The Enrichment of Milk Fat with Fatty Acids of Importance in Human Health Maintenance and Disease Prevention

THE ENRICHMENT OF MILK FAT WITH FATTY ACIDS OF IMPORTANCE IN HUMAN HEALTH MAINTENANCE AND DISEASE PREVENTION

Sponsoring Institution

National Institute of Food and Agriculture

Project Status

TERMINATED

Funding Source

HATCH

Reporting Frequency

Annual

Accession No.

0201691

Grant No.

(N/A)

Project No.

NYC-127437

Proposal No.

(N/A)

Multistate No.

(N/A)

Program Code

(N/A)

Project Start Date

Oct 1, 2004

Project End Date

Sep 30, 2008

Grant Year

(N/A)

Project Director
Bauman, D. E.

Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853

Performing Department
ANIMAL SCIENCE

Non Technical Summary
Milk fat contains key fatty acids that are beneficial for health maintenance and disease prevention. Our goal is to develop methods for sustainable production of milk fat with a naturally enhanced content of omega-3 fatty acids, vaccenic acid and conjugated linoleic acid, fatty acids which have been shown to help prevent cancer and heart disease in biomedical studies with animal models.

Animal Health Component

(N/A)

Research Effort Categories

Basic

40%

Applied

60%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
308	3410	1010	50%
502	3450	1010	50%

Knowledge Area
308 - Improved Animal Products (Before Harvest); 502 - New and Improved Food Products;

Subject Of Investigation
3450 - Milk; 3410 - Dairy cattle, live animal;

Field Of Science
1010 - Nutrition and metabolism;

Goals / Objectives
There is increasing consumer awareness that diet can affect health status and an increasing scientific commitment to identify micro components in foods that may be beneficial to human health. The recent National Academy of Sciences Report titled Frontiers in Agricultural Research: Food, Health, Environment, and Communities highlighted this area as one of the five 'frontiers in agriculture research.' Key fatty acids shown to be beneficial to human health and health maintenance include conjugated linoleic acids (CLA), vaccenic acid (VA), and the omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The overall objective of this project is to understand the biology of the dairy cow related to these fatty acids and produce milk with an enhanced content of these fatty acids. Specific objectives are two fold. First, to focus on rumen biohydrogenation of these fatty acids including the extent of biohydrogenation, methods to protect dietary supplements from biohydrogenation, and effects on the production of unique biologically active biohydrogenation intermediates. Second, to focus on application including field studies to evaluate sustainability and effectiveness of the alterations in the fatty acid composition of milk and assessments of milk quality characteristics and consumer acceptance.

Project Methods
The proposed research has an applied focus and the goal of enhancing beneficial fatty acids in milk fat. Our approach has two phases or dimensions. Phase I will focus on rumen biohydrogenation and have several complimentary aspects that include: i) Evaluation of the extent of biohydrogentation of omega-3 fatty acids in the rumen; if extensive then methods of rumen protection dietary supplements of these fatty acids will be developed with industry collaborators. ii) Examine the impact of EPA and DHA on 18:2 and 18:3 biohydrogenation. iii) Examine the effects of altered rumen biohydrogenation on the formation of unique intermediates and their effect on milk fat synthesis. Specific procedures used to conduct these investigations are ones in which we have previous experience. They include in vitro cultures with rumen fluid and in vivo investigations where we supply fatty acids to the rumen or bypass the rumen with abomasal infusions. The analytical methodology is of special importance and depending on the specific needs our analysis of the fatty acids would include gas chromatography, high-pressure liquid chromatography, and/or GC-MS. Based on preliminary experiments, our hypothesis is that rumen biohydrogenation of dietary supplements of EPA and DHA will be extensive, but with rumen-protection technology we can formulate dietary supplements that will minimize the metabolism of these fatty acids by rumen bacteria and allow for a marked increase in milk fat content of EPA and DHA. Our hypothesis is also that under certain dietary situations unique fatty acids are produced during rumen biohydrogenation, some of which inhibit milk fat synthesis. We have established trans-10, cis-12 CLA is one such intermediate (16,17), but in preliminary studies we have noted correlated changes in other cis/trans CLA isomers including trans-10, trans-12, trans -9, trans -11 CLA, trans-9, cis-11 CLA and cis-10, trans-12 CLA, and we plan to follow up on these. These unique CLA isomers are not commercially available so we will be required to synthesize them, and we have experience in this as well. Phase II will focus on application of the results. This will involve long-term field studies on a commercial dairy farm to evaluate sustainability and effectiveness of the enhancement of specific milk fatty acids that are functional food components. The particular feed ingredients and diet formulation that will be used will be based on the results and knowledge gained from Phase I as well as our previous experience (16,17,20). An additional aspect of this focus will be an assessment of milk quality characteristics and consumer acceptance. Again, we have experience in the specific procedures and the required collaborations for the approaches required for Phase II are already established.

