Probiotics in Gastric and Intestinal Disorders As Functional Food and Medicine Nils-Georg Asp, Roland Mo¨Llby, Lisa Norin and Torkel Wadstro¨M

æConference summary Probiotics in gastric and intestinal disorders as functional food and medicine Nils-Georg Asp, Roland Mo¨llby, Lisa Norin and Torkel Wadstro¨m

The chairman of the first session, Tore Midtvedt, scribed as the dominant indigenous lactobacilli of opened the conference by reminding the audience the human intestine. From 130 intestinal biopsies that since ancient time, food, bowel and health have the following lactobacilli were cultured: 38% L been interrelated medical topics. Microorganisms, gasseri, 20%, L fermentum, 8% L crispatus, 7% L especially lactobacilli and some yeasts, have been rhamnosus, 4.4% L salivarius and 4.4% L mucosae- used as health-promoting agents since ancient time. like probiotic strains (unpublished data). Versalovic Metchnikoff suggested that the long healthy life of stressed that there is a demand for a more detailed Bulgarian peasants resulted from consumption of understanding of the composition of the commensal fermented milk products. The term ‘‘probiotic’’ is intestinal microbiota and their interactions with the still under debate. In all definitions there are two intestinal immune system, which would create prerequisites: 1) the microbes have to be alive, and breakthroughs in probiotic research. Gene and 2) the microbes are given for other than nutritional protein discovery efforts with defined clones of reasons, i.e., it is not the caloric or nutrient content specific intestinal lactobacilli and other lactic acid of the probiotics that counts. ME Sanders’ defini- bacteria would lead to the unravelling of mechan- tion from 1996 says that probiotics, simply defined, isms of probiosis and development of new thera- are microbes consumed for health effects. The term peutic strategies with such probiotic bacteria. These probiotics is used in food applications, and biother- could be achieved by apeutics is often used in clinical applications. In selecting probiotic/biotherapeutic strains, Midtvedt . A detailed mapping of lactic acid bacteria in the emphasised the importance of thinking function mammalian intestine rather than disease, and of investigating functions in . Clone-based investigations of commensal mi- specified compartments of the body. For instance, b crobes and of the functions of different probio- glucuronidase activity of the colonic microflora may tics modify conjugation of endo- and exogenous substances, and the presence of cytochrome P 450 in The question is raised whether one can alter or human intestinal flora may influence the expression restore the microbial balance in human individuals. of hepatic cytochrome P 450. And does restoration of a microbial balance lead to restoration of an immunologic balance? The gastrointestinal microflora Go¨ ran Molin reviewed recent work on the intest- James Versalovic presented an overview of the inal microflora, in collaboration with B. Jeppsson, intestinal microflora. A number of Lactobacillus S. Ahrne´ and M. Wang. By the use of phenotypical species colonise the stomach and intestine immedi- identification methods and anaerobic culture tech- ately after birth, adhere to epithelial cells and niques, the GI-flora has been reported to be become a part of the stable intestinal flora during dominated by genera such as Bacteroides, Eubac- development and adulthood. The genus Lactoba- terium, Clostridium, Ruminococcus, Peptococcus, cillus includes more than 60 different species, and Peptostreptococcus, Bifidobacterium and Fusobac- has received attention as a source for probiotic terium. However, culture-based methods provide an agents and protein delivery systems for the mam- incomplete assessment of the bacterial GI-flora and malian intestine. Only few species have been de- phenotypic features are not always reliable or

Scandinavian Journal of Nutrition 2004; 48 (1): 15Á25 # 2004 Taylor & Francis ISSN 1102-6480 15

