The Impact of a Powdered Meal Replacement on Metabolism and Gut Microbiota
Condition: Dietary Modification
Study type: Interventional

Summary: 
      This study will investigate the impact of a 12-week powdered meal replacement on
      inflammatory, metabolic, and hormonal markers of obesity-associated conditions and to
      correlate this response to compositional shifts within the gut microbiota. Moreover, resting
      energy expenditure, body composition, appetite sensations and soy metabolomics will be
      explored.

      This study will be a randomized, parallel group, clinical trial of a 12-week nutritional
      intervention. A sample size of n=88 participants will be randomly allocated into one of the
      following groups:

        -  Control group (CON): Participants will be asked to maintain their usual dietary intake
           over 12 weeks. Their usual dietary intake is expected to reflect the North American
           dietary pattern (i.e. ~15% of total energy intake coming from protein, ~50% from
           carbohydrate and ~35% from fat).

        -  Powdered Meal Replacement group (PMR): Participants will be asked to maintain their
           usual dietary intake and consume a powdered meal replacement composed of soy protein,
           honey and yogurt twice daily (in two snacks) over 12 weeks. The addition of the meal
           replacement to a North American Dietary Pattern (described on the CON group diet) will
           result in a diet composed of, approximately, 22% of protein, 48% of carbohydrate and 30%
           of fat of total energy intake.

      The following variables will be analyzed:

        -  Interleukin (IL)-6.

        -  Gut microbiota diversity and composition, specifically taxa that have been associated
           with health benefits, obesity, and weight loss.

        -  Systemic inflammatory biomarkers (high-sensitivity C-reactive protein, IL-8, IL-10 and
           tumor necrosis factor-α);

        -  Metabolic blood markers (glucose, insulin, lipid panel, peptide tyrosine-tyrosine,
           glucagon-like peptide-1, ghrelin, adiponectin, leptin, free glycerol, free fatty acids,
           and thyroid stimulating hormone)

        -  Resting energy expenditure;

        -  Body composition;

        -  Appetite sensations (hunger, satiety, fullness, and prospective food consumption);

        -  Soy polyphenols' metabolomics.

        -  Gene expression and genetic polymorphisms. At baseline and after 6 and 12 weeks,
           individuals will attend our Human Nutrition Research Unit where all assessments will
           take place. In order to assess participants' adherence and follow-up, dietary intake,
           body weight and appetite sensations (only for participants assigned to the PMR group)
           will be assessed weekly during the 12-week intervention period. Additionally,
           participants will be contacted by phone weekly and reminded to maintain their
           journal/log.
    

Detailed description: 
      Overweight and obesity increase the risk of developing several diseases having a negative
      effect on people's health. The prevalence of these conditions is increasing worldwide, but
      successful treatments are lacking. As excess body weight is a result of an imbalance between
      calories in and calories out, dietary intake plays an important role in maintaining a healthy
      body weight and overall health status. Meal replacements are nutritionally complete formula
      foods used to substitute a meal. They can be a drink, bar, or soup. These products have been
      gaining popularity because they can help individuals lose weight. In addition, depending on
      its ingredients, meal replacements may affect our health. For this reason, meal replacements
      have been studied for health benefits. However, how meal replacements affect the microbes
      living in our gut, inflammation, and our genes is not known. Well-designed studies using
      state-of-the-art equipment can help elucidate the mechanisms by meal replacements act in
      individuals with overweight or obesity.

      The overall purpose of this research is to investigate the impact of a 12-week powdered meal
      replacement on inflammatory, metabolic, and hormonal markers of obesity-associated conditions
      and to correlate this response to compositional shifts within the gut microbiota. Moreover,
      resting energy expenditure, body composition, appetite sensations, soy metabolomics, gene
      expression, and genetic polymorphisms will be explored.

      This study will be a randomized, parallel group, clinical trial of a 12-week nutritional
      intervention. A sample size of n=88 participants will be randomly allocated into one of the
      following groups:

        -  Control group (CON): Participants will be asked to maintain their usual dietary intake
           over 12 weeks. Participants' usual dietary intake is expected to reflect the North
           American dietary pattern (i.e. ~15% of total energy intake coming from protein, ~50%
           from carbohydrate and ~35% from fat).