Progress 10/01/04 to 09/30/08

Outputs
OUTPUTS: Milk contains several fatty acids that are of potent benefit for health maintenance and disease prevention. Of special importance are the long chain omega-3 fatty acids (EPA and DHA), conjugated linoleic acids (CLA) and vaccenic acid (VA). We found there was extensive rumen biohydrogenation of EPA and DHA when they were supplied by fish oil supplements, and they were biohydrogenated to a similar extent even when supplied as Ca-salts. Thus, better protection methods are needed to allow long-chain omega-3 fatty acids to bypass rumen biohydrogenation. In the case of VA and CLA, we demonstrated that diet was a major factor affecting the milk fat content of these biohydrogenation intermediates. However, there was also a genetic component based on the 3-fold variation in VA and CLA content of milk fat that was observed among individuals. With typical Northeastern dairy diets, it is difficult to sustain a rumen environment that leads to increased milk fat VA and CLA, and this continues to be a research focus. In terms of dairy products, we demonstrated that milk enriched in VA and CLA was not different from standard milk in terms of sensory tests or susceptibility to the development of oxidative off-flavors. The anti-cancer effects of CLA and VA have been well-established in biomedical studies with animal models. However, implications in cardiovascular disease (CVD) were of interest because both CLA and VA are trans fatty acids (TFA), and TFA have been implicated as risk factors in CVD. Our initial studies used hamsters as the animal model and showed that in contrast to industrial sources of TFA, butter oil naturally enriched in VA and CLA had no negative effects on biomarkers of CVD risk. We then participated in the TRANSFACT study, an international collaboration that extended these results in a human clinical study, and again results provided no evidence that natural sources of TFA (milk fat) are risk factors for CVD. Overall, results from our investigations provide additional insight of the functional food role of milk fat and demonstrate the potential that conjugated linoleic acid and vaccenic acid may be beneficial in health maintenance and the prevention of chronic diseases. PARTICIPANTS: ODonnell, A.M., (PhD Graduate Program), Department of Animal Science, Cornell University, Ithaca, NY. Tyburczy, C., (MS Graduate Program), Department of Animal Science, Cornell University, Ithaca, NY. Barbano, D.M., Department of Food Science, Cornell University, Ithaca, NY. Overton, T., Department of Animal Science, Cornell University, Ithaca, NY. Chardigny, J.-M., National Institute de Recherche Agronomique, Clermont-Ferrand, France. Destaillats, F., Nestle Research Center, Lausanne, Switzerland. Dionisi,F., Nestle Research Center, Lausanne, Switzerland. Malpuech-Brugere, C., University of Clermont, UMR 1019, Clermont-Ferrand, France. Sebedio, J.-L., National Institute de Recherche Agronomique, Clermont-Ferrand, France. Bezelgues, J.-B., Nestle Research Center, Lausanne, Switzerland. German, J.B., Department of Food Science and Technology, University of California, Davis, Davis, CA. Combe, N., Department of Nutrition Institut des Corps Gras, Bordeaux I University, France. Mensink, R.P., Department of Human Biology Maastricht University, Maastricht, Netherlands. Salter, A.M., Division of Nutritional Sciences, University of Nottingham, Leicestershire, UK. Major, C.A., Division of Nutritional Sciences, University of Nottingham, Leicestershire, UK. Carey, G.B., Department of Animal & Nutritional Sciences, University of New Hampshire, Durham, NH. Moutsioulis, A.A., Department of Animal & Nutritional Sciences, University of New Hampshire, Dunham, NH. Rule, D.C., Department of Animal Sciences, University of Wyoming, Laramie, WY. TARGET AUDIENCES: Results relate to those who produce dairy products and those who consume dairy products and other ruminant-derived foods. Therefore, target audience includes dairy producers, nutrition educators, dieticians, and consumers. PROJECT MODIFICATIONS: None. Project Completed.

