Hydrogen excretion upon ingestion of dairy products in lactose-intolerant male subjects: importance of the live flora

European Journal of Clinical Nutrition (2001) 55, 509±512 ß 2001 Nature Publishing Group All rights reserved 0954±3007/01 $15.00 www.nature.com/ejcn Original Communication Hydrogen excretion upon ingestion of dairy products in lactoseintolerant male subjects: importance of the live ¯ora X Pelletier1*, S Laure-Boussuge1 and Y Donazzolo1 1 OPTIMED, GieÁres, France Objective: To assess the effects of the ingestion of milk, yoghurt (108 bacteria=ml), heat-treated yoghurt (< 15 bacteria=ml) and two products obtained by dilution of yoghurt with heat-treated product (106 and 105 bacteria=ml) on hydrogen production and symptoms of lactose intolerance in lactose malabsorbers. Design: Double-blind, randomised cross-over design. Setting: The study was performed in the phase 1 clinical unit of OPTIMED, Nancy, France. Subjects: Twenty-four male lactose malabsorbers were selected for the study. Interventions: Hydrogen production and adverse events were followed during 8 h after ingestion of the products. Results: The results clearly demonstrate that ingestion of yoghurt with 108 bacteria=ml leads to lower H2 excretion and complaints than the other products. Results observed with the products containing a reduced population of live ¯ora remain better than those observed with milk. Conclusions: The importance of a high population of the live ¯ora is underlined. Sponsorship: This work was supported by the `Mission Scienti®que de SYNDIFRAIS'. Descriptors: dairy product; yoghurt; live ¯ora; lactose malabsorbtion; human European Journal of Clinical Nutrition (2001) 55, 509±512 Introduction Milk is an important source of calcium and of animal proteins. In subjects who lack the ability to digest lactose (lactose malabsorbers), milk consumption may result in development of digestive discomfort symptoms (Bayless & Rosenweig, 1966; Littman & Hammond, 1965). This may lead them to spontaneously reduce their consumption of milk and dairy products (Gilliland & Kim, 1984), thus diminishing their calcium and protein intake. It is known that the presence of a living ¯ora improves milk tolerance in lactose poor digesters (Kolars et al, 1984; Savaiano et al, 1984; Dewitt et al, 1988). When yoghurt is heated before consumption, the concentration of living bacteria diminishes, depending on the conditions of heating. The consequences of this treatment are unclear: the production of hydrogen, which re¯ects the lactose maldigestion, is either enhanced after thermisation (Gilliland & Kim, 1984; Lerebours et al, 1989; McDonough et al, 1987) or *Correspondence: X Pelletier, OPTIMED, 2 avenue de Vignate, 38610 GieÁres, France. E-mail: Guarantor: X Pelletier. Contributors: S Laure-Boussuge and Y Donazzolo. Received 22 February 2000; revised 7 December 2000; accepted 11 December 2000 unchanged (Martini et al, 1987; Shermak et al, 1995; Varela-Moreiras et al, 1992). This study was undertaken to determine whether the extent of the thermisation might explain those discrepancies and, more generally, to compare the responses to the ingestion of dairy products with different living ¯ora contents in lactose malabsorbers. Methods This study was performed after submitting the protocol to the Ethics Committee (Comite Consultatif pour la Protection des Personnes dans la Recherche MeÂdicale). Volunteers received written information and an oral presentation of the study. They all gave their written informed consent before the beginning of the study. Subjects Twenty-four male lactose malabsorbers were selected. Subjects were 28.4  4.1 y old (range 21 ± 35), weighed 69.3  9.5 kg (56 ± 88), were 173.6  8.1 cm tall (159 ± 191) (means  s.d.). Lactose malabsorption was con®rmed after consuming 25 g lactose in 250 ml tap water. Hydrogen concentration was determined in breath during 3 h following lactose ingestion. Subjects with a breath H2 increase of more then 30 ppm over the basal value were considered lactose malabsorbers. Yoghurt and lactose malabsorption X Pelletier et al 510 Products Subjects then ingested ®ve dairy products according to a double-blind randomised scheme. Products were: standard yoghurt (108 bacteria=ml); heat-treated yoghurt (70 C30 s; 15 bacteria=ml); a geli®ed and acidi®ed milk (no live ¯ora); and two fermented dairy products (106 bacteria=ml and 105 bacteria=ml), obtained by dilution 1=100 and 1=1000, respectively, of yoghurt (108 bacteria=ml) with the heat-treated yoghurt (15 bacteria=ml). All products were processed from the same batch of milk by CIRDC (Le Plessis-Robinson, France). Fermented products were obtained after inoculation of Streptococcus thermophilus ‡ Lactobacillus bulgaricus starter culture (S85). Both products obtained by dilution and heat-treated product contained 0.54% gums to obtain the same texture as yoghurt. Acidi®ed milk was obtained by addition of lactic acid and Glucono-delta-lactone to a milk with 2.5% starch to thicken it. The ®nal pH was 4.60. The lactose concentration and the number of living bacteria were checked using standard procedures throughout the conservation of the products and remained constant. The characteristics of the products are listed in Table 1. At each test, subjects received 25 g lactose in one of the products. Hydrogen excretion was monitored before (T0) and every 30 min during 8 h after administration of the product, using an H2 monitor with electrochemical cell Table 1 (GMI, UK). Adverse events, either spontaneously reported or reported after interview, were thoroughly documented. A 3-day-or-more wash-out period was observed between two administrations. Subjects excreting more than 25 ppm hydrogen in breath under fasting conditions (T0) were asked to undergo another test. Statistical analysis The analysis was performed on the following data, calculated for hydrogen concentration (ppm) in breath: (1) AUCi, incremental area under the curve, calculated in reference to the T0 value, expressed as ppm H2min; (2) Cmax, maximal hydrogen concentration in ppm; (3) Tmax, time of the maximal value, in min; (4) variation, (Cmax 7 C0)100=C0. Results were analysed with a two-way ANOVA. If ANOVA produced a statistically signi®cant difference, products were compared with the Bonferonni test. The frequency of the observed adverse events has been compared using the w2 test. Results The evolution of hydrogen excretion upon ingestion of the different products is described in Figure 1. The calculated parameters are detailed in Table 2. Characteristics of the products Yoghurt: 108 bacteria=ml Diluted product: 106 bacteria=ml Diluted product: 105 bacteria=ml Heat treated yoghurt: 15 bacteria=ml Geli®ed milk: no live ¯ora L. bulgaricus (cell=ml) S. thermophilus (cell=ml) Lactose (%) Dry matter (%) Fat (%) Total beta-galactosidase (U=ml) 2.2108 2.7106 2.6105 < 15 Ð 6.6108 7.7106 7.2105 < 15 Ð 5.7 5.6 5.6 5.6 5.1 15.2 15.1 15.2 14.5 17.0 3.8 3.8 3.8 3.7 4.3 5.200 0.500 0.030 0.009 0.007 0.008 < 0.001 0 Figure 1 Evolution of H2 concentra (...truncated)