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Scientific Opinion on the substantiation of health claims related to partially hydrolysed guar gum (PHGG) and decreasing potentially pathogenic gastro-intestinal microorganisms (ID 788), changes in short chain fatty acid (SCFA) production and/or pH in the gastro-intestinal tract (ID 787, 813), changes in bowel function (ID 813, 853, 1902, 1903, 1904, 2929, 2930, 2931), and reduction of gastro-intestinal discomfort (ID 813, 1902, 1903, 1904, 2929, 2930, 2931) pursuant to Article 13(1) of Regulation (EC) No 1924/2006[sup]1[/sup] EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA)2, 3 European Food Safety Authority (EFSA), Parma, Italy
Słowa kluczowe: Partially hydrolysed guar gum   bowel function   gastro-intestinal discomfort   health claims   potentially pathogenic gastro-intestinal microorganisms  
ID:    853      788      787      1904      1903      1902      2931      2929      813      2930  
Produkty: Częściowo hydrolizowana guma guar  

1. Charakterystyka żywności / składnika

The food constituent that is the subject of the health claims is partially hydrolysed guar gum (PHGG).
PHGG is produced from guar gum by digestion with D-mannanase. It has a low viscosity and a molecular weight of about 20 kDa. PHGG is not naturally occurring in foods, and is usually consumed in the form of food supplements. PHGG can be measured in foods by established methods.
The Panel considers that the food constituent, partially hydrolysed guar gum, which is the subject of the health claims, is sufficiently characterised.

2. Znaczenie oświadczenia dla zdrowia człowieka


2.1. Zmniejszenie ilości potencjalnie patogennych mikroorganizmów przewodu pokarmowego (ID 788)

The claimed effect is “bowel health/prebiotic effect”. The Panel assumes that the target population is the general population.
In the context of the proposed wordings, the Panel assumes that the claimed effect refers to increasing numbers of bacteria that are considered to be “beneficial”.
The numbers/proportions of bacterial groups that would constitute a “beneficial/healthy/good/or natural balance” of gastro-intestinal flora have not been established. Increasing the number of any group of microorganisms, including lactobacilli and/or bifidobacteria, is not in itself considered to be a beneficial physiological effect.
The Panel considers that the evidence provided does not establish that increasing numbers of gastro- intestinal microorganisms is a beneficial physiological effect.
The Panel considers that the claimed effect, in the context of decreasing potentially pathogenic gastro- intestinal microorganisms, might be a beneficial physiological effect.

2.2. Zmiana produkcji krótkołańcuchowych kwasów tłuszczowych (SCFA) i/lub odczynu pH w przewodzie pokarmowym (ID 787, 813)

The claimed effects are “bowel health/SCFA production” and “improved intestinal conditions (pH, SCFA production) and intestinal function”. The Panel assumes that the target population is the general population.
The Panel notes that the claimed effect refers to changes in short chain fatty acid (SCFA) production and/or pH in the gastro-intestinal tract. The Panel considers that changes in SCFA production and pH in the gastro-intestinal tract are not beneficial physiological effects per se, but need to be linked to a beneficial physiological or clinical outcome. No information has been provided about the context in which the claimed effect could be considered as a beneficial physiological effect.
The Panel concludes that a cause and effect relationship has not been established between the consumption of partially hydrolysed guar gum and a beneficial physiological effect related to changes in SCFA production and/or pH in the gastro-intestinal tract.

2.3. Zmiany w funkcjonowaniu jelit (skrócenie czasu pasażu jelitowego, zwiększenie częstości ruchów jelit, zwiększenie objętości stolca) (ID 813, 853, 1902, 1903, 1904, 2929, 2930, 2931)

The claimed effects are “improved intestinal conditions (pH, SCFA production) and intestinal functions”, “bowel function”, and “intestinal health and regularity”. The Panel assumes that the target population is the general population.
In the context of the proposed wordings, the Panel assumes that the claimed effects refer to changes in bowel function.
The Panel considers that changes in bowel function such as reduced transit time, more frequent bowel movements, increased faecal bulk, or softer stools may be a beneficial physiological effect, provided that these changes do not result in diarrhoea.