        -  Powdered Meal Replacement group (PMR): Participants will be asked to maintain their
           usual dietary intake and consume a powdered meal replacement composed of soy protein,
           honey and yogurt twice daily (in two snacks) over 12 weeks. The addition of the
           nutritional supplement to a North American Dietary Pattern (described on the CON group
           diet) will result in a diet composed of, approximately, 22% of protein, 48% of
           carbohydrate and 30% of fat of total energy intake. The amount of protein is considered
           higher than the North American dietary pattern (i.e. 15%); however, still within the
           Acceptable Macronutrient Distribution Range (AMDR) recommended by the Dietary Guidelines
           for Americans (10-35%).

      The following variables will be analyzed:

        -  Interleukin (IL)-6.

        -  Gut microbiota diversity and composition, specifically taxa that have been associated
           with health benefits, obesity, and weight loss.

        -  Systemic inflammatory biomarkers (high-sensitivity C-reactive protein [hs-CRP], IL-8,
           IL-10 and tumor necrosis factor-α [TNF-α]);

        -  Metabolic blood markers [glucose, insulin, lipid panel (i.e. total cholesterol, LDL,
           HDL, and triglycerides), peptide tyrosine-tyrosine (PYY), glucagon-like peptide-1
           (GLP-1), ghrelin, adiponectin, leptin, free glycerol, free fatty acids, and thyroid
           stimulating hormone (TSH)];

        -  Resting energy expenditure;

        -  Body composition;

        -  Appetite sensations (hunger, satiety, fullness, and prospective food consumption);

        -  Soy polyphenols' metabolomics.

        -  Gene expression and genetic polymorphisms. At baseline and after 6 and 12 weeks,
           individuals will attend our Human Nutrition Research Unit where all assessments will
           take place. In order to assess participants' adherence and follow-up, dietary intake,
           body weight and appetite sensations will be assessed weekly during the 12-week
           intervention period. Additionally, participants will be contacted by phone weekly and
           reminded to maintain their journal/log. Dietary intake will be assessed by a 3-day
           dietary record (2 week days and 1 weekend day) at baseline, at mid-point and end of the
           study. Participants will also be asked to complete a 1-day dietary record on one
           weekday, each week of the study. The purpose of this regular assessment is to avoid
           daily fluctuations in eating patterns, also ensuring a personalized feedback for those
           experiencing weight fluctuations. Both of these assessments (i.e. 1-day and 3-day
           dietary records) will be conducted using the online Automated Self -Administered 24-hour
           Recall (ASA24) Canada. The ASA24 is a validated web-based program that uses the
           validated U.S. Department of Agriculture's Automated Multiple-Pass Method, and is
           modified to support the Canadian food supply.

      Participants will receive a digital scale and will be asked to weight themselves daily.
      Participants from the PMR group will also be asked to rate their appetite sensations on a
      100-mm VAS paper sheet. Appetite sensation should be completed in the morning (after waking
      up and while fasting) and 30 minutes after consuming the supplement snacks in order to assess
      hunger, satiety, fullness, and prospective food consumption.
    

Intervention name(s): Soy protein, honey and yogurt.
Intervention type(s): Dietary Supplement
Intervention description(s): Participants will be asked to maintain their usual dietary intake and consume a powdered meal replacement composed of soy protein, honey and yogurt twice daily (in two snacks) over 12 weeks. The addition of the nutritional supplement to a North American Dietary Pattern (described on the CON group diet) will result in a diet composed of, approximately, 22% of protein, 48% of carbohydrate and 30% of fat of total energy intake. The amount of protein is considered higher than the North American dietary pattern (i.e. 15%); however, still within the Acceptable Macronutrient Distribution Range (AMDR) recommended by the Dietary Guidelines for Americans (10-35%).
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Powdered meal replacement; Inflammation; Gut microbiota; Energy metabolism; Body composition