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| Yak Milk From Nepal Found To Produce Heart-healthy Cheese |
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| Living - Food & Fitness | |||
| TS-Si News Service | |||
| Friday, 21 March 2008 17:00 | |||
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Yak cheese has only recently become available in the United States and is available in select gourmet food stores. Studies by others have shown that certain types of dairy-derived fatty acids, particularly conjugated linoleic acid (CLA), may help fight heart disease, cancer and even diabetes.
Fatty Acid Composition of yak (Bos grunniens) Cheese Including Conjugated Linoleic Acid and trans-18:1 Fatty Acids. Mamun M. Or-Rashid, Nicholas E. Odongo, Bhishma Subedi, Pralhad Karki, and Brian W. McBride. J. Agric. Food Chem., 56 (5), 1654–1660, 2008. 10.1021/jf0725225. Previous evidence has linked an increased omega-3 to omega-6 intake ratio to improved health. The higher ratio of omega-3 to omega-6 fatty acids found in yak's cheese would mean it could be "classified as a healthy food in human diets" by several counries.
Little has been known about the fatty acid composition of yak cheese. "Our results suggest that cheese from yak, grazed on Himalayan alpine pastures, might have a more healthful fatty acid composition compared to cheese manufactured from dairy cattle fed grain-based diets," wrote lead author Mamun Or-Rashid. Photos courtesy of the National Oceanic and Atmospheric Administration (NOAA).
In the new study, Brian W. McBride and colleagues compared the fatty acid composition of yak cheese from Nepal with that of cheddar cheese obtained from Canada. The yak cheese from Nepal was found to contain more polyunsaturated fatty acids (PUFAs).
Nepalese yak cheese had four times the conjugated linoleic acid (CLA) than Canadian cheddar cheese made from cow's milk (0.87 versus 0.2, respectively). CLA are found predominantly in dairy products such as milk, cheese and meat, and are formed by bacteria in ruminants that take linoleic acids — fatty acids from plants — and convert them into CLA. Specific data on the comparative health benefits of the acids has increased in recent years, with studies indicating potential benefits for weight management, bone health and possibly even cancer.
"Eicosapentaenoic acid (C20:5n3, [EPA]) and docosahexaenoic (C22:6n3, [DHA]) were also present in a higher percentage of total FA in yak's cheese than in dairy cattle cheese, and both come from alpha-linolenic acid metabolism in animal tissues." Moreover, the content of CLA (cis-9, trans-11 CLA) and in the cheese from yak's milk was 4.2 times higher than that observed in the dairy cow cheddar.
"On the basis of animal trial data extrapolation, 100 g of yak cheese in the human diet might be enough to supply the necessary amounts of cis-9, trans-11 CLA and trans-11 C18:1 to promote health," wrote the researchers.
Yak cheese is made from the milk of the long-haired humped animals native to Tibet and the Himalayan region of south central Asia. It is already commercially available, but has so far remained a delicacy, commanding high prices in the West.
Fatty Acid Composition of yak (Bos grunniens) Cheese Including Conjugated Linoleic Acid and trans-18:1 Fatty Acids. Mamun M. Or-Rashid, Nicholas E. Odongo, Bhishma Subedi, Pralhad Karki, and Brian W. McBride. J. Agric. Food Chem., 56 (5), 1654–1660, 2008. 10.1021/jf0725225. Abstract. The esterified fatty acid composition of cheese (YC) from yak (Bos grunniens), reared in the highlands of the Nepalese Himalayas, was studied using capillary gas–liquid chromatography and compared with that of dairy cow Cheddar cheese (DC) purchased in a local market. The YC was collected from Dolakha, Nepal. The YC had a lower (P < 0.001) myristic acid (C14:0; 6.7 vs 10.3%, YC vs DC, respectively) and palmitic acid content (C16:0; 23.3 vs 29.2%, YC vs DC, respectively) compared to DC. The YC had a lower (P < 0.01) total medium-chain saturated fatty acids (C10:0−C16:0) content compared to DC (36.7 vs 47.3%, YC vs DC, respectively). On the other hand, the YC had a 24.8% higher (P < 0.01) level of total long-chain saturated fatty acids (C17:0−C26:0) and a 3.2 times higher (P < 0.001) content of total n-3 PUFA than DC. The ratio of n-3 PUFA to n-6 PUFA in YC was 0.87 compared to 0.20 in DC. YC had a 2.8 times higher (P < 0.001) total trans-18:1 (9.18 vs 3.31%, YC vs DC, respectively) content. The percentage of vaccenic acid (trans-11-C18:1) in YC was 4.6 times higher (6.23 vs 1.35% of total fatty acids, YC vs DC, respectively) than in DC. Vaccenic acid constituted 67.9% of total trans-C18:1 in YC. The Δ9-desaturase index for YC was lower than that of DC. The total conjugated linoleic acid (CLA) content in YC was 2.3% of total fatty acids compared to 0.57% in DC. The cis-9, trans-11 CLA isomer in YC constituted 88.5% of the total CLA. The results suggest that cheese from yak, grazed on Himalayan alpine pastures, may have a more healthful fatty acid composition compared to cheese manufactured from dairy cattle fed grain-based diets.
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| Last Updated on Friday, 21 March 2008 17:36 |






Little has been known about the fatty acid composition of yak cheese. "Our results suggest that cheese from yak, grazed on Himalayan alpine pastures, might have a more healthful fatty acid composition compared to cheese manufactured from dairy cattle fed grain-based diets," wrote lead author Mamun Or-Rashid.
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The TS-Si News Service is a collaboration of TS-Si staff, contributors, and corresponding institutions. Contents do not necessarily convey official positions of TS-Si, its partners, or affiliates