Progress 10/01/08 to 09/30/10
Outputs
OUTPUTS: Consumers are increasingly aware that some foods components may have long term effects on health and the prevention of chronic diseases. Milk fat was the focus of this research project because it is often perceived to have negative health effects; however milk contains bioactive fatty acids (FA) shown to have potent anti-carcinogenic and anti-atherosclerotic properties, such as conjugated linoleic acid (CLA) and omega-3 FA. A major component of our project involved two national surveys of the fatty acid composition of milk. The first survey evaluated FA composition of retail milk collected from 56 major processing plants representing the 12 U.S. Milk Marketing Areas and the California Department of Food and Agriculture. The study design also allowed an evaluation of regional and seasonal differences. The retail dairy case often includes milk choices with specialty labels based on production practices. Our second survey examined differences among specialty labeled milks - specifically comparing unlabeled conventional milk with retail milk labeled as rbST-free or organic. For this purpose, matched retail milk samples differing only in label claim were collected throughout the U.S. Milk FA composition is highly affected by diet, thus our secondary focus for this project involved studies to naturally enhance CLA and omega-3 FA in milk fat through the use of dietary lipid supplements. Two of these studies utilized soybean oil or linseed and fish oil to enhance milk bioactive FA, with the inclusion of a high dose of dietary vitamin E to mitigate diet-induced milk fat depression caused by lipid supplementation. A third study utilized transgenic soybeans that had been genetically altered to have a high oil content of stearidonic acid (18:4 omega-3 FA), an acid which can be effectively utilized by cows and humans to synthesize the important long-chain omega-3 FA. Project events included the presentation of results as oral abstracts and posters at Annual Meetings of the American Dairy Science Association and presentations at Cornell Nutrition Conferences and the Canadian Western Nutrition Conference. Dissemination of results from the project also involved a Keynote address for the World Buiatrics Congress in Santiago, Chile, and other invitational presentations on the opportunities and challenges of enhancing the healthfulness of milk fat for international audiences in the U.S., Canada, and Mexico. Major products from the research were publications and conference proceedings that are listed elsewhere; these were designed to reach a broad audience including producers, nutritionists and scientists. Additional popular press articles about the project appeared in media publications such as Boston Globe, Eastern Dairy Business, Feedstuffs, Performance Nutrition, and Dairy Reporter, and at the World Buiatrics Congress we recorded interviews about the health benefits of milk and milk fat with Studio Bovine (available at www.studiobovine.com). PARTICIPANTS: D.M. Barbano, Department Food Science, Cornell University; J.L. Vicini, Monsanto Co., St Louis MO; G.F. Hartnell, Monsanto Co., St Louis MO; A.L. Lock, Department Animal Science, Michigan State University. TARGET AUDIENCES: Consumers, producers, extension staff, nutritionists. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Milk fatty acids (FA) are of special interest in human dietary considerations and this project evaluated the FA composition of U.S. retail milk and investigated the potential to naturally enhance bioactive FA in milk by using dietary supplements. We conducted two surveys to evaluate the FA composition of U.S. retail milk. The first used retail milk collected from processing plants across the contiguous 48 states. Relative to the last U.S. retail survey, conducted in 1984, improvements in analysis allowed us to provide FA values not previously characterized including CLA, trans-18:1 isomers and omega-3 FA. We found that milk FA composition was surprisingly consistent across all regions and seasons. Although there were statistical differences for some FA, without exception the differences were minor and of no public health relevance. The similarity in milk FA composition across regions and seasons indicates that increased use of total mixed diets, lipid supplements and by-product feeding in dairy production systems must be well established in all regions and in routine use across all seasons. Our second survey focused on milk with specialty labels based on production practices; this labeling is not well understood and often perceived by consumers to reflect differences in milk quality. We compared the FA composition of conventional milk containing no specialty labeling with retail milk samples labeled as rbST-free or organic. Milk labeled rbST-free was not different from conventional milk, but there were differences for milk labeled organic. Some of these differences could be considered desirable (CLA, omega-3) and some less desirable (saturated and trans FA), but without exception differences among conventional milk and milk labeled as rbST-free or organic were minor having little or no public health relevance. A relatively wide range in the milk fat content of CLA and omega-3 FA was observed in organic labeled milk, and this is most likely due to differences in diet and feeding management among organic producers. When findings from our survey of FA composition for specialty labeled US retail milk is combined with analyses of other milk variables, results indicated that all retail milk is similar in quality and nutritional value regardless of production management practices. Current intake of omega-3 FA is well below recommendations for the U.S. population. Supplements of stearidonic acid (SDA)-enhanced soybean oil (SBO) have the potential to increase the milk content of omega-3 fatty acids (FA) and our investigations were the first to examine this. Using genetically-modified soybeans, we demonstrated that abomasal infusion of SDA-enhanced SBO resulted in a 5-fold increase in the omega-3 FA content of milk fat. Relative to meeting the human dietary requirements, an increase in SDA has an advantage over alpha-linolenic acid because we can more efficiently convert SDA to very long chain omega-3 FA required by humans. Furthermore, when dietary consumption of dairy products is considered, the observed increases would allow dairy products to make an important contribution to meeting human dietary requirements for omega-3 FA.