DOI: 10.1080/11026480410028968 Asp N-G et al. sufficiently descriptive in bacterial systematics. Sixty ing oesophageal adenocarcinoma. How to reduce to eighty percent of the GI-bacteria have been the discomfort/problems in dyspepsia subjects? The claimed to be unculturable. One way to circumvent most important way to achieve improvement is by a the need for cultivation is the use of DNA lifestyle modification, e.g. by reducing use of amplification by PCR and subsequent cloning of tobacco, alcohol and coffee, and weight reduction 16S rRNA genes, followed by comparisons with by an overall dietary alteration. Patients with a available databases. Microbes that are in close Helicobacter pylori (H.p) infection were formerly contact with the body are more likely to interact also included in this group. Thus 25Á30% of middle- with human physiology, and this part of the flora of aged patients with earlier diagnosed reflux problems the GI tract may be involved in developing chronic have been identified as H.p patients. After eradica- inflammation and colon cancer. It can also be tion of the infection, there was surprisingly a affected by antibiotics, cytotoxic drugs and radio- significantly higher risk of GORD symptoms in therapy, trauma, and intensive care therapy. It is one study, but the disease signs had almost totally thus important to map the mucosa-associated flora disappeared two years after the H.p eradication in a in healthy individuals in order to clarify the group of almost 1700 subjects, and the risk of pathogenic risk under stressed and other disturbed relapse was also strongly reduced. Lundell’s overall conditions in man, before one tries to perform conclusion was that the benefit of eradicating H.p in similar studies in diseased subjects. non-ulcer dyspepsia and GORD is greater than the possible risks. Dyspepsia, gastric reflux disease and gastric cancer The state of the art regarding probiotics and F. Bazzoli introduced this subject by stating that Helicobacter pylori gastritis was reviewed by A. epidemiological investigations in the US show that Gasbarrini, whose full paper is published in this 25% of the population suffer from recurrent dys- issue of the Scandinavian Journal of Nutrition (pp. pepsia, but less than 50% seek medical treatment for 26Á31). Proposed mechanisms of action of oral their symptoms. These symptoms have, however, a bacteriotherapy include synthesis of antimicrobial significant impact on the quality of life. Dyspepsia substances such as organic fatty acids, ammonia, is defined as pain or discomfort from the upper hydrogen peroxide and bacteriocines, a competitive abdomen. In practice, there is considerable overlap interaction with pathogens for ‘‘space and food’’, of dyspepsia and gastro-oesophageal reflux disease through the use of available nutrients and occupa- (GORD/GERD). A key element to effectively tion of microbial adhesion sites, modification of managing patients with dyspeptic symptoms is the toxins or toxin receptors, and immuno-modulation. identification and exclusion of GORD through H. pylori is one of the most prevalent infectious proton pump inhibitor (PPI) therapy to dyspeptic agents worldwide and has been indicated as one persons. These are individuals who are exposed to pathogenic factor in the development of chronic the risk of physical complications or who experience gastritis, peptic ulcer disease and gastric malignan- clinically significant impairment of health-related cies. One suggested mechanism related to probiotic well-being due to episodes of GORD (after reassur- therapy is that Lactobacilli spp. are supposed to ance). A probiotic treatment approach in relation to adhere and even transiently reside in the stomach, GI disorders, aiming to restore or alter/balance the enhance the immune response and reduce the H. intestinal microflora, might have an anti-inflamma- pylori inflammation effect on the host gastric tory effect, could reduce gas production, could mucosa. Furthermore, probiotics have been shown promote intestinal motility and could have a visceral to improve patients’ compliance with antibiotic analgesic effect. Moreover, by including prebiotics, treatment by reducing side effects. a proximal colon dysfunction might be corrected via Y. Koga, together with A. Tamura, K. Kobayashi carbohydrate fermentation. The proximal gastric and A. Takagi, presented studies on H. pylori tone could also be inhibited with a role in the inhibition in experimental animals and man. Lac- regulation of gastric motility. tobacilli are the dominant bacteria found in the Lars Lundell described GORD as ‘‘a burning fasting stomach although their number is small. feeling rising from your stomach or lower chest up However, it increases by a factor of thousands in towards the neck’’. There is one major concern with individuals with low gastric acidity, suggesting that dyspepsia Á an increased risk with time of develop- the stomach is potentially an organ which lactoba-

16 Conference summary cilli may colonise in high numbers. More than 200 countries tend to maintain the high-risk character- strains of lactobacilli were investigated in order to istics, whereas the offspring acquire a risk closer to select strains exhibiting high lactic acid production, that of the host countries. Low socioeconomic efficient detachment of the H. pylori, and strong status is also shown to be associated with high risk. resistance to gastric acidity. The evidence that diets high in vegetables and Lactobacillus gasseri strain OLL 2716 (LG21) fruits protect against stomach cancer is convincing. was selected for further studies in 5-week-old Summarised evidence suggests that raw vegetables gerbils. H. pylori were inoculated with LG21 and and fruit containing vitamins C and E, beta- the animals were followed. After one year, 83% of carotene and minerals such as selenium protect the gerbils inoculated with LG21 were without against stomach cancer. The protective effect of detectable amounts of H. pylori, whereas 26% ascorbic acid against gastric carcinogenesis is due to carried these microbes when the gerbils initially its ability to inactivate reactive oxygen species (ROS, not were inoculated with LG21. Thus, oral admin- ‘‘free radicals’’) as well as its nitrite scavenging istration of LG21 as a probiotic to H. pylori- effects. infected Mongolian gerbils significantly prevented The suggested association between gastric cancer the incidence of gastritis and gastric ulcers. and H. pylori infection is mainly based on the fact Thirty-one human subjects with documented H. that H. pylori is the major causative agent of chronic pylori infection (exclusion criteria antibiotic therapy gastritis, developing into atrophic gastritis and within less than 1 month) were given 90 g of yoghurt intestinal metaplasia, the precursor lesion of gastric twice daily for 8 weeks. One week following the cancer. In this process, dietary factors play an completion of the first part (week 9), the subjects important role. However, no direct evidence exists were given 90 g of yoghurt containing more than in the literature on the relationship between pro- 6 6/10 CFU/g of LG21, twice daily for 8 weeks. biotics and gastric cancer. Urease tests showed significantly lower values at the end of the study (week 18) than at week 0 and 9 Bacterial translocation Á impact of probiotics on

