Effects of White Potato Consumption on Measures of Cardiometabolic Health in Individuals With Type 2 Diabetes Mellitus
Condition: Type2 Diabetes; Cardiometabolic Syndrome; Arterial Stiffness; Overweight and Obesity
MeSH terms: Diabetes Mellitus; Diabetes Mellitus, Type 2; Overweight; Metabolic Syndrome
Study type: Interventional

Summary: 
      The investigators are examining the effects of potato consumption on indices of glycemic
      control and cardiovascular health in overweight and obese individuals with type two diabetes
      mellitus (T2D) to provide feasible and effective dietary ways for individuals to enhance
      their quality of life. The overall objective of this crossover study is to collect data
      regarding the effects of potato consumption on indices of glycemic control and cardiovascular
      health among overweight and obese individuals with T2D. The central hypothesis of this
      crossover study is that the daily consumption of 100 g white potato for 12 weeks will
      contribute to improvements in glycemic control, reductions in inflammation, and improvements
      in blood lipids and vascular function in overweight and obese individuals with T2D compared
      to a macronutrient-matched refined grain (75 g cooked long-grain white rice) for 12 weeks
      (with a 2 week washout period between interventions).

      Specific Aim) The assessment of blood glucose control, vascular function, body composition
      and overall cardiovascular risk after consumption of potatoes (100g/d for 12 weeks) in
      individuals with T2D compared to a calorie matched refined grain at the initial baseline
      visit as well as the 6-, and 12-week study visits (for each 12-week intervention period).

      This aim will assess changed in blood glucose, insulin, HbA1c, HOMA-IR, and HOMA-β as well as
      the following:

        1. blood pressure (BP)

        2. markers of endothelial function [flow-mediated dilation (FMD), pulse wave velocity
           (PWV), and endothelin-1 (ET-1)]

        3. markers of inflammation (C-reactive protein)

        4. body composition via bioelectrical impedance (BIA), lean mass and fat mass assessment

        5. lipid profiles, consisting of total cholesterol (TC), triglycerides (TG), high-density
           lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and
           oxidized LDL (Ox-LDL). Atherogenic risk ratios (TC/HDL-C, LDL-C/HDL-C, HDL-C/LDL-C) will
           also be assessed

        6. anthropometrics [weight, height, waist circumference (WC), hip circumference (HC),
           waist-to-hip ratio (WC/HC)]
    

Detailed description: 
      A total of 50 men and postmenopausal women between the ages of 45 and 80 who have T2D will be
      recruited for this study. Participants with T2D will be recruited from Tallahassee, FL and
      surrounding areas through campus and community advertisements through flyers, newspaper
      articles, and public events. After an initial telephone screening, all participants will be
      requested to report to the clinical area of the Sandels building at FSU (study site) for
      their first on-site visit (and all visits if the participant qualifies). On the first visit
      (screening), the potential participants will be provided with verbal and written explanation
      of the project and will have any questions regarding the study answered by trained research
      personnel during the informed consent process. Then the individual will be asked to sign an
      informed consent form, followed by a medical history questionnaire to confirm their diabetic
      state, and measurements of their fasting blood glucose levels and HbA1c will also be done to
      assess any changes that may occur throughout the study. Anthropometrics will be measured and
      questions on medical history and medication use will be asked during the screening visit to
      confirm eligibility. Randomization of participants in the potato or the calorie-matched
      refined grain group will be done after the screening visit and following completion of a
      Seven-Day Food Frequency Questionnaire (FFQ), which will indicate if individuals frequently
      consume potatoes. If participants are considered "non-frequent" white potato consumers (<2
      servings per week), they will be included in this study and asked to come for following
      visits, additionally during this visit participants will be familiarized with vascular
      assessments prior to their baseline appointment. On the second (baseline) visit participants
      will be randomly assigned to one of two groups: 1) 100 g cooked white potato or 2) 75 g
      calorie-matched cooked refined grain (cooked long-grain white rice) daily for 12 weeks
      following a 2-week washout period prior to the other intervention group (a total of 26 weeks
      upon completion of the study). Study foods will be prepared at the Florida State University
      Metabolic Kitchen and Diet Assessment Lab following SafeStaff Foodhandler Training, an
      approved Florida foodhandler program, protocols for preparation, storage and handling. At the
      baseline visit participants will be asked to come fasted; BP and vascular function will be
      measured followed by blood draw, anthropometrics, body composition (via BIA), and a physical
      activity questionnaire will be administered. Participants will be provided with their
      assigned dietary regimen and will receive instructions on how to fill out daily diaries for
      their dietary regimen and will be given three-day food records to bring back for their
      subsequent visits to assess typical intake throughout the study. BP, vascular function, blood
      draw, and anthropometric, body composition, diet, and physical activity assessments will be
      repeated at 6-, and 12-week visits for both intervention periods with a 2-week washout
      between each intervention period (for a total of 5 study visits). After the 2-week washout
      period, participants will be asked to come to the study site, to receive the other
      intervention group and be given instruction on their new dietary regimen. Participants will
      be asked to come to the study site on a bi-weekly basis to pick up potato and white rice
      regimen, which can be stored in the freezer/refrigerator prior to consumption. Additionally,
      participants will be given portioned cooked rice to take home with them for the long-grain
      white rice regimen. All cardiovascular measurements will be performed between 7:00-10:00
      A.M., in a quiet temperature-controlled room after an overnight fast and 12 hours after the
      abstinence of caffeine and/or 24 hours after the last bout of moderate to heavy physical
      activity.
    

Intervention name(s): Potato Regimen; Refined Grain Regimen
Intervention type(s): Other; Other
Intervention description(s): 100 grams cooked white russet potato with the skin; 75 grams of cooked long-grain white rice
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: For this randomized cross-over study, participants (45-80 y, BMI 25-35 kg/m2, fasting blood glucose >126 g/dL, HbA1c 6.5-9%, non-frequent white potato consumption of <2 servings per week) will be randomly assigned to receive pre-prepared baked white potato (100g cooked with skin; 100kcals) or a calorie-matched refined grain (75g cooked long-grain white rice; control) daily for each or two 12-week treatment periods, separated by a 2-week washout. Randomization of participants in the potato or the calorie-matched refined grain group will be done during the screening visit.
Masking: None (Open Label)
Primary purpose: Other
Keywords: Functional Foods; Chronic Diseases; Carbohydrates; Endothelial Dysfunction; Cardiometabolic Health