Study of the Impact of Dairy Fat on Cardiovascular Health.
Condition: Metabolic Syndrome
MeSH terms: Metabolic Syndrome
Study type: Interventional

Summary: 
      Market trends depicted by Agriculture and Agri-Food Canada suggest stagnation in cheese
      consumption, with potentially important impact on this key industry in Canada. This is in
      part due to the commonly accepted notion that saturated fat in the diet, of which cheese
      contributes significantly, increases the risk of heart disease. Yet, a rather large body of
      recent evidence suggests that saturated fat may have been unfairly demonized and that its
      impact on the risk of heart disease may in fact be less important than originally thought.
      This concept that dairy fat increases the risk of heart attacks therefore needs to be
      revisited, and this is one of the key objectives of this proposed research program.

      The proposed research is designed to investigate for the first time if dairy fat improves the
      levels of the so-called "good cholesterol", a protective risk factor that has been
      essentially ignored in the arguments supporting the reduction of saturated fat for heart
      health.

      Our hypothesis is that consumption of SFA from dairy (cheese) compared with a low fat diet
      and diets rich in MUFA and PUFA leads to favorable changes in plasma HDL-C concentrations and
      functional characteristics. Consumption of SFA from dairy (cheese) also increases LDL
      particle size, reduces inflammation and has no deleterious impact on plasma LDL-C and
      apolipoproteins B (apoB) concentrations compared with a low fat diet.
    

Detailed description: 
      This is a multi-center randomized crossover controlled feeding study. Briefly, adult men and
      women will be recruited in the Quebec City and Winnipeg metropolitan area through the media
      (newspaper, radio), local lipid clinics and mailing lists (n=90).

      Participants will be randomized to a series of 5 experimental diets of 4 weeks each: 1-
      Cheese diet, 2- Butter diet, 3- Carbohydrate (CHO) diet, 4- MUFA diet, 5- PUFA diet. Usual
      energy intake will be estimated at the beginning of the study using validated tools.
      Experimental diets will be provided as part of a full feeding protocol under carefully
      controlled isocaloric conditions to maintain body weight constant. All meals and foods will
      be provided to participants so that control for energy and macronutrient intake will be
      optimized. The breakfast meal will represent approximately 30% of the daily energy intake
      whereas the lunch and dinner meals each will provide 35% of daily energy intake. Participants
      will be instructed to consume their entire meals. A seven-day cyclic menu will be used. The
      diets will be separated by washout periods of 4 weeks. Blood samples will be collected on two
      consecutive days before and after each dietary phase. The mean of the two consecutive
      measurements will be used in the analyses.
    

Intervention name(s): Cheese diet; Butter diet; CHO diet; MUFA diet; PUFA diet
Intervention type(s): Other; Other; Other; Other; Other
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Prevention