***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Summary The effectiveness of a new beta-D-galactosidase pellet formation in the treatment of lactose intolerance was studied . The encapsuled beta-D-galactosidase ( lactase ) pellets were first tested in vitro for their enzymatic activity within an environment simulating gastric conditions and subsequently within an environment simulating duodenal conditions . Effectiveness was measured by the % of glucose formed by hydrolysis of lactose . The pellets were found to retain their enzymatic activity in gastric pH conditions ( mean 69±1mg/dl glucose ) and were found to hydrolyse lactose in human duodenal fluid ( 106.35±1 mg/dl).Finally the effectiveness of the new lactase formation on glucose absorption was studied in 8 lactose intolerant subjects in a r and omized , double blind , crossover trial . After fasting , the subjects were given one capsule containing 100 u/ml beta-galactosidase ( i.e. 10 pellets of 10 u/ml each ) or one capsule containing placebo pellets , followed by 100 g lactose dissolved in water . The washout period between lactose challenges was one week . Plasma glucose concentrations were measured before and at intervals after the challenges and the subjects completed symptom question naires every eight hours for 24 hours . Results showed a statistically significant in plasma glucose levels 30 , 60 , 90 and 120 min after lactose ingestion ( repeated measures analysis of variance , p<0.01 ) . Subjective ratings of the severity of abdominal cramping , belching , flatulence , vomiting and diarrhoea were significantly decreased following ingestion of the lactase pellets and lactose ( no incidence of diarrhoea ) compared with after ingestion of placebo and lactose . The results of the study were considered to be very promising as the beta-D-galactosidase formulation ( which was produced at very low cost and with great ease ) resisted inactivation in the stomach , effectively transformed lactose to glucose in vivo and reduced symptoms of lactose intolerance OBJECTIVE To evaluate the efficacy of the addition to milk , 5 min and 10 h before its consumption , of a lactase obtained from Kluyveromyces lactis in lactose malabsorbers with intolerance . DESIGN Double-blind , placebo-controlled , crossover study . SETTING University Hospital . SUBJECTS In total , 11 male and 19 female ( aged from 18 to 65 y , mean age 43.3 y ) lactose malabsorbers with intolerance participated . INTERVENTIONS Each patient underwent three H(2 ) breath tests , in a r and om order . We used 400 ml of cow 's semiskimmed milk as substrate and a beta-galactosidase obtained from K. lactis . The test A was carried out adding to the milk the enzyme ( 3000 UI ) , 10 h before its consumption ; the test B was performed adding the beta-galactosidase ( 6000 UI ) 5 min before milk ingestion and the test C was made using placebo . We evaluated the maximum breath H(2 ) concentration , the cumulative H(2 ) excretion and a clinical score based on intolerance symptoms ( bloating , abdominal pain , flatulence and diarrhoea ) . RESULTS Our study showed a significant reduction of the mean maximum H(2 ) concentration after both test A ( 12.07 + /- 7.8 p.p.m . ) and test B ( 13.97 + /- 7.99 p.p.m . ) compared with test C ( 51.46 + /- 16.12 p.p.m . ) ( ANOVA F = 54.33 , P < 0.001 ) . Similarly , there was a significant reduction of the mean cumulative H(2 ) excretion after both test A ( 1428 + /- 1156 p.p.m . ) and test B ( 1761 + /- 966 p.p.m . ) compared with test C ( 5795 + /- 2707 p.p.m . ) ( ANOVA F = 31.46 , P < 0.001 ) . We also observed a significant reduction of the mean clinical score after both test A ( 0.36 + /- 0.55 ) and test B ( 0.96 + /- 0.85 ) compared with test C ( 3.7 + /- 0.79 ) ( ANOVA F = 106.81 , P < 0.001 ) . Moreover , with regard to the mean clinical score , there was a significant reduction after test A with respect to test B ( Bonferroni 's P = 0.03 ) . CONCLUSIONS Our study shows that in lactose malabsorbers with intolerance , the lactase obtained from K. lactis can represent a valid therapeutic strategy , with objective and subjective efficacy and without side effects Low-lactose milk was produced by incubating cow 's milk with yeast lactase .  