Walnuts vs. Walnut-Oil, Glucose Homeostasis, PCOS

Summary

Principal Investigator: SIDIKA E KARAKAS
Abstract: [unreadable] DESCRIPTION (provided by applicant): Our overall aim is to investigate the effects of dietary fatty acid composition on glucose homeostasis in women with polycystic ovary syndrome (PCOS). This common disease affects one out of sixteen women and causes insulin resistance and increases the risk for diabetes. Treatment of insulin resistance, and consequent hyperinsulinemia, improves ovarian function and increases fertility. Since epidemiological and experimental studies indicate that replacement of the dietary saturated fats with unsaturated fats improves insulin sensitivity, these women are advised to increase polyunsaturated fat (PUFA) intake from nuts, seeds and fish-oil. This advice is not evidence based. [unreadable] [unreadable] We recently investigated the effects of a PUFA-rich nut, walnuts, on glucose homeostasis in an insulin in PCOS patients. Unexpectedly, walnut-intake increased plasma glucose both at fasting and during oral glucose tolerance test. The clinical consequence of this finding depends upon the underlying mechanism: If the rise in blood glucose is due to an impairment in pancreatic function, this can potentially accelerate development of diabetes. On the other hand, if it is due to re-setting of the pancreatic glucose-sensor to a higher threshold, this can benefit PCOS patients by reducing [unreadable] hyperinsulinemia. Based on our initial observations, we anticipate that the latter mechanism may be valid. [unreadable] [unreadable] The hypotheses of this revised proposal are: [unreadable] 1. PUFA-rich walnuts, but not MUFA-rich almonds, alter glucose homeostasis in PCOS patients. [unreadable] 2. The PUFA-rich oil component of the walnuts is responsible for the changes in glucose homeostasis. [unreadable] 3. Effects of walnut-oil on glucose homeostasis differ from those of the fish-oils. [unreadable] [unreadable] This hypothesis will be tested in 96 women with PCOS. After an initial habitual-diet control phase, patients will be randomized to consume almonds, walnuts, walnut-oil or fish-oil in a parallel-design intervention. Changes in glucose homeostasis will be investigated. [unreadable] [unreadable] This pilot study will identify the favorable as well as unfavorable effects of different PUFA-rich foods and determine the most beneficial intervention to be tested in future clinical trials. The proposed research will make important contributions by testing cost-effective nutrition interventions in forestalling the development of diabetes, cardiovascular disease risk, and infertility in young women--an understudied population. [unreadable] [unreadable]
Funding Period: 2006-04-01 - 2008-03-31
more information: NIH RePORT

Top Publications

  1. pmc Serum fatty acid binding protein 4, free fatty acids, and metabolic risk markers
    SIDIKA E KARAKAS
    Department of Internal Medicine, Division of Endocrinology, Clinical Nutrition and Vascular Medicine, The University of California at Davis, Davis, CA 95817, USA
    Metabolism 58:1002-7. 2009
  2. ncbi Lean mass and insulin resistance in women with polycystic ovary syndrome
    Kevin B Comerford
    Nutritional Biology Graduate Group, Department of Nutrition, The University of California at Davis, Davis, California, USA
    Metabolism 61:1256-60. 2012
  3. ncbi Utility of hemoglobin-A1C in nondiabetic women with polycystic ovary syndrome
    Rami Mortada
    Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of California Davis, Davis, CA 95817, USA
    Endocr Pract 19:284-9. 2013
  4. pmc In polycystic ovary syndrome, adrenal steroids are regulated differently in the morning versus in response to nutrient intake
    Dumindra Gurusinghe
    Department of Internal Medicine, Division of Endocrinology, Clinical Nutrition and Vascular Medicine, The University of California at Davis, Davis, California, USA
    Fertil Steril 93:1192-9. 2010
  5. pmc Determinants of impaired fasting glucose versus glucose intolerance in polycystic ovary syndrome
    SIDIKA E KARAKAS
    Department of Internal Medicine, Division of Endocrinology, Clinical Nutrition and Vascular Medicine, University of California, Davis, Davis, California, USA
    Diabetes Care 33:887-93. 2010
  6. ncbi Differential effects of walnuts vs almonds on improving metabolic and endocrine parameters in PCOS
    S Kalgaonkar
    Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, The University of California at Davis, Davis, CA, USA
    Eur J Clin Nutr 65:386-93. 2011

