The challenges of synbiotics

In theory, synbiotics give food manufacturers the chance to develop products with targeted health benefits by matching specific pre- and probiotics. Why then are so few synbiotics products making an appearance on the commercial stage? Lynda Searby reports

The underlying principle of synbiotics is straightforward enough — pair a probiotic with a prebiotic and bingo, their combined effect is greater than the sum of their individual parts.

But if it really were that easy, supermarket shelves would be teeming with synbiotic products, and the reality is, most consumers have probably never heard of synbiotics, let alone tried them. With so much attention focused on pre- and probiotics, it's easy to forget that synbiotics are a relatively new concept and the supporting science is still in its infancy.

Broadly speaking, synbiotics can work in two ways: to improve the viability of probiotics and to deliver specific health benefits. The idea that synbiotics might be more potent that their pre- and probiotic components alone first emerged in the mid '90s. This concept has since been further investigated and both in vitro and in-vivo experiments have established that the survivability and viability of probiotics is enhanced when they are combined with prebiotics.

Beneo inulin and oligofructose prebiotics ingredients from Belgian-based manufacturer Orafti have been the subject of much of this research. A study conducted at Michigan State University, for example, showed that Beneo P95 had a beneficial effect on the viability of bifidobacteria.

Orafti researchers also have found that both Beneo P95 and Beneo Synergy1 protect the probiotic bacteria during intestinal transit, demonstrating the vitality of synbiotic products.

In terms of specific health effects, synbiotics have been linked to a string of benefits, from lowering cholesterol levels to reducing liver-related brain dysfunctions. However, the most promising results have been in the areas of improved gut function, better resistance to gastrointestinal infections, irritable bowel syndrome improvement and reduction of the risk of some chronic gut disorders, according to professor Glenn Gibson of Reading University in the UK, who coordinated the European Union-funded SYNCAN project.

The SYNCAN project has provided the most conclusive evidence to date that synbiotics can reduce the risk of colorectal cancer. The central feature of the study was a human dietary intervention study, in which an enriched inulin composition patented by Orafti was shown, when taken with probiotics Bifidobacterium bifidum BB12 and Lactobacillus rhamnosus LGG, to significantly limit damage to cell DNA.

But how easy is it to translate this theory into a convincing product concept?

The technical challenges
From a technical perspective, it is the survivability of the probiotics strains that dictates what synbiotics products can be developed, as prebiotics can be used in most applications.

"Beneo inulin is a fibre and can be used in almost all food applications, except in long shelf-life acid environments, without losing its nutritional benefits. This is obviously not the case with probiotics, as they are living bacteria and need a chilled environment to survive," explains Christine Nicolay, global marketing and communications manager with Orafti.

It follows, therefore, that most synbiotics product launches to date have been in the dairy category.

Müller's Vitality range of yoghurts and yoghurt drinks in the UK is perhaps the best-known example of a synbiotic dairy product. Vitality contains the probiotic strain Lactobacillus acidophilus and Bifidobacterium, as well as the prebiotic inulin.

But it's not just the big players that are dipping a toe in the synbiotics market. Spanish family-owned dairy company Priégola made its foray into the functional dairy market four years ago with a 750ml synbiotic drink. The drink contains probiotics — Lactobacillus acidophilus LA-5, Lactobacillus casei LC-01 and Bifidobacterium BB12 — and prebiotics provided by Orafti. Then last June, the company launched a range of synbiotic yoghurts with omega-3s.

In Malaysia meanwhile, the first synbiotic cultured-milk product appeared on the market in July. Targeted at children aged 4-13, the product contains DHA and omega-3 fatty acids, Lactobacillus casei and Lactobacillus acidophilus probiotics, and inulin. The drink's manufacturer is Mamee-Double Decker (M) Bhd.

Eastern Europe might seem an unlikely breeding ground for synbiotics, but Russian manufacturer Wimm-Bill-Dann Foods OJSC clearly thinks there's potential. The company has launched Neo 2Bio, a synbiotic dairy drink with cherry flavours and hawthorn extracts.

