Field of the Invention

The present invention relates to a method for the prevention of the incidence of and/or a reduction in the duration of acute diarrhoea, particularly in travellers, by orally administering an oligosaccharide composition, in particular a non-digestible oligosaccharide composition. The composition preferably comprises a mixture of galactooligosaccharides. Galactooligosaccharides are non-digestible carbohydrates which are resistant to mammalian gastrointestinal digestive enzymes but are fermented by specific colonic bacteria.

Background of the Invention

Diarrhoea in travellers, particularly acute diarrhoea, is one of the most common conditions experienced by individuals travelling abroad to a foreign country, especially to a developing country. Diarrhoea in travellers, hereafter referred to as travellers' diarrhoea or TD, has an attack rate of 20 to 50% and it has been estimated that the disorder can affect over eleven million people annually. In 90% of patients who contract TD, symptoms occur within the first two weeks of travel. It has been shown that bacteria and some viruses are the most common causative agents of TD, with enterotoxigenic Escherichia coli (ETEC) being reported as the bacterial cause of 50% of TD cases.

To date, the management of TD has been based on the treatment of the condition using antibiotic and anti-diarrhoea medications such as fluoroquinolones, ciprofloxacin, rifamixin and loperamide. However, these agents can potentially also have an impact on the composition of the commensal gut microflora.

The human gut flora comprises pathogenic, benign and beneficial microbial genera. A predominance of the former can lead to intestinal disorders, that can be both acute, such as travellers' diarrhoea, and chronic, such as inflammatory bowel disease. Attempts have been made to influence the balance of the gut flora in favour of beneficial microorganisms, such as the bifidobacteria, by adding one or more such microbial strains to an appropriate food vehicle such as yoghurt. Such a live microbial feed supplement is known as a probiotic. However, it is difficult to guarantee the survival of live bacteria in foods and also after digestion.

An alternative approach to dietary manipulation of the gut microflora is the use of a prebiotic. Prebiotics are defined as non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and which may thus improve the health of the host.

One group of compounds that is classified as prebiotics are the galactooligosaccharides. These are galactose containing oligosaccharides of the form GIc βl-4 [Gal βl-6] _π , where n = 2 to 5 and are produced from lactose syrup using the transgalactosylase activity of the enzyme β-galactosidase (Chrittenden, (1999) Probiotics: A Critical Review, Tannock, G (ed) Horizon Scientific Press, Wymondham, pp 141-156).

EP 1 644 482 discloses a novel strain of Bifidobacterium bifidum that produces a galactosidase enzyme activity that converts lactose to a novel mixture of galactooligosaccharides. This mixture of galactooligosaccharides has been shown to have prebiotic properties and to increase the population of the beneficial bacteria bifidobacteria and lactobacilli.

Summary of the Invention

In a double blind, placebo controlled, randomised human study, the present inventors have now surprisingly found that oral administration of an oligosaccharide composition results in the prevention of the incidence of and/or a reduction in the duration/ severity of acute diarrhoea, particularly in travellers.

The present method has the advantage that the active principle is safe and can be suitably admixed to a drink or food. In one aspect, the present invention comprises the oral administration of a nutritional composition which reduces the occurrence and/or severity of acute diarrhoea, particularly in travellers.

Detailed Description of Preferred Embodiments

The present invention provides a method for the prevention of the incidence of and/or a reduction in the duration/severity of acute diarrhoea, said method comprising orally administering a composition to a mammal, said composition comprising an effective amount of an oligosaccharide.

The oligosaccharide composition may comprise a mixture of galactooligosaccharides, such as the mixture of galactooligosaccharides disclosed in EP 1 644 482. This mixture comprises disaccharides Gal-Gal, trisaccharides Gal-Gal-Glc, a tetrasaccharide Gal-Gal-Gal-Glc and a pentasaccharide Gal-Gal-Gal-Gal-Glc, where Gal represents a galactose residue and GIc represents a glucose residue.