Scientific Experts

  • SIDIKA E KARAKAS
  • Rami Mortada
  • Kevin B Comerford
  • S Kalgaonkar
  • Kyoungmi Kim
  • Rogelio U Almario
  • Dumindra Gurusinghe
  • K James Kallail
  • Kevin Comerford
  • W Buchan
  • K Kim
  • D Gurusinghe
  • R U Almario
  • E M Garamendi
  • Nancy L Keim
  • William F Horn
  • Jennifer Lee
  • Sharan Gill

Detail Information

Publications6

  1. pmc Serum fatty acid binding protein 4, free fatty acids, and metabolic risk markers
    SIDIKA E KARAKAS
    Department of Internal Medicine, Division of Endocrinology, Clinical Nutrition and Vascular Medicine, The University of California at Davis, Davis, CA 95817, USA
    Metabolism 58:1002-7. 2009
    ..In conclusion, fasting FABP4 related to metabolic risk markers more strongly than fasting FFA. Nadir FABP4 and nadir FFA measured after glucose loading may provide better risk assessment than the fasting values...
  2. ncbi Lean mass and insulin resistance in women with polycystic ovary syndrome
    Kevin B Comerford
    Nutritional Biology Graduate Group, Department of Nutrition, The University of California at Davis, Davis, California, USA
    Metabolism 61:1256-60. 2012
    ..7±1.7 and 48.9±1.6 kg) but discordant for fat mass (43.3±2.6 vs 30.3±8.9 kg) showed no differences in insulin resistance parameters. These novel findings indicate that lean mass relates directly to insulin resistance in PCOS...
  3. ncbi Utility of hemoglobin-A1C in nondiabetic women with polycystic ovary syndrome
    Rami Mortada
    Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of California Davis, Davis, CA 95817, USA
    Endocr Pract 19:284-9. 2013
    ..Compared to the general population, women with polycystic ovary syndrome (PCOS) have a higher risk for diabetes. Our goal was to determine what glucose homeostasis abnormalities can be identified by A1C ≥5.7% in women with PCOS...
  4. pmc In polycystic ovary syndrome, adrenal steroids are regulated differently in the morning versus in response to nutrient intake
    Dumindra Gurusinghe
    Department of Internal Medicine, Division of Endocrinology, Clinical Nutrition and Vascular Medicine, The University of California at Davis, Davis, California, USA
    Fertil Steril 93:1192-9. 2010
    ..To investigate adrenal steroid regulation in polycystic ovary syndrome...
  5. pmc Determinants of impaired fasting glucose versus glucose intolerance in polycystic ovary syndrome
    SIDIKA E KARAKAS
    Department of Internal Medicine, Division of Endocrinology, Clinical Nutrition and Vascular Medicine, University of California, Davis, Davis, California, USA
    Diabetes Care 33:887-93. 2010
    ..To determine insulin resistance and response in patients with polycystic ovary syndrome (PCOS) and normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance, and combined glucose intolerance (CGI)...
  6. ncbi Differential effects of walnuts vs almonds on improving metabolic and endocrine parameters in PCOS
    S Kalgaonkar
    Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, The University of California at Davis, Davis, CA, USA
    Eur J Clin Nutr 65:386-93. 2011
    ..Our goal was to compare the effects of MUFA-rich almonds vs n-3/n-6 PUFA-rich walnuts on metabolic and endocrine parameters in PCOS...