ID 1143 - Żywe kultury bakterii jogurtowych (Lactobacillus delbrueckii subsp. bulgaricus i Streptococcus thermophilus)

PL: Żywe kultury bakterii jogurtowych (Lactobacillus delbrueckii subsp. bulgaricus i Streptococcus thermophilus)
EN: Yoghurt cultures (live): Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus
Pdf: live yoghurt cultures

Oświadczenie (4)

Oświadczenie (2)

1. Charakterystyka żywności / składnika

The food constituent that is the subject of the health claim is “yoghurt cultures (live)”, which contain the starter micro-organisms “Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus”. These starter cultures “Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus” are well specified for their use in yoghurt manufacture by Codex Alimentarius Standard No. 243/2003.
The Panel considers that live yoghurt cultures, which are the subject of the health claim, are sufficiently characterised in relation to the claimed effect.

2. Znaczenie oświadczenia dla zdrowia człowieka

The claimed effect is “lactose digestion”. The Panel assumes that the target population is individuals with lactose maldigestion.
In the context of the proposed wording, the Panel assumes that the claimed effect refers to improved lactose digestion. Lactose maldigestion is a common condition characterised by reduced levels of intestinal lactase.
The Panel considers that improved lactose digestion is a beneficial physiological effect for individuals with lactose maldigestion.