Preferably, the galactooligosaccharide mixture comprises disaccharides Gal (β 1-3)- GIc; Gal (β l-3)-Gal; Gal (β l-6)-Gal; Gal (α l-6)-Gal; trisaccharides Gal (β l-6)-Gal (β 1- 4)-Glc; Gal (β l-3)-Gal (β l-4)-Glc; tetrasacchride Gal (β l-6)-Gal (β l-6)-Gal (β l-4)-Glc and pentasaccharide Gal (β l-6)-Gal (β l-6)-Gal (β l-6)-Gal (β l-4)-Glc. This mixture of galactooligosaccharides is marketed commercially under the name Bimuno (registered trade mark) and is available from Clasado Ltd (Milton Keynes, UK).

Bimuno comprises 49% w/w of galactooligosaccharide. The remainder of the composition may comprise non-active components such as glucose, lactose, acacia gum and citric acid.

The composition may be presented in freeze-dried powder form or as a syrup. It is preferably taken orally on a daily basis. The composition preferably comprises from 1.35g to 9.6g of oligosaccharide in 2.75g to 2Og of the powdered composition, preferably from 1.96g to 4.9g of oligosaccharide in 4g to 1Og of the powder, most preferably 2.7g oligosaccharide in 5.5g of composition. This can be taken in a single dose or in two separate doses several hours apart. The composition may be added to a drink, preferably a hot drink, or sprinkled on food.

In order to prevent the incidence of and/or reduce the duration/severity of acute diarrhoea whilst travelling to another country, the composition should preferably be consumed daily by the person travelling for several days prior to departure for a foreign country. Preferably, it should be taken for seven days prior to departure and then every day whilst staying in the foreign country.

Example 1

Freeze-dried powdered composition packaged in a 'stick-pack' and containing per 5.5g final product:-

Galactooligosaccharide (GOS) mixture 2.67g

Lactose 1.44g

Monosaccharides (glucose, galactose) 0.68g

Drying aid 0.24g

Ash 0.23g

Protein 0.05g

Moisture 0.19g

Example 2

Effectiveness of galactooligosaccharides in preventing the incidence and/or reducing the duration of acute diarrhoea in travellers.

Materials and Methods

The study was placebo-controlled, randomised, double blind of parallel design and the target enrolment was healthy volunteers, who would travel and stay in a country of low or high risk for TD for a minimum of 14 days and maximum of 60 days. High risk destinations for incidence of TD included Asia, the Middle East, Africa, Mexico, Central and South America, whereas, low risk areas included Turkey, South Africa and the Caribbean Islands as determined by the Centre for Disease Control and Prevention (CDC, 2008). Recruitment of subjects was conducted through advertisement of the study in the local and national press. Respondents to the advertisement were contacted by telephone and the study was explained to them. A series of screening questions were asked about their holiday, past and current medical conditions, travel details and TD history and concomitant medication, if any. Inclusion and exclusion criteria are given in Table 1. Prohibited medication during the study period included antidepressants, narcotic analgesics, anticholinergic, anti-spasmodic agents for bowel diseases, immunosuppressive drugs and anti-tumour necrosis factors. However, antibiotics, antidiarrheals (such as loperamide) and laxatives were allowed in the case of significant infections as "rescue" medication. Subjects who met the inclusion criteria were sent a volunteer information leaflet and asked to read it thoroughly before taking part. Those who agreed to participate were then randomised into groups with an equal probability of receiving either of the two treatments. This ensured that numbers of subjects allocated to each treatment group were equal after every block of subjects. Following allocation of the participant's number, they were sent a volunteer pack which included: volunteer information leaflet (for reference), consent form, diary card, clinical report form (to be filled in case of diarrheal incidence), instructions of how to consume the product, an explanatory letter for immigration purposes, and the test product or placebo. The product used in this study was prebiotic B-GOS (Bimuno, RTM) (Clasado Ltd, Milton Keynes, UK), served in sachets (5.5g), once daily, B-GOS is a galactooligosaccharide mixture already marketed in Europe and is generally recognised as safe (GRAS) as defined by United States of America Food and Drug Administration (FDA) (FDA, 2008). The galactooligosaccharide content of B-GOS is 48% (w/w) and its composition in terms of degree of polymerisation (DP) and saccharide linkages have been given previously. The placebo was maltodextrin (oligosaccharide without prebiotic effect) served in sachets (5.5g), once daily. The interventions were in white aluminium foil sachets blind code labelled. 30 such sachets contained a blank paper box showing all the necessary information such as description of use and researcher contact details were provided to the volunteers at the beginning of the study.

