Before pinitol/placebo administration a four weeks run-in period of a healthy diet will be follow for all subjects. After this adaptation period, each subject will be randomized (1:1) into one of two groups: one that received the pinitol-enriched beverage (4 g/day) (n=20), and the other a placebo beverage (n=20) for 12 weeks.

Before pinitol/placebo administration a four weeks run-in period of a healthy diet will be follow for all subjects. After this adaptation period, each subject will be randomized (1:1) into one of two groups: one that received the pinitol-enriched beverage (4 g/day) (n=20), and the other a placebo beverage (n=20) for 12 weeks.

Before pinitol/placebo administration a four weeks run-in period of a healthy diet will be follow for all subjects. After this adaptation period, each subject will be randomized (1:1) into one of two groups: one that received the pinitol-enriched beverage (4 g/day) (n=20), and the other a placebo beverage (n=20) for 12 weeks.

Fruit Up® (diluted with mineral water to a final volume of 250 ml) will be evaluated, and will be equivalent to an intake of 2 g of pinitol. The placebo beverage will contain equal amounts of non-polyol carbohydrates with similar macronutrient composition and energy intake as that those obtained through the pinitol beverage, but excluding pinitol.

Blood samples were collected in vacutainer serum separator tubes, after 12- hour overnight fasting, to analyze glucose and insulin concentration at baseline (after a four weeks run-in period of a healthy diet), 6 and 12 weeks after pinitol/placebo administration. Glucose concentrations were measured by means of enzymatic assay in an autoanalyzer. Insulin concentrations were determined by enzyme-linked immunosorbent assay.

In a representative group of patients of all groups at time 0 and 10 weeks, a 24 hours glucose levels control were assessed (by means of a continuous glucose monitoring system) for 3 days.

Insulin resistance was estimated by the homeostasis model assessment of insulin resistance (HOMA-IR) index (fasting insulin (μIU/ml) x fasting glucose (mg/dl) /405). Glycosylated hemoglobin (HbA1c) was measured at baseline and 12 weeks in diabetic and impaired fasting glucose subjects.

Total cholesterol and triglycerides were measured by means of enzymatic assays and HDL cholesterol concentrations were recorded using a direct method with an autoanalyzer. LDL cholesterol concentration was calculated using the Friedewald method. Non-HDL cholesterol concentration was obtained by calculating the difference between total and HDL cholesterol. Atherogenic index of plasma was obtained by calculating the logarithm of the ratio of plasma concentration of triglycerides to HDL-cholesterol. Apolipoprotein A-I and B were determined by immunonephelometry. These parameters were measured at baseline, 6 and 12 weeks after pinitol/placebo administration.