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

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

The purpose of the proposed pilot study is to evaluate the effects of a soy protein isolate with naturally occurring isoflavones on the properties of HDL-C (total HDL-C, HDL particle size and HDL function), central blood pressure, and indices of 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.

Inclusion Criteria:

• Male and Female
• 35-60 years old,with
• Systolic blood pressure greater than 120 mm Hg
• Diastolic blood pressure greater than 80 mm Hg
• BMI within 18-39 kg/m2 ,
• non smokers with
• no inflammatory diseases and
• not taking medication for high cholesterol, blood pressure, or glucose control

Exclusion Criteria:

• Under 35 years of age or over 60 years old
• Systolic blood pressure <120 or Diastolic blood pressure <80
• smoker
• inflammatory disease
• BMI outside of 18-39kg/m2 range
• taking medication
• refusal to discontinue any other supplement use