Seven days prior to reaching their final destination, volunteers started consuming the product on a daily basis and kept a daily diary noting the number of bowel movements and average consistency of the stools (formed, loose, water or bloody), as well as occurrences of abdominal discomfort, flatulence, bloating or vomiting. The volunteers continued consuming the treatment whilst on their holidays. The outcome measures that were used for the holiday period, related to:

• Number of bowel movements

• Stool consistency (1 = formed, 2 = loose, 3 = watery, 4 = bloody)

• Abdominal pain (0 = none, 1 = present but well tolerated, 2 = present but interfering with but not preventing daily activities, 3 = preventing normal daily activities)

• Bloating (0 = none, 1 = present but well tolerated, 2 = present and interfering with but not preventing daily activities, 3 = preventing normal daily activities)

• Flatulence (0 = none, 1 = present but well tolerated, 2 = present and interfering with but not preventing daily activities, 3 = preventing normal daily activities)

• Vomiting (= absence, 1 = presence)

In the case of diarrheal incidence, the volunteer completed a clinical report form describing the signs, symptoms and duration of incidence, hospital admission history, history of exposure and onset, and progress of the diarrheal incidence. Incidence of TD with respect to subjects' age, gender and place of travel in subjects taking prebiotic was compared to the placebo.

Following completion of the study, volunteers were also asked to complete the short World Heath Organisation Quality of Life (WHO-QOL-BREF) questionnaire (post-study questionnaire). This consisted of 22 questions concerning how they felt about their quality of life, health, or other areas of their life during the last four weeks. A scoring system was introduced and scores for each group were calculated based on specific equations as described in WHOQOL-BREF (WHO, 2004). Questions concerned different aspects of subjects' quality of life during their vacation were divided into four domains. Domain 1 related to physical health (daily living activities, dependence on medical substances and medical aids, pain and discomfort, sleep and rest), Domain 2 mainly concerned their psychological condition (positive/negative feelings, self esteem), whereas domain 3 looked at social relationships (personal relationships, social support). Last, domain 4 related to their overall feeling of health as influenced by the environment while being abroad (physical safety, participation in and opportunities for recreation/leisure activities).

Completed diary cards were collected for assessment, along with any unused sachets. Adverse effects were also addressed along with any concomitant medications used.

Ethics

The procedures followed were in accordance with the ethical standards of the Research Ethics Committee of the University of Reading on human experimentation and with the Helsinki Declaration of 1975 as revised in 1983. Ethical approval for the study was granted by the Research Ethics Committee of the University of Reading in July 2007 (approval reference number: 07/21). The study lasted for 9 months.

Statistics

For the power calculation, we predicted that 50% of the subjects would experience diarrhoea and that GOS may reduce this rate by 20%. For 80% power and 5% significance, this gave 93 subjects per treatment group (MGH Biostatistics Software, Massachusetts General Hospital, Boston, MA). Statistical analysis was conducted using GENSTAT statistical package version 10.0 (VSN International Ltd). A value of P <0.05 was taken to indicate statistical significance. Data were analysed by Fisher's exact text, t test, ANOVA and multiple regression analysis. In the regression analysis, the dependent variable was one of the outcome measures mentioned above, and independent variables were included, corresponding to the outcome measure for the pre-holiday period. Thus, each subject's bowel score on holiday was analysed and compared between treatments taking into account corresponding pre-holiday scores. Other independent variables were included where appropriate such as duration of travel, TD risk of holiday destination, recent travel history and recent TD.

Results

A total of 201 subjects were recruited and randomised but 42 subsequently did not complete the study, of whom 23 had been allocated to the placebo group and 19 the test (B-GOS) group. Table 5 shows the total number of people who enrolled and finished the study and reasons for not completing. Five subjects did not complete due to adverse reactions and their main complaint was occurrence of mild abdominal pain which was reported during the pre-holiday period.

