Grains Reduce Adiposity and Improve Nutrition Study
Condition: Metabolic Syndrome; Insulin Resistance
MeSH terms: Metabolic Syndrome; Insulin Resistance; Obesity
Study type: Interventional

Summary: 
      Whole grain intake beneficially affects body weight, body fat and glucose metabolism, and the
      investigators' previous work has shown that a high whole grain intake significantly reduced
      body fat in the abdominal region as measured by dual energy X-ray absorptiometry (DEXA)
      compared to a refined grain intake. Additional research is needed with regard to the
      mechanisms by which whole grains may affect visceral adiposity and the adipokines, which have
      been associated with risk for insulin resistance and type 2 diabetes. Therefore the proposed
      study aims to address these issues and in addition, includes exploratory work with adipocytes
      in cell culture to evaluate the effects of whole grains on adipocyte function.

      Hypothesis:

      There will be a greater reduction in visceral adiposity, indicators of insulin resistance
      (HOMA score), improvement in inflammatory status and improvement in adipokine levels after
      six weeks of a weight stable period and after six weeks of weight loss in subjects consuming
      6-9 servings compared to 0 servings of whole grains per day.
    

Detailed description: 
      Including whole grains as part of a heart-healthy diet has been shown to be beneficial in
      decreasing body weight and body fat. The beneficial effects of whole grains on body weight
      may be explained by the larger volume and relatively low energy density of whole grain food
      thus leading to increased satiation. Reducing visceral fat is of particular importance as
      visceral adiposity has been associated with increased risk for metabolic diseases and
      cardiovascular disease.

      The proposed study is a randomized, 2-parallel arm controlled feeding study. Subjects will be
      fed one of two weight maintenance diets (refined grain and whole grain) for 6 weeks, followed
      by a 6 week controlled weight loss period where subjects are fed the same diets, but at a
      reduced calorie level, designed to elicit weight loss (~2 lbs per week). Diets for both
      groups will have the same nutrient profile (percent of calories from fat, protein,
      carbohydrates, etc.); however, the whole grain (WG) group will substitute whole grains for
      refined grains in their grain intake (breads, tortillas, cereals, etc.). The WG group will be
      expected to take in 6-9 servings of whole grains per day on both diets. Plasma endpoints will
      be measured at baseline and at the end of the 6-week diet periods. Blood samples also will be
      taken at the mid-point of each period and held for analysis if deemed appropriate after
      initial data is reviewed. Endo-PAT will be conducted at baseline and at the end of each diet
      period as well as DEXA and MRI testing.
    

Intervention name(s): Whole grain diet; Refined grain
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Participants in this group will receive 6-9 servings of whole grain daily to replace the refined grains typically included in the average American diet. Number of servings will depend upon calorie assignment.; Participants in this group will receive only refined grains as typically consumed in the average American diet.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: grains; fiber; metabolic syndrome; insulin