DIGESTIBILITY: SHEEP’S MILK IS NATURALLY EASIER TO DIGEST
Proteins
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Proteins in sheep’s milk are very different to those in cow’s milk, in both structure and composition.
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There are two types of protein in milk: whey and casein:
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The whey proteins are a soluble, easily digested form of protein and sheep’s milk is three times higher in this form of protein than cow’s or goat’s milk, making the whole milk easier to digest.
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The Casein proteins are 3 different fractions: Alpha, Beta and Kappa.
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There are two types of Beta-casein protein found naturally occurring in cow milk – A1 and A2. The A1 type is largely attributed to be the cause of common digestive issues (bloating, cramps, gassiness) in humans, which can be mistaken for lactose intolerance.
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Sheep’s milk is purely A2-type protein which is more easily digested and free from the A1 beta-casein protein found in cow’s milk and, to a lesser extent, goat’s milk, and associated with digestive discomfort.
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Recent but limited randomised control trials suggest that in some individuals, A1 milk causes symptoms of digestive discomfort which can potentially be confused with a lactose intolerance.
References:
Brooke-Taylor, S., Dwyer, K., Woodford, K., & Kost, N. (2017). Systematic Review of the Gastrointestinal Effects of A1 Compared with A2 β-Casein. Advances in nutrition (Bethesda, Md.), 8(5), 739–748. https://doi.org/10.3945/an.116.013953
He, M., Sun, J., Jiang, Z. Q., & Yang, Y. X. (2017). Effects of cow's milk beta-casein variants on symptoms of milk intolerance in Chinese adults: a multicentre, randomised controlled study. Nutrition journal, 16(1), 72. https://doi.org/10.1186/s12937-017-0275-0
S Ho, Woodford K et al., (2014). Comparative effects of A1 versus A2 beta-casein on gastrointestinal measure: a blindfolded randomised cross-over pilot study. European Journal of Clinical Nutrition volume 68, pages 994-1000
Daniela Küllenberg de Gaudry, Szimonetta Lohner, Christine Schmucker et al., (2019) Milk A1 β-casein and health-related outcomes in humans: a systematic review, Nutrition Reviews, Volume 77, Issue 5, Pages 278–306 https://doi.org/10.1093/nutrit/nuy063
Fats
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Fat is an essential part of a healthy, balanced diet. Fat is a source of essential fatty acids, which the body cannot make itself as well as vitamin A, D, E and K.
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Sheep’s milk is lower in saturated fats compared to other dairy milks. 45 % of the fatty acids in sheep milk are heart-healthy mono or poly-unsaturated fats, including Omega 3.
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Omega 3 fats reduce risk of heart disease and have a vital anti-inflammatory role within the body. They are also needed for a strong immune system and to maintain normal brain function.
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Sheep’s milk has a favourable fat profile as it contains short- and medium-chain fatty acids which are an extremely important part of a healthy human diet (5 below). These enables the fat to be evenly distributed throughout the milk, which naturally aids digestion. This natural homogenisation also increases lactose absorption; of benefit for those who are lactose intolerant.
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These medium chain fatty acids also play a role in effective weight control by promoting satiety (feeling fuller for longer), reducing fat deposits and increasing energy as they’re easier to metabolise (turn into energy in the body).
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Medium chain fatty acids are unique because they do not follow the normal digestive route through the lymph system, instead they are transferred directly from the intestine into the blood system. Thus, they constitute a rapid energy supply for the body. Owing to this pathway, they may contribute to lower total circulating cholesterol, especially ‘bad’ LDL cholesterol (2 below).
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Mono and polyunsaturated fatty acids in sheep milk may contribute to the prevention of cardiovascular diseases due to the atherogenic and thrombogenic (anti-clotting) properties (3 below).
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Among ruminants, sheep’s milk fat contains one of the highest levels of conjugated linoleic acid (CLA). Studies have shown the beneficial functional value of CLA as anticarcinogenic (anti-cancer) and weight loss effects.
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Studies have also shown that CLA exhibits beneficial outcomes in the occurrence of type 2 diabetes and Alzheimer’s disease.
References:
1. Molica et al., 2021. Milk Fatty Acid Profiles in Different Animal Species: Focus on the Potential Effect of Selected PUFAs on Metabolism and Brain Functions
2. Raynal-Ljutovac K, Lagriffoul G, Paccard P, Guillet I, Chilliard Y. 2008. Composition of goat and sheep milk products: an update. Small Rum Res 79:57–72.
3. Balthazar, C. Pimentel, T. Ferrao C, et al (2016). Sheep Milk: Physicochemical Characteristics and Relevance for Functional Food Development. doi: 10.1111/1541-4337.12250
4. Park YW, Pariza MW. (2007). Mechanisms of body fat modulation by conjugated linoleic acid (CLA). Food Res Int 40:311–23.
5. Sinanoglou V.J., Koutsouli P., Fotakis C., Sotiropoulou G., Cavouras D., Bizelis I. Assessment of Lactation Stage and Breed Effect on Sheep Milk Fatty Acid Profile and Lipid Quality Indices. Dairy Sci. Technol. 2015;95:509–531. doi: 10.1007/s13594-015-0234-5
6. Revilla I., Escuredo O., González-Martín M.I., Palacios C. Fatty Acids and Fat-Soluble Vitamins in Ewe’s Milk Predicted by near Infrared Reflectance Spectroscopy. Determination of Seasonality. Food Chem. 2017;214:468–477. doi: 10.1016/j.foodchem.2016.07.078
7. Flis, Z., & Molik, E. (2021). Importance of Bioactive Substances in Sheep's Milk in Human Health. International journal of molecular sciences, 22(9), 4364. https://doi.org/10.3390/ijms22094364
8. Savoini G., Farina G., Dell’Orto V., Cattaneo D (2016;). Through Ruminant Nutrition to Human Health: Role of Fatty Acids. Adv. Anim. Biosci. 7:200–207. doi: 10.1017/S2040470016000133.
9. Zervas G., Tsiplakou E (2011). Effect of Feeding Systems on the Characteristics of Products from Small Ruminants. Small Rumin. Res. 2011;101:104–149. doi: 10.1016/j.smallrumres.2011.09.034.
10. J.M. Jandal (1996) Comparative aspects of goat and sheep milk. Small Ruminant Research 22 (1996) 177-18
Lactose
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Lactose intolerance is a life-long, reduced ability to digest this natural sugar in milk, due to lacking the gene for the enzyme Lactase. Currently about 10% of our UK population are diagnosed as lactose intolerant. Cow’s Milk Allergy on the other hand, is an immune reaction to the protein in milk. It is uncommon but serious, occurring mostly in young children who often grow out of it.
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Some people can experience discomfort after drinking cow’s milk and often assume this is lactose intolerance. However, recent but limited randomised control trials suggest that in some individuals, it’s the A1-type protein in cow’s milk that causes symptoms of digestive discomfort which could potentially be confused with a lactose intolerance.
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Sheep’s milk is naturally an A2-type protein which is why it can be tolerated and enjoyed by those who suffer with an inability to digest the A1-type protein.
References:
Brooke-Taylor, S., Dwyer, K., Woodford, K., & Kost, N. (2017). Systematic Review of the Gastrointestinal Effects of A1 Compared with A2 β-Casein. Advances in nutrition (Bethesda, Md.), 8(5), 739–748. https://doi.org/10.3945/an.116.013953
Szilagyi, A., & Ishayek, N. (2018). Lactose Intolerance, Dairy Avoidance, and Treatment Options. Nutrients, 10(12), 1994. https://doi.org/10.3390/nu10121994
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