The potential of dietary fiber to aid weight loss and management is dependent on the type and structure of the fiber, but impressive results can be achieved for the right fibers, says a new review from Wageningen University and Kellogg Europe.
Consuming so-called viscous fibers like pectins, beta-glucans and guar gum may reduce appetite by about 60% according to a new article published in Obesity Reviews , compared with about 14% for non-viscous fibers.
A review of randomized trials involving fiber supplementation revealed that fiber was associated with a reduction in body weight of about 0.4% over a four-week period. Such a reduction would be equivalent to losing about 300 grams every month for a 79 kg person, added the European scientists.
“However, not all fibers appeared to be equally efficient for long-term effects,” they added. “Dextrins, marine polysaccharides and chitosan showed the highest effect rates in body-weight reduction, whereas arabinoxylan-rich fibers, mannans and fructans showed the highest effect rates in long-term energy intake reduction.”
Fiber market growth
According to a report from Packaged Facts last year, consumer interest in dietary fiber has been growing with scientific studies linking increased intake to reduced risks of cancers such as colorectal and cardiovascular disease, digestive health benefits and weight management.
A 2008 International Food Information Council survey found 77% of people are proactively trying to consume additional fiber.
Despite such good intentions, however, many Americans only achieve about 50% of their recommended amount of 25 to 30 grams of fiber daily.
While interest in all types of fibers – insoluble and soluble – is expected to increase, the biggest growth is expected for so-called novel fibers. Packaged Facts defined novel fiber as “one that has not historically been viewed as a fiber food ingredient. This includes, but is not limited to inulin, FOS, GOS, resistant maltodextrin and soluble corn fiber”.
Indeed, growth of 750% is predicted for the use of novel fibers in food products, added the report.
The new paper sought to systematically review the scientific literature to-date to elucidate if dietary fiber types affected appetite, energy intake, and body weight.
Results showed that the effects of fiber were related to the chemical structure of the fibers, with the greatest effects observed for viscous fibers. Energy intake was reduced by an impressive 70% for viscous fiber consumption, compared to 30% for non-viscous.
“Several mechanisms of action for effects of viscous ﬁbers have been proposed,” said the researchers. “Viscous solutions may increase sensory delivered satiety by increased exposure time in the oral cavity. Because viscous dietary ﬁbers can hold large quantities of water, they can increase stomach distension which may trigger afferent vagal signals of fullness. They may also delay gastric emptying and thereby prolong the absorption of nutrients.
“Furthermore, the increased viscosity of digesta in the small intestine can also result in prolonged presence of nutrients in the small intestine which in turn affects the release of appetite-regulating peptides throughout the intestine, such as cholecystokinin (CCK) in the duodenum and peptide tyrosine tyrosine (PYY) and glucagon-like peptide 1 (GLP-1) in the distal ileum and proximal colon. As a result, subjective appetite may be reduced.”
Despite a strong effect on appetite and energy intake, as well as biological plausibility, the scientists called for more research to focus on the short- and long-term effects of fibers on appetite, energy intake and body weight, and “a thorough characterization of the ﬁbers used in terms of physicochemical properties is encouraged”.
According to the World Health Organization (WHO), by 2015 1.5 billion consumers will be overweight, producing health costs beyond $117 billion per year in the US alone.
As a result, the opportunities for a scientifically-substantiated weight management food product are impressive: The market for food, beverage and supplement weight management products is already valued at $3.64bn (2009 figures) in the US, according to Euromonitor. In Western Europe, the market was worth $1.3bn in 2009.
Weight Management 2011
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Source: Obesity Reviews
Published online ahead of print, doi: 10.1111/j.1467-789X.2011.00895.x
“Effects of dietary fibre on subjective appetite, energy intake and body weight: a systematic review of randomized controlled trials”
Authors: A. J. Wanders, J. J. G. C. van den Borne, C. de Graaf, T. Hulshof, M. C. Jonathan, M. Kristensen, M. Mars, H. A. Schols, E. J. M. Feskens