Scientific Opinion on the substantiation of health claims related to rye fibre  
and changes in bowel function (ID 825), reduction of post-prandial  
glycaemic responses (ID 826) and maintenance of normal blood  
LDL-cholesterol concentrations (ID 827) 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:
LDL-cholesterol
 
Rye fibre
 
bowel function
 
glycaemic response
 
health claims
 
post-prandial
 
	
	1. Charakterystyka żywności / składnika
	
        
		The food constituent that is the subject of the health claims is rye fibre.
The rye (Secale cereale L.) fibre is predominantly composed of non-starch polysaccharides. The main  components of the non-starch polysaccharides in whole grain rye are arabinoxylan (8-12 %), fructan  (4.6-6 %), beta-glucan (1.3-2.2 %) and cellulose (1.0-1.7 %) (Kamal-Eldin et al., 2009). More than  80 % of rye fibre is insoluble. Beta-glucan and arabinoxylan are the soluble types of fibre in rye.
Rye bran products may differ with regard to chemical composition and particle size depending on the  milling process.
The Panel considers that the food constituent, rye fibre, which is the subject of the health claims, is  sufficiently characterised in relation to the claimed effects.
		
	
	
    
	
	
		
 
	
	2. Znaczenie oświadczenia dla zdrowia człowieka
	
        
		
		
	
	
    
	
	
		
			
2.1. Zmiany w funkcjonowaniu jelit (skrócenie czasu pasażu jelitowego, zwiększenie częstości ruchów jelit, zwiększenie objętości stolca) (ID 825)
	
	
			The claimed effect is “gut health”. The Panel assumes that the target population is the general  population.
In the context of the clarifications provided by Member States, the Panel assumes that the claimed  effect refers 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  these changes do not result in diarrhoea.
	
    
			
	
		
			
2.2. Ograniczenie wzrostu stężenia glukozy (glikemii) po posiłku (ID 826)
	
	
			The claimed effect is “carbohydrate metabolism and insulin sensitivity”. The Panel assumes that the  target population is individuals wishing to reduce their post-prandial glycaemic responses.
In the context of the proposed wordings, the Panel assumes that the claimed effect relates to the  reduction of post-prandial glycaemic responses.
Postprandial glycaemia is interpreted as the elevation of blood glucose concentrations after  consumption of a food and/or meal. This function is a normal physiological response which varies in  magnitude and duration, and which may be influenced by the chemical and physical nature of the food  or meal consumed, as well as by individual factors (Venn and Green, 2007). Reducing post-prandial  blood glucose responses may be beneficial, for example, to subjects with impaired glucose tolerance  as long as post-prandial insulinaemic responses are not disproportionally increased. Impaired glucose  tolerance is common in the general population of adults.
The Panel considers that a reduction of post-prandial glycaemic responses (as long as post-prandial  insulinaemic responses are not disproportionally increased) may be a beneficial physiological effect.
	
    
			
	
		
			
2.3. Utrzymanie prawidłowego stężenia cholesterolu LDL we krwi (ID 827)
	
	
			The claimed effect is “cardiovascular system”. The Panel assumes that the target population is the  general population.
In the context of the proposed wordings and clarifications provided by Member States, the Panel  assumes that the claimed effect refers to the maintenance of normal blood LDL-cholesterol  concentrations.
Low-density lipoproteins (LDL) carry cholesterol from the liver to peripheral tissues, including the  arteries. Elevated LDL-cholesterol, by convention >160 mg/dL (>4.14 mmol/L), may compromise the  normal structure and function of the arteries.
The Panel considers that maintenance of normal blood LDL-cholesterol concentrations is a beneficial  physiological effect.
	
    
			
	
		
 
	
	3. Naukowe uzasadnienia wpływu na zdrowie człowieka - 
	
        
		
		
	
	
    
	
	
		
			
3.1. Zmiany w funkcjonowaniu jelit (skrócenie czasu pasażu jelitowego, zwiększenie częstości ruchów jelit, zwiększenie objętości stolca) (ID 825)
	
