Prebiotics, probiotics, and gut health: the development of functional foods in Japan

Bioavailability

Gut Health and Nutrition

L

The gut is in healthy condition when good bacteria suppress the action of bad intestinal bacteria (Fong 2007). At the same time, good bacteria help digest and absorb food, synthesize nutrients it carries and enhance immunity and resistance. This was the pronouncement of Senior Research Fellow Dr. Masaaki Watanuki of the Yakult Central Institute for Microbiological Research during his presentation on probiotics and functional food. When bad bacteria outweigh the action of good bacteria, an imbalance develops and leads to intestinal putrefaction and the production of carcinogenic substances and toxins. There are more than 300 kinds of bacteria living in normal, healthy intestines. While most of them are harmless, some can become harmful, he said (Fong).

A recent study found that topical nutrients are utilized by the gut mucosa to maintain its structure and function (O'Keefe 2008). Colonic microbiota produces these nutrients. Finding suggested that the right diet influences the diversity of the microbiota. The diet, thus, is involved in the development of colonic disease and colon cancer and the microbiota is critical in colonic health and disease. Further research on the composition, characterization, and metabolism of the microbiota in needed to understand its influence on colonic health and disease O'Keefe).

Prebiotics and Probiotics and Their Products

Prebiotic food ingredients support the growth beneficial probiotic bacteria in the gastrointestinal tract (Bailey 2008). This is the bottom line of the concept introduced in Japan. The public recognized and accepted the idea that beneficial bifidobacteria probiotics require special nutrients to make the gut healthy and to survive. The nutrients were identified as bifidus factors the Japan Bifidus Foundation was established in 1981 to provide support research on prebiotics and probiotics. Morinaga Company is considered the first to introduce a bifidus product in Japan in 1977. The product was fermented milk with the bifidobacteria longum. In 1978, Yakult introduced the bifidus yogurt with the bifidus breve, bifidus bifidum and lactobacillus acidophilus. And in 1984, Meiji Seika produced the first commercial bifidus factor, a fructooligosaccharide prebiotic that cultivates the growth of bifidobacteria in the gut. The Yakult Honsha Company is considered the producer of the first branded probiotic in Japan more than 70 years ago (Bailey).

Yakult is a probiotic drink, said to be contain good bacteria to keep the gut healthy (Yakult.co.uk 2009). These good bacteria are strong enough to withstand stomach acids and survive until they reach the intestines in sufficient numbers to perform their function. It is made of skimmed milk powder, sugar, water and live good bacteria, the Lactobacillus casei Shirota strain. The drink was named after Minoru Shirota who investigated the benefits of good bacteria in the gut all his life (Yakult.co.uk).

Although the term probiotic had not evolved at this time, Yakult, with its probiotic bacteria strain, lactobacillus casei Shirota, became the scientific base for the brand (Bailey 2008). The company says that more than 25 million people in 26 countries now ingest Yakult every day (Bailey). They are those with gastrointestinal disorders, those who want to prevent these disorders and everyone else who wants to promote and maintain gastrointestinal or gut health.

Market Development, Claims and Evidence of Efficacy

Gastrointestinal health issues in Japan enhanced the development of the prebiotics and probiotics market (Bailey 2008). Statistics said that cancer death rates in the country were higher than in the rest of the world at 51.2 per 100,000 people, compared with the U.S. At 5.3 and Mexico at 5.4. Of these figures, 40,000 deaths were linked with diseases of the digestive system, of which 3,400 were from gastric and duodenal ulcers. Of the additional reports of 1,600 food poisoning cases and 5 deaths in 2004, 70% were bacteria-related (Bailey).