2.4. Zmniejszenie dolegliwości ze strony przewodu pokarmowego (ID 813, 1902, 1903, 1904, 2929, 2930, 2931)

The claimed effects are “improved intestinal conditions (pH, SCFA production) and intestinal function” and “intestinal health and regularity”. The Panel assumes that the target population is the general population.
In the context of the proposed wordings, the Panel assumes that the claimed effects refer to the reduction of gastro-intestinal discomfort.
The Panel considers that reduction of gastro-intestinal discomfort is a beneficial physiological effect.

3. Naukowe uzasadnienia wpływu na zdrowie człowieka - 


3.1. Zmniejszenie ilości potencjalnie patogennych mikroorganizmów przewodu pokarmowego (ID 788)

Among the references provided were narrative reviews which did not provide original data for the scientific substantiation of the claim, one human intervention study on the combination of fructo- oligosaccharides and PHGG which provided no information about the effects of PHGG alone, and human intervention studies which addressed the effects of PHGG on health outcomes (e.g. SCFA concentration in faeces, cholecystokinin concentration in blood, colonic fluid secretion, intestinal transit, constipation, and incidence of diarrhoea in patients receiving total parenteral nutrition) other than the claimed effect. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
In an open label, one-arm, uncontrolled human intervention study, Okubo et al. (1994) evaluated the effect of 7 g of PHGG given three times daily on intestinal microflora. The Panel considers that no conclusions can be drawn from this uncontrolled study for the scientific substantiation of the claim.
The Panel notes that no human studies have been provided from which conclusions could be drawn for the scientific substantiation of the claim. The Panel considers that evidence provided in animal and in vitro studies is not sufficient to predict the occurrence of an effect of PHGG consumption on potentially pathogenic gastro-intestinal microorganisms in vivo in humans.
The Panel concludes that a cause and effect relationship has not been established between the consumption of partially hydrolysed guar gum and decreasing potentially pathogenic gastro-intestinal microorganisms.

3.2. Zmiany w funkcjonowaniu jelit (skrócenie czasu pasażu jelitowego, zwiększenie częstości ruchów jelit, zwiększenie objętości stolca) (ID 813, 853, 1902, 1903, 1904, 2929, 2930, 2931)

Among the references provided for the scientific substantiation of the claim were textbooks and narrative reviews which did not contain any original data for the scientific substantiation of the claim. Some human studies were not related to the food constituent which is the subject of the claim, examined the effect of PHGG in combination with other substances, or addressed health outcomes (e.g. prevention and treatment of diarrhoea) other than the claimed effect. One reference was not accessible to the Panel after every reasonable effort to retrieve it had been made. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
Five human intervention studies addressed the effects of PHGG on intestinal transit time/frequency of defecations.
Four of the human studies provided were one-arm, uncontrolled, open label studies which evaluated the effects of PHGG supplementation on different measures of bowel function (Giaccari et al., 2001; Patrick et al., 1998; Takahashi et al., 1993; Takahashi et al., 1994). The Panel notes that these studies were uncontrolled, and considers that no conclusions can be drawn from these studies for the scientific substantiation of the claim.
A randomised, controlled, cross-over study by Meier et al. (1993) reported on the effects of a standardised diet and two liquid formula diets, with and without supplementation of PHGG (21 g/L), on oro-caecal and colonic transit time in 12 healthy male volunteers. The diets were consumed in a randomised order for seven days each. PHGG did not significantly affect oro-caecal transit time. Colonic transit time, however, was significantly prolonged (55 hours) with the liquid diet containing PHGG compared to the liquid diet without PHGG (39 hours), and to the normal diet (30 hours) (p<0.01). Stool frequency and consistency were not significantly affected by PHGG supplementation. The Panel notes that this study does not show a significant effect of PHGG on stool frequency or consistency, and that PHGG increased rather than decreased colonic transit time.
In weighing the evidence, the Panel took into account that the only human intervention study provided from which conclusions could be drawn for the scientific substantiation of the claim did not show any effect of PHGG on stool frequency or consistency, and that PHGG induced an increase rather than a decrease in colonic transit time.
The Panel concludes that a cause and effect relationship has not been established between the consumption of partially hydrolysed guar gum and changes in bowel function.

