Scientific Opinion on the substantiation of health claims related to  
beta-glucans from oats and barley and maintenance of normal blood  
LDL-cholesterol concentrations (ID 1236, 1299), increase in satiety leading  
to a reduction in energy intake (ID 851, 852), reduction of post-prandial  
glycaemic responses (ID 821, 824), and “digestive function” (ID 850)  
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:
Beta-glucans
 
barley
 
blood cholesterol
 
digestion
 
fibre
 
glycaemic responses
 
health claims
 
oats
 
satiety
 
	
	1. Charakterystyka żywności / składnika
	
        
		The foods/food constituents that are the subject of the health claims are “barley grain fibre”, “oat  grain fibre”, “oats beta-glucan”, “barley beta-glucan”, “barre céréalière diététique contenant de  l'avoine”, and “oatbran and oatbran products”.
From the conditions of use and references provided, the Panel assumes that the food constituent  responsible for the claimed effects is beta-glucans from oats and barley.
Beta-glucans are soluble cereal fibres. They are non-starch polysaccharides composed of glucose  molecules in long linear glucose polymers with mixed β-(1→4) and β-(1→3) links with an  approximate distribution of 30 % to 70 %. Their molecular weight varies from 50 to 2,000 kDa.  Beta-glucans occur naturally in the bran of cereal grasses such as barley (~7 %), oats (~5 %), rye and  wheat (1-2 %), and are measurable in foods by established methods. This opinion applies to beta- glucans naturally present in foods, and added to foods.
The mixed linkages are important for their physical properties, such as solubility and viscosity. Their  viscosity is a function of the concentration of dissolved beta-glucans, and of their molecular weight  (Wood et al., 2000), and further depends on differences in raw materials, processing and methods of  determination.
The Panel considers that the food constituent, beta-glucans from oats and barley, which is the subject  of the health claims, is sufficiently characterised.
		
	
	
    
	
	
		
 
	
	2. Znaczenie oświadczenia dla zdrowia człowieka
	
        
		
		
	
	
    
	
	
		
			
2.1. Utrzymanie prawidłowego stężenia cholesterolu LDL we krwi (ID 1236, 1299)
	
	
			The claimed effects are “fibres solubles (beta-glucane) et cholestérol sanguin” and “blood cholesterol  level”. 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  maintenance of normal blood LDL-cholesterol concentrations.
A claim on beta-glucans and maintenance of normal blood cholesterol concentrations has already  been assessed with a favourable outcome (EFSA Panel on Dietetic Products Nutrition and Allergies  (NDA), 2009).
	
    
			
	
		
			
2.2. Zwiększenie sytości prowadzące do redukcji przyjmowanej energii (ID 851, 852)
	
	
			The claimed effect is “increases satiety, prolongs satiety”. The Panel assumes that the target  population is the general population.
Satiety is the decrease in motivation to eat after consumption of food. The effect may persist up to  several hours, may reduce energy intake either at the next meal or across the day and, if sustained,  may lead to a reduction in body weight.
The Panel considers that an increase in satiety leading to a reduction in energy intake, if sustained,  might be a beneficial physiological effect.
	
    
			
	
		
			
2.3. Ograniczenie wzrostu stężenia glukozy (glikemii) po posiłku (ID 821, 824)
	
	
			The claimed effect is “carbohydrate metabolism and insulin sensitivity”. The Panel assumes that the  target population is individuals who wish to reduce their post-prandial glycaemic responses.
In the context of the proposed wordings, the Panel assumes that the claimed effect refers 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 that 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). Decreasing post-prandial  glycaemic responses may be beneficial to subjects with, for example, impaired glucose tolerance, as  long as post-prandial insulinaemic responses are not disproportionally increased. Impaired glucose  tolerance is common in the general adult population.
The Panel considers that the reduction of post-prandial glycaemic responses (as long as post-prandial  insulinaemic responses are not disproportionally increased) may be a beneficial physiological effect.
	
    
			
	
		
			
2.4. Funkcje trawienne (ID 850)
	
	
			The claimed effect is “beta-glucan improves digestive function”. The Panel assumes that the target  population is the general population.
Improved digestion or absorption of nutrients might be considered as beneficial physiological effects  in a situation where digestion or absorption is a limiting factor for the maintenance of adequate status  of the nutrient. The Panel considers that “improving digestive function” without identification of the  nutrients which are the target of the claim is not sufficiently defined.
The Panel considers that the claimed effect is general and non-specific, and does not refer to any  specific health claim as required by Regulation (EC) No 1924/2006.
	
