The effects of bulking, viscous and gel-forming dietary fibres on satiation.

The objective was to determine the effects of dietary fibre with bulking, viscous and gel-forming properties on satiation, and to identify the underlying mechanisms. We conducted a randomised crossover study with 121 men and women. Subjects were healthy, non-restrained eaters, aged 18-50 years and with normal BMI (18.5-25 kg/m(2)). Test products were cookies containing either: no added fibre (control), cellulose (bulking, 5 g/100 g), guar gum (viscous, 1.25 g/100 g and 2.5 g/100 g) or alginate (gel forming, 2.5 g/100 g and 5 g/100 g). Physicochemical properties of the test products were confirmed in simulated upper gastrointestinal conditions. In a cinema setting, ad libitum intake of the test products was measured concurrently with oral exposure time per cookie by video recording. In a separate study with ten subjects, 4 h gastric emptying rate of a fixed amount of test products was assessed by C-13 breath tests. Ad libitum energy intake was 22% lower for the product with 5 g/100 g alginate (3.1 (SD 1.6) MJ) compared to control (4.0 (SD 2.2) MJ, P<0.001). Intake of the other four products did not differ from control. Oral exposure time for the product with 5 g/100 g alginate (2.3 (SD 1.9) min) was 48% longer than for control (1.6 (SD 0.9) min, P=0.01). Gastric emptying of the 5 g/100 g alginate product was faster compared to control (P<0.05). We concluded that the addition of 5 g/100 g alginate (i.e. gel-forming fibre) to a low-fibre cookie results in earlier satiation. This effect might be due to an increased oral exposure time.