(pB/0.05). However, 3 months later, a reversal was barrier function detected, which means that the H. pylori were not Bacterial translocation is defined as the passage of completely eradicated. A significant decrease in the bacteria or bacterial products across an intact urease levels was found after LG21 treatment, which gastrointestinal tract barrier. Bengt Jeppson re- indicates a reduction of the H. pylori in the ported that there is ample evidence that this occurs stomach. Moreover, a significant improvement in in humans, but its role in the pathogenesis of the degree of gastric mucosal inflammation was different diseases is unclear. In order for bacterial demonstrated by analysis of the serum PGI/PGII translocation to be involved in disease processes, levels. there must be elements of both permeability dis- Koga’s overall conclusion was that orally admi- turbance and reticulo-endothelial dysfunction. Dis- nistered LG21 might efficiently suppress H. pylori ruption of the intestinal bacterial microflora colonising the human stomach and thus alleviate balance may increase the incidence of bacterial the inflammation. translocation by modifying a normal intestinal Stomach cancer, reviewed by T. Rokkas, is the barrier function. The area is reviewed in a separate second most common cancer in the world. In 1996, paper in this issue (pp. 37Á41). In a number of it was estimated that over 1 million new cases were studies showing positive effects of probiotics there diagnosed worldwide, accounting for nearly 10% of has been an increased risk of secondary bacterial all new cancers. Nearly two-thirds of all cases occur infections of enteric origin, due to the surgical in developing countries. Gastric cancer mortality trauma or ongoing infection. By altering the lumi- and incidence show a geographical variation with nal content of bacteria it seems possible to reduce the highest rates found in Japan, Central and South the incidence of secondary infections. Although America and eastern Asia. In developed countries these results need to be confirmed in larger pro- rates have steadily declined, with Australia, Canada spective studies they indicate a new concept of and the USA showing the lowest rates. Today, altering the luminal bacterial milieu resulting in stomach cancer rates are 50% lower in women reduced secondary infections. The influence of the than in men. Migrants from high- to low-risk luminal milieu on bacterial translocation is still

17 Asp N-G et al. not fully understood. We have convincing evidence by interactions with mucosal immune cells. A from experimental studies, but so far only circum- probiotic preparation (VSL#3) that contains a stantial evidence can be found from clinical studies. combination of three species of bifidobacteria, four strains of lactobacilli and one streptococcus Probiotics in irritable bowel syndrome (IBS) strain has shown promise in maintaining remissions IBS is a multi-factorial condition that accounts for in ulcerative colitis and pouchitis, as well as in 20Á50% of referrals to gastro-intestinal (GI) clinics preventing the postoperative recurrences of Crohn’s in the UK, said Jennifer Madden. Typical symptoms disease. On the other hand, a well studied probiotic are excessive flatus, abdominal pain and variable strain Lactobacillus rhamnosus GG, was reported as bowel habit, for which no pathological cause can be ineffective in preventing recurrences of CD in two determined. Suggested aetiologies include psycho- studies done in adults but giving some improve- social factors, altered GI motility, heightened sen- ments in children with CD. Although well planned sory function of the intestine and/or malfermen- and controlled clinical studies are obviously re- tation of foods. Changes in species composition and quired to delineate fully the potential for probiotics metabolic activities of the intestinal microbiota may in IBD, basic studies are even more important to also play a role. Several studies have shown that the elucidate mechanisms of anti-inflammatory activity onset of IBS is significantly higher after specific of so many different probiotic bacteria. event(s) such as an antibiotic treatment, abdominal or pelvic surgery or gastroenteritis. The intestinal Probiotic bacteria, infections and allergies flora in IBS has been extensively studied and higher This section was introduced by a review presenta- numbers of facultative anaerobes with lower num- tion by M. Mikelsaar on probiotics basis in bers of bifidobacteria and lactobacilli have been prevention and treatment of infections and allergy. found. So far, however, it has not been possible to Microbial interference therapy (MIT) has been determine whether an altered intestinal microflora applied in many infectious diseases, including composition is a contributory factor to the aetiol- travellers’ diarrhoea, antibiotic-associated colitis, ogy of IBS. Some studies are described in a full Clostridium difficile related infections, rotavirus paper in this issue (pp. 32Á36), using symptomatic enteritis, urinary tract infections, vaginosis and differences as a definable endpoint, have shown many other diseases of infectious origin. significant improvements following probiotics, Mikelsaar mentioned several mechanisms of ac- though others are subjective and likely to contain tion of probiotics: (a) probiotic specific competitive a certain amount of placebo response. Most studies exclusion of infectious agents by anti-adhesion using IBS patients have been on small sample factors, competition for nutrients, antimicrobial populations and further studies are needed, with metabolites, bacteriocins, suppression of toxin pro- either larger patient numbers, or in defined subsets duction, altogether sustaining the balance of the e.g. diarrhoea predominant. Some results suggest a microflora; (b) probiotic and host-specific immune trend towards a preventive, rather than a therapeu- response towards foreign antigens of microbial tic role, for probiotics in the management of IBS. origin by immune modulation, enhancing the activity of macrophages, increasing the amount of Probiotics in Inflammatory Bowel Disease (IBD) natural killer (NK) T-cells and the level of inter- The possible role of probiotics in inflammatory feron gamma, stimulating the production of anti- bowel disease (IBD) was reviewed by P.B. Heczko bodies; (c) induction of some protective factors such and co-workers. ‘‘This area unfortunately contains as cytokines, mucus, SCFA and defensins against more hopes and discussions than well performed pathogens in epithelial cells. studies,’’ said Heczko. During the last 3 years there Allergy is defined as an inflammatory disease have been 13 reported clinical trials with varying resulting from abnormal reaction to some innoc- outcomes, but they have given rise to 24 critical uous antigen. The prevalence of allergic diseases reviews. However, data in animals with colon such as asthma, rhino-conjunctivitis and atopic inflammation corroborate that bacterial products, dermatitis has increased over the past decades including those of Lactobacillus species, may be worldwide. Several clinical trials with probiotic involved in the process in two ways: either perpetu- administration have been conducted. The majority ating or modifying the course of the inflammation can be divided into two groups: allergy preventive

