Regular Consumption of Pears May Improve Parameters Associated with Metabolic Syndrome in Men and Women
Navaei, Negin (author)
Arjmandi, Bahram H. (professor directing dissertation)
Levenson, Cathy W. (university representative)
Spicer, Maria T. (committee member)
Ilich-Ernst, Jasminka Z. (committee member)
Kim, Jeong-Su (committee member)
Florida State University (degree granting institution)
College of Human Sciences (degree granting college)
Department of Nutrition, Food, and Exercise Sciences (degree granting department)
Background and Significance: MetS encompasses a cluster of cardiometabolic abnormalities that increase the risk for developing chronic diseases including cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). Its prevalence among middle-aged and older adults has increased to 45% among adults aged 60 years and older. Epidemiological studies suggest that higher fruit and vegetable consumption is associated with improved overall health as well as a reduced incidence of CVD and T2DM. Animal research and limited human studies suggest that pears and their bioactive compounds may improve certain parameters associated with MetS including body weight and abdominal obesity, lipid profiles, insulin sensitivity, and glycemic control; however, there is a paucity of such studies in general and in humans in particular. The central hypothesis of this 12-week randomized, open-label, placebo-controlled crossover clinical trial was to examine the extent to which daily consumption of two medium-sized pears (green D' Anjou and/or green Bartlett, ~166 g each) would improve clinical signs of MetS and improve underlying factors contributing to its development and progression in middle-aged and older adults (men and women aged 45-60 years) with MetS. Methods: Fifty men and women (age: 59.0 ± 1 years; body mass index [BMI]: 33 ± 1 kg/m2; systolic blood pressure (SBP): 135 ± 2 mmHg, diastolic blood pressure (DBP): 82 ± 1 mmHg; fasting blood glucose: 97 ± 2 mg/dL; HDL-C: 44 ± 2 mg/dL; and TG: 182 ± 13 mg/dL) were randomly assigned to one of two treatment groups: 1) two medium-sized fresh pears (green Bartlett or green D' Anjou depending on the season)/day for 12 weeks, or 2) 50 g of calorie and carbohydrate matched control powder/day for 12 weeks. The initial treatment period was 12 weeks in duration followed by a 4-week washout period. After the 4-week washout period, participants crossed over into the other group for an additional 12-week period. Serum samples were directly analyzed enzymatically for TC, HDL-C, LDL-C, TG levels, Apo-B, fasting blood glucose levels, insulin levels, and high-sensitivity CRP at baseline, 6- and 12-week. Body composition including percent fat mass, fat free mass, as well as android/gynoid ratio were assessed at baseline, 6- and 12-week using dual energy x-ray absorptiometry. Waist and hip circumferences were measured to the nearest 0.5 cm during each visit. Questionnaires were used for monitoring dietary and physical activity patterns over the course of the study. Analyses were performed for the 43 subjects who completed the entire study. Results: Self-reported compliance with the treatments was 82% on average for each group. The retention of participants was excellent as only seven out of fifty participants dropped over the course of the study (14% attrition). A daily intake of two-medium-sized pear resulted in improvements of certain parameters associated with MetS including SBP tended to be reduced (130 ± 2 mmHg vs. 134 ± 2 mmHg at baseline, - 4 mmHg, P = 0.07) and pulse pressure was significantly reduced (50 ± 1 vs. 54 ± 1 at baseline, P < 0.05) at 12 weeks while no changes were observed in the control group. Waist circumference was significantly reduced (- 0.6 cm, P < 0.05) at 12 weeks in the pear group (107.5 ± 1.9 cm vs. 108.1 ± 2.0 cm at baseline) while waist circumference was significantly increased (108.4 ± 1.9 cm vs. 107.9 ± 2.0 cm at baseline, P < 0.05) at 6 weeks in the control group and was sustained at 12 weeks. Additionally, at 6 weeks, waist circumference tended to be lower (P = 0.0987) in the pear group (107.8 ± 1.9 cm) than the control group (108.4 ± 1.9 cm). Moreover, waist-to-hip ratio was significantly reduced (0.925 ± 0.011 vs. 0.930 ± 0.011 at baseline, P < 0.05) at 12 weeks in the pear group, and at 6- and 12- week values were significantly lower (P < 0.05) in the pear group (0.926 ± 0.011 and 0.925 ± 0.011, respectively) than the control group (0.933 ± 0.010 and 0.932 ± 0.010, respectively) at 6- and 12-week. Android-to-gynoid ratio (abdominal fat to hip fat) was significantly higher (P < 0.05) in the control group at 6 weeks (0.60 ± 0.01 vs. 0.57 ± 0.02 at baseline) and 12 weeks (0.61 ± 0.02 vs. 0.57 ± 0.02 at baseline) compared to baseline while no changes were noted in the pear group. Pear consumption for 12 weeks also tended to increase HDL-C by 7% (P = 0.07) and numerically lowered TG levels by 4%. The remaining parameters assessed in this study were not impacted by pear consumption. Discussion: The findings of this study suggest that daily consumption of fresh pears may improve certain features of MetS and therefore may improve cardiometabolic health in middle-aged and older adults.
March 20, 2017.
A Dissertation submitted to the Department of Nutrition, Food, and Exercise Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
Includes bibliographical references.
Bahram H. Arjmandi, Professor Directing Dissertation; Cathy W. Levenson, University Representative; Maria T. Spicer, Committee Member; Jaminka Ilich-Ernst, Committee Member; Jeong-Su Kim, Committee Member.
Florida State University
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