	
			The references provided for the substantiation of the claim included two textbooks, one guideline  document, one human study and one animal study, all of which reported on health outcomes unrelated  to the claimed effect (e.g. faecal bile acids and formation of intestinal polyps). One reference was an  abstract from a conference proceeding which did not provide sufficient information for a full  scientific evaluation, and one reference on a human study was not accessible to the Panel after every  reasonable effort had been made to retrieve it. The Panel considers that no conclusions can be drawn  from these references for the scientific substantiation of the claim.
A randomised, cross-over intervention study conducted in 28 overweight men investigated the effect  on faecal weight of consuming foods (90 g) which contained either whole-grain rye flour or  whole-grain wheat flour and provided about 21 g/day of dietary fibre vs. consuming refined cereal  foods which provided 6 g/day of dietary fibre, for four weeks (McIntosh et al., 2003). Total 24 h  faecal weight after consumption of high rye fibre foods was significantly higher than after  consumption of low-fibre refined cereal foods (mean ±SEM=278±16 g vs. 203±18 g, p<0.005).
In a randomised, cross-over study, Gråsten et al. (2000) compared the effect of a whole-meal rye  bread diet vs. a wheat bread diet in 17 healthy volunteers (nine women). Both interventions lasted  four weeks. Subjects were advised to eat a minimum of 20 % of their total daily energy intake in the  form of the tested breads. The intake of total dietary fibre from the tested products was estimated as  17.4±2.1 g/day for the rye bread period and 3.9±0.9 g/day for the wheat bread period. Wet and dry  faecal weight, faecal frequency and intestinal transit time measured by a radiopaque method were  evaluated. Differences between interventions were assessed by the Wilcoxon signed-ranks test. The  results were presented separately for women and men. Compared to the wheat bread diet, the whole- meal rye bread diet significantly increased faecal weight (women 203±58 vs. 151±63 g/day, p<0.05;  men 335±921 vs. 198±61, p<0.05) and faecal frequency (women 1.2±0.4 vs. 0.9±0.4 times per day,  p<0.05; men 1.6±0.6 vs. 1.4±0.6 times per day, p<0.05), and significantly shortened intestinal transit  time (women 44.8±13.1 vs. 56.2±22.0 hours, p<0.05; men 30.9±12.1 vs. 39.4±15.6 hours, p<0.05), in  both women and men.
In a randomised, parallel study, Hongisto (2006) evaluated the effect of rye bread (containing 12.3 g  fibre/100 g) with or without the bacterial strain Lactobacillus rhamnosus GG (LGG, ATCC53103)  vs. low-fibre toast (control) on bowel function in a group of 59 women with self-reported constipation  (mean age 41 years). Rye bread provided 37 g/day of dietary fibre, while low-fibre toast provided  6.6 g/day. During the three-week dietary intervention, the frequency of bowel movements was  significantly higher in the rye bread group (n=15) compared to the control group (n=15) (mean  difference 0.3 defecations/day, CI 95 % 0.1 to 0.5, p<0.001). Total intestinal transit time (measured  by radiopaque method) was significantly shorter in the rye bread group than in the low-fibre toast  group (mean difference = -0.7 days, CI 95 % -1.1 to -0.2, p=0.007).
Gråsten et al. (2007) in a randomised, cross-over study in 39 post-menopausal women with  hypercholesterolaemia (mean age 59 years) administered rye bread with high fibre content  (approximately 17 %) and white wheat bread with low fibre content (approximately 2.8 %) at doses  covering at least 20 % of daily energy intakes for eight weeks each, with an eight-week wash-out  period in between. The Wilcoxon test with Bonferroni adjustments was used for comparisons between  the two intervention periods. The mean fibre intake in the rye bread period was 21.5 g/day higher than  in the white wheat bread period (47±9 and 15±4 g/day during the rye bread and the white wheat bread  periods, respectively). Frequency of defecation was significantly higher during the rye bread period  than during the white wheat bread period (11.3±2.7 vs. 8.5±2.1 times per week, p<0.05). The  proportion of soft stools was significantly higher and the proportion of hard stools was significantly  lower during the rye bread period than during the white wheat bread period (p<0.05).
The Panel notes that the mechanism by which rye fibre could exert an effect on faecal weight, transit  time and stool consistency is known and relates to an increase in water holding capacity of the content  of the intestine.
In weighing the evidence, the Panel took into account that the results of all four human intervention  studies considered showed an effect of rye fibre on various outcome measures related to bowel  function. The Panel also noted the known mechanism by which rye fibre exerts the claimed effect.
The Panel concludes that a cause and effect relationship has been established between the  consumption of rye fibre and changes in bowel function.
	