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and treatment trials. Recent investigators have In the future, there is a need to expand studies on distinguished the sensitisation phase of allergy, the therapeutic and prophylactic use of probiotics in phase of allergic manifestations and its down- diarrhoea, especially in bacterial diarrhoea and in regulation phase. Several cross-sectional and pro- developing countries. This can be done by e.g., spective studies have shown pronounced differences searching for strains with optimal therapeutic in the establishment of both lactobacilli and other potential in humans, including the optimal dose, intestinal microbes in allergic as compared to non- by developing better ways to measure colonisation allergic children, and Mikelsaar concluded that in humans, and by investigating mechanisms of studies to create an adequate scientific basis of action, including immune stimulation. The final aim probiotics would be needed to start trials with host- is to obtain probiotics that promote normalising of oriented and well-targeted functional foods for the flora and thereby enhance the healing of small prevention and treatment of different inflammatory bowel mucosa. disorders. The last presentation in the section on probiotic Studies investigating probiotics in infectious diar- bacteria, infections and allergies was given by A. rhoea in children were reviewed by Merja Ashorn. Wold. The small intestine contains relatively few Rotavirus gastroenteritis in Finland account for 3% bacteria. An intake of 1010Á1011 bacteria per day via of all children hospitalised between 1985 and 1995, the food is probably sufficient to significantly and in general, rotavirus diarrhoea accounts for influence the gut-associated immune system. Bac- over 50% of all cases of gastroenteritis in Finland. teria are taken up by M cells covering the Peyer’s The mean hospital stay due to paediatric diarrhoea patches and are processed by macrophages and was 3.3 days in 1985 vs. 2.3 days in 1995. One way dendritic cells in these patches, leading to stimula- to minimise this disease has been to use probiotics. tion of innate immunity and specific immune Adherence of some probiotic bacterial strains to responses to the bacteria. Monocytes react differ- human intestinal mucus in infants in relation to ently to Gram-positive and Gram-negative bacteria,

rotavirus infection has been tested in vitro, using i.e. Gram/ organisms elicit more of IL12 and Lactobacillus GG, L. casei Shirota, L. paracasei F19, TNFa, while GramÁ organisms give rise to relatively L. acidophilus and Bifidobacterium lactic Bb12. more IL6, IL8, IL10 and PGE2. The former Adhesion to mucus, isolated from patients one response stimulates a cell-mediated immune reac- month after virus infection, was strongest with tion and a concomitant macrophage activation, Bb12 and LGG, and strains proven to shorten the while the latter induces a maturation of dendritic duration of rotavirus diarrhoea are LGG, L. reuteri, cells and antibody production. L. casei Shirota and Bifidobacterium lactis Bb 12. As reviewed above, probiotics have been convin- A review published by Szajewska and Mrukowicz cingly shown to shorten acute watery diarrhoeal (1) concluded that LGG consistently reduced the episodes in children, mainly those caused by duration of diarrhoea in children as compared to rotavirus. Such diarrhoea episodes are self-limiting placebo. Van Niel et al. (2) showed that in 9 and of short duration. Wold thought that it is not randomised studies, LGG, L. reuteri and L. acid- very likely that this has much to do with specific ophilus/L. bulgaricus reduced diarrhoea duration of immune responses to the rotavirus, since these 0.7 days and the frequency of 1.6 stools/day. A dose appear later. Rather, one may assume that the effect response relationship was observed: optimal dose of bacteria and their products on cells of the innate 10 /10 CFU during the first 48 hours. Guandalini et immune system leads to changes in secretion, al. (3) investigated an acute onset of diarrhoea in permeability and motility via effects on cytokines, children 1 month to 3 years of age, and he showed hormones and the function of the enteric nervous that in group A, in which the children got oral system. rehydration and placebo, the mean duration of Probiotics have also been shown to shorten C. diarrhoea was 72 hours as compared to 56 hours difficile-induced diarrhoea. Such diarrhoea is eli-

in group B (pB/0.008) which got rehydration/ cited in the large intestine through the action of C. LGG therapy. In another placebo controlled study difficile toxins. The mechanism by which probiotics of Peruvian undernourished children (4), there was counteract C. difficile-induced diarrhoea is not a significantly decreased amount of adenovirus known. The most convincing effect was shown gastroenteritis in the LGG group. using the yeast Saccharomyces boulardii, an organ-