The distribution of destinations was similar between placebo and prebiotic group (Table 2). Data area presented as average values or percentages of enrolled population. Statistical analysis was performed using ANOVA in Gentstat 10.0 to determine significant differences between groups. In total, 159 subjects completed the study, of which 81 consumed the B-GOS powder and 78 were in the placebo group. Relevant information is summarised in Table 2 concerning the age group (average), sex and previous history of TD.

Bowel habit data for the two time periods (pre-holiday, holiday) in the two groups based on the analysis of the received and completed diaries are given in Table 3 and statistically significant differences indicated. Data presented as average values + standard deviation of enrolled population. Statistical analysis was performed using multiple regression analysis in Gentstat 10.0 to determine significant differences between groups and treatment periods (independent variables included sex, age, duration of travel and high or low risk destination). Regression analysis indicated that the number of bowel movements (average per day) significantly increased during the holiday compared to the pre-holiday period in the placebo group (p<0.05), but not in the B-GOS group (p=0.12). The average bowel movement number was not significantly different during the holiday period between treatments but it should be noted that the baseline (pre-holiday) number was significantly higher for the B-GOS group when compared to placebo, indicating substantial heterogeneity amongst the interventions as far as the average daily number of bowel movements was concerned. For stool consistency and abdominal pain, significant differences occurred between pre- and holiday periods in the placebo group (p<0.05) but not in B-GOS (p=0Λ0). There was no difference (p=0.23) between the two treatments during the holiday period. A similar analysis for flatulence and bloating showed that neither the study period nor treatment exerted a significant effect.

The analysis of clinical report forms concerning incidence of diarrhoea and related symptoms, showed a striking effect of B-GOS on the incidence and duration of TD. 31% of persons who took part in.the study reported diarrhoea during the holiday period. Data in Table 4 is presented as average values + standard deviation of population experienced diarrhoea or duration of each symptom and were analysed by using Fischer's exact test and multiple regression analysis in Gentstat 10.0 (independent variables: sex, age, duration of travel and high or low risk destination). The data show the incidence and duration of diarrhoea as well as the duration of other symptoms such as abdominal pain, vomiting, fever, anorexia, headache and dizziness. Fisher's exact test indicated that a significantly (p=0.03) lower number of volunteers who consumed B-GOS (n=19) had diarrheal during the holiday period compared to the placebo group (n=30). Regression analysis similarly indicated that the duration of diarrhoea and associated abdominal pain was significantly lower in the B-GOS group when compared to placebo, regardless of destination or holiday duration. There were no other differences in other symptoms between the two treatment groups. 34% of volunteers in the placebo group followed a "relief treatment (such as Imodium, loperamide or ciprofloxamin) versus 22% in the B-GOS group (data not presented). Analysis of the overall feeling of subjects, as based on a scoring system, showed that people enrolled in the prebiotic B-GOS group reported better (PO.05) overall feelings concerning their health than those in the placebo group. Analysis of scores (data not presented), showed that the B-GOS group were more satisfied with their health condition compared to the placebo group.

Conclusion

The results show striking findings concerning not only the duration but also on the incidence of TD. A significantly lower number of subjects who consumed the prebiotic B- GOS experienced diarrheal episodes during their holiday period compared to the placebo group (/Kθ.05). Similarly, the duration of diarrhoea and abdominal pain were significantly lower in the B-GOS group compared to the placebo (p<0.05). In a previous study, the use of another prebiotic (FOS) did not show such an effect (Cummings, et al, 2001, Aliment. Pharmacol. Ther., JJi, 1139-1145) as the incidence of diarrhoea and several measures of bowel habit, stool frequency, consistency and size, recorded in the diary, did not demonstrate significant differences between the two groups at any study period. The only significant effect was noticed in flatulence, which significantly increased in the FOS group.

In the current study with B-GOS, a different class of prebiotic molecule, a significant increase in the number of bowel movements, stool consistency and abdominal pain was obtained between pre- and holiday periods for the placebo group but not for B- GOS. This was not unexpected as diarrheal incidence was significantly higher in the placebo group. Additionally, the duration of diarrhoea and abdominal pain were reported to be significantly lower in the group of people that consumed B-GOS compared to placebo.