3.3. Zmniejszenie dolegliwości ze strony przewodu pokarmowego (ID 813, 1902, 1903, 1904, 2929, 2930, 2931)

A number of the references provided in relation to the claim were textbooks and narrative reviews which did not provide any original data for the scientific substantiation of the claim. Some human studies were not related to the food constituent which is the subject of the claim, examined the effect of PHGG in combination with other substances, or addressed outcomes (e.g. measures of bowel function, and prevention and treatment of diarrhoea) unrelated to the claimed effect. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
Four human intervention studies which addressed gastro-intestinal discomfort, were provided.
One of the human studies was a one-arm, open label, uncontrolled study on the effects of PHGG (5 g/day for 24 weeks) on frequency of defecation and intensity of symptoms in patients with irritable
bowel syndrome (IBS) (Giaccari et al., 2001). The Panel considers that no conclusions can be drawn from this uncontrolled study for the scientific substantiation of the claim.
In a randomised, not placebo-controlled, open label study, Parisi et al. (2005) assessed the effects of PHGG supplementation on gastro-intestinal symptoms and quality of life in IBS patients, who were randomly assigned to consume 60 mL of an apple-flavoured beverage providing either 10 g/day (n=40) or 5 g/day (n=46) of PHGG for 12 weeks. The Panel considers that no conclusions can be drawn from this uncontrolled study for the scientific substantiation of the claim.
In a multicentre, randomised, open label study, Parisi et al. (2002) investigated the effect of PHGG (5 g/day) compared to wheat bran (30 g/day) on gastro-intestinal symptoms in 188 IBS patients. After four weeks, patients were allowed to voluntarily change intervention, depending on their subjective evaluation of symptoms. The severity of abdominal pain was assessed in a semi-structured interview designed for the purpose of the study, and the overall effect of the intervention was assessed by asking the subjects whether IBS symptoms were worse, unchanged or better compared to baseline. No information on the validity of this method was given. The Panel notes that this study was not blinded, and that no information was given about the validity of the methods used for assessing the effect of the intervention. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claim.
In a parallel study in 40 patients with constipation predominant IBS (28 females, mean age 54 years), Uneddu et al. (2005) assessed the effect of consuming 10 g/day of PHGG compared to 100 g of bread (made of 70 % hard wheat flour, bran and refined bran, consisting in a total of 10.4 g of fibre on average) for 60 days. The frequency and intensity of abdominal symptoms were assessed by a 4-point Likert scale questionnaire. No information about the validity of the questionnaire used was given. The Panel notes that the intervention was not blinded, and that successful blinding of subjects is particularly important when evaluating self-reported health outcomes for which a high placebo effect can be expected. The Panel considers that no conclusions can be drawn from this unblinded study, which used a non-validated questionnaire for abdominal symptom assessment, for the scientific substantiation of the claim.
The Panel notes that no human studies have been provided from which conclusions could be drawn for the scientific substantiation of the claim. The Panel considers that evidence provided in animal and in vitro studies is not sufficient to predict the occurrence of an effect of partially hydrolysed guar gum consumption on a decrease in potentially pathogenic gastro-intestinal microorganisms in vivo in humans.
The Panel concludes that a cause and effect relationship has not been established between the consumption of partially hydrolysed guar gum and reduction of gastro-intestinal discomfort.