Impacts
There is increasing consumer awareness that diet can affect health status and prevent chronic diseases. Milk fat contains fatty acids that have been implicated as functional food components which promote health maintenance and these include very long-chain omega-3 fatty acids, conjugated linoleic acid (CLA) and vaccenic acid (VA). This project has identified nutritional and physiological factors that affect the content of these fatty acids in milk fat. We have also demonstrated that CLA and VA are anti-carcinogenic and anti-atherogenic in biomedical studies with animal models. CLA and VA are both trans fatty acids (TFA) so potential risk for cardiovascular disease (CVD) is an important consideration. To evaluate this we participated in the TRANSFACT study, a worldwide initiative to compare industrial sources of TFA (partially hydrogenated vegetable oil) and natural sources of TFA (milk fat). Results demonstrated that the TFA found in dairy products had no impact on CVD risk. Overall, results provide further evidence that dairy products enriched in CLA and VA offer exciting possibilities as functional foods that aid in health maintenance.

Publications

Chardigny, J.-M., Destaillats, F., Malpuech-Brugere, C., Moulin, J., Bauman, D.E., Lock, A.L., Barbano, D.M., Mensink, R.P., Bezelgues, J.-B., Chaumont, P., Combe, N., Cristiani, I., Joffre, F., German, J.B., Dionisi, F., Boirie, Y., and Sebedio, J.-L. 2008. Do industrially-produced and natural trans fatty acid sources have the same impact on cardiovascular diseases risk in healthy subjects Am. J. Clin. Nutr. 87:558-566.
Destaillats, F., Chardigny, J.-M., Malpuech-Brugere, C., Bauman, D.E., Sebedio, J.-L., Bezelgues, J.-B., and Dionisi, F. 2008. Unraveling the complexity of health effects of trans fatty acids: Insight from the TRANSFACT study. Lipid Techn. 20:129-131.
Moutsioulis, A.A., Rule, D.C., Murrieta, C.M., Bauman, D.E., Lock, A.L., Barbano, D., and Carey, G.B. 2008. Human breast milk is enriched in conjugated linoleic acid (CLA) after consumption of a CLA-rich food product. Nutr. Res. 437-442.
ODonnell, A.M., Capper, J.L., Overton, T.R., and Bauman, D.E. 2008. Effect of dietary vitamin E, plant oil and fish oil supplements on milk fat yield and CLA content in dairy cows. Cornell Nutr. Conf. pp. 147-155.
Bauman, D.E. and Lock, A.L. 2008. Modifying animal fat to enhance animal and human health. Proc. 19th Western Nutrition Conf. pp. 265-277. Edmonton, Alberta, CA.
ODonnell, A.M., Mittelman, N.S., Capper, J.L., and Bauman, D.E. 2008. Effect of linoleic acid and dietary vitamin E supplementation on sustained conjugated linoleic acid production in milk fat from dairy cows. J. Dairy Sci. 91(Suppl. 1):120.
Bauman, D.E. and A.L. 2008. Milk fat and risk of cardiovascular disease. J. Dairy Sci. 91(E-Suppl. 1):522.
Tyburczy, C., Lock, A.L., Dwyer, D.A., Destaillats, F., Mouloungui, Z., Candy, L., and Bauman, D.E. 2008. Uptake and utilization of trans octadecenoic acids in lactating dairy cows. J. Dairy Sci. (in press).

Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: Our goal is to identify bioactive fatty acids in milk fat that impact health and enrich milk fat with those fatty acids that have beneficial effects on disease prevention. One milk fatty acid with human health benefits is conjugated linoleic acid (CLA). Dairy products are the main dietary source and we have shown that the major isomer is cis-9, trans-11 CLA, also known as rumenic acid (RA). We have continued to identify nutrition and management approaches that can be used with dairy cows to allow for the sustainable production of milk fat naturally enriched in RA. In dairy cows, RA originates from conversion of vaccenic acid (VA) by the delta-9 desaturase. VA originates as an intermediate in rumen biohydrogenation of linoleic and linolenic acids, and as a result VA is also present in dairy products. Humans also have delta-9 desaturase and can convert VA to RA; VA, however, is a trans fatty acid (TFA) and adverse health effects are often associated with dietary intake of TFA. Our hypothesis is that VA has positive health effects rather than the adverse effects typically associated with industrial-derived TFA. We examined this by comparing industrial sources of TFA with those derived from dairy products in a clinical study; healthy individuals were used and plasma cholesterol profiles were monitored as biomarkers of risk for coronary heart disease. We observed that the VA/CLA enriched dairy products had no adverse effects on plasma cholesterol profiles. Thus, the TFA in dairy products (mainly VA) do not have the negative effects on human health that are associated with the TFA from industrial sources. Additional studies examined the metabolism of different TFA isomers. We initially investigated the use of two TFA, elaidic acid (EA) and VA, in dairy cows and we found that these fatty acids were taken up by the mammary gland and used for milk fatty synthesis. Using the hamster as the biomedical model, we then compared EA and VA with partially hydrogenated vegetable oil (PHVO). PHVO is the source of industrial TFA in foods, and we observed that in the hamster model it caused changes in plasma cholesterol biomarkers consistent with an increased risk of coronary heart disease. In contrast, EA and VA gave no indication of increased risk. The process of partial hydrogenation of polyunsaturated fatty acids causes the production of many unique fatty acid isomers and our original results raise the possibility that the health risks associated with PHVO may be related to more than just the TFA. Other fatty acids in milk fat that are of interest include the long chain omega-3 fatty acids and enrichment of milk fat with omega-3 fatty acids would be beneficial because of their role in human health and disease prevention. Success in enriching the milk fat content of omega-3 depends on their bypassing rumen biohydrogenation, but we found dietary omega-3 fatty acids were extensively biohydrogenated in the rumen even when provided by as a formulation of Ca salts. Providing omega-3 as components of fish meal was modestly effective, but our results demonstrate there is a clear need for novel formulations to advance this area. PARTICIPANTS: E. Castaneda-Gutierrez, (PhD Graduate Program), Department of Animal Science, Cornell University, Ithaca, NY. C. Tyburczy, (MS Graduate Program), Department of Animal Science, Cornell University, Ithaca, NY. A. O'Donnell, (PhD Graduate Program), Department of Animal Science, Cornell University, Ithaca, NY. D. Barbano, Department of Food Science, Cornell University, Ithaca, NY. A. Lock, Department of Animal Science, University of Vermont, Burlington, VT. A. Salter, Division of Nutritional Sciences, University of Nottingham, Nottingham, UK. M. de Veth, BASF AG, Nutritional Research Station, Offenback/Queich, Germany. F. Destaillats, Nestel Research Center, Lausanne, Switzerland. J.-M. Chardigny, National Institute for Agromonic Research, Clermont-Ferrand, France.

Impacts
Consumers are increasingly aware of the link between diet and health, and the potential role for functional food components in disease prevention. Conjugated linoleic acid (CLA) and long chain omega-3 fatty acids have been identified as bioactive components in dairy products that may benefit the maintenance of human health. We have investigated the origin of these fatty acids in milk fat and made progress in identifying diet and management practices that will allow for a sustainable production of milk fat with enriched concentrations of these fatty acids. We have also continued efforts that elucidate the role of these bioactive fatty acids in human health through biomedical studies with animal models, in particular models of breast cancer and cardiovascular disease. Nevertheless, extrapolating these results to humans has been limited and remains problematic because chronic diseases have long latency periods and in the case of cancer there are no consensus biomarkers. Overall, our results provide further evidence that the CLA and omega-3 fatty acids in milk fat represent bioactive fatty acids that offer potential benefits for human health and the prevention of chronic diseases, and that dairy products enriched in these fatty acids offer exciting possibilities as functional foods.