The Japanese Ministry of Health, Labor and Welfare emphasized the consequences of not adequately addressing major health issues (Bailey 2008). In response, the Foods for Specified Health Uses or FOSHU were developed in the regulatory category in the late 1980s. Suntory's Yogurina lactic acid bacteria drink with xylo-oligosaccharide was approved in October 1993. The company claimed that it increases intestinal bifidobacteria and keeps the gut in good condition. The Calpis Food Industry was next approved to introduce the Oligo CC carbonated beverage with solybean oligosaccharide with a very similar claim. These two were prebiotic products. The first probiotic drink, Takanashi Milk, a yogurt with lactobacillus GG, was approved in May 1996. It claimed to help increase intestinal bifidobacteria and lactobacilli and to regulate the gastrointestinal condition. In November of the same year, Morinaga's bifidus plain yoghurt with bificobacterium longum BB 536 and Meiji Milk Product's Bulgaria Yoghurt LB 81 with lactobacillus delbreukii and streptococcus salivarius were approved for the market. They made similar claims of regulating gut health. These and the entire line of Yakult products made large sales instantly upon converting to FOSHU status (Bailey).

In April 2006, the Japan Health Food and Nutrition Food Association announced that 44% of the 583 approved products, primarily prebiotics and probiotics, addressed gastrointestinal health (Bailey 2008). They achieved $3.6 billion in sales in 2005 but their growth had declined. In order invigorate sale, new claims on the products' benefits were made. The products were said to contain dextrin dietary fiber for the moderate absorption of sugar and fructooligosaccharide to increase calcium absorption rate. Nestle Japan's LCI lactic bacteria drink was promoted as reducing pathogenic bacteria in the gut (Bailey).

New data confirmed disturbances in the gut flora in irritable bowel syndrome or on account of bacterial overgrowth or changes in the microbiota (Quigley 2007). More evidence also pointed to the role of inflammation or immune activation in irritable bowel syndrome. Studies on bifidobacterium animalis showed shortened colonic transit time in healthy women and elderly subjects. Another study revealed a more direct effect in stimulating motility by probiotics. Other studies on lactobacillus and bifidobacterium infantis strains demonstrated their significant effects on pain and inflammation. These findings suggested that probiotics can strengthen the epithelial barrier to restore barrier function (Quigley).

Several randomized trials and meta-analyses of probiotics on children and adults showed their efficacy in preventing primary and secondary gastroenteritis as well as its treatment in children (Guarino et al. 2009). Their efficacy was most promising in preventing and treating bacterial diarrhea (Guarino et al.).

Health Claims Rejected

Of the 180 claims for probiotic ingredients, 10 were rejected outright and the remaining 170 could not be assessed by the 21-member NDA panel because the ingredients could not be identified (Hickman 2009). The decision was a big blow on the 220-million-pound dairy industry in the UK. Best-selling Actimel yogurt and Yakult drinks were not evaluated because their manufacturers withdrew their claims before these could be examined. These claims were re-submitted but the results would be available next year (Hickman).

The panel rejected 523 applications under the general health claims category for 200

vitamins, minerals, fiber, fats, carbohydrates and "probiotics bacteria, which, an EFSA spokeswoman said, did not have sufficient evidence to back them (Hickman 2009). Five articles and 14 claims were submitted by the Institute of Biotechnology, Sera and Vaccines Biomed SA on probiotics (Starling 2008). Each claim was denied for failure to present the cause-and-effect relationship between the probiotic supplement and the claimed effects. Article 14 claims centered on children's health and reduction of disease for a Biomed probiotic called lactoral and its three strains. The submitted studies supported the health claim of the strains but not to the bacterial strains of the probiotic. Biomed's phenotypic testing were not accepted as sufficient to properly identify the bacterial strains. The claim, "natural intestinal microflora during travel," had not been sufficiently characterized. On the four other claims, the panel said that in vitro trials cannot sufficiently predict in vivo efficacy in human subjects of experiment (Starling).

A Yakult spokesman, however, said that their products still had to be assessed

(Starling 2009). According to him, their company's claims for Lactobacillus casei Shirota probiotic strain had strong evidence for its health benefits from more than 70 human studies and more than 70 years of research (Starling). The World Health Organization itself recognized probiotics as "live micro-organisms & #8230;which provide measurable health benefits (Cooper 2009)." And 30 million shoppers accepted the claims of probiotics makers for good bacteria to defeat bad bacteria in their gut. Lately, both their effectiveness and safety were questioned by academicians (Cooper). These are signals that functional food companies may be exploiting people's interest in improving their health and, at the same time, overcharging them for promised health benefits that have not been proved, non-existent or downright false. #