Form of Dairy Products on Satiety, Food Intake and Post-meal Glycaemia in Young and Older Adults
Condition: Type 2 Diabetes Mellitus; Obesity
MeSH terms: Diabetes Mellitus, Type 2
Study type: Interventional

Summary: 
      The proposed study is planned to determine the potential role for regular fat dairy products
      in short-term metabolic control in younger and older adults and the metabolic flexibility in
      response to food components, which are areas that have not yet been explored. Subjects would
      be served with solid (cheese), semi-solid (yogurt) and liquid (milk) dairy products and skim
      milk (control) and water (non-caloric control) in three separate studies.
    

Detailed description: 
      Over the last 30 years, overweight and obesity have become characteristic of the majority of
      Canadians. Approximately 60% of adults in Canada are overweight or obese. The Canadian Health
      Measures Survey, conducted during 2007-2009, estimated prevalence of metabolic syndrome at
      19.1% in the adult population. In addition, according to the 2010 Canadian Community Health
      Survey, 18.1% of Canadian adults have been reported obese. Along with the health burden, it
      has also brought about an estimated economic burden of $ 4.3 billion annually in 2001, which
      has likely doubled as of today.

      Metabolic syndrome and type 2 diabetes occur concurrently with insulin resistance marked by
      increased blood glucose levels at fasting and postprandial, glycosylated blood proteins
      leading to arterial damage, inflammation and comorbidities such as cardiovascular disease.
      Despite increased consumer interest in consuming foods that may help treat or prevent obesity
      and diabetes, effective countermeasures against metabolic diseases have yet to be
      established. Thus, food products that are capable of controlling parameters of metabolic
      diseases including blood glucose, insulin levels and food intake are in urgent need of
      investigation and identification. Dairy products are believed to hold this potential because
      of their functional physiological properties.

      There have been many observational and long-term clinical studies showing that regular
      consumption of dairy products correlate with a better body composition and a lower incidence
      of obesity and type 2 diabetes. Studies have also found that dairy proteins are more
      satiating than other types of proteins, and that they are effective in lowering the increase
      in glycemic response after high GI food intake, but most studies have been done in isolated
      proteins. Hence, the role of dairy proteins, in their conventional food form reflecting usual
      intake, on food intake and glycemia and their interactions with these metabolic diseases is
      of interest.

      From short-term studies done in our lab, the investigators have shown that dairy products can
      bring about benefits in glycemic control and food intake when consumed before or within ad
      libitum meals, which can be achieved by both insulin dependent and independent mechanisms.
      The investigators have shown that fluid milk products and yogurt improve post-meal glycemic
      excursions when consumed before or within an ad libitum meal by healthy young adults. Except
      the yogurt study conducted in our lab, there have been no other studies reporting the role of
      solid or semi-solid dairy products consumed before a meal, within a meal, immediately
      post-meal or as between meal snacks on glycemia and appetite control. Our study on yogurt
      showed that yogurts, especially those with high protein to carbohydrate ratio, reduced
      pre-meal glucose incremental areas under the curve. Further studies on solid and semi-solid
      dairy need to be conducted because milk, like other caloric beverages, lead to calorie
      accumulation if consumed before or with a meal even though it provides more nutrients, lowers
      post-meal blood glucose excursions and leads to greater post-meal satiety in young adults.

      Moreover, the evidence appears to be relatively consistent with respect to a beneficial role
      of low-fat dairy products in the prevention of type 2 diabetes (T2D), however, the role of
      regular/high-fat dairy is less clear. A number of cross-sectional and prospective
      epidemiological studies have identified a positive association between the intake of dietary
      fat and the risk for development of either insulin resistance or T2D20. More research is
      needed to better understand the role of regular-fat dairy products on food intake as well as
      of glycemic control.

      Three studies are proposed:

        -  Study 1 investigates the effects of 2-servings of pre-meal regular fat; cheese, yogurt
           and milk on food intake at 2 hours, satiety and glycemia in normal weight young adults
           (20-30 yrs) and normal weight/overweight older adults (60-70 yrs).

        -  Study 2 investigates the effects of 1-serving of pre-meal regular fat; cheese, yogurt
           and milk on satiety and glycemia in normal weight young adults (20-30 yrs) and normal
           weight/overweight older adults (60-70 yrs).

        -  Study 3 investigate the effects of 1 serving for pre-meal regular fat; cheese, yogurt
           and milk on food intake at 15 min and 30 min, satiety and glycemia in normal
           weight/overweight older adults (60-70 yrs).
    

Intervention name(s): Dietary intervention
Intervention type(s): Other
Intervention description(s): All arms are given to all participants, in a randomized order
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Dairy; Milk; Yogurt; Cheese; Postprandial glycaemia; Satiety; Food Intake; Elderly; Prevention and Treatment