3. Naukowe uzasadnienia wpływu na zdrowie człowieka - Trawienie laktozy

Forty-three references were cited to substantiate the claim. Among these references, the non-pertinent references included review articles and text books, or were related to yoghurt and gut functions in general, survival of lactic acid bacteria in the human stomach, “probiotics” and “prebiotics” in promotion of lactose digestion, production of β-galactosidase by Streptococcus thermophilus, the effect of Lactobacillus acidophilus on lactose maldigestion and survival of starter cultures and lactase in heated and frozen yoghurts. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
The following 14 human intervention studies were considered pertinent to the claim (Kolars et al., 1984; Savaiano et al., 1984; Dewit et al., 1988; Lerebours et al., 1989; Onwulata et al., 1989; Pochart et al., 1989; Marteau et al., 1990; Martini et al., 1991; Rosado et al., 1992; Varela-Moreiras et al., 1992; Shermak et al., 1995; Rizkalla et al., 2000; Labayen et al., 2001; Pelletier et al., 2001).
Many studies have compared the effect of consumption of fresh yoghurt with live cultures to pasteurised yoghurt with reduced or no live cultures on intestinal lactose utilisation in lactose maldigesters (Savaiano et al., 1984; Dewit et al., 1988; Lerebours et al., 1989; Pochart et al., 1989; Varela-Moreiras et al., 1992; Shermak et al., 1995; Rizkalla et al., 2000; Labayen et al., 2001; Pelletier et al., 2001). Also, in some studies pasteurised milk (Kolars et al., 1984; Marteau et al., 1990), milk inoculated with Lactobacillus acidophilus (Onwulata et al., 1989), lactose-hydrolysed milk (Onwulata et al., 1989; Rosado et al., 1992) and lactase tablets (Onwulata et al., 1989) were compared with yoghurt (fresh or heated) in order to investigate the effect on lactose digestion.
In most pertinent studies, the breath hydrogen concentration (BHC) method has been applied to measure lactose digestion. This method is based on the measurement of the concentration of hydrogen released into the breath from lactose hydrolysed after ingestion of a certain amount of lactose (usually 18 grams or higher). The method is not specific but is generally applied in clinical practice for the diagnosis of lactose maldigestion.
In most studies, lactose digestion has been investigated upon a single dose of the test product (Kolars et al., 1984; Savaiano et al., 1984; Dewit et al., 1988; Lerebours et al., 1989; Martini et al., 1991; Rosado et al., 1992; Varela-Moreiras et al., 1992; Shermak et al., 1995; Onwulata et al., 1989; Pelletier et al., 2001) whereas in a few studies lactose digestion was studied after prolonged ingestion of fresh or heat-treated yoghurt (Lerebours et al., 1989; Marteau et al., 1990; Rizkalla et al., 2000; Labayen et al., 2001).
All of the 14 studies mentioned above were performed using the yoghurt cultures Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) and Streptococcus thermophilus (S. thermophilus).
Dewit et al. (1988) investigated breath hydrogen concentration (BHC) after ingestion of lactose in water, milk, fresh or heated yoghurt by 26 healthy, young adults with or without lactose maldigestion. The fresh yoghurt contained 3 x 108 CFU/g S. thermophilus and 3 x 108 CFU/g L. bulgaricus. The total amount of lactose ingested with each product was 18 g. Ingestion of fresh yoghurt reduced BHC significantly (p<0.001) compared to lactose or milk, whereas after ingestion of heated yoghurt BHC was higher (p<0.01) compared to fresh yoghurt.
The double-blind study by Lerebours et al. (1989) evaluated lactose digestion (using BHC) after short-term (24 h) or prolonged (8 day) ingestion of yoghurt and fermented-then-pasteurised milk (FPM) by 16 lactase-deficient subjects. Consumption of yoghurt (125 g three times per day) enhanced lactose digestion (18 g lactose in yoghurt) and this effect was destroyed by pasteurisation. Similar results were obtained in both study periods and no adaptation of lactase activity was observed in long- term ingestion of yoghurt.
Marteau et al. (1990) measured BHC in eight lactase-deficient volunteers who ingested 18 g of lactose in the form of milk (400 mL whole milk per day), yoghurt (450 g per day) and heated yoghurt (450 g per day) for three consecutive days. Total BHC was significantly lower after consumption of yoghurt and heated yoghurt compared with milk consumption (p<0.001). Significantly less lactose was recovered from the terminal ileum after yoghurt than after heated yoghurt meals (p<0.05), and approximately one-fifth of the lactase activity contained in yoghurt reached the terminal ileum.
Varela-Moreiras et al. (1992) evaluated lactose maldigestion after ingestion of three dairy products by 53 healthy institutionalised elderly people; 36 % of them were found to be lactose maldigesters using the BHC test. The effect of consuming an equivalent amount of lactose (11 g lactose in 200 mL of product) contained in yoghurt and fermented-then-pasteurised milk (FPM) was assessed in these subjects. BHC was significantly higher after ingestion of milk than after ingestion of yoghurt (p<0.05). This effect was partially eliminated when FPM was tested. Moreover, BHC was significantly higher three hours after ingestion of FPM compared to normal yoghurt (p< 0.05).
In the study of Rizkalla et al. (2000), two groups of 12 healthy men with or without lactose maldigestion were recruited using the BHC test with a 30 g lactose load. Subjects were randomly assigned in a cross-over design to 500 g per day of either fresh or heat-treated yoghurt for two periods of 15 days each, separated by a 15 days washout interval. In subjects with lactose maldigestion, BHC values were significantly lower after consumption of fresh compared to heat-treated yoghurt consumption (p<0.01).
In the double-blind, cross-over designed study of Labayen et al. (2001), 22 lactose maldigesters received daily 25 g of lactose in fresh yoghurt (live yoghurt bacteria >108 CFU/g) or heat-treated yoghurt (<102 CFU/g) for 15 days, followed by a cross-over (15 days) after a wash-out period (14 days). The test dose was 500 mL per day for both products. The BHC test indicated more effective lactose digestion after fresh yoghurt intake as compared to heat-treated yoghurt. The orocaecal transit time (OCTT) was shorter after heated yoghurt ingestion as compared with fresh yoghurt and there were less severe gastrointestinal symptoms (p< 0.05) after fresh yoghurt intake.
