Using the commercially available sodium alginate Protanal LFR 5/60 from FMC Biopolymers, researchers from the University of Copenhagen report that obese people taking the alginate supplements lost an average of 1.74 kg more of body weight than those on placebo.
The additional loss of body weight was “mainly attributed to a reduction in the percentage of body fat”, they wrote in the American Journal of Clinical Nutrition.
“These results suggested that alginate may be a potential agent to achieve a clinically relevant reduction in body weight in obese subjects when consumed as prescribed as an adjuvant to an energy-restricted diet.”
Several groups and enterprises are exploring the potential of alginates-containing products to enhance satiety and offer weight management potential. In 2007 researchers from the University of Buffalo in collaboration with McNeil Nutritionals reported on the potential of an alginate-pectin product to reduce energy intake between lunch and dinner (Am. J. Clin. Nutr., Vol. 86, pp. 1595-1602).
Scientists from the University of Sheffield and Sheffield Hallam University have also reported the potential of a novel beverage containing sodium alginate to slow the emptying of the stomach and prolong the feeling of fullness (Appetite, Vol. 51, pp. 713-719; Nutrition Research, Vol 28, pp. 501-505).
The Copenhagen researchers have also reported potential benefits of alginate to increase the feeling of fullness and decrease subsequent energy intake (Food Chemistry, Vol. 132, pp. 823-829).
With the World Health Organization estimating that by 2015, there will be more than 1.5 billion overweight consumers, the opportunities for a scientifically-substantiated weight management 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.
For their new a parallel, double-blind, placebo-controlled 12 week study, Morten Georg Jensen, Mette Kristensen, and Arne Astrup recruited 96 obese subjects and assigned them to consume an energy-restricted diet plus a placebo preload or the same diet with an alginate-based preload supplement (15 g fiber), derived from brown seaweed (Laminaria hyperborea and Laminaria digitata).
The preloads were given as a beverage three times per day before main meals.
Analysis of data from the 80 people who completed the study indicated that people consuming the alginate-supplemented diet lost an average of 6.78 kg during 12 weeks, compared to 5.04 kg in the placebo group.
However, the researchers reported that the placebo group experienced larger decreases in systolic and diastolic blood pressure than the alginate group.
“Special attention should be given to the sodium content and sensory property of the alginate formulation, which led to elevated blood pressure and lower palatability ratings in the group who received alginate compared with the control group,” added Jensen, Kristensen, and Astrup.
“To our knowledge, changes in body fat mass in humans after alginate intake have not been reported previously. Besides the effect of weight loss on a reduction in fat mass, it could also be hypothesized that the decreased percentage of body fat could have been because of a prebiotic effect.
“Such a prebiotic effect could act through gut fermentation and processes such as increased bifidiobacteria growth and short-chain fatty acid production, which have been proposed to be mechanistically involved in the modulation of adipose tissue.”
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.3945/ajcn.111.025312
“Effect of alginate supplementation on weight loss in obese subjects completing a 12-wk energy-restricted diet: a randomized controlled trial”
Authors: M.G. Jensen, M. Kristensen, A. Astrup