    
			
	
		
			
3.2. Ograniczenie wzrostu stężenia glukozy (glikemii) po posiłku (ID 826)
	
	
			The references provided for the substantiation of the claim included one human intervention study  which reported on health outcomes other than the claimed effect (e.g. bowel function); human  intervention studies conducted in insulin-dependent diabetic patients or in ileostomy patients with  ulcerative colitis; human intervention studies on post-prandial glycaemic and insulinaemic responses
to whole foods in which either the amount of rye fibre was not reported or a certain amount of rye  fibre in bread was compared to the same amount of, for example, wheat fibre, and thus did not allow  conclusions to be made on the effects of rye fibre per se; and human intervention studies in healthy  subjects which did not assess post-prandial blood glucose responses following consumption of rye  fibre, but rather the effects of longer-term consumption of rye fibre-containing food products on  glucose tolerance (i.e. using the frequently sampled intravenous glucose tolerance test or the oral  glucose tolerance test). The Panel considers that no conclusions can be drawn from these references  for the scientific substantiation of the claim.
Three intervention studies provided investigated the effects of rye fibre in rye products on post- prandial blood glucose and insulin responses (Juntunen et al., 2002; Juntunen et al., 2003; Leinonen et  al., 1999).
In the study by Leinonen et al. (1999), the effects of wheat bread (61 g available carbohydrates; 2.3 g  fibre), whole kernel rye bread (55 g available carbohydrates; 13.5 g fibre), wholemeal rye bread (43 g  available carbohydrates; 10.1 g fibre) and wholemeal rye crispbread (45 g available carbohydrates;  12.1 g fibre) consumed with a standard breakfast were compared with respect to induced post-prandial  glucose and insulin responses (measured every 30 min for three hours, and at 15 min post-prandial) in  20 subjects (10 female) with normal glucose tolerance using a randomised cross-over design. Direct  comparisons were made between wheat bread and whole kernel rye bread (two types of cereals), and  between wholemeal rye bread and wholemeal rye crispbread (two types of rye bread). The Panel  considers that only the first comparison is appropriate for the scientific substantiation of the claim. No  significant differences in post-prandial blood glucose responses at any time point, or measured as  areas under the curve, were observed between wheat bread and whole kernel rye bread. Insulin  concentrations were significantly lower at 45 (p=0.025), 60 (p=0.002), 90 (p=0.0004), 120 (p=0.05)  and 150 (p=0.033) min after the whole kernel rye bread than after the wheat bread (p=0.002 for the  area under the curve). The Panel notes that this study did not show an effect of rye fibre on post- prandial glycaemic responses.
In the study by Juntunen et al. (2002), the effects of wheat bread made from white wheat flour (3.1 g  fibre), whole kernel rye bread (12.8 g fibre), wholemeal pasta (5.6 g fibre) and wholemeal rye bread  containing oat beta-glucan concentrate (17.1 g fibre) were compared with respect to induced  post-prandial glucose and insulin responses (measured every 30 min for three hours and at 15 min  post-prandial) using a randomised cross-over design and standard portions containing 50 g of  available carbohydrates for all test foods. Subjects were 20 healthy men and women (mean age  28±1 years; BMI 22.9±0.7 kg/m2). The Panel notes that wholemeal rye bread containing oat beta- glucan concentrate cannot be used to address the effects of rye fibre, and that wheat bread is more  appropriate than pasta to test the effects of rye fibre in whole kernel rye bread on post-prandial blood  glucose responses. No significant differences in post-prandial blood glucose responses at any time  point, or measured as areas under the curve, were observed between wheat bread and whole kernel rye  bread. A significant decrease in post-prandial insulinaemic responses was observed after consumption  of the whole kernel rye bread compared to the wheat bread (p<0.05). The Panel notes that this study  did not show an effect of rye fibre on post-prandial glycaemic responses.
In the study by Juntunen et al. (2003) the effects of wheat bread made from white wheat flour (2.7 g  fibre), endosperm rye bread (6.1 g fibre), traditional rye bread (15.2 g fibre) and high-fibre rye bread  (29.0 g fibre) were compared with respect to induced post-prandial glucose and insulin responses  (measured every 30 min for three hours, and at 15 min post-prandial) using a randomised cross-over  design and standard portions containing 50 g of available carbohydrates for all test foods in a random  order. Subjects were 19 healthy post-menopausal women aged 61±1 years and with a BMI of  26.0±0.6 kg/m2. No differences in post-prandial blood glucose responses (measured as maximal  response or as incremental areas under the curve) were observed between wheat bread and the  different rye breads. A significant decrease in post-prandial insulinaemic responses was observed
after consumption of the endosperm rye bread and the traditional rye bread compared to the wheat  bread (p<0.05). No significant difference was observed between the high-fibre rye bread and the  wheat bread. The Panel notes that this study did not show an effect of rye fibre on the reduction of  post-prandial glycaemic responses.  In weighing the evidence, the Panel took into account that the three human intervention studies  provided from which conclusions could be drawn for the scientific substantiation of the claim did not  show an effect of rye fibre on post-prandial glycaemic responses.
The Panel concludes that a cause and effect relationship has not been established between the  consumption of rye fibre and reduction of post-prandial glycaemic responses.
	
    
			
	
		
			
3.3. Utrzymanie prawidłowego stężenia cholesterolu LDL we krwi (ID 827)
	
	
			The references provided for the substantiation of the claim included textbooks, a meta-analysis and a  review paper on the consumption of wholegrain foods and cardiovascular disease, a meta-analysis on  the effect of oat products on blood lipids, a review on viscous fibres, and human intervention studies  in ileostomy patients with ulcerative colitis. The Panel considers that no conclusions can be drawn  from these references for the scientific substantiation of the claim.
One randomised, cross-over study in humans was provided which investigated the effects of rye fibre  on blood cholesterol concentrations (Leinonen et al., 2000). A total of 30 subjects (22 women)  consumed rye and wheat breads (20 % of energy intake) for four weeks each with a four-week  wash-out period in between. Men consumed on average 219 g of rye bread daily containing 22.1 g  fibre (vs. 4.7 g/day fibre from wheat bread), and women 163 g of rye bread daily containing 16.4 g  fibre (vs. 3.6 g/day fibre from wheat bread). The estimated daily amounts of beta-glucan were 2 g/day  in men and 1.5 g/day in women. Data were analysed separately for men and women. No significant  changes in total, LDL- or HDL-cholesterol concentrations were observed during the rye bread  intervention compared to the wheat bread intervention. The Panel notes that this study did not show  an effect of rye fibre consumption on blood cholesterol concentrations.
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 an  effect of rye fibre on blood LDL-cholesterol concentrations.
The Panel concludes that a cause and effect relationship has not been established between the  consumption of rye fibre and maintenance of normal blood LDL-cholesterol concentrations.
	
    
			
	
		
 
	
	4. Uwagi do zaproponowanego brzmienia oświadczenia
	
        
		
		
	
	
    
	
	
		
			
4.1. Zmiany w funkcjonowaniu jelit (skrócenie czasu pasażu jelitowego, zwiększenie częstości ruchów jelit, zwiększenie objętości stolca) (ID 825)
	
	
			The Panel considers that the following wording reflects the scientific evidence: “Rye fibre contributes  to normal bowel function”.
	
    
			
	
		
 
	
	5. Warunki i możliwe ograniczenia stosowania oświadczenia
	
        
		
		
	
	
    
	
	
		
			
5.1. Zmiany w funkcjonowaniu jelit (skrócenie czasu pasażu jelitowego, zwiększenie częstości ruchów jelit, zwiększenie objętości stolca) (ID 825)
	
	
			The Panel considers that in order to bear the claim a food should be at least “high in fibre” as per  Annex to Regulation (EC) No 1924/2006. The target population is the general population.
	
    
			
	
		
 
Wnioski
	
		On the basis of the data presented, the Panel concludes that:  
The food constituent, rye fibre, which is the subject of the health claims, is sufficiently  characterised in relation to the claimed effects.  
Changes in bowel function (ID 825)  
The claimed effect is “gut health”. The target population is assumed to be the general  population. In the context of the clarifications provided by Member States, it is assumed that  the claimed effect refers to changes in bowel function. 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 these changes do not result in diarrhoea.  
A cause and effect relationship has been established between the consumption of rye fibre and  changes in bowel function.  
The following wording reflects the scientific evidence: “Rye fibre contributes to normal  bowel function”.  
In order to bear the claim a food should be at least “high in fibre” as per Annex to Regulation  (EC) No 1924/2006. The target population is the general population.   
Reduction of post-prandial glycaemic responses (ID 826)  
The claimed effect is “carbohydrate metabolism and insulin sensitivity”. The target  population is assumed to be individuals who wish to reduce their post-prandial glycaemic  responses. In the context of the proposed wordings, it is assumed that the claimed effect  relates to the reduction of post-prandial glycaemic responses. A reduction of post-prandial  glycaemic responses (as long as post-prandial insulinaemic responses are not  disproportionally increased) may be a beneficial physiological effect.  
A cause and effect relationship has not been established between the consumption of rye fibre  and reduction of post-prandial glycaemic responses.  
Maintenance of normal blood LDL-cholesterol concentrations (ID 827)  
The claimed effect is “cardiovascular system”. The target population is assumed to be the  general population. In the context of the proposed wordings and clarifications provided by  Member States, it is assumed that the claimed effect refers to the maintenance of normal  blood LDL-cholesterol concentrations. Maintenance of normal blood LDL-cholesterol  concentrations is a beneficial physiological effect.  
A cause and effect relationship has not been established between the consumption of rye fibre  and maintenance of normal blood LDL-cholesterol concentrations.