Publications

Salter, A.M., Lock, A.L., Garnsworthy, P.C. and Bauman, D.E. 2007. Milk fatty acids: Implications for human health. Recent Advances in Animal Nutrition-2007. pp. 1-18. Nottingham University Press, Nottingham, UK.
Castaneda-Gutierrez, E., de Veth, M.J., Lock, A.L., Dwyer, D.A., Murphy, K.D. and Bauman, D.E. 2007. Effect of supplementation with calcium salts of fish oil on n-3 fatty acids in milk fat. J. Dairy Sci. 90:4149-4156.
Tyburczy, C., Lock, A.L., Dwyer, D.A., Destaillants, F., Mouloungui, Z., Candy, L. and Bauman, D.E. 2007. Characterization of the utilization of trans octadecenoic acids in lactating dairy cows. J. Dairy Sci. 90(Suppl. 1):205.
Bauman, D.E., Tyburczy, C., O Donnell, A.M. and Lock, A.L. 2007. Production and use of high CLA foods in human health. J. Dairy Sci. (Suppl. 1):429.
Tyburczy, C., Lock, A.L., Dwyer, D.A., Destaillats, F., Mouloungui, Z., Candy, L. and Bauman, D.E. 2007. Uptake and utilization of trans octadecenoic acids during lactation. FASEB J.:21(5):LB58.
Bauman, D.E. 2007. Biology of CLA: An Overview of the Ruminant Perspective. II International Congress on Conjugated Linoleic Acid (CLA): From experimental models to human applications. pg. 2.
Tyburczy, C., Bauman, D., Destaillats, F., Lock, A. and Salter, A. 2007. Evidence that neither elaidic nor vaccenic acid are responsible for the plasma cholesterol-raising properties of partially hydrogenated vegetable oil. II International Congress on Conjugated Linoleic Acid (CLA): From experimental models to human applications. pg. 30.
Chardigny, J.-M., Destaillats, F., Malpuech-Brugere, C., Moulin, J., Bauman, D.E., Lock, A.L., Barbano, D.M., Mensink, R.P., Bezelgues, J.B., Chaumont, P., Combe, N., Cristiani, I., Joffre, F., German, J.B., Dionisi, F., Boirie, Y. and Sebedio, J.-L. 2007. Do industrially-produced and natural trans fatty acid sources have the same impact on cardiovascular diseases risk in healthy subjects? Am. J. Clin. Nutr. 81:in press.

Progress 01/01/06 to 12/31/06

Outputs
One of the milk fatty acids that may have special benefits in the maintenance of human health is conjugated linoleic acid (CLA). There are over 20 CLA isomers, but the major isomer in milk fat is cis-9, trans-11 CLA (75-90 pct of total CLA), also referred to as rumenic acid (RA), we have shown this CLA isomer has anti-carcinogenic and anti-atherogenic effects in biomedical studies with animal models. Diet is the major factor affecting milk fat content of CLA and we demonstrated that increases of over 300 pct can easily be achieved. However, we have found that sustaining these increases is difficult and this will be an area of continued focus. We also established that physiological factors like stage of lactation, breed and parity have minimal effects on milk fat CLA, but there is over a 3-fold variation among individuals. Our research demonstrated that RA originates mainly via endogenous synthesis from rumen-derived vaccenic acid (trans-11 18:1, VA) via the mammary enzyme delta-9 desaturase. This enzyme appears to be the basis for much of the differences among individuals and the regulation of delta-9 desaturase will be one focus over the next year. The ratio of VA to RA is typically 3:1; thus any increase in milk fat CLA has a corresponding increase in VA. This is of special interest because VA is a trans fatty acid (TFA), and TFA have been implicated as risk factors in coronary heart disease (CHD). Contrary to industrial sources of TFA (predominately trans-9 18:1, elaidic acid), we have shown that VA is both anti-carcinogenic and anti-atherogenic in animal models and these beneficial effects are related to its conversion to RA. To extend these results to humans, we have produced a butter oil that is high in VA and compared it to foods enriched in industrial TFA in a human study. We have completed the clinical study with the end points being plasma biomarkers related to the risk of CHD; samples and results are currently being analyzed and completing this landmark study will be one focus for next year.

Impacts
Overall, our results provide additional insight of the functional food role of milk fat and demonstrate the potential that conjugated linoleic acid may be beneficial in health maintenance and the prevention of chronic human diseases.

Publications

Bauman, D.E., Lock, A.L., Corl, B.A., Ip, C., Salter, A.M. and Parodi, P.W. 2006. Milk fatty acids and human health: Potential role of conjugated linoleic acid and trans fatty acids. In: Ruminant Physiology: Digestion, Metabolism and Impact of Nutrition on Gene Expression, Immunology and Stress. pp. 529-561. (Eds. K. Sejrsen, T. Hvelplund and M.O. Nielson). Wageningen Academic Publishers, Wageningen, The Netherlands.
Bauman, D.E., Tyburczy, C., ODonnell, A.M. and Lock, A.L. 2006. Conjugated linoleic acid in dairy products. Lipid Tech. 18:245-249.
Bauman, D.E. and Lock, A.L. 2006. Conjugated linoleic acid: Biosynthesis and nutritional significance. In: Advanced Dairy Chemistry. Volume 2: Lipids, 3rd Edition. pp. 93-136. (Eds. P.F. Fox and P.L.H. McSweeney). Springer, New York, NY.
Bauman, D.E. 2006. Animal products and human health: present situation and future potential. Sir John Hammond Memorial Lecture. Proc. Brit. Soc. Anim. Sci. pg. 207.
Destaillats, F., Malpuech-Brugere, C., Dionisi, F., Bauman, D.E., Lock, A.L., German, J.B., Mensink, R.P., Combe, N., Chaumont, P., Barbano, D.M., Enjalbert, F., Bezelgues, J.-B., Cristiani, I., Moulin, J., Boirie, Y., Sebedio, J.-L. and Chardigny, J.-M. 2006. Assessment of the effect of the two different dietary sources of trans fatty acids on cardiovascular risk factors in humans: Results of the TRANSFACT study. Int. Dairy Fed. 27th Int. Congress World Dairy Summit, Shanghai, China.
Chardigny, J.-M., Malpuech-Brugere, C., Dionisi, F., Bauman, D.E., Lock, A.L., German, J.B., Mensink, R.P., Combe, N., Chaumont, P., Barbano, D.M., et al. 2006. Assessment of the effect of the two different dietary sources of trans fatty acids on cardiovascular risk factors in humans: Results of the TRANSFACT study. German Society for Fat Science (DGF) Symposium: Fats and Health - Update on Dietary Phytosterols, Trans-fatty Acids and Conjugated Linoleic Acids, Frankfurt, Germany.
Tyburczy, C., Lock, A.L., Kelsey, J.A., Peterson, D.G., Corl, B.A. and Bauman, D.E. 2006. Effect of individual cow variation and interaction with diet on the content of health-promoting fatty acids in milk fat from dairy cows. J. Dairy Sci. 89(Suppl. 1):179.
Chen, S., Zeng, S., Rovai, M., Gipson, T., Bauman, D., Lock, A., Bah, B. and Goetsch, A. 2006. Effects of CLA supplementation on texture profile of semi-hard goat cheese. J. Dairy Sci. 89(Suppl. 1):327.
Lock, A.L., Bauman, D.E. and Salter, A.M. 2006. Conjugated linoleic acid from butter fat is absorbed and incorporated into tissue lipids to a greater extent than when consumed as a dietary free fatty acid supplement. J. Dairy Sci. 89(Suppl. 1):179.
Lock, A.L., Early, R.M., Bauman, D.E. and Sinclair, L.A. 2006. The effect of trans-10, cis-12 CLA on milk fat synthesis and cheese yield in sheep fed at two levels of energy intake. J. Dairy Sci. 89(Suppl. 1):65-66.
Kay, J.K., Mackle, T.R., Bauman, D.E., Thomson, N.A. and Baumgard, L.H. 2006. Effects of conjugated linoleic acid on bioenergetic and milk production parameters in grazing dairy cows offered ad libitum or restricted pasture. N.Z. Soc. Anim. Prod. 66:423-428.
Sinclair, L.A., Lock, A.L., Early, R. and Bauman, D.E. 2006. Dietary supplementation of ewes with conjugated linoleic acid improves the eating quality of cheese. 4th Euro-Fed Lipid Congress, pg. 565. Madrid, Spain.
Lock, A.L. and Bauman, D.E. 2006. Use of fatty acid transfer to milk fat as an in vivo approach to evaluate rumen protection and post-rumen bioavailability of bioactive fatty acids. 4th Euro-Fed Lipid Congress, pg. 568. Madrid, Spain.
Chardigny, J.-M., Malpuech-Brugere, C., Dionisi, F., Bauman, D.E., German, B., Mensink, R.P., Combe, N., Chaumont, P., Barbano, D.M., Enjalbert, F., Bezelgues, J.-B., Cristiani, I., Moulin, J., Boirie, Y., Golay, P.-A., Giuffrida, F., Sebedio, J.-L. and Destaillats, F. 2006. Rationale and design of the TRANSFACT Project Phase I: A study to assess the effect of the two different dietary sources of trans fatty acids on cardiovascular risk factors in humans. Contemporary Clin. Trials. 27:364-373.
Chardigny, J.-M., Malpuech-Brugere, C., Dionisi, F., Bauman, D.E., Lock, A.L., German, J.B., Mensink, R.P., Combe, N., Chaumont, P., Barbano, D.M., Enjalbert, F., Bezelgues, J.-B., Cristiani, I., Moulin, J., Boirie, Y., Sebedio, J.-L. and Destaillats, F. 2006. Assessment of the effect of the two different dietary sources of trans fatty acids on cardiovascular risk factors in humans: Results of the TRANSFACT study. 4th Euro-Fed Lipid Congress, pg. 565. Madrid, Spain.
Bauman, D.E. and Lock, A.L. 2006. Animal products and human health: Perceptions, opportunities and challenges. Proc. Cornell Nutr. Conf. pp. 45-57. Cornell University Agricultural Experiment Station, Department of Animal Science, Ithaca, NY.

Progress 01/01/05 to 12/31/05

Outputs
Milk contains several fatty acids that are potentially beneficially for health maintenance and disease prevention. These include two trans fatty acids, rumenic acid (cis-9, trans-11 conjugated linoleic acid; RA) and vaccenic acid (trans-11 18:1; VA), as well as omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Omega-3 fatty acids are very low in milk fat and we investigated the basis for this. We found that there was an extensive rumen biohydrogenation of the omega-3 fatty acids when they were supplied by typical dietary sources used for dairy cows. Further, even with formulations using Ca-salts as a means to minimize their availability to rumen bacteria the biohydrogenation was extensive so that little omega-3 fatty acids passed to the small intestine. Thus, better methods for rumen protection are needed for the formulation of dietary omega-3 supplements for dairy cows. In the case of VA and CLA, we demonstrated that the content of these fatty acids in milk fat was markedly affected by diet but physiological factors such as parity, stage of lactation and level of milk production had little impact. However, we observed a substantial variation ( 3-fold) among individuals regardless of diet and this suggests a genetic basis that might be utilized in genetic selection. We further demonstrated that milk that contained enhanced levels of RA and VA was not different from standard milk in terms of sensory tests or susceptibility to the development of oxidized off-flavors even when oxidation was induced by light. Of special interest, we demonstrated using animal models that butter which had been naturally enriched in VA and RA results in a plasma lipoprotein cholesterol profile that is associated with a reduced risk of atherosclerosis. Thus, milk fat enriched in these two fatty acids has been shown to have both anti-atherogenic and anti-carcinogenic properties in biomedical studies with animal models. Presently we are collaborating to extend these results to studies of disease prevention in humans.

Impacts
In addition to the traditional value of dairy products as an important source of key nutrients, it is increasingly apparent that some of the fatty acids in milk fat may have beneficial effects on health maintenance. We have identified dietary and physiological factors that affect the milk fat content of these specific fatty acids and shown consumer acceptability when their levels are naturally enhanced in dairy products. Further we established that increasing the milk fat content of rumenic acid and vaccenic acid containing enhanced levels results in plasma lipoprotein cholesterol profile that is associated with reduced risk of atherosclerosis.

Publications

Lynch, J.M., Lock, A.L., Dwyer, D.A., Norbaksh, R., Barbano, D.M. and Bauman, D.E. 2005. Flavour and stability of pasteurized milk with elevated levels of conjugated linoleic acid and vaccenic acid. J. Dairy Sci. 88:489-498.
Lock, A.L., Bauman, D.E. and Garnsworthy, P.C. 2005. Short Communication: Effect of production variables on the cis-9, trans-11 conjugated linoleic acid content of cows milk. J. Dairy Sci. 88:2714-2717.
Lock, A.L., Horne, C.A.M., Bauman, D.E. and Salter, A.M. 2005. Butter naturally enriched in conjugated linoleic acid and vaccenic acid alters tissue fatty acids and improves the plasma lipoprotein profile in cholesterol-fed hamster. J. Nutr. 135:1934-1939.
Chardigny, J.-M., Destaillats, F., Malpuech-Brugere, C., Enjalbert, F., Bauman, D.E., Barbano, D.M., German, B., Mensink, R.P., Combe, N., Chaumont, P., Guiffrida, F., Bezelgues, J.-B., Cristiani, I., Moulin, J., Boirie, Y., Dionisi, F., Golay, P.-A. and Sebedio, J.-L. 2005. Comparative effect of the two different sources of trans fatty acids (milk fat vs hydrogenated oil) on cardiovascular risk factors in humans. First International Symposium on Trans Fatty Acids and Health. Rungstedgaard. Copenhagen, Denmark.
Lock, A.L., Parodi, P.W. and Bauman, D.E. 2005. The biology of trans fatty acids: implications for human health and the dairy industry. Aust. J. Dairy Technol. 60:134-142.
Palmquist, D.L., Lock, A.L., Shingfield, K.J. and Bauman, D.E. 2005. Biosynthesis of conjugated linoleic acid in ruminants and humans. In: Advances in Food and Nutrition Research. (Ed. by S.L. Taylor). Elsevier Inc., San Diego, CA. Volume 50, pp. 179-218.
Kay, J.K., Weber, W.J., Moore, C.E., Bauman, D.E., Hansen, L.B., Chester-Jones, H., Crooker, B.A. and Baumgard, L.H. 2005. Effects of week of lactation and genetic selection for milk yield on milk fatty acid composition in Holstein cows. J. Dairy Sci. 88:3886-3893.
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Sims, H.M., Major, C., Lock, A.L., Bauman, D.E. and Salter, A.M. 2005. Inhibition of stearoyl CoA desaturases activity induces hypercholesterolaemia in cholesterol-fed hamsters. Nutrition Society Summer Meeting, Norwich, UK.
Lock, A.L., Horne, C.A.M., Bauman, D.E. and Salter, A.M. 2005. Effect of vaccenic acid/conjugated linoleic acid-enriched butter on plasma lipoproteins in the cholesterol-fed hamster. J. Dairy Sci. Vol. 88 (Suppl. 1):290.
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Ryan, K.J.P., Major, C., Lock, A.L., Bauman, D.E. and Salter, A.M. 2005. Interactive effects of dietary cholesterol and inhibition of stearoyl CoA desaturase activity on lipogenic gene expression. Nutrition Society Summer Meeting, Norwich, UK.
Salter, A.M., Lock, A.L., Claire, C.A.M. and Bauman, D.E. 2005. Effect of butter naturally enriched in conjugated linoleic acid and vaccenic acid on plasma lipoproteins the cholesterol-fed hamsters. 2nd European Symposium on Dietary Fatty Acids and Health. Euro. Fed Lipid. Frankfurt, Germany.
Salter, A.M., Lock, A.L. and Bauman, D.E. 2005. Absorption and tissue accumulation of conjugated linoleic acid: A comparison of butter fat and a free fatty acid supplement. 2nd European Symposium on Dietary Fatty Acids and Health. Euro. Fed Lipid. Frankfurt, Germany.
McConnell, C., Lock, A.L. and Bauman, D.E. 2005. Rumen vs. abomasal infusion of fish oil as a novel approach to determine the extent of rumen biohydrogenation of omega-3 fatty acids and their transfer into milk fat. J. Dairy Sci. Vol. 88 (Suppl. 1):180.