    
			
	
		
 
	
	3. Naukowe uzasadnienia wpływu na zdrowie człowieka - 
	
        
		
		
	
	
    
	
	
		
			
3.1. Zwiększenie sytości prowadzące do redukcji przyjmowanej energii (ID 851, 852)#ID:34244
	
	
			The two references provided for the scientific substantiation of the claim reported on human  intervention studies which assessed the effects of oat or barley products on appetite ratings (including  satiety) after eating the test food on a single occasion (Berti et al., 2005; Granfeldt et al., 1994). One  of the studies also reported on the effects of barley and oat product consumption (on a single  occasion) on subsequent energy intake (Berti et al., 2005). The Panel notes that none of these studies  tested the sustainability of an effect of beta-glucans on appetite ratings and subsequent energy intake  (i.e. effects were tested on a single occasion and no information has been provided on the repeated  consumption of the food constituent). The Panel considers that no conclusions can be drawn from  these studies for the scientific substantiation of the claim.
The Panel concludes that a cause and effect relationship has not been established between the  consumption of beta-glucans from oats and barley and a sustained increase in satiety leading to a  reduction in energy intake.
	
    
			
	
		
			
3.2. Ograniczenie wzrostu stężenia glukozy (glikemii) po posiłku (ID 821, 824)
	
	
			The references provided for the scientific substantiation of the claim included publications on the  health effects of dietary fibre in general, on the health effects of low glycaemic foods and/or diets, and  on the effects of barley and/or oat products and/or beta-glucans on health outcomes unrelated to the  claimed effect (e.g. blood lipids). The references also included human intervention studies which  reported on measures of blood glucose in which the amount of beta-glucans consumed was not  specified (Granfeldt et al., 1994; Liljeberg et al., 1992), or in which the study population was  insulin-dependent or non-insulin dependent diabetic subjects on either insulin or oral hypoglycaemic  medications (Braaten et al., 1994; Jenkins et al., 2002; Pick et al., 1996; Pick et al., 1998; Tappy et al.,  1996). The evidence provided does not establish that results obtained in patient populations treated  with anti-diabetic medications can be generalised to the target population with respect to post-prandial  glycaemic responses. The Panel considers that no conclusions can be drawn from these references for  the scientific substantiation of the claim.
Three human intervention studies investigated the effects of barley and/or oat beta-glucans on post- prandial glycaemic and insulinaemic responses in healthy subjects using a standardised meal protocol  in which whole-meal bread products (from oats, barley, and rye) were compared to white wheat bread  (Juntunen et al., 2002; Liljeberg et al., 1996; Östman et al., 2006). All of these studies had a  randomised cross-over design with washout periods longer than three days, and sample sizes between  9 and 20 subjects (men and women). Two out of the three studies (Liljeberg et al., 1996; Östman et  al., 2006) observed a statistically significant reduction in post-prandial glycaemic and insulinaemic  responses following consumption of the test meals which included beta-glucan-containing products  (from oats or barley), compared to the test meals not containing beta-glucans, at doses between  4.6-14 g beta-glucans per 30 g of available carbohydrates. The study by Juntunen et al. (2002) did not  show a significant effect on post-prandial glycaemic responses of rye bread containing 5.4 g  beta-glucans in 50 g of available carbohydrate compared to white wheat bread, whereas post-prandial  insulinaemic responses were significantly reduced.
Two human intervention studies investigated the effects of incorporating oat (Holm et al., 1992) or  barley (Yokoyama et al., 1997) beta-glucans into pasta products (control pasta made with plain durum  wheat flour) in 10 and 5 healthy subjects, respectively. These studies had a randomised cross-over  design with washout periods longer than three days. Consumption of pasta with 12 g of beta-glucans  in a 100 g available carbohydrate portion (about 3.6 g/30 g available carbohydrates) resulted in  significantly lower and delayed peak glucose responses, and in lower peak insulin responses
(Yokoyama et al., 1997), whereas enrichment with oat bran (28 %) giving 6 % beta-glucans in the  final product only slightly decreased post-prandial insulinaemic responses, while post-prandial  glycaemic responses were unchanged compared to the control pasta (Holm et al., 1992).
Another test meal study, which investigated the effects on post-prandial blood glucose and insulin  responses of oat and barley beta-glucan products in healthy subjects, used a standardised protocol in  which sucrose was used as a control (Behall et al., 2005). Ten overweight women (mean age 50.1±7.7  years; BMI 30.3±2.2 kg/m2) consumed glucose (1 g/kg body weight) and four test meals consisting of  0.33 g/kg body weight of carbohydrate from pudding (predominantly sucrose) plus 0.67 g/kg body  weight of carbohydrates from oat flour, oatmeal, barley flour, or barley flakes to constitute a total of  1 g carbohydrates/kg body weight at breakfast after a 10 h fast. The content of beta-glucans in the test  food grains was 4 and 15 g/100 g dry matter in the oat and barley test foods, respectively (about  1.8 and 6.5 g/30 g available carbohydrates, respectively). Blood samples were collected at fasting and  every 30 min up to 180 min after the acute loads. Peak glucose and insulin concentrations after the  barley test foods were significantly lower than those after the glucose or oat test foods. Post-prandial  glucose responses (area under the curve) were significantly reduced after the consumption of oat and  barley test foods when compared to sucrose. Post-prandial glucose responses after barley (flour and  flakes) were significantly lower than the post-prandial glucose responses after oat (flour and oatmeal).  Post-prandial insulinaemic responses were significantly reduced by barley test foods only (44-56 %,  p<0.005). The content of beta-glucans in the barley test foods was almost four times higher than in the  oat test foods, which could have explained the differential effects of the barley and oat test foods on  post-prandial glucose and insulin responses.
The Panel notes that the studies above consistently show an effect of oat and barley beta-glucans in  decreasing post-prandial glycaemic responses, without disproportionally increasing post-prandial  insulinaemic responses, at doses of at least 4 g per 30 g of available carbohydrates.
The mechanism by which beta-glucans from oats or barley could exert the claimed effect is well  established, and relates to the increased viscosity of the meal bolus when beta-glucans are added.  When the meal bolus reaches the small intestine, a high viscosity delays the rate of absorption of  nutrients, including glucose (Battilana et al., 2001; Wood et al., 2000; Wursch and Pi-Sunyer, 1997).
In weighing the evidence, the Panel took into account that intervention studies in healthy subjects  consistently show an effect of oat and barley beta-glucans in decreasing post-prandial glycaemic  responses, without disproportionally increasing post-prandial insulinaemic responses, at doses of  about 4 g per 30 g of available carbohydrates in bread and pasta products when consumed alone or in  the context of a meal, and that the mechanism by which beta-glucans could exert the claimed effect is  well established.
The Panel concludes that a cause and effect relationship has been established between the  consumption of beta-glucans from oats and barley and a reduction of post-prandial glycaemic  responses.
	
