A pilot, randomized controlled trial to examine the health outcomes of raisin consumption in patients with diabetes

Nutrition. 2014 Mar;30(3):358-64. doi: 10.1016/j.nut.2013.07.020. Epub 2013 Nov 18.


Objectives: Dried fruits, like their fresh homologues, contain relatively high concentrations of antioxidants. The aim of this study was to determine the health outcomes of raisin consumption on patients with diabetes.

Methods: We examined the effects of dried grapes (Vitis vinifera) cultivated in Greece, namely Corinthian Raisins (CR) on blood pressure, fasting glucose, glucated hemoglobin (HbA1c), lipid peroxidation, high-sensitivity C-reactive protein, antioxidant status, and cytokines in patients with type 2 diabetes mellitus (T2DM). Forty-eight well-controlled patients with T2DM from the diabetes outpatient clinic of our hospital were recruited to a two-armed, randomized, controlled, 24-wk prospective intervention trial in order to examine the health outcomes of CR consumption. All participants were reported to consume less fruits and vegetables than the recommended amount of five servings daily. Participants in the intervention were instructed to consume CR equal to two fruit servings (36 g/d), replacing snacks with similar energy density twice during the day. Anthropometric and blood pressure measurements, assessment of dietary intake, and fasting blood draws were conducted at baseline and at week 24. Also, phenolic compounds present in CR were analyzed in plasma of the patients. t Test for parametric data and Mann-Whitney test or Wilcoxon test for non-parametric data were performed. Significance was set at P < 0.05.

Results: Body weight, glycemic control, and lipid profile were not affected in either arm. Patients in the CR arm reduced their diastolic blood pressure and increased their total antioxidant potential significantly compared with baseline. The differences between the two groups at week 24 were significant. No change in high-sensitivity C-reactive protein was observed. A significant difference in plasma circulating p-hydroxybenzoic acid was observed between groups at the end of the trial.

Conclusions: Our study shows that naturally CR may improve health features in patients with well-controlled T2DM.

Keywords: Antioxidant potential; Blood pressure; Dried fruits; Plasma phenolics; Raisins.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antioxidants / pharmacology
  • Biomarkers / blood
  • Blood Glucose / metabolism
  • Blood Pressure / physiology
  • Body Weight
  • C-Reactive Protein / metabolism
  • Diabetes Mellitus, Type 2 / diet therapy*
  • Female
  • Fruit / chemistry*
  • Greece
  • Humans
  • Lipid Peroxidation
  • Male
  • Middle Aged
  • Nutritional Status
  • Oxidative Stress
  • Parabens / analysis
  • Phenols / pharmacology
  • Pilot Projects
  • Prospective Studies
  • Treatment Outcome
  • Vitis / chemistry*


  • Antioxidants
  • Biomarkers
  • Blood Glucose
  • Parabens
  • Phenols
  • C-Reactive Protein