histidine and proline at position 67 in the peptide chain. This paper summarizes the effects of A1 and A2 β-casein on the physicochemical properties of dairy products and evaluates the effects on human health, and the genotyping methods were also concluded. Impressively, this review presents possible future opportunities and challenges for the promising field of A2 β-casein, providing a valuable reference for the development of the functional dairy market.
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Affiliation(s)
- Yilin Sun
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Yixin Ding
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Biqi Liu
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Jinfeng Guo
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Yue Su
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Xinyan Yang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Chaoxin Man
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Yu Zhang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China.
| | - Yujun Jiang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China; Food Laboratory of Zhongyuan, Luohe, Henan 462300, China.
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Gard F, Flad LM, Weißer T, Ammer H, Deeg CA. Effects of A1 Milk, A2 Milk and the Opioid-like Peptide β-Casomorphin-7 on the Proliferation of Human Peripheral Blood Mononuclear Cells. Biomolecules 2024; 14:690. [PMID: 38927093 PMCID: PMC11201611 DOI: 10.3390/biom14060690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 06/05/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
Special attention is given to cow's milk and its variants, with ongoing discussions about health-related impacts primarily focusing on the A1 variant in contrast to the A2 variant. The difference between these variants lies in a single amino acid alteration at position 67 of β-casein. This alteration is presumed to make the A1 variant more susceptible to enzymatic breakdown during milk digestion, leading to an increased release of the peptide β-casomorphin-7 (BCM-7). BCM-7 is hypothesized to interact with µ-opioid receptors on immune cells in humans. Although BCM-7 has demonstrated both immunosuppressive and inflammatory effects, its direct impact on the immune system remains unclear. Thus, we examined the influence of A1 and A2 milk on Concanavalin A (ConA)-stimulated human peripheral blood mononuclear cells (PBMCs), as well as the effect of experimentally digested A1 and A2 milk, containing different amounts of free BCM-7 from β-casein cleavage. Additionally, we evaluated the effects of pure BCM-7 on the proliferation of ConA-stimulated PBMCs and purified CD4+ T cells. Milk fundamentally inhibited PBMC proliferation, independent of the β-casein variant. In contrast, experimentally digested milk of both variants and pure BCM-7 showed no influence on the proliferation of PBMCs or isolated CD4+ T cells. Our results indicate that milk exerts an anti-inflammatory effect on PBMCs, regardless of the A1 or A2 β-casein variant, which is nullified after in vitro digestion. Consequently, we deem BCM-7 unsuitable as a biomarker for food-induced inflammation.
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Affiliation(s)
- Felix Gard
- Chair of Animal Physiology, Department of Veterinary Sciences, Ludwig Maximilian University of Munich, D-82152 Martinsried, Germany
| | - Lili M. Flad
- Chair of Animal Physiology, Department of Veterinary Sciences, Ludwig Maximilian University of Munich, D-82152 Martinsried, Germany
| | - Tanja Weißer
- Chair of Animal Physiology, Department of Veterinary Sciences, Ludwig Maximilian University of Munich, D-82152 Martinsried, Germany
| | - Hermann Ammer
- Chair of Pharmacology, Toxicology and Pharmacy, Department of Veterinary Sciences, Ludwig Maximilian University of Munich, D-80539 Munich, Germany
| | - Cornelia A. Deeg
- Chair of Animal Physiology, Department of Veterinary Sciences, Ludwig Maximilian University of Munich, D-82152 Martinsried, Germany
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Bolat E, Eker F, Yılmaz S, Karav S, Oz E, Brennan C, Proestos C, Zeng M, Oz F. BCM-7: Opioid-like Peptide with Potential Role in Disease Mechanisms. Molecules 2024; 29:2161. [PMID: 38731652 PMCID: PMC11085506 DOI: 10.3390/molecules29092161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 04/25/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
Bovine milk is an essential supplement due to its rich energy- and nutrient-rich qualities. Caseins constitute the vast majority of the proteins in milk. Among these, β-casein comprises around 37% of all caseins, and it is an important type of casein with several different variants. The A1 and A2 variants of β-casein are the most researched genotypes due to the changes in their composition. It is accepted that the A2 variant is ancestral, while a point mutation in the 67th amino acid created the A1 variant. The digestion derived of both A1 and A2 milk is BCM-7. Digestion of A2 milk in the human intestine also forms BCM-9 peptide molecule. The opioid-like characteristics of BCM-7 are highlighted for their potential triggering effect on several diseases. Most research has been focused on gastrointestinal-related diseases; however other metabolic and nervous system-based diseases are also potentially triggered. By manipulating the mechanisms of these diseases, BCM-7 can induce certain situations, such as conformational changes, reduction in protein activity, and the creation of undesired activity in the biological system. Furthermore, the genotype of casein can also play a role in bone health, such as altering fracture rates, and calcium contents can change the characteristics of dietary products. The context between opioid molecules and BCM-7 points to a potential triggering mechanism for the central nervous system and other metabolic diseases discussed.
