Effects of Various Higher Fat and Lower Fat Snacks on Cardiovascular Risk Factors in Men and Women.
Condition: Hypercholesterolemia
MeSH terms: Hypercholesterolemia
Study type: Interventional
Phase: Phase 2

Summary: 
      The purpose of this study is to determine whether snacks differing in fat amount and type
      result in changes in cardiovascular disease risk factors in men and women who have mildly
      elevated cholesterol levels. Our hypothesis is that a diet containing snacks rich in
      polyunsaturated fats lead to a more favorable cardiovascular disease risk profile than a diet
      containing snacks rich in saturated and trans fats or one containing low-fat snacks.
    

Detailed description: 
      The overall goals of this study are to determine whether snack foods rich in polyunsaturated
      fats (PUFA) produce beneficial effects on cardiovascular disease risk compared to snacks rich
      in saturated fats (SFA) and trans fats and snacks rich in refined carbohydrates. The primary
      objective of this study is to determine the effects of substituting n-6 PUFA (linoleic acid)
      from snack chips for SFA/trans fat and refined carbohydrate on serum lipids -principally
      LDL-C - and lipoproteins in moderately hypercholesterolemic men and women. A secondary
      objective is to assess effects on lipoprotein subclass particle size, intramyocellular
      lipids, and C-reactive protein (CRP). Forty-two men and women will be recruited to
      participate in a randomized, crossover, controlled feeding experiment for 3 periods of 4
      weeks each. Each feeding phase will be separated by an 8-week washout period. The control
      diet will be a National Cholesterol Education Program Step 1 diet consisting of approximately
      30% energy from total fat, <10% energy from SFA, 5% energy from PUFA, 15% energy from
      monounsaturated fatty acids (MUFA), 1% energy from trans fat, 55% energy from carbohydrates,
      and 15% energy from protein. To achieve an isocaloric substitution with PUFA, 300 kcal coming
      from low-fat, high-carbohydrate snacks will be removed from the Step 1 diet (NCEP diet) and
      replaced with 300 kcal of PUFA-rich snacks (LO diet). Similarly, 300 kcal from snacks rich in
      SFA/trans fat will replace the same 300 kcal from the high-carbohydrate from the Step 1 diet
      for the high SFA diet (SF diet). Subjects will consumed all foods provided by the GCRC and
      nothing else during each feeding phase. Breakfast and lunch meals will be consumed at the
      GCRC on weekdays and breakfast on Saturdays. All other meals will be packed and consumed at
      home. The primary study variable will be serum/plasma LDL-cholesterol. Secondary variables
      will include lipids and lipoproteins including total cholesterol (TC), HDL-cholesterol,
      VLDL-cholesterol, and triglycerides, and intramyocellular lipids. Exploratory variables will
      include assessment of lipid subclass particle size and CRP, a marker of systemic
      inflammation. Supportive variables will include fasting blood glucose and insulin, percent
      body fat mass, blood pressure and demographic information. All variables will be measured at
      baseline and endpoint of each feeding phase.
    

Intervention name(s): higher fat, high polyunsaturated fat diet; higher fat, high saturated and trans fat diet; lower fat diet
Intervention type(s): Behavioral; Behavioral; Behavioral
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: cardiovascular disease; saturated fat; trans fat; polyunsaturated fat; diet; intramyocellular lipid