Soy and Lipoproteins in Postmenopausal Women
Condition: Atherosclerosis; Cardiovascular Diseases; Heart Diseases; Menopause
MeSH terms: Cardiovascular Diseases; Heart Diseases; Atherosclerosis
Study type: Interventional

Summary: 
      To determine the effects of soy on lipids, lipoproteins and lipoprotein subclass in a sample
      of African-American and white postmenopausal women with low-density lipoprotein (LDL)
      cholesterol elevations that may increase their lifetime risk for cardiovascular disease but
      would not qualify for definite pharmacotherapy under current guidelines.
    

Detailed description: 
      BACKGROUND:

      Cardiovascular disease (CVD) remains the leading cause of mortality and disability in
      postmenopausal women. Menopause alters serum lipids and lipoproteins to produce a more
      atherogenic lipid profile that may contribute significantly to the increased risk for the
      development of CVD over the lifetime of women. Clinical trials have demonstrated a beneficial
      effect of soy protein containing isoflavones (soy) on plasma lipids and lipoproteins;
      however, these studies included small numbers of postmenopausal women and virtually none
      included sufficient African-American women. In addition, no published data existed in 2001 on
      the impact of soy on atherogenic lipoprotein subclasses in postmenopausal women.

      DESIGN NARRATIVE:

      The study was a double blind, parallel group, randomized clinical trial. A total of 216
      healthy postmenopausal women (50 percent African-American) with LDL cholesterol between 130
      mg/dL and 190 mg/dL were enrolled. Following a pre-randomization run-in period on a NCEP Step
      I diet, women were randomized to receive soy containing isoflavones or casein dietary
      supplements for 3 months. Major outcome variables were assessed in both groups at baseline
      and again at 3 months. It was hypothesized that soy supplementation would result in
      significantly greater reduction in LDL cholesterol, LDL particle concentration, and
      prevalence of dense LDL particles and improvement in menopausal quality of life compared with
      placebo and that these effects would be comparable in African-Americans and whites. This was
      the first study to determine whether a natural plant product could ameliorate the unfavorable
      changes in known and novel lipid risk factors that are a consequence of menopause in both
      African-American and white women. The unique transitional outcomes explored in this study
      added substantially to the limited body of knowledge of the effects of soy. Evaluation of
      this nutritional alternative to hormone replacement therapy (HRT) that may provide a
      beneficial effect on lipid risk factors and menopausal symptoms but would be free of the
      adverse effects on triglycerides, the breast and uterus, and thrombotic events associated
      with HRT could have significant public health implications for postmenopausal women.
    

Intervention name(s): Soy; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Dietary supplement of isolated soy protein containing isoflavones; dietary supplement casein placebo
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Prevention