Associate Professor Food Science & Human Nutrition Washington State University Pullman WA 99164-6376   Phone: 509-335-3896 FAX: 208-335-4815 E-mail: smcguire@wsu.edu   Ph.D., 1994 Cornell University RESEARCH INTERESTS:   Mammary Physiology   RESEARCH SUMMARY: Although breastfeeding is considered the optimal form of infant feeding, the regulation of milk constituents is not fully understood. A more comprehensive understanding of the variability and regulation of milk composition in humans is important both for scientific and public health purposes. Furthermore, it is known that lactation is beneficial for the postpartum woman. For example, lactation results in a period of infertility and a decreased risk for certain forms of breast cancer. Thus, we have been interested in studying the influence of lactation and breastfeeding on both maternal and infant health. Specifically, our research has focussed recently on the investigation of maternal fatty acid intake on milk composition (and thus, infant nutrition) as well as risk of breast cancer in the mother. Of particular interest to us is a group of fatty acids called the "conjugated linoleic acids (CLA)," which have been shown to influence breast cancer risk in animal models as well as growth and nutrient partitioning in the growing animal. Studies in lactating women show clearly that maternal CLA intake influences milk CLA content. Further, we have shown that supplementation with commercially-available CLA can quickly and significantly decrease milk fat content. Currently, we are continuing this research by helping to elucidate which CLA isomer is responsible for these effects on milk composition as well as studying the potential interaction between lactation and CLA intake on risk of mammary cancer. Our studies utilize both human subjects and animal models and are intended to add to our understanding of the regulation of milk composition as well as the health implications of variations in maternal and infant nutrition and behaviors during the postnatal period.   REPRESENTATIVE PUBLICATIONS Anderson, N.K., Beerman, K.A., McGuire, M.A., Dasgupta, N., Griinari, M.J., Williams, J. & McGuire, M.K. 2005 Type of dietary fat influences total milk fat content in lean women J Nutr 135(3):416-21. Ritzenthaler, K.L., Chew, B., Shultz, T.D., McGuire, M.A., Williams, J, Dasgupta, N. & McGuire, M.K. 2005 Consumption of conjugated linoleic acid (CLA) from CLA-enriched cheese does not alter milk fat or immunity in lactating women. J Nutr 135(3):422-30. McCann, SE, Ip, C, Ip, MM, McGuire, MK, Muti, P, Edge, SE, Trevisan, M, & Freudenheim, JL. 2004 Dietary intake of conjugated linoleic acids and risk of pre- and postmenopausal breast cancer, Western New York Exposures and Breast Cancer Study (WEB Study). Cancer Epidemiol Biomarkers Prev 9:1480-4 Ritzenthaler, K., M.K. McGuire, R. Falen, T.D. Shultz and M.A. McGuire. 2001. Estimation of conjugated linoleic acid intake by written dietary assessment methodologies underestimates actual intake evaluated by food duplicate methodology. J. Nutr. 131:1548-1554. Precht, D., J. Molkentin, M.A. McGuire, M.K. McGuire, and R.G. Jensen. 2001. Overestimates of oleic and linoleic acid contents in materials containing trans fatty acids and analyzed with short packed gas-chromatographic columns. Lipids 36:213-216.   McGuire, M.A., and M.K. McGuire. 2000. Conjugated linoleic acid (CLA): A ruminant fatty acid with beneficial effects on human health. (Invited Review). Proc. Am. Soc. Anim. Sci., 1999. Available at: http://www.asas.org/jas/symposia/proceedings/0938.pdf. Accessed September 6, 2000. McGuire, M.K., McGuire, M.A., Ritzenthaler, K. & Shultz, T.D. (1999) Dietary sources and intakes of conjugated linoleic acid intake in humans. In: Conjugated Linoleic Acid, Yurawecz et al., eds., AOCS Press, Champaign, IL, pp. 369-377.   McGuire, M.A., McGuire, M.K., Jensen, R. & Parodi, P. (1999) Conjugated linoleic acids in human milk. In: Conjugated Linoleic Acid, Yurawecz et al., eds., AOCS Press, Champaign, IL, pp. 296-306.   Park, Y.S., Behre, R.A., McGuire, M.A., Shultz, T.D. & McGuire, M.K. (1999) High fat dairy product consumption icnreases 9c,11t-18:2 (rumenic acid) and total lipid concentrations of human milk. Lipids 34:543-549.   Herbel, B.K., McGuire, M.K., McGuire, M.A. & Shultz, T.D. (1998) Safflower oil consumption does not increase plasma conjugated linoleic acid concentrations in humans. Am J Clin Nutr 67:332-337.   Houseknecht, K., McGuire, M.K., McGuire, M.A. & Beerman, K. (1997) Leptin is present in human milk; relationship with maternal plasma leptin concentrations and adiposity Biochem Biophys Res Comm 240:742-747. McGuire, M.K., Park, Y.S., Shultz, T.D., Harrison, L.Y. and McGuire, M.A. (1997) Conjugated linoleic acid concentrations of human milk and infant formula. Nutr Res 17:1277-1283.   Gournis, E., McGuire, M.K. and Rasmussen, K.M. (1997) Food supplementation during lactation shortens anestrus and elevates gonadotropins in rats. J Nutr 127:785-790. Weissman, L.T., Gournis, E., McGuire, M.K. and Rasmussen, K.M. (1997) Documentation of second-by-second breastfeeding behaviors using a novel method. J Hum Lact 13:23-27.