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Affiliation(s)
- Ecem Bolat
- Department of Molecular Biology and Genetics, Çanakkale Onsekiz Mart University, Çanakkale 17100, Türkiye; (E.B.); (F.E.); (S.Y.)
| | - Furkan Eker
- Department of Molecular Biology and Genetics, Çanakkale Onsekiz Mart University, Çanakkale 17100, Türkiye; (E.B.); (F.E.); (S.Y.)
| | - Selin Yılmaz
- Department of Molecular Biology and Genetics, Çanakkale Onsekiz Mart University, Çanakkale 17100, Türkiye; (E.B.); (F.E.); (S.Y.)
| | - Sercan Karav
- Department of Molecular Biology and Genetics, Çanakkale Onsekiz Mart University, Çanakkale 17100, Türkiye; (E.B.); (F.E.); (S.Y.)
| | - Emel Oz
- Department of Food Engineering, Faculty of Agriculture, Atatürk University, Erzurum 25030, Türkiye; (E.O.); (F.O.)
| | - Charles Brennan
- School of Science, RMIT University, Melbourne, VIC 3001, Australia;
| | - Charalampos Proestos
- Laboratory of Food Chemistry, Department of Chemistry, School of Sciences, National and Kapodistrian University of Athens Zografou, 157 84 Athens, Greece;
| | - Maomao Zeng
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China;
| | - Fatih Oz
- Department of Food Engineering, Faculty of Agriculture, Atatürk University, Erzurum 25030, Türkiye; (E.O.); (F.O.)
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Dantas A, Pierezan MD, Camelo-Silva C, Zanetti V, Pimentel TC, da Cruz AG, Verruck S. A discussion on A1-free milk: Nuances and comments beyond implications to the health. ADVANCES IN FOOD AND NUTRITION RESEARCH 2024; 110:197-241. [PMID: 38906587 DOI: 10.1016/bs.afnr.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/23/2024]
Abstract
This chapter provides an overarching view of the multifaceted aspects of milk β-casein, focusing on its genetic variants A1 and A2. The work examines the current landscape of A1-free milk versus regular milk, delving into health considerations, protein detection methods, technological impacts on dairy production, non-bovine protein, and potential avenues for future research. Firstly, it discussed ongoing debates surrounding categorizing milk based on A1 and A2 β-casein variants, highlighting challenges in establishing clear regulatory standards and quality control methods. The chapter also addressed the molecular distinction between A1 and A2 variants at position 67 of the amino acid chain. This trait affects protein conformation, casein micelle properties, and enzymatic susceptibility. Variations in β-casein across animal species are acknowledged, casting doubt on non-bovine claims of "A2-like" milk due to terminology and genetic differences. Lastly, this work explores the burgeoning field of biotechnology in milk production.
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Affiliation(s)
- Adriana Dantas
- Food Quality and Technology, Institute of Agrifood Research and Technology (IRTA), Finca Camps i Armet, Monells, Girona, Spain
| | - Milena Dutra Pierezan
- Department of Food Science and Technology, Agricultural Sciences Center, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Callebe Camelo-Silva
- Department of Food Chemistry and Engineering, Technological Center, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Vanessa Zanetti
- Food Quality and Technology, Institute of Agrifood Research and Technology (IRTA), Finca Camps i Armet, Monells, Girona, Spain
| | | | - Adriano Gomes da Cruz
- Department of Food, Federal Institute of Education, Science and Technology of Rio de Janeiro (IFRJ), Rio de Janeiro, Rio de Janeiro, Brazil
| | - Silvani Verruck
- Department of Food Science and Technology, Agricultural Sciences Center, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil.
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