Effect of Soy on HDL-C Function, Central Blood Pressure, and Arterial Stiffness

The investigators propose to conduct a randomized three-period, crossover study to evaluate the effect of soy protein supplementation on HDL function. To ensure that there are no effects of treatment order on outcome measures, subjects will be randomized to a treatment sequence. Healthy males and females (n = 20; 35 to 60 years of age) with systolic blood pressure greater than 120 mm Hg and/or diastolic blood pressure greater than 80 mm Hg will be recruited for this study. Subjects will undergo 3 treatment periods in random order. These treatment periods will include: A) 25 g/d soy protein powder; B) 50 g/d soy protein powder; C) 0 g/d protein powder (control). Each treatment will be provided for 6 weeks separated by a 2-week break between treatment periods. All subjects will be encouraged to maintain body weight and physical activity levels during the study.