Publications
- ODonnell-Megaro, A.M., Barbano, D.M., and Bauman, D.E. 2011. Survey of the fatty acid composition of retail milk in the United States including regional and seasonal variations. J. Dairy Sci. 93:(in press).
- Rice, B.H., Kraft, J., Destaillats, F., Bauman, D.E., and Lock, A.L. 2010. Ruminant-produced trans-fatty acids raise plasma total and small HDL particle concentrations in male Hartley guinea pigs. J. Nutr. 140:2173-2179.
- ODonnell, A.M., Spatny, U.P., Vicini, J.L. and Bauman, D.E. 2010. Survey of the fatty acid composition of retail milk differing in label claims based on production management practices. J. Dairy Sci. 93:1918-1925.
- Bauman, D.E. and Lock, A.L. 2010. Milk fatty acid composition: Challenges and opportunities related to human health. XXVI World Buiatrics Congress, pp. 278-289. Santiago, Chile.
- Bauman, D.E., Tyburczy, C., ODonnell, A.M., and Lock, A.L. 2011. Milk lipids: Conjugated linoleic acid (CLA). In: Encyclopedia of Dairy Science, 2nd Edition, J. Fuquay, H. Roginski, and P. Fox (Ed). Elsevier, Kidlington, UK. (in press).
- Bernal Santos, G., ODonnell, A.M., and Bauman, D.E. 2011. Functional food components in ruminant-derived foods. In: Encyclopedia of Animal Science, 2nd Edition, W.G. Pond and A.W. Bell, ed. Taylor and Francis, New York, NY. (in press).
- Bauman, D.E. and Lock, A.L. 2011. Conjugated linoleic acid. In: Encyclopedia of Animal Science, 2nd Edition, W.G. Pond and A.W. Bell, ed. Taylor and Francis, New York, NY. (in press).
- Lock, A.L., Givens, D.I., and Bauman, D.E. 2011. Dairy fat: Perceptions & realities. Chapter 6. In: Milk and Dairy Products as Functional Foods. (in press).
- Bauman, D.E., McGuire, M.A., and Harvatine, K.J. 2011. Milk biosynthesis and secretion: Milk fat. In: Encyclopedia of Dairy Science, 2nd Edition, J. Fuquay, H. Roginski, and P. Fox (Ed). Elsevier, Kidlington, UK. (in press).
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Milk contains bioactive fatty acids (FA) shown to have potent anti-carcinogenic and anti-atherosclerotic properties, such as conjugated linoleic acid (CLA) and omega-3 FA. One activity during this period involved two national surveys of the fatty acid composition of milk. The first survey evaluated FA composition of U.S. retail milk collected from 56 major processors representing the 12 milk marketing areas and the California Department of Food and Agriculture. These samples were collected throughout the year to allow evaluation of regional and seasonal differences. The second survey focused on retail specialty labeling based on production practices and examined differences among unlabeled conventional milk and milk labeled rbST-free or organic. For this purpose, matched retail milk samples differing only in label claim were collected throughout the U.S. Milk FA composition is highly affected by diet, thus our second activity was to naturally enhance CLA and omega-3 FA in milk fat through the use of dietary lipid supplements. This involved a series of three studies. The first two studies utilized soybean oil or linseed and fish oil to enhance milk bioactive FA, with the inclusion of a high dose of dietary vitamin E to mitigate diet-induced milk fat depression (MFD) caused by lipid supplementation. The third study utilized transgenic soybeans that produced an oil enhanced with stearidonic acid (18:4 omega-3 FA) and examined the effects on milk fat composition in lactating dairy cows. Events included the presentation of preliminary results in a series of oral abstracts and posters at the Annual Meetings of the American Dairy Science Association and at the Cornell Nutrition Conference. Dissemination of results involved major invitational presentations on the opportunities and challenges of enhancing the healthfulness of milk fat to national audiences in the U.S., Canada, and Mexico. PARTICIPANTS: Collaborators include Cornell graduate students and staff (A.M. ODonnell, C. Tyburzy, K.P. Spatny, J.C. Alishauskas, D.A. Dwyer, P. Lawrence, and J.M. Lynch), Cornell faculty (D.A. Barbano and J.T. Brenna). Scientists from other Universities (A.L. Lock, Michigan State University; A.M. Salter, University of Nottingham; G. Bernal-Santos, University of Queretaro) and industry (J.L. Vicini and G.F. Hartnell, Monsanto; F. Destaillats, Nestle) also made valuable contributions. TARGET AUDIENCES: Target audiences for these results will be producers and consumers. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The overall objective of this project is to evaluate current FA composition of retail milk in the U.S. and investigate the potential to naturally enhance and sustain bioactive FA in milk by using dietary supplements. The last national milk retail survey was conducted in 1984, and we conducted two separate surveys examining the FA composition of U.S. retail milk. The first consisted of conventionally produced milk collected from processing plants across the contiguous 48 states for the duration of one year. We found that milk FA composition was surprisingly consistent across all regions and seasons, although there were statistical differences of minor magnitude. Thus, the increased use of total mixed diets, lipid supplements and by-product feeding must be well established in all regions and in routine use across all seasons. Relative to 1984, the content of saturated, mono- and polyunsaturated FA were similar and improvements in analysis allowed us to provide a documentation of CLA, trans-18:1 and omega-3 FA. This updated report of the FA composition of U.S. retail milk may serve as a reference for estimating dietary intake of FA from dairy products. Our second survey focused on evaluating the FA composition of milk with specialty labels based on production practices. We compared conventional milk containing no specialty labeling with retail milk samples labeled as rbST-free or organic. Milk labeled rbST-free was not different from conventional milk, but there were differences for milk labeled organic. Some of these differences could be considered desirable (CLA, omega-3) and some less desirable (saturated and trans FA), but without exception differences among conventional milk, milk labeled as rbST-free or organic were minor having little or no public health relevance. A relatively wide range in the milk fat content of CLA and omega-3 FA was observed in organic labeled milk, and this is most likely due to differences in diet and feeding management among organic producers. Our survey was the first to analyze FA composition for specialty labeled US retail milk and when combined with analyses of other milk variables, results indicated that all retail milk is similar in quality and nutritional value regardless of production management practices. Current intake of omega-3 FA is well below recommendations for the U.S. population. Supplements of stearidonic acid (SDA)-enhanced soybean oil (SBO) have the potential to increase the milk content of omega-3 fatty acids (FA) and our investigation is the first to examine this. The source was genetically-modified soybeans and we demonstrated that abomasal infusion of SDA-enhanced SBO resulted in a 5-fold increase in the omega-3 fatty acid content of milk fat. Relative to meeting the human dietary requirements, an increase in SDA has an advantage over alpha-linolenic acid because we can more efficiently convert SDA to very long chain omega-3 FA required by humans. Furthermore, when dietary consumption of dairy products is considered, the observed increases would allow dairy products to make an important contribution to meeting human dietary requirements for omega-3 FA.
Publications
- Bauman, D.E. and Lock, A.L. 2008. Modifying animal fat to enhance animal and human health. Page 267 to 277 in Proc. 29th Western Nutrition Conference. Edmonton, Alberta Canada.
- Lock, A.L., Kraft, J., Rice, B., and Bauman, D.E. 2009. Biosynthesis and biological activity of rumenic acid: a natural CLA isomer. In F. Destaillats, J.-L. Sebedio, F. Dionisi, and J.-M. Chardigny (ed.), Trans Fatty Acid in Human Nutrition, Second Edition. The Oily Press. Bridgewater, UK, p. 195-230.
- Bernal-Santos, G., ODonnell, A.M., Vicini, J.L., Hartnell, G.F., and Bauman, D.E. 2009. Enhancing omega-3 fatty acids in milk fat of dairy cows by using stearidonic acid-enriched soybean oil from genetically modified soybeans. J. Dairy Science 93:32-37.
- ODonnell, A.M. and Bauman, D.E. 2009. An evaluation of milk fatty acid composition of whole fluid milk in the United States. Pages 20 - 216 in Proc. Cornell Nutrition Conference. Syracuse, NY.
- Lock, A.L., Kraft, J., ODonnell, A.M., and Bauman, D.E. 2009. Effect of farm production practices on ruminant-derived foods: fatty acid profile, product quality and human health outcomes. J. Dairy Science, 92(E-Suppl. 1): 535-536. (abstr.).
- ODonnell, A.M., Barbano, D.M., and Bauman, D.E. 2009. Milk fatty acid composition of whole fluid milk in the United States. J. Dairy Science, 92(E-Suppl. 1): 45. (abstr.).
- ODonnell, A.M., Spatny, K.P., Alishauskas, J.C., and Bauman, D.E. 2009. Effect of linolenic acid, fish oil and dietary vitamin E supplementation on sustained conjugated linoleic acid production in milk fat from dairy cows. J. Dairy Science, 92(E-Suppl. 1): 339. (abstr.).
- Tyburczy, C., Major, C., Lock, A.L., Destaillats, F., Lawrence, P., Brenna, J.T., Salter, A.M., and Bauman, D.E. 2009. Individual trans octadecenoic acids and partially hydrogenated vegetable oil differentially affect hepatic lipid and lipoprotein metabolism in Golden Syrian Hamsters. J. Nutrition, 139: 257-263.
- Bernal, G., ODonnell, A.M., Harvatine, K.J., Aguilera, A., and Bauman, D.E. 2009. Influence of fish oil on milk fat production in dairy cows. Pages 1 to 5 in VI Encuentro Participacion de la Mujer en la Ciencia. Mayo 13-15, 2009. Centro de Investigaciones en Optica, A.C. Leon, Guanajuato, Mexico.
- Kaylegian, K.E., Dwyer, D.A., Lynch, J.M., Bauman, D.E., Fleming, J.R., and Barbano, D.M. 2009. Impact of fatty acid composition on the accuracy of mid-infrared fat analysis of farm milks. J. Dairy Science, 92: 2502-2513.
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