Development of a Novel Method to Study in Vivo Fatty Acid Metabolism Using Stable Isotope Labeled Fatty Acids in Humans
Condition: Dyslipidemia
MeSH terms: Dyslipidemias
Study type: Interventional

Summary: 
      Specific Aim 1: To compare the metabolic fate (transport, conversion and oxidation) of
      labeled 18:0 (13C18:0) and its metabolic product 18:1 (13C18:1) in the fed state after
      habituation to diets enriched in the corresponding fatty acid.

      Hypothesis: In the fed state, the metabolic fate of 13C18:0 compared to 13C18:1 will be
      characterized by similar transport, higher conversion, and similar oxidation rates..
    

Detailed description: 
      Vegetable oils high in the specific fatty acids of interest - stearic (found in cocoa butter,
      meats), palmitic (found in meats, dairy and some plant oils) and stearic acid's metabolic
      product, oleic (found in olive and corn oil) - will be used to displace each other in a
      standardized diet and fed to mildly hypercholesterolemic postmenopausal women using a
      randomized-controlled crossover design. Six women who are enrolled in 10150 - Study A will be
      invited to participate in this study. Each of the phases will be 5 weeks in length with a 2-4
      week break between phases. All food and drink will be provided to study volunteers. Blood
      pressure and body weight will be monitored once per week and adjustments made, if necessary,
      to maintain a stable weight. During week 1 of the 18:0 and 18:1 dietary phases, a fasting
      blood sample will be drawn. A single stool sample will be collected on any of the study
      visits after week three. On Day 1 of week 5, following a 12 hour fast, each volunteer will
      receive their usual diet divided into 15 hourly small meals. A purified tracer dose (1 mg/kg
      bodyweight [BW]) of 13C fatty acid will be incorporated into the 1pm meal. Blood samples will
      be collected from a catheter inserted into the subcubital vein just before consuming the
      first hourly meal and then 2, 5, 7, 8, 9, 11, 13 and 15 hours thereafter. Breath samples will
      be collected before the first hourly meal as well as at various time-points after. Additional
      fasting blood samples will be collected on Days 2, 3, 4 and 5 of the 18:0 and 18:1 diet
      phases. At the end of Day 1, volunteers will have the option of returning home or staying
      overnight at the Jean Mayer Human Nutrition Research Center.
    

Intervention name(s): Oleic Diet; Palmitic Diet; Stearic Diet
Intervention type(s): Other; Other; Other
Intervention description(s): The 18:1 (oleic) diet will contain 55%E carbohydrate, 15%E protein, 30%E fat, 100 mg cholesterol/1000 kcal and 15 g fiber/1000 kcal. The vegetable oils and/or fats (henceforth collectively referred to as experimental oils) that will be used to formulate the diets were selected not only take into account the fatty acid of interest but also the fatty acid displaced within the context of an unchanged total fat content. This was accomplished by formulating a diet containing 10%E fat and then adding the experimental oils (oleic) to 30%E total fat by incorporating them into various food items intended for consumption throughout the day. The actual food items comprising the 3 diets will be similar, only differing in the experimental oils.; The 16:0 (palmitic) diet will contain 55%E carbohydrate, 15%E protein, 30%E fat, 100 mg cholesterol/1000 kcal and 15 g fiber/1000 kcal. The vegetable oils and/or fats (henceforth collectively referred to as experimental oils) that will be used to formulate the diets were selected not only take into account the fatty acid of interest but also the fatty acid displaced within the context of an unchanged total fat content. This was accomplished by formulating a diet containing 10%E fat and then adding the experimental oils (palmitic) to 30%E total fat by incorporating them into various food items intended for consumption throughout the day. The actual food items comprising the 3 diets will be similar, only differing in the experimental oils.; The 18:0 diet (stearic) will contain 55%E carbohydrate, 15%E protein, 30%E fat, 100 mg cholesterol/1000 kcal and 15 g fiber/1000 kcal. The vegetable oils and/or fats (henceforth collectively referred to as experimental oils) that will be used to formulate the diets were selected not only take into account the fatty acid of interest but also the fatty acid displaced within the context of an unchanged total fat content. This was accomplished by formulating a diet containing 10%E fat and then adding the experimental oil (stearic) to 30%E total fat by incorporating them into various food items intended for consumption throughout the day. The actual food items comprising the 3 diets will be similar, only differing in the experimental oils.
Other intervention name(s): Diet enriched in oleic acid; 18:1; Diet enriched in palmitic acid.; 16:0; Stearic acid enriched diet.; 18:0
Intervention MeSH terms: Palmitic Acid
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Treatment
Keywords: fatty acid kinetics