Dietary Intervention for Visceral Adiposity
Condition: Obesity
MeSH terms: Obesity
Study type: Interventional

Summary: 
      The purpose of this research study is to determine whether increased intake of dietary fiber
      during a 12-week, low-calorie weight loss intervention affects abdominal fat change and
      improves cardiovascular risk factors in African-American women more than a standard weight
      loss intervention.

      The investigators are testing two main hypothesis:

      Hypothesis 1: Women in the high dietary fiber intervention group will lose significantly more
      abdominal fat around their organs than women in the standard fiber group.

      Hypothesis 2: Women in the high dietary fiber intervention group will have lower blood
      pressure, fasting glucose, fasting lipids and inflammatory factors at 3-months compared to
      women in the control group.
    

Detailed description: 
      OBJECTIVES:

      Specific Aim 1: To test, in a small clinical trial of 30 pre-menopausal African American
      women, whether increased intake of dietary fiber embedded in a 12 week weight loss
      intervention will reduce VAT accumulation more than a standard weight loss intervention.

      Hypothesis 1: Women in the high dietary fiber intervention group will lose significantly more
      VAT than women in the standard fiber group.

      Specific Aim 2: To test, in a small clinical trial of 30 pre-menopausal African American
      women, whether increased intake of dietary fiber embedded in a 12 week weight loss
      intervention will improve cardiovascular risk factors more than a standard weight loss
      intervention.

      Hypothesis 2: Women in the high dietary fiber intervention group will have lower blood
      pressure, fasting glucose, fasting lipids and inflammatory factors at 3-months compared to
      women in the control group.

      Specific Aim 3: To characterize our ability to recruit and retain 30 African-American,
      premenopausal women to a 12 week weight loss intervention study

      Specific Aim 4: To determine participant compliance with serum and other measurement
      evaluations and dietary compliance logs.

      METHODS AND MEASURES

      Design:

      This study will be a randomized masked controlled trial design of 30 pre-menopausal African
      American women aged 20-50 years with BMI ≥ 30 kg/ m2 and waist circumference > 88 cm
      evaluating the effect of fiber supplementation on change in abdominal fat deposition. The
      fiber intervention will be nested within a 3-month weight loss trial. The placebo and active
      interventions will appear identical to the participant. The only person who will know of the
      intervention (fiber vs. placebo) is the Clinical Research Unit (CRU) (former General Clinical
      Research Center) Nutrition staff. All women will have ~ 800 kcal/day calorie restriction, for
      12 weeks, designed lead to 0.5 kg - 0.9 kg per wk weight loss or 9-18 kg lost during the
      study. Diets will all contain at least 0.8 grams of protein/kg IBW and be limited to 15 grams
      total fiber. Calorie restriction will occur either through CRU prepared meal replacements or
      participant instituted calorie restriction learned via nutritional education sessions.
      Participants will be randomized and started on the 12-week study intervention on a rolling
      basis. At any one time, there will be 8 women enrolled in the study. The enrollment will
      continue until all 30 women are started. The women will not be held and then started as a
      group.

      Randomization:

      Although enrollment will be rolling, participants will be randomized in groups of eight to
      ensure that the capacity of the metabolic kitchen is always maintained. The randomization
      will be to one of four groups (1- intervention/feeding; 2- intervention/nutritional
      education; 3- placebo/feeding; 4-placebo/nutritional education). Participants will be
      randomized to one of these four groups at the close of her baseline visit. Randomization will
      occur via envelope. There will be an envelope for fiber intervention and one for caloric
      restriction method. The intervention envelope will contain four fiber cards (marked B) and
      four placebo cards (marked A). The calorie restriction envelope will contain for meal
      replacement cards (marked D) and four nutrition education cards (marked C). Participants will
      be given randomization assignment by CRU staff. The PI and participants will be blinded to
      the fiber intervention.

      Setting:

      This study will take place in two main settings, the CRU and each participant's home. All
      clinical measurements, nutritional education, meal replacement pick- up and distribution
      dietary supplements will take place at the CRU. The CRU has agreed to: 1) perform CT, RMR,
      and anthropomorphic measures as indicated for screening, baseline and 12-week follow-up; 2)
      draw, process and assay blood, as indicated, for screening, baseline and 12-week follow-up;
      2) to provide two nutritional education sessions, two weeks apart (for the nutrition
      education group); 3) to prepare and distribute lunch and dinner (for the meal replacement
      group); 4) prepare and distribute daily fiber supplements for all participants; and 5) to
      prepare, distribute and collect weekly food compliance logs from each participant.