There will be various modifications, improvements and application of the disclosed invention that will be apparent to those of skill in the art, and the present application encompasses such embodiments to the extent allowed by law. Although the present invention has been described in the context of certain preferred embodiments, the full scope of the invention is not so limited, but is in accordance with the scope of the following claims. All references, patents and other publication are specifically incorporated by reference herein.

Table 1: Inclusion and exclusion criteria

Inclusion Criteria Exclusion criteria

The period of travel should be a

Subject is unwilling to participate minimum of 14 days and a maximum

Subject is taking a probiotic and/or prebiotic preparation of 60 days (outside of study product).

Aged 18 years or older

Subjects willing and able to enter data

Subject is unable to comply with the protocol in the diary card

Subject suffers from a medical condition that causes regular

Subjects willing and able to take the gastrointestinal symptoms - e.g. irritable bowel syndrome, study supplement as per protocol thyrotoxicosis, post-vagotomy, diabetic autonomic neuropathy, malabsorption, short bowel syndrome, Crohn's disease, Coeliac disease, Ulcerative Colitis, previous bowel surgery, cystic fibrosis

Subjects must have adequate general

Subject regularly takes medication that alters gastrointestinal health (as determined by the function investigators)

Subject is suffering from diabetes (Type I or Type II)

Ability to communicate well with the Subject takes long-term antibiotics (e.g. for acne or recurrent investigator and to comply with the urinary infections) requirements of the study.

Subject plans to take doxycycline as anti-malarial prophylaxis Prophylactic use of Ciprofloxacin

The volunteer has given written

Antibiotics should be avoided whilst subjects are taking the informed consent to participate and is study preparation. However, short-term use of antibiotics in the willing to participate in the study. case of acute illnesses will not be an exclusion criterion Known allergic reaction to dairy products

Use of any investigational or non-registered drug other than the study supplement within 30 days preceding the first dose of the study supplement

Subject is pregnant or lactating

Table 2: Baseline characteristics of prebiotic GOS and placebo group

B-GOS GROUP Placebo Group

(n = 81) (n = 78)

Age (average) 38 30 High Risk Destination (%) 91 88 Travelled in past 12 months (%) 76 72 Travellers' diarrhoea incidence 30 33 in past 12 months (5)

B OW el Habit Period B-GOS Group Placebo Group (n=81) (n=78)

Movements (avg Pre-holiday 1.373^=0.514 1.146±0.438 number/day) Holiday 1.286±0.514 1.292*±0.512

Stool Consistencj Pre-holiday 1.157±0.328 1.060±0.295

(avg score/day) Holiday 1.166±0.339 1.168*±0.379

Abdominal Pain Pre-holiday 0.119±0.206 0.116±0.191

(avg score/day) Holiday 0.183±0.174 0.231*±0.252

Bloating Pre-holiday 0.227±0.291 0.242±0.367

(avg score/day) Holiday 0.218±0.268 0.237±0.337

Flatulence Pre-holiday 0.472±0.477 0.488±0.439

(avg score/day) Holiday 0.436±0.541 0.549±0.651

Table 3: Bowel habit of volunteers by study period and treatment

* Significant difference between study period (P <0.05) ¥ Significant difference between treatments (P <0.05)

Subjects with diarrheal 19 30* incidence

Diarrhoea duration (avg 2.368±2.060 4.567*±3.026 number of days) Duration of abdominal pain 2.000±1.987 3.533*±2.583 (avg number of days) Duration of vomiting 0.526±0.722 0.433±0.675 (avg number of days) Duration of fever 0.210±0.713 0.133±0.581 (avg number of days) Duration of anorexia 0.157±0.688 0.233±0.466 (avg number of days) Duration of headache 0.578±0.961 0.600±1.695 (avg number of days) Duration of dizziness 0.663±0.806 0.800±1.763 (avg number of days)

Table 4: Diarrheal incidence and associated symptoms duration per treatment

Significant difference between treatments (P <0.05) Table 5: Shows the number of subjects at each stage of the study