Pelletier et al. (2001) assessed in a double-blind, randomised cross-over study the effects of ingestion of milk, yoghurt (108 CFU/mL), heat-treated (70 °C, 30 sec) yoghurt (<15 CFU/mL) and two products obtained by dilution of yoghurt with heat-treated product (106 and 105 CFU/mL) on hydrogen production and symptoms of lactose intolerance in 24 male lactose maldigesters. Hydrogen production and adverse events were followed during eight hours after ingestion of a single dose of each test product. The volume of each serving was not indicated. At each test, subjects received 25 g lactose in one of the products. Ingestion of yoghurt with 108 CFU/mL led to significantly lower BHC values (p<0,001 for AUCi (incremental area under curve, p=0.036 for Cmax maximal hydrogen concentration variation)) and a reduced number of complaints compared to the other products.
Kolars et al. (1984) used the BHC test to determine in 10 lactose-intolerant subjects (20 to 28 years of age) whether lactase-deficient subjects digested lactose better in yoghurt than in milk. Breath samples were obtained in the fasting state and hourly for eight hours after ingestion of the following test meals: lactulose (10 g in 200 mL of water), lactose (20 g in 400 mL of water), milk (400 mL containing 18 g of lactose) and commercial unflavoured yoghurt (440 g containing 18 g of lactose, and 270 g containing 11 g of lactose, respectively). Ingestion of 440 g of test yoghurt resulted in only about one third as much hydrogen excretion as a similar load of lactose in milk or water. This difference was statistically significant (p<0.01). In case of lactulose, the increase in breath hydrogen was comparable to that obtained with lactose. The symptoms reported by the subjects after ingestion of test meals supported the perception that lactose was digested better in yoghurt than in milk; 80 per cent of the subjects ingesting milk versus 20 per cent of those ingesting yoghurt reported diarrhoea or flatulence.
Onwulata et al. (1989) evaluated lactose digestion after intake of commercial plain yoghurt, sweet acidophilus milk, hydrolysed-lactose milk, a lactase tablet, and whole milk by 10 lactose-intolerant subjects. In a 5 x 5 Latin square design, BHC was measured for five hours after the subjects had consumed one of the products (totally 18 g lactose in each except lactose-hydrolysed milk, which provided 5 g). The products were consumed in a single dose (volume was not indicated) in five periods at five weekly intervals. Mean BHC values (ppm) were significantly (p<0.05) lower for yoghurt than for sweet acidophilus milk and whole milk. With regard to alleviating symptoms of lactose maldigestion, yoghurt was as effective as lactose-hydrolysed milk, but was significantly (p<0.05) more effective than commercial lactase consumed along with milk.
Shermak et al. (1995) compared symptoms of lactose maldigestion and breath hydrogen production after typical servings of milk, heat-treated yoghurt (85 °C, 30 min), and yoghurt containing live bacteria ingested by 14 lactose-maldigesting children (mean age 9.5 years). Symptoms and BHC values were recorded for eight hours after ingestion of 12 g lactose served in milk and yoghurts. Live yoghurt contained 1.6 x 108 CFU/g of both yoghurt cultures and the pasteurised yoghurt contained 2.5 x 103 CFU/g of both cultures. Lactose-maldigesting children experienced significantly fewer symptoms after consuming yoghurt with live cultures than after intake of milk (p<0.005). Pasteurised yoghurt showed an intermediate effect. Lactose from yoghurt was not better digested than lactose from milk, as indicated by similar areas under the hydrogen curve in the BHC test. However, yoghurt was associated with a delayed time to rise and lower rate of rise of the hydrogen concentration in the breath.
Rosado et al. (1992) compared the efficiency of lactose digestion after consumption of two unmodified plain yoghurts, a low-fat yoghurt and a yoghurt produced from lactose-hydrolysed milk by assessing BHC in 14 lactose-maldigesters. Compared to whole milk, the hydrogen breath response to two varieties of unmodified yoghurt and the lactose-hydrolysed yoghurt was significantly (p<0.05) attenuated while the hydrogen response to low-fat yoghurt was intermediate. Intolerance symptoms were significantly (p<0.05) and equally reduced (50 %, p<0.05) with all four yoghurt products compared to whole milk.
The results from human studies carried out by Savaiano et al. (1984), Pochart et al. (1989) and Martini et al. (1991) are consistent with those from the above studies and can be considered as supportive although the number of subjects enrolled in those studies was relatively small (less than 12 per study).
In addition, Drouault et al. (2002) applied a bacterial luciferase to monitor gene expression of Streptococcus thermophilus in the digestive tract of germ-free mice. The main result was that the bacterium was able to produce active β-galactosidase enzyme in the digestive tract, although the bacterium did not multiply during gastrointestinal transit. The enzyme production was enhanced when lactose (the inducer) was added to the diet.
In weighing the evidence, the Panel took into consideration that thirteen of fourteen human studies showed enhanced digestion of lactose in yoghurt in lactose maldigesters, when live yoghurt starter cultures were ingested in yoghurt, that the one study which did not show such an effect reported reduced symptoms and that there was strong evidence for the biological plausibility of the effect.
The Panel concludes that a cause and effect relationship has been established between the consumption of live yoghurt cultures in yoghurt and improved digestion of lactose in yoghurt in individuals with lactose maldigestion.11

4. Uwagi do zaproponowanego brzmienia oświadczenia

The Panel considers that the following wording reflects the scientific evidence: “Live yoghurt cultures in yoghurt improve digestion of lactose in yoghurt in individuals with lactose maldigestion”.

5. Warunki i możliwe ograniczenia stosowania oświadczenia

In order to bear the claim, the yoghurt should contain at least 108 CFU live starter microorganisms (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus) per gram. 13 The target population is individuals with lactose maldigestion.

Warunki i możliwe ograniczenia stosowania oświadczenia

Lactobacilli delbruekii subsp. bulgaricus and Streptococcus thermophilus, with "yoghurt" as defined by Codex Standard for Fermented Milks (codex stan 243-2003)