19 Asp N-G et al. ism that does not colonise the large intestine. In vaccine adjuvants, as well as vehicles for antigens some way, probiotic intake must change the milieu for active immunisation. Probiotics have been in the large intestine so that the clostridia do not experimentally used for parenteral immunisation, thrive, and produce their toxins, or that the but their most promising use is for oral delivery of intestinal mucosa becomes less sensitive to the immunoglobulin-like molecules or vaccination. toxin. A great variety of effects of probiotic strains on Probiotics have been tried to treat or prevent the immune system may be used to elicit different allergy. A large study by Trapp and co-workers (5) immune response, depending on the disease to be suggested that live or inactivated yoghurt might prevented, and various probiotics may deliver anti- reduce asthma symptoms. Whereas yoghurt versus gens in specific compartments of the immune inactivated yoghurt treated groups were rando- system. In addition to express vaccine antigens, mised, subjects not eating yoghurt were those who these microorganisms are now further modified to refused to take yoghurt, which limits the conclu- co-express interleukins and other immunomodula- sions from the study. Wheeler and co-workers (6) tory molecules. Evidence is accumulating that found no effect in 15 patients with moderate asthma probiotic-based vaccine and drug delivery strategies of yoghurt with lactobacilli. Lactobacillus GG has are efficacious in animal models. For example, IL- been tried both as treatment of cow’s milk allergy in 10 producing Lactococcus lactis have been shown to young children and as a means to prevent occur- cure experimentally induced colitis in IL-10 defi- rence of allergy (7,8). A reduction of eczema, but cient mice. Evidence is awaited to determine not IgE antibodies, has been detected in these whether these strategies can be applied in human studies. No effect of probiotics was seen on hay beings. fever or on respiratory allergy. The mechanism In the search for cheap production of recombi- behind the anti-eczematous effect is unknown, but nant vaccines for oral use and to facilitate specific there is nothing to indicate that probiotics reduce vaccination procedures, vaccine antigens, combined IgE production through any immuno-regulatory with adjuvants, have been produced in edible plants, mechanism. The effect might instead be on gut especially in potato tubers. These approaches may permeability and inflammation and possibly, in be of particular interest for developing countries addition, on the local conditions in the skin. where more expensive vaccines are not optimally Wold ended by asking if the increased frequencies available. Whether living microorganisms are given of diseases like IgE-mediated allergies, Type 1 to humans or recombinant crops are grown for diabetes, inflammatory bowel diseases and multiple recombinant protein production, uncontrolled re- sclerosis could be related to ‘‘microbial deprivation lease of genetically-modified organisms will occur if disorders’’. There are several possibilities for a these vaccine strategies are applied in medical dysfunctional microbial stimulation caused by hy- practice. Such a release has already elicited major gienic measures in western societies (‘‘The hygiene concerns about and opposition to food products, hypothesis’’): which will apply to vaccine-related organisms. In addition, specific vaccine-related problems may . Some key groups of microbes may have disap- have to be considered. Indeed, unplanned vaccina- peared tion may occur, with possible adverse events, and . Some other group of microbes with untoward repeated exposure to vaccine antigens may induce effects may have increased due to lack of oral tolerance. competition . The turnover of strains in the microflora may be The safety of probiotics too low to generate a sufficient number of The assessment of the safety of probiotics is an activation events for the immune system important part of their characterisation for human use. The presentation on this subject by S. Salminen Probiotics and food-based vaccines is presented as a separate article (pp. 42Á48). This subject was presented by P. Michetti. The It is essential that a probiotic does not have the immuno-modulatory capacity of probiotics has ability to invade the host intestinal tissue and cause stimulated the use of lactobacilli, streptococci, an infection. Probiotic organisms must be sensitive lactococci, Bacillus spores, and Saccharomyces as to broad-spectrum and commonly used antibiotics.

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This is a significant issue where the intestinal barrier Regardless of whether probiotic products are is immature as in infants, and where its integrity is food products or medicines, effect documentation impaired by radiotherapy, antibiotic treatment or in human clinical trials is essential. A. Melander disease; and in immuno-compromised states, such stressed that every medical intervention (lifestyle as human immunodeficiency virus (HIV) infection. modification, surgery, radiation, pharmacotherapy Epidemiological surveillance studies have reported or probiotic therapy) should be based on genuine extremely rare cases of bacteraemia with lactic acid and confirmed evidence of patient benefit. More- bacteria and bifidobacteria. The cases were not over, the benefit should be greater than the risks. associated with probiotic use and were often pre- When evaluating the benefit, and the benefit/risk ceded by serious underlying diseases and previous ratio, it is important to consider the aim of the antibiotic-treated bacteraemia. Studies on probiotic treatment: Is it supposed to be curative, to sub- use by immuno-compromised subjects together with stitute, to alleviate symptoms, or to prevent future the epidemiology studies support the safety of disease or complications? The number of subjects current probiotics. and the duration of the clinical trial needed to Correct taxonomic identification of both species evaluate benefits and risks differ markedly between and strain is a safety issue for quality control of the these situations. This was illustrated by examples product, consumer and prescriber information, from the pharmaco-therapeutic area. It is also diagnosis and appropriate treatment of suspected important to consider the difference between evi- clinical cases, as well as for epidemiological surveil- dence of efficacy (i.e. the potential of a drug as lance of the exposed population. Spore-forming shown in a randomised, controlled clinical trial), bacteria is a special issue, where rigorously designed effectiveness (i.e. in the epidemiological/observa- studies are needed to characterise and demonstrate tional, real-life situation of routine treatment) and both the efficacy and safety of the probiotic efficiency (i.e. when cost effectiveness is also in- microorganism. cluded). The history of safe use of food microorganisms Curative drugs, with penicillin as the prime has been reviewed recently specifically for dairy example, are rather few. Due to their curative foods through the International Dairy Federation. nature, such drugs are given for a short period of As a result a list of cultures with safe history of use time. Hence, their efficacy is usually easy to evaluate has been produced. Especially rigorous procedures in short-lasting controlled trials, in which the are required for novel organisms and for GMO control is either placebo or an already established microbes. standard drug. Also the effectiveness may be ascertained in short-term observational analyses. However, the safety aspect may not be sufficiently Claims and their substantiation elucidated by short-term studies, as witnessed by the Products with probiotics as active ingredient can be drastic increase in bacterial resistance against most either ‘‘functional food’’ or medicine, depending on antibiotics. Recent studies have shown that the product characteristics Á food or tablet, capsule, extent of resistant pathogenic bacteria correlates powder Á as well as intended use and claims in with the extent of exposure to various antibiotics labelling and marketing. G. Reid, presenting the not only in the individual but also at the population International Scientific Association for Probiotics level. This development was not foreseen for several and Prebiotics (ISAPP), mentioned the fact that decades after the introduction of antibiotics in there are websites around with ridiculous claims by general practice. companies with unreliable products containing Proton pump inhibitors (PPI), such as omepra- strains of dubious and unproven properties. zole, were mentioned by Melander in this context, as ISAPP exists to foster high-quality scientific they not only alleviate symptoms of gastric hyper- information for the probiotic and prebiotic fields acidity and gastro-duodenal ulcers but even help to and to provide guidance for collaborative and enhance the rate of ulcer healing. On the other multidisciplinary research. ISAPP’s intent and hand, there is reason to assume that they may also hope is that this information will be translated by enhance ulcer relapse rate and may favour re- industry into high-quality, healthful products which infection with Helicobacter pylori. Moreover, a benefit people all over the world (www.isapp.net). rebound effect (hypergastrinaemia) may lead to a

