Carbohydrates and Health

Cellulose
Faecal weight and intestinal transit time
A5.13 Three randomised controlled trials were identified that presented evidence on
cellulose in relation to faecal weight and intestinal transit times (Spiller et al.,
1980; Hillman et al., 1983; Behall et al., 1987). The transit time methodologies were
insufficiently comparable to allow a meta-analysis to be performed. No further
trials were identified in the update search (Colo-rectal health review).
A5.14 An effect of cellulose (14-23g/day) is demonstrated on increasing faecal weight
in all trials. Two trials report an effect of cellulose on reducing intestinal transit
time, but one trial reports no significant effect in subjects with a relatively fast
initial intestinal transit time (Behall et al., 1987). The effect sizes are comparable
to wheat fibre.
Cellulose and faecal weight and intestinal transit time
• Effect
• Moderate evidence
• The direction of the effect demonstrates consumption of cellulose is potentially
beneficial to health
• The effect is potentially biologically relevant, but demonstrated at concentration of
intake achieved through supplementation
Mixed isolated fibres
Isolated gums and gelling agents
Blood Pressure
A5.15 Seven randomised controlled trials were identified that presented evidence on
isolated gums and gelling agents in relation to blood pressure (Bell et al., 1990;
Landin et al., 1992; Pasman et al., 1997a; Marett & Slavin, 2004; Lehtimaki et al.,
2005; Schwab et al., 2006; Wood et al., 2007). Two trials could not be included
in a meta-analysis as they did not report the necessary data (Pasman et al., 1997a;
Marett & Slavin, 2004) (Cardio-metabolic review, incident hypertension and blood
pressure chapter). The trials included in the analysis supplemented subjects’ diets
with either pectin, guar gum, chitosan, or konjac mannan.
A5.16 No significant effect is demonstrated for various isolated gums and gelling agent
supplements on systolic blood pressure (-0.82mmHg, 95% CI -5.2, 3.6; p=0.72).
A5.17 No consistent effect is demonstrated for various isolated gums and gelling agent
supplements on diastolic blood pressure on the forest plot. Furthermore the
heterogeneity was above the pre-specified cut-off of 75% (I 2 =81%) therefore, the
pooled estimate has not been reported.
A5.18 The two trials that are not included in the meta-analysis report no significant
effect of either guar gum or arabino-galactans on blood pressure (Pasman et al.,
1997a; Marett & Slavin, 2004).
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