      Interventions:

      Dietary Fiber Intervention:

      Benefiber® powder will be used as our dietary supplement intervention. Benefiber® powder
      contains wheat dextrin, a 100% natural fiber. It's taste-free, sugar-free, dissolves
      completely in noncarbonated beverages and soft foods, and won't thicken. Benefiber® powder
      can be mixed into any hot or cold beverage such as water, coffee, or juice; into soft foods
      such as applesauce, pudding or yogurt; or cooked into recipes for such foods as muffins,
      sauces or soups, without affecting the taste or consistency. Benefiber® powder is not
      recommended for carbonated beverages. Benefiber has a shelf life of 2 years when stored at a
      controlled room temperature of 20-25°C (68-77°F). Benefiber® Powder, which contains less than
      20 ppm of gluten and is therefore considered "gluten-free," based on both the FDA and the
      Codex Alimentarius Commission's proposed definition of less than 20 ppm. Participants in the
      intervention arm will receive 3 supplement packets to be consumed per day.

      Each active dietary supplement packet contains 8 grams of Benefiber® powder and 3 grams of
      TRUE® lemon flavoring, a 100% natural with no artificial ingredients or sweeteners,
      preservatives, sodium or gluten. The TRUE® Lemon product is made from cold-pressed and
      crystallized lemons which contain 0 calories and 0g carbohydrates. Each placebo dietary
      supplement packet contains 8 grams of Splenda and 3 grams of true lemon sweetener. Each
      packet is designed to be added to 8 oz of fluid. The three packets should be consumed each
      day in a total of 24 fluid ounces.

      Weight Loss Methods:

      All participants will have a daily caloric restriction of ~ 800 kcal in order to facilitate a
      loss of 0.5 kg - 0.9 kg per week weight loss or a 9-18 kg loss during the 12-week study
      period. All participants will undergo a resting metabolic rate determination using
      MedGraphics Ultima™ metabolic cart and the accompanying Breeze software. Based on the caloric
      need determined to maintain weight, a new caloric plan, 800 kcal lower than basal needs, will
      be determined. At minimum, however, all women will receive 1000 kcal per day. Once caloric
      goals are determined, these will be achieved with through CRU-prepared meal replacements or
      participant- instituted calorie restriction techniques learned via nutritional education
      group sessions.

      Participants receiving nutritional education will two individual sessions (spaced approx. 2
      weeks apart). The nutritional sessions will focus on knowledge, self-regulation, motivation,
      experience and environment.

      All participants will be weighed at baseline and then weekly until the close of the study,
      week 13. Additionally, all participants will, with CRU-prepared meals, be asked to return
      uneaten food, record any foods eaten that were not part of the plan and complete weekly food
      compliance logs. Participants with self-directed food selection after nutritional education
      will be asked to completed detailed records of foods selected each day. All logs and food
      records will be reviewed by the PI and the CRU study dietician. If participants have: 1)
      increased weight by ≥ 5 pounds between weigh-in sessions; 2) a trend of weight gain for two
      consecutive sessions; or 3) failed to return 2 consecutive food logs; they will be flagged
      for additional nutritional counseling.

      OUTCOMES Study Outcomes: The primary outcome, change in VAT between baseline and 12 weeks,
      will be obtained via repeat computed tomography (CT) scans. The secondary outcomes are change
      in CVD risk factors (blood pressure, fasting lipids, insulin sensitivity, C-reactive protein)
      and liver attenuation. Abdominal fat mass will be measured at the L4/L5 vertebral regions by
      CT. Height and weight will be measured to the nearest 0.5 cm and 0.1 kg, respectively, and
      BMI will be calculated (kg/m2). Systolic and diastolic blood pressure will be obtained after
      a 5-minute rest; the average of the final two of three measurements will be used in analysis.
      Fasting blood samples will be collected for the measurement of glucose, insulin, LDL,
      HDL,25-OH vitamin D, ghrelin, adiponectin, TNF-alpha, IL-6 and high sensitivity C-reactive
      protein. Insulin resistance will be calculated via a HOMA model. Covariates such as smoking
      status, physical activity, alcohol intake, sleep, and depressive symptoms will be ascertained
      at baseline.
    

Intervention name(s): Benefiber; TrueLemon
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Benefiber® powder will be used as our dietary supplement intervention. Benefiber® powder contains wheat dextrin, a 100% natural fiber. Participants in the intervention arm will receive 3 supplement packets to be consumed per day.
Each active dietary supplement packet contains 8 grams of Benefiber® powder and 3 grams of TRUE® lemon flavoring, a 100% natural with no artificial ingredients or sweeteners, preservatives, sodium or gluten.; Each placebo dietary supplement packet contains 8 grams of Splenda and 3 grams of TRUE® Lemon sweetener. Each packet is designed to be added to 8 oz of fluid. The three packets should be consumed each day in a total of 24 fluid ounces.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Treatment
Keywords: Intra-Abdominal Fat; Metabolic Syndrome; Hepatic steatosis