Wnioski

On the basis of the data presented, the Panel concludes that:
The food constituent, partially hydrolysed guar gum, which is the subject of the health claims, is sufficiently characterised.
Decreasing potentially pathogenic gastro-intestinal microorganisms (ID 788)
The claimed effect is “bowel health/prebiotic effect”. The target population is assumed to be the general population. Decreasing potentially pathogenic gastro-intestinal microorganisms might be a beneficial physiological effect.
A cause and effect relationship has not been established between the consumption of partially hydrolysed guar gum and decreasing potentially pathogenic gastro-intestinal microorganisms.
Changes in short chain fatty acid (SCFA) production and/or pH in the gastro-intestinal tract (ID 787, 813)
The claimed effects are “bowel health/SCFA production” and “improved intestinal conditions (pH, SCFA production) and intestinal function”. The target population is assumed to be the general population. No evidence has been provided to indicate the context in which the claimed effect could be considered as a beneficial physiological effect.
A cause and effect relationship has not been established between the consumption of partially hydrolysed guar gum and a beneficial physiological effect related to changes in SCFA production and/or pH in the gastro-intestinal tract.
Changes in bowel function (ID 813, 853, 1902, 1903, 1904, 2929, 2930, 2931)
The claimed effects are “improved intestinal conditions (pH, SCFA production) and intestinal functions”, “bowel function”, and “intestinal health and regularity”. The target population is assumed to be the general population. Changes in bowel function such as reduced transit time, more frequent bowel movements, increased faecal bulk, or softer stools may be a beneficial physiological effect, provided that these changes do not result in diarrhoea.
A cause and effect relationship has not been established between the consumption of partially hydrolysed guar gum and changes in bowel function.
Reduction of gastro-intestinal discomfort (ID 813, 1902, 1903, 1904, 2929, 2930, 2931)
The claimed effects are “improved intestinal conditions (pH, SCFA production) and intestinal function”, and “intestinal health and regularity”. The target population is assumed to be the general population. In the context of the proposed wordings, it is assumed that the claimed effects refer to the reduction of gastro-intestinal discomfort. Reduction of gastro-intestinal discomfort is a beneficial physiological effect.
A cause and effect relationship has not been established between the consumption of partially hydrolysed guar gum and reduction of gastro-intestinal discomfort.
Documentation provided to EFSA
Health claims pursuant to Article 13 of Regulation (EC) No 1924/2006 (No: EFSA-Q-2008-1574, EFSA-Q-2008-1575, EFSA-Q-2008-1600, EFSA-Q-2008-1640, EFSA-Q-2008-2635, EFSA-Q-2008- 2636, EFSA-Q-2008-2637, EFSA-Q-2008-3661, EFSA-Q-2008-3662, EFSA-Q-2008-3663). The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly from stakeholders.
The full list of supporting references as provided to EFSA is available on: http://www.efsa.europa.eu/panels/nda/claims/article13.htm.
REFERENCES
Giaccari S, Grasso G, Tronci S, Allegretta L, Sponziello G, Montefusco A, Siciliano IG, Guarisco R, Candiani C and Chiri S, 2001. Partially hydrolyzed guar gum: a fiber as coadjuvant in the irritable colon syndrome. Clinica Terapeutica, 152, 21-25.
Meier R, Beglinger C, Schneider H, Rowedder A and Gyr K, 1993. Effect of a liquid diet with and without soluble fiber supplementation on intestinal transit and cholecystokinin release in volunteers. JPEN: Journal of Parenteral and Enteral Nutrition, 17, 231-235.
Okubo T, Ishihara N, Takahashi H, Fujisawa T, Mujo K, Yamamoto T and Mitsuoka T, 1994. Effects of Partially Hydrolyzed Guar Gum Intake on Human Intestinal Microflora and Its Metabolism. Bioscience, Biotechnology, and Biochemistry, 58, 1364-1369.
Parisi G, Bottona E, Carrara M, Cardin F, Faedo A, Goldin D, Marino M, Pantalena M, Tafner G, Verdianelli G, Zilli M and Leandro G, 2005. Treatment effects of partially hydrolyzed guar gum on symptoms and quality of life of patients with irritable bowel syndrome. A multicenter randomized open trial. Digestive Diseases and Sciences, 50, 1107-1112.
Parisi GC, Zilli M, Miani MP, Carrara M, Bottona E, Verdianelli G, Battaglia G, Desideri S, Faedo A, Marzolino C, Tonon A, Ermani M and Leandro G, 2002. High-fiber diet supplementation in patients with irritable bowel syndrome (IBS): a multicenter, randomized, open trial comparison between wheat bran diet and partially hydrolyzed guar gum (PHGG). Digestive Diseases and Sciences, 47, 1697-1704.
Patrick PG, Gohman SM, Marx SC, DeLegge MH and Greenberg NA, 1998. Effect of supplements of partially hydrolyzed guar gum on the occurrence of constipation and use of laxative agents. Journal of the American Dietetic Association, 98, 912-914.
Takahashi H, Yang SIL, Hayashi C, Kim M, Yamanaka J and Yamamoto T, 1993. Effect of partially hydrolyzed guar gum on fecal output in human volunteers. Nutrition Research, 13, 649-657.
Takahashi H, Wako N, Okubo T, Ishihara N, Yamanaka J and Yamamoto T, 1994. Influence of Partially Hydrolyzed Guar Gum on Constipation in Women. Journal of Nutritional Science and Vitaminology, 40, 251-251.
Uneddu A, 2005. Diet therapy in constipation -predominant irritable bowel syndrome (C-IBS): comparison between sardinian brown bread and soluble non-gelling fibre (PHGG) dietary supplementation. European Bulletin of Drug Research, 13, 1-6.