21 Asp N-G et al. situation of PPI habituation and dependence. As in more, it is important to analyse not only the relative, the case of antibiotics, this emphasises the impor- but also the absolute efficacy, preferably expressed tance of long-term evaluation of all potential as numbers of individuals needed to treat (NNT) in consequences even of short-term interventions. order to prevent one death or other major event. Therefore, evaluation of the anti-Helicobacter effi- Studies of the effectiveness of preventive drugs, cacy and effectiveness of probiotics seems highly subsequent to those of efficacy, are particularly important. important for several reasons. For practical and Substituting drugs may, like curative drugs, allow economic reasons, even the best of efficacy studies a normal life, although on condition that the have been limited to a few years and some thousand substitution is continuous, e.g. as with insulin in subjects. Hence, the representativity of the trial is type 1 diabetes, thyroid hormone in hypothyroidism often insufficient concerning long-term patient and corticosteroids in Addison’s disease. The eva- benefit. Moreover, long-term or unusual but serious luation of substitutive drug efficacy and effective- risks, e.g. cancer, may be missed in trials. In ness is usually easy; without insulin the patient with addition, patient adherence to treatment is com- type 1 diabetes will rapidly become ill and die. This monly low, especially in long-term, preventive would apply also to probiotics, if potentially life- treatment. In addition, interactions with other saving agents of this kind become available. drugs may occur in routine treatment. Melander Symptom-alleviating drugs are predominant in concluded that, particularly as long-term trials of pharmacotherapy, including analgesic, anxiolytic, probiotics used in disease prevention seem far away, hypnotic, antiepileptic, neuroleptic, antidepressant, it is important to initiate effectiveness studies, i.e. anti-Parkinson, anti-allergic, antacid and several epidemiological-observational ones, on probiotics other drugs. The patient’s self-rating of symptoms employed to prevent disease and disease complica- (less pain, easier movements, less depressed, etc.) is central in the evaluation of efficacy and effective- tions. ness of such drugs. However, controlled studies involving placebo or an established standard drug The legal framework for ‘‘functional food’’ are necessary, as placebo/nocebo effects often are Different types of food products, relevant for pronounced. This should be applicable to present or probiotics, were reviewed by A˚ . Bruce. There are a future symptom-alleviating probiotics as well. number of legally defined subgroups of foods which Preventive drugs are rapidly increasing in both are identified and characterised by various national number and use, and the pharmaceutical industry and international regulations: invests more resources in this area than in any other. Such drugs, by definition, are to be taken for many . Foodstuffs intended for particular nutritional uses years, if not life-long, and because they may be . Novel foods indicated for use by large segments of the popula- . Fortified foods (with added vitamins and/or tion. Prime examples are blood pressure lowering, minerals) lipid-lowering, glucose-lowering and weight-redu- . Dietary supplements (tablets etc. with vitamins cing drugs. The purchase costs of the two former and/or minerals or /in future/ with other com- drug groups already comprise more than 10% of the pounds) current total drug purchase costs in Sweden. . (Functional foods Á not legally defined in the EU Evaluation of the efficacy of preventive drugs or by Codex Alimentarius) presents a much more laborious, time-consuming and expensive task than that of other drugs. This is Two types medicinal products are also relevant: because the aim is to reduce morbidity and/or mortality, necessitating studies lasting several years . Natural remedies and including large numbers of patients. Moreover, . Ordinary medicinal products the patients ought to be representative of major segments of the population, including different Foodstuffs for ‘‘Particular Nutritional Uses’’ are groups of age, sex, ethnicity, co-morbidity and intended for certain categories of persons who are in concurrent treatment. However, this has only rarely a special physiological condition or whose digestive been the case even in latter-day studies. Further- processes or metabolism are disturbed.

