Isolated soluble fibre supplementation improves weight, glucose in obese adults
Anthropometric and metabolic outcomes have improved in overweight and obese adults taking isolated soluble fibre supplementation, suggesting its potential to improve fibre intake and health in these at-risk population, according to the results of a systematic review and meta-analysis of randomized controlled trials (RCTs).
“[B]ecause of the observed improvements in body composition, glucose, and insulin in the present study and the extensive dietary fibre intake gap between recommended intake and actual dietary fibre intake in the United States, isolate soluble fibre supplementation may be a feasible approach to improve weight and metabolic health in overweight and obese individuals,” researchers said.
Findings from 12 RCTs involving 609 participants from 2‒17 weeks of duration showed that soluble fibre supplementation, compared with placebo, reduced body mass index by 0.84 kg/m2 (95 percent CI, ‒1.35 to ‒0.32; p=0.001), body weight by 2.52 kg (‒4.25 to ‒0.79 kg; p=0.004), body fat by 0.41 percent (‒0.58 to ‒0.24 percent; p<0.001), fasting glucose by 0.17 mmol/L (‒0.28 to ‒0.06 mmol/L; p=0.002), and fasting insulin by 15.88 pmol/L (‒29.05 to ‒2.71 pmol/L; p=0.02). [Am J Clin Nutr 2017;106:1514-1528]
Slight reductions in weight, even small ones, can improve metabolic outcomes, according to researchers. For every kilogram of lost body weight, risk of type 2 diabetes was reduced by 16 percent, and a 2‒5-percent weight loss was associated with improvements in fasting blood glucose and glycated haemoglobin. [Diabetes Care 2006;29:2102–2107; Diabetes Care 2011;34:1481–1486]
No publication bias was identified, but there was a considerable heterogeneity for most outcomes among the included studies.
Soluble fibres with different viscosity and fermentability profiles have been found to confer variable physiologic effects based on previous research. [Clin Nurs Stud 2013;1:82–92; J Am Acad Nurse Pract 2012;24:476–87; Crit Rev Food Sci Nutr 2006;46:649–63]
“Soluble, viscous, fermentable fibre is known to lower blood glucose and lipid concentrations, and emerging research has indicated that similar metabolic improvements may result from nonviscous, fermentable fibre consumption,” researchers said. [Clin Nurs Stud 2013;1:82–92; Br J Nutr 2014;111:1147–1161]
These findings provide evidence that isolated soluble fibre supplementation may benefit overweight and obese adults, which has important implications to food regulators, manufacturers, clinicians, and even consumers.
“Although caution is warranted when evaluating our findings because of the high between-study heterogeneity, these results suggest that isolated soluble fibre supplementation has promising implications for weight management and improved glucose and insulin homeostasis in overweight and obese individuals,” researchers said.
PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library databases were searched for RCTs that compared isolated soluble fibre with placebo treatments without energy-restriction protocols.
Researchers used random-effects models to estimate pooled effect sizes and 95 percent CIs. They also performed meta-regressions to evaluate outcomes in relation to the intervention duration, fibre dose, and fibre type. Publication bias was assessed via Begg’s and Egger’s tests and funnel plot inspection.