The 120 volunteers (mean age 34, range 19–50) were divided into 2 groups, with 60 randomly assigned to placebo and 60 to IGOB131 (active). Of these initial 120 volunteers, 102 completed the 10 week study; 50 from the placebo group, and 52 from the IGOB131 group. Eighteen volunteers [placebo (n = 12) and IGOB131 (n = 6)] dropped out of the study for the following reasons – not experiencing rapid weight loss (n = 10); influenza attack (n = 3); dryness of mouth (n = 3); no reason given (n = 2).

Food Intake

The mean daily energy intake in the IGOB131 group was 2767 ± 187 kcal of which 56% was from carbohydrate, 29% from protein, and 15% from fat. In the placebo group, the mean daily energy intake was 3156 ± 185 kcal of which 56% was from carbohydrate, 29% was from protein, and 15% was from fat. Seven-day dietary and activity assessment of the subjects at baseline showed similar food intake habits and energy levels.

Body weight, waist size and body fat

Baseline characteristics of the two groups were well-matched and without significant differences at baseline (Table 1). There were no significant differences in the baseline body weight, waist circumference and serum leptin measurements between the placebo and experimental group (Table 1). However, by the tenth week, significant differences were observed between the placebo and experimental intervention groups, respectively, for body weight (95.7 kg vs. 85.1 kg, respectively, p < 0.01), waist circumference (101.1 cm vs. 88.1 cm, respectively, p < 0.05). Body fat decreased over time in both groups but the experimental group lost significantly more body fat (6.3%, p < 0.05) compared to the placebo group (1.9%) (Table 1).

Table 1 Changes* in body weight, waist, leptin, fat, total cholesterol, LDL cholesterol, glucose and adiponectin measurements in the course of the study. Full size table

When corrected for placebo response, the pattern of relative changes in weight and waist circumference was found to be different between the two groups, consistent with a difference in response to the intake of the extract (Figure 1).

Figure 1 Changes in body weight and waist circumference measurements in IGOB131 group corrected for placebo values. Full size image

Total and LDL cholesterol, C-reactive proteins, leptin

These variables decreased from baseline, though at different rates and magnitudes associated with duration of the study, with the experimental group showing statistically significant changes compared with the placebo group at week-10 (Table 1).

While baseline levels of serum lipids were similar in the two groups, significant differences were observed between the two as the study progressed with the experimental group showing progressively greater improvement. At week-10, significant differences were observed for total cholesterol (placebo: 142.5 mg/dl vs. IGOB131: 111.9 mg/dl, p < 0.05) and LDL cholesterol (placebo: 77.7 mg/dl vs IGO131: 59.77 mg/dl, p < 0.01). Compared to baseline values, total cholesterol decreased by 1.9% in the placebo group as opposed to 26.2% for the IGOB131 group while LDL cholesterol levels fell by 4.8% in the placebo compared to 27.3% in the IGOB131 group. Correcting for placebo values, the relative change in the total cholesterol and LDL cholesterol was observed to follow a similar pattern (Figure 2) in the experimental group, suggesting a similar response mechanism to IGOB131 intake.

Figure 2 Changes in measured characteristics in IGOB131 group corrected for placebo values. Full size image

Like in the case of the other parameters measured, C-reactive protein and leptin levels decreased over time in both groups. The rate of decrease was however accelerated in the IGOB131 relative to the placebo-group. Serum levels of CRP fell by 1.2% in the placebo group as opposed to 52.0% in the experimental group relative to baseline. On the other hand, leptin levels decreased by 9.3% in the placebo group compared to a 48.6% in the IGOB131 group over the 10-week experimental period.

Fasting blood glucose levels

Blood glucose levels in the experimental group (85.6 mg/dl ± 5.6 mg/dl) and in the placebo group (81.4 ± 9.6 mg/dl) were similar at baseline but decreased to significantly different levels (P < 0.05) at week-10 of the study (Table 1). In relative terms, decreases in placebo and treatment groups were 5.3% vs. 22.5%, respectively (Figure 3). Corrected for the placebo values, the changes in blood glucose levels were similar to that of lipids (Figure 2).

Figure 3 Percentage decrease in body weight (WT), Waist size (WS), Fat (FAT), Total Cholesterol (TCHOL), LDL cholesterol (LDL), Glucose (GLU), Leptin (LEP), C-reactive protein (CRP) and Adiponectin (ADIP) after 10 weeks of use of extract IGO131. Full size image

Adiponectin levels

Baseline serum adiponectin levels were comparable between the two groups (placebo: 12.1 mg/l ± 3.21 mg/l; IGOB131: 12.16 mg/l ± 3.04 mg/l), but increased with time (Table 1). By week-10 of the study adiponectin levels in the placebo group increased by 23.4% compared to 159.8% in the experimental group. Corrected for placebo values, the rate of increase in serum adiponectin levels in IGOB131 group followed an exponential curve (Figure 4).

Figure 4 Changes in the adiponectin levels in IGOB131 group corrected for placebo. Full size image

Adverse events

Treatment of overweight and obese subjects with IGOB131 was well-tolerated. Adverse events with an incidence >n = 3 included headache (n = 5), sleep difficulty (n = 6), and intestinal flatulence (n = 6). The incidence of all reported side effects was similar in the placebo group as well as in the treatment group.