Soluble fibre boosts satiety, aids weight loss: study

A soluble fibre supplement improved cholesterol levels in overweight and obese subjects, who also lost about four kilograms more than people in the placebo group over 16 weeks, report scientists in the British Journal of Nutrition .

The study taps into the burgeoning weight loss and management market, estimated to already be worth $7bn (€5.2bn) globally.

With 50 per cent of Europeans and 62 per cent of Americans classed as overweight, the food industry is waking up to the potential of products for weight loss and management.

The slimming ingredients market can be divided into five groups based on the mechanisms of action - boosting fat burning/ thermogenesis, inhibiting protein breakdown, suppressing appetite/ boosting satiety (feeling of fullness), blocking fat absorption, and regulating mood (linked to food consumption).

The researchers, led by Jordi Salas-Salvado from Saint Joan University Hospital in Reus, Spain, randomly assigned 200 overweight or obese patients to receive either a mixed fibre dose (three grams of Plantago ovata husk and one gram of glucomannan)

twice or three times a day, or placebo for 16 weeks.

The study was a parallel, double-blind, placebo-controlled clinical trial.

At the end of the study, the researchers report that weight loss 'tended' to be higher in both fibre groups (4.52 and 4.60 kg lost in the twice and three times a day group, respectively), compared to the placebo group (0.79 kg lost).

In addition, satiety was reported to be increase after consumed the fibre-rich meals.

Moreover, LDL cholesterol levels - a cardiovascular risk marker - decreased by 0.38 and 0.24 mmol/l in the twice and three times a day group, respectively, compared to a decrease of only 0.06 mmol/l in the placebo group, state the authors.

Improvements in the ratio of total cholesterol to HDL-cholesterol and HDL to LDL were also reported.

"In conclusion, a 16-week dietary supplement of soluble fibre in overweight or obese patients was well tolerated, induced satiety and had beneficial effects on some CVD risk factors, the most important of which was a significant decrease in plasma LDL-cholesterol concentrations," wrote Salas-Salvado.

Soluble versus insoluble fibre Studies have also reported that insoluble fibre, which contains cellulose, hemicellulose and lignin and cannot be dissolved in water, may reduce the risk of obesity and diabetes, but the biological mechanism underlying the benefits has only been assumed.

The assumption was that the fibre reduced the glycemic response (a rise in blood glucose), thereby increasing satiety and decreasing energy intake.

A lower glycemic response decreases the demand for insulin, therefore reducing the risk of type 2 diabetes.

In Europe and Japan, soluble fibre has the greater market share than insoluble.

In the US, where the entire fibre market was worth $192.8m (€151.0m) in 2004, insoluble fibre dominates the market with $176.2m (€138.0m), and $16.6m (€13.0m) soluble.

But while Frost and Sullivan predicts overall growth in the US to $470m (€369m) by 2011, the soluble fibre sector is expected to increase by almost twice the compound annual growth rate (CAGR) compared to insoluble fibre - 26.3 per cent compared to 13.1 per cent.

Source: British Journal of Nutrition Volume 99, Issue 6, Pages 1380-1387 "Effect of two doses of a mixture of soluble fibres on body weight and metabolic variables in overweight or obese patients: a randomised trial" Authors: J. Salas-Salvado, X. Farres, X. Luque, S. Narejos, M. Borrell, J. Basora, A. Anguera, F. Torres, M. Bullo, R. Balanza, for the Fiber in Obesity-Study Group.