22 Conference summary

A new subgroup is ‘‘Dietary foods for special ‘‘Proposal for a regulation of the European Parlia- medical purposes’’, products intended to meet the ment and of the Council on nutrition and health particular nutritional requirements of persons af- claims made on foods’’ [COM (2003) 424 final 2003/ fected by or malnourished because of a specific 0165 (COD)] was presented. disease, disorder or medical condition. Codex Alimentarius has dealt with these issues in Novel Foods follow the Regulation of the Eur- the labelling committee as well as in the committee opean Parliament and of the Council of 27 January on nutrition and foods for special dietary uses. For 1997. The regulation applies to the placing on the the time being their definitions are not entirely in market of foods or food ingredients which have not agreement with those of the EU. hitherto been used for human consumption to a significant degree in the EU and which fall under Japanese perspectives the following categories of foods and food ingre- The functional foods concept emerged in Japan in dients: the 1980s. T. Sasaki reviewed the current status of health claims for functional foods in Japan. It is . containing or consisting of genetically modified widely recognised that food has both a nutritional organisms (GMO) function (primary function) and a palatability . produced from, but not containing, GMO function (second function). In Asian countries . with a new or intentionally modified primary such as China, Korea and Japan, people have long molecular structure believed that food has an additional function, . consisting of or isolated from microorganisms, namely the ability to prevent disease (third func- fungi or algae tion). This idea came from the traditional belief that . consisting of or isolated from plants or animals, food and medicine come from the same origin and except for foods and food ingredients obtained serve the same purpose. by traditional propagation and breeding prac- A terminology for ‘‘functional food’’ first arose tices and which have a history of safe use when an ad hoc research group in Japan began a . to which has been applied a production process relevant study in early 1980s. The third function of not currently used, where that process gives rise food was scientifically evaluated by the group with a to significant changes in the composition or large grant from the Ministry of Education, Science structure of the foods or food ingredients which and Culture, Japan. The International Life Science affect their nutritional value, metabolism or the Institute of Japan (ILSI Japan) has also contributed level of undesirable substances. greatly to the establishment of this new concept by publishing reports and organising domestic and Natural remedies in Sweden are medicinal pro- international meetings. ILSI Japan together with ducts whose constituents have natural origins, and 26 food companies will set up a laboratory at the which are parts of an animal or a vegetable, a University of Tokyo this year and begin research on bacterial culture, a mineral, salt or salt solution. The nutrigenomics in order to clarify physiological product must be suitable for home cures in accor- functions of foods. dance with well-proven Swedish tradition, or tradi- In 1991, the Ministry of Health and welfare, tions in other countries considered to have Japan, issued the ‘‘Labelling Regulation for Foods medicinal traditions similar to those in Sweden. for Specified Health Use (FOSHU)’’ and Japan was The Medicinal Products Agency should approve thus the first country that formally accepted the any new product. ‘‘functional food’’ concept. The FOSHU-approved International and national activities. The matters foods containing oligosaccharide created a new of functional foods and health claims about foods market in Japan. This market increased greatly have been more and more discussed during the last when two yoghurt products were approved as decade within a number of international contexts. FOSHU in 1997. The number of approved FOSHU The European Commission stated, in a ‘‘White Paper products is 369 (June 2003) and the market is on Food Safety’’ published at the beginning of 2000, growing (about 2,000 million euro in 2002). The that an investigation is to be carried out on this FOSHU system is fairly well-known to Japanese matter during the first years of this decade, and it and consumers easily recognise FOSHU products started in fact in 2002. This summer a new by the certification mark along with the general

23 Asp N-G et al. description of the health claims. It should be noted, Á Food studies cannot always be blinded (although though, that in China 3,357 products are approved in the case of probiotics true placebo products (March 2002). without the active probiotic microorganism can Among the 369 products approved so far, 57 are usually be made enabling double blind studies) yoghurts or fermented milks, which amount to more Á Foods provide energy and nutrients and hedonic than 60% of the sales in 2002. This clearly shows value for money, in addition to the specific health how probiotics are important in the FOSHU effect, whereas the one and only value of a market. The approved probiotics include six Lacto- medicine is its health-promoting or symptom- bacillus spp., one Streptococcus sp. and three reducing effect Bifidobacterium spp. The claims allowed on these Á When provided in a food, the active component 57 products with probiotics are restricted to ‘‘pro- cannot be excessively overdosed due to the moting the maintenance of good intestinal environ- volume, caloric content and satiety effects of a ment’’. Other allowed claims for probiotic yoghurts food are: ‘‘helps increase intestinal bifidobacteria and Á Costs for good clinical studies with foods are lactobacilli. This promotes the maintenance of a often regarded as too high and difficult to pay good intestinal environment and regulates the GI back condition’’, ‘‘helps regulate the balance of intestinal microflora which leads to the maintenance of a good GI condition’’, ‘‘helps improve intestinal The need for markers useful as surrogate endpoints environment and regulates the GI condition’’. in effect studies was stressed. The EU-concerted However, current and future research will clarify action project PASSCLAIM (Procedure for the the specific health-promoting effects of probiotics Assessment of Scientific Support of Claims) has a beyond basic maintenance of a healthy intestinal focus on markers, as reported by Nils-Georg Asp environment. Approval of additional health claims (http://europe.ilsi.org/passclaim). With the excep- in the near future is desirable as scientific evidence tion of some established markers such as serum amounts. cholesterol/LDL cholesterol level, effect studies with Sasaki concluded that consumers expect more probiotics generally have to measure real end-points applications in health-promoting foods, especially such as symptom reduction in irritable bowel-like as preventive agents of ‘‘life-style related diseases’’. conditions, allergic manifestations or signs of infec- In order to improve public health, it would be tion such as diarrhoea or common cold. The desirable to extend the concept of ‘‘probiotics’’ to validation of markers such as parameters reflecting those bacteria which are effective in promoting the immune system and inflammation is an im- healthy conditions in the oral cavity, throat, sto- portant issue for further research. mach or vagina. These should be regarded as A bottom line in documentation is the correct probiotics, if the scientific evidence is clear. Further- labelling of genus, species and count of viable more, there is a need for international agreements probiotic microorganisms. A recent survey on the on definitions and permitted claims in this area. European market has shown that many products do not meet such basic criteria. The possibility to define general criteria for a Discussions and conclusions ‘‘probiotic microorganism/product’’ Á such as sur- The final discussion, opened by Director General vival of gastrointestinal passage, adherence, coloni- Gunnar Alva´n, Medical Products Agency, Uppsala, sation, effects on colonic pH etc. Á was discussed. Sweden, was focused on documentation of effects of The general opinion, however, was that such criteria probiotics as functional foods and medicinal pro- would not be meaningful, since the physiological ducts. All agreed that effects claimed in the market- effects of probiotic microorganism are species- and ing have to be based on a solid scientific basis, but is strain-specific, and may even be clone-specific. it reasonable Á and possible Á to require the same However, Bengt Bjo¨ rkste´n stressed the importance placebo control and GCP (Good Clinical Practice) of making studies also with wild strains Á for standard for functional foods as for medicine? A instance in relation to allergy in children, which is number of differences between foods and medicines much less common in the Baltic countries than in are relevant in this context: Scandinavia, and related to the occurrence of

