Insoluble fiber, from wholegrains, is currently enjoying more attention from consumers and the food industry than soluble fiber, but interest in the soluble variety is rising fast, according to Frost and Sullivan.
According to a recent market report, the entire fiber market in the US was worth $192.8 million in 2004, $176.2 million of which is insoluble fiber and $16.6 million soluble.
But while Frost and Sullivan predicts overall growth to $470 million by 2011, the soluble fiber sector is expected to increase by almost twice the compound annual growth rate (CAGR) compared to insoluble fiber - 26.3 percent compared to 13.1 percent.
This balance is in sharp contrast to the European and Japanese markets, where soluble already has a greater share.
Fiber is edible matter, often from plants, that is not absorbed by the small intestine. When it passes through to the large intestine, soluble fiber, such as beta-glucan from oats and barley, inulin and polysaccharides, is fermented. It is understood to help slow blood glucose absorption and have a prebiotic effect (stimulate probiotic bacteria in the gut).
Insoluble fiber, meanwhile, are excreted intact, providing fecal bulking and helping to regulate bowel function and prevent constipation.
However although they have quite different functions in the body, most of the advice on fiber clumps the two together.
The IOM recommends that American adults consume between 28 and 35g of fiber per day, but in practice most Americans consumer only 15g. One reason for this may be because fruits and vegetables do not figure as largely as they should in the American diet.
The message contained in the USDA's new dietary guidelines was heavily weighted towards insoluble fiber, advising that people should eat at least six servings of grains per week, three of which should be wholegrain. But in fact Frost and Sullivan points out that the correct balance is the subject of some controversy with no nutritional expert having yet set out the correct balance.
Certainly the whole grain message is responsible for boosting the segment as a whole.
But there are several consumer trends are stirring interest in soluble fiber in particular.
In particular, the low carb trend has mutated into a low-gi, whereby consumers are keen to prevent peaks and troughs in their blood sugar levels. The approach was originally developed to help diabetics with glucose control. Despite some criticism that it is complicated for consumers to follow, it has gained popularity as an approach to weight loss in Australia and Europe, and the signals are that the US is following suit.
Moreover there is increasing awareness of the importance of gut health, as probiotics make a mark on consumers awareness. This creating a favorable marketing environment for products with prebiotic properties.
One area for adding soluble fiber that food and beverage companies may find attractive is fruit juice. Last week PepsiCo announced the launch of the first nationwide fiber added orange juice in the US in the Pure Premium Essentials range.
Industry commentators have said that other beverage companies are likely to follow suit. Moreover, the soluble fiber used in the Tropicana product, ADM's FiberSol-2, has also found a use in Dannone's prebiotic yoghurt.
Other soluble fiber ingredient companies are basing their marketing on heart health claims that are intrinsic to the source - such as Cargill's Barliv from barley betaglucan, and Cevena's ViscoFiber from oat or barley beta glucan.