While the US has been slower than Europe and Asia to embrace probiotics, let alone synbiotics, Stonyfield Farm in New Hampshire seems to be bucking that trend. All of its yoghurts contain both beneficial bacterial cultures and prebiotics (inulin), and continue to perform well thanks to a loyal consumer following; the company says sales have grown by an average 22 per cent annually for the last decade.

Orafti sees potential for product development in other chilled categories, like fruit and vegetable juices or cheeses. However, beyond the chiller cabinet it gets a little more tricky, as the probiotic organisms will not survive exposure to humidity or heat.

Powdered dietary supplements are a possible application area, but while the probiotic component might not cause formulation issues, the prebiotic ingredient might.

"With dietary supplements you have a small product, so you need to make sure the prebiotic isn't too bulky," explains Per Bengtsson, CEO of Swedish biotech firm Probi, which produces Lactobacillus plantarum 299v, Lactobacillus rhamnosus 271 and Lactobacillus plantarum 299.

One company that has successfully developed a synbiotic dietary supplement is Institut Rosell, a Canadian probiotic specialist. ProTummy is touted as 'helping people to maintain intestinal balance and regular intestinal transit, resulting in a flat stomach.' It contains two Rosell probiotics — Lactobacillus rhamnosus Rosell 11 and Bifidobacterium bifidum Rosell 71 — and a prebiotic composed of fructo-oligosaccharides.

Institut Rosell says Bifidobacterium bifidum Rosell 71 helps digestion of starch, thereby diminishing flatulence and reducing bloating. Lactobacillus rhamnosus Rosell 11, meanwhile, is said to 'restore the natural balance that favours a better intestinal transit.'

Educating the public
Technical challenges aren't the only barrier to the development of the synbiotics market — consumer understanding presents an equally monumental obstacle.

Ralph Koekkoek is from the functional foods ingredients business unit of DSM Food Specialties, which produces the probiotics Lactobacillus acidophilus Lafti L10, Lactobacillus casei Lafti L26 and Bifidobacterium Lafti B94. As he puts it: "I think consumers understand probiotics, but if you ask them about prebiotics, they don't understand them so well and they understand synbiotics even less."

That said, he thinks the large dairy companies have been very successful in educating consumers about probiotics, so he's confident that in time they will be able to educate them about synbiotics, too.

It's not surprising, therefore, that while some manufacturers are opting to include both prebiotics and probiotics in formulations, they are not marketing the products as synbiotic.

Activia yoghurts from Danone, for example, contain inulin for its fat replacement properties, but make no mention of it in their marketing, focusing instead on the ability of Bifidus digestivum to help improve natural digestive transit.

Bengtsson suggests that one way of circumventing the consumer understanding obstacle is to market on 'feeling.' "You don't have to be explicit about mechanisms or physiological functions, you can just say that it makes you feel better."

Going on gut instinct
Konjac gum might be best known for its use as a texturant in food products, but in the future, it could find application in synbiotic products. French company Kalys, the largest supplier of konjac gum in Europe, is currently investigating the prebiotic, synbiotic and cholesterol-binding properties of the soluble gum fibre.

"As is the case for many plant extracts, the variety of the plant you use can influence the type and functions of the gum," explains Philippe Vieille, managing director of Kalys.

In vitro research carried out by the company indicates that some specific konjac derivatives called glucomannan oligosaccharides may have a more potent prebiotic effect on lactobacillus and bifidobacteria than inulin and fructo-oligosaccharide.

Kalys is currently investigating the chemical structure of these konjac extracts and what dosages are required to bring about a prebiotic effect.

Vieille sees great potential for the ingredient in clinical nutrition. "In certain gastro-entero pathologies, or affections where patients suffer from diarrhoea, a combination of carbohydrates, including konjac gum, could be used as a food supplement to reduce side effects and improve gut ecology," he says.


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