24 Conference summary

Lactobacilli in the colon. Ideally, studies of specific in children: a meta-analysis. Pediatrics 2002; 109: 678Á probiotic microorganisms should have placebos 84. both without the microorganism and with a com- 3. Guandalini S, Pensabene L, Zikri MA, Dias JA, Casali parable wild strain. The issue is further complicated LG, Hoekstra H et al. Lactobacillus GG administered in by the fact that also dead microorganisms seem to oral rehydration solution to children with acute diarrhea: have some physiological effects, e.g. on the immune a multicenter European trial. J Pediatr Gastoenterol Nutr system. 2000; 30: 54Á60. A general conclusion was that there is intense 4. Oberhelm RA, Gilman RH, Sheen P, Taylor DN, Black research with many indication of health effects RE, Cabrera L et al. A placebo-controlled trial of of probiotics, promising for the further develop- Lactobacillus GG to prevent diarrhea in undernourished ment of both functional foods and medicinal Peruvian children. J Pediatr 1999; 134: 15Á20. products. However, there is a great need for 5. Trapp CL, Chang CC, Halpern GM, Keen CL, Gershwin further well-controlled studies in both patients ME. The influence of chronic yoghurt consumption on with various diseases and healthy individuals to populations of young and elderly adults. Int J Immuno- explore further the health-promoting potential of ther 1993; IX: 53Á64. probiotics. 6. Wheeler JG, Shema SJ, Bogle ML, Shirrell MA, Burks AW, Pittler A et al. Immune and clinical impact of Lactobacillus acidophilus on asthma. Ann Allergy Selected references Asthma Immunol 1997; 79: 229Á33. 1. Szajewska H, Mrukowicz. Probiotics in the treatment and 7. Majamaa H, Isolauri E. Probiotics: A novel approach prevention of acute infectious diarrhea in infants and in the management of food allergy. J Allergy Clin children: a systematic review of published randomized, Immunol 1997; 99: 179Á85. double-blind, placebo-controlled trials. J Pediatr Gas- 8. Kallioma¨ki M, Salminen S, Arvilommi H, Kero P, toenterol Nutr 2001; 33(Suppl. 2): S17Á25. Koskinen P, Isolauri E. Probiotics in primary preven- 2. Van Niel CW, Feudtner C, Garrison MM, Christakis tion of atopic disease: a randomised placebo-controlled DA. Lactobacillus therapy for acute infectious diarrhea trial. Lancet 2001; 357: 1076Á9.

Chairs and speakers

Gunnar Alvan, Uppsala, Sweden ([email protected]), Merja Ashorn, Tampere, Finland([email protected]), Nils- Georg Asp, Lund, Sweden ([email protected]), Franco Bazzoli, Bologne, Italy ([email protected]), Bengt Bjo¨rkste´n, Stockholm, Sweden ([email protected]), A˚ ke Bruce, Uppsala, Sweden ([email protected]), A˚ ke Danielsson, Umea˚, Sweden ([email protected]), Antonio Gasbarrini, Rome, Italy ([email protected]), Lennart Hammarstro¨m, Stockholm, Sweden ([email protected]), Piotr Heczko, Krakow, Poland ([email protected]), Bengt Jeppson, Malmo¨, Sweden ([email protected]), Yasuhiro Koga, Kanagawa, Japan ([email protected]), Lars Lundell, Stockholm, Sweden ([email protected]), Jennifer Madden, Dundee, United Kingdom ([email protected]), Arne Melander, Malmo¨, Sweden ([email protected]), Pierre Michetti, Lausanne, Switzerland ([email protected]), Tore Midtvedt, Stockholm, Sweden ([email protected]), Marika Mikkelsaar, Tartu, Estonia ([email protected]), Go¨ran Molin, Lund, Sweden ([email protected]), Elisabeth Norin, Stockholm, Sweden ([email protected]), Gregor Reid, London, Canada ([email protected]), Theodor Rokkas, Athens, Greece ([email protected]), Seppo Salminen, Turkku, Finland ([email protected]), Takashi Sasaki, Kanagawa, Japan ([email protected]), Torkel Wadstro¨m, Lund, Sweden ([email protected]), James Versalovic, Houston, U.S.A. ([email protected]), Agnes Wold, Go¨teborg, Sweden ([email protected])