Sixteen lactose tolerant and 15 intolerant volunteers ingested 500 ml of the product twice daily for 1 month . During the testing period all subjects received on three occasions the same volume of unmodified milk in double-blind tests . Symptoms recorded throughout the study and for an additional 15 day base-line observation period were : diarrhea , abdominal pain and distention , flatulence , heartburn , and headache . Low-lactose milk acceptance was excellent . No significant differences were found between tolerants and intolerants during the base-line period and while ingesting low-lactose milk . By contrast , unmodified milk induced severe symptoms only in the intolerants . Availability of low-lactose milk and of its by-products allows consumption of greater volumes of this highly nutritious food by subjects with lactose intolerance with none or less symptoms compared to unmodified milk Acidophilus milk has been reported to help patients with irritable bowel syndrome by correcting the " imbalance of flora " and to be tolerated better by lactase-deficient subjects by providing bacterial lactase in the small intestine . In a double-blind r and omized study , 61 lactase-sufficient patients with irritable bowel syndrome each ingested 240 ml of milk three times a day for 2 wk and the same amount of acidophilus milk for an additional 2 wk . The degree of symptoms during the two milk-drinking periods was the same as during the control periods . Also , 18 lactase-deficient patients ingested unaltered milk for 1 wk and acidophilus milk for 1 additional wk . There was no difference in the degree of tolerance to the two varieties of milk . In summary , patients with irritable bowel syndrome were not helped by the ingestion of acidophilus milk , and lactase-deficient patients were as intolerant to  acidophilus milk  as to unaltered milk We conducted blinded , controlled crossover studies to determine the effect of daily lactose feeding on colonic adaptation and intolerance symptoms . The initial study with nine lactose maldigesters showed a threefold increase in fecal beta-galactosidase activity after 16 d of lactose feeding . To determine the effects of this adaptation on breath hydrogen and intolerance symptoms , 20 lactose-maldigesting adults were r and omly assigned to lactose or dextrose supplementation for 10 d ( days 1 - 10 ) , crossing over to the other period for days 12 - 21 . The sugar dosage was increased from 0.6 to 1.0 g.kg-1.d-1 , subdivided into three equal doses , by adjusting the dose every other day . Symptoms during lactose supplementation and comparison of symptoms during the lactose and dextrose feeding periods showed no significant differences . On days 11 and 22 , challenge doses of lactose ( 0.35 g/kg ) were administered after an overnight fast , and breath hydrogen and intolerance symptoms ( abdominal pain , flatulence , and diarrhea ) were carefully monitored for 8 h. Frequency of flatus passage and flatus severity ratings after the lactose challenge decreased 50 % when studied at the end of the lactose period compared with the dextrose period . The sum of hourly breath-hydrogen concentrations ( 1 - 8 h ) was significantly reduced after the lactose feeding period ( 9 + /- 38 ppm.h ) compared with after the dextrose period ( 385 + /- 52 ppm.h , P < 0.001 ) . We conclude that there is colonic adaptation to regular lactose ingestion and this adaptation reduces lactose intolerance symptoms The possible usefulness of low-lactose milk for those lactose-intolerant subjects who develop symptoms from milk consumption was investigated . In the first part of the study , 16 intolerant subjects ( blood glucose rise less than 25 mg/100 ml ) received low-lactose skim milk containing 15 g lactose ( 2.5 cups ) and 7.5 g lactose ( 2.5 cups ) , regular skim milk containing 30 g lactose ( 2.5 cups ) , and all three milks plus a small breakfast . The low lactose milks produced significantly fewer symptoms . The food given with the milk had no significant effect on symptomatic response . The second group of 17 subjects received 25 g lactose in water ( 250 ml ) , skim milk ( 500 ml ) and whole milk ( 500 ml ) ; 10 g lactose in lactose-reduced skim ( 500 ml ) and whole milk ( 500 ml ) and whole milk ( 500 ml ) ; and a placebo ( 250 ml ) . There was a significant positive relationship between amount of lactose consumed and symptom response . The form in which the lactose was administered ( e.g. , whole versus skim milk ) was not significantly related to symptoms . It is concluded that in a symptomatic subjects a significantly greater quantity of  low-lactose milk  than regular milks can be consumed The use of fermented dairy foods is common in areas of the world where lactase deficiency is prevalent . Recently , we have shown that the digestion of lactose from yogurt is enhanced as compared to that from milk . This enhanced digestion is apparently due to inherent B-galactosidase in yogurt which is active in the gastrointestinal tract after consumption of the yogurt . Furthermore , yogurt is well tolerated by lactase-deficient subjects result ing in little or no gastrointestinal distress . Since other fermented and microbial-containing dairy foods are consumed worldwide and may also contain some " lactase " activity , we chose to evaluate the digestion of lactose from three of these products : pasteurized yogurt , cultured milk ( buttermilk ) , and sweet acidophilus milk .  Breath hydrogen techniques were used to evaluate lactose malabsorption in nine lactase-deficient subjects . The studies demonstrated that yogurt is unique among the products tested in enhancing the digestion of lactose . Furthermore , pasteurization of yogurt eