EFFECTS OF SOY AND DAIRY MILK ON LIPIDS

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. BACKGROUND: A 1995 meta-analysis concluded that, based on the literature avaliable at that time, soy protein consumption lead to a significant decrease in serum cholesterol. Since that time, much more research has been added to the literature, some positive, some not. There is now some belief that the cholesterol-lowering effect might be the result of a specific subunit found in some soy products. This subunit is lost during some processing techniques, thus potentially explaining the discrepancies between studies. In addition, the cholesterol-lowering effect of the soy protein may only be seen in those individuals who begin the study with low density lipoproteins (LDL)-cholesterol levels > 160 mg/dL. OBJECTIVE: The primary objective of this study is to compare the potential cholesterol-lowering effects of two soy beverages, one with the subunit in question and one without, to a control beverage of low-fat dairy milk. The primary outcome measured will be serum lipids. SUBJECTS: Individuals with elevated serum LDL-cholesterol levels (160-220 mg/dL) will participate in this randomized cross-over trial. Aside from elevated cholesterol levels, these will be low-risk participants. Low-risk will be defined as a Framingham risk score of <10% (indicates 10-year risk of a "hard" coronary heart disease (CHD) event; based on gender, age, LDL, high density lipoproteins (HDL), blood pressure, diabetes, and smoking). METHODS: All participants will consume all three milk beverages for four weeks each, but in different orders. Serum lipids will be measured at the beginning, middle, and end of each beverage phase. In addition, insulin sensitivity will be assessed once at the beginning of the study, and then at the end of each beverage phase