    
			
	
		
 
	
	4. Uwagi do zaproponowanego brzmienia oświadczenia
	
        
		
		
	
	
    
	
	
		
			
4.1. Ograniczenie wzrostu stężenia glukozy (glikemii) po posiłku (ID 821, 824)
	
	
			The Panel considers that the following wording reflects the scientific evidence: “Consumption of  beta-glucans from oats or barley contributes to the reduction of the glucose rise after a meal”.
	
    
			
	
		
 
	
	5. Warunki i możliwe ograniczenia stosowania oświadczenia
	
        
		
		
	
	
    
	
	
		
			
5.1. Zmniejszenie stężenia glukozy we krwi po posiłku (ID 821, 824)
	
	
			In order to obtain the claimed effect, 4 g of beta-glucans from oats or barley for each 30 g of available  carbohydrates should be consumed per meal. The target population is individuals who wish to reduce  their post-prandial glycaemic responses.
	
    
			
	
		
 
Wnioski
	
		On the basis of the data presented, the Panel concludes that:  
The food constituent, beta-glucans from oats and barley, which is the subject of the health  claims, is sufficiently characterised.  
Maintenance of normal blood LDL-cholesterol concentrations (ID 1236, 1299)  
The claimed effects are “fibres solubles (beta-glucane) et cholestérol sanguin” and “blood  cholesterol level”. 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  maintenance of normal blood LDL-cholesterol concentrations.  
A claim on beta-glucans and maintenance of normal blood cholesterol concentrations has  already been assessed with a favourable outcome.  
Increase in satiety leading to a reduction in energy intake (ID 851, 852)  
The claimed effect is “increases satiety, prolongs satiety”. The target population is assumed to  be the general population. An increase in satiety leading to a reduction in energy intake, if  sustained, might be a beneficial physiological effect.  
A cause and effect relationship has not been established between the consumption of beta- glucans from oats and barley and a sustained increase in satiety leading to a reduction in  energy intake.  
Reduction of post-prandial glycaemic responses (ID 821, 824)  
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 refers  to the reduction of post-prandial glycaemic responses. 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 been established between the consumption of beta-glucans  from oats and barley and a reduction of post-prandial glycaemic responses.  
The following wording reflects the scientific evidence: “Consumption of beta-glucans from  oats or barley contributes to the reduction of the glucose rise after a meal”.  
In order to obtain the claimed effect, 4 g of beta-glucans from oats or barley for each 30 g of  available carbohydrates should be consumed per meal. The target population is individuals  who wish to reduce their post-prandial glycaemic responses.  
“Digestive function” (ID 850)  
The claimed effect is “beta-glucan improves digestive function”. The target population is  assumed to be the general population. “Improving digestive function” without an indication of  the nutrients which are the target of the claim, is not sufficiently defined. 
The claimed effect is general and non-specific, and does not refer to any specific health claim  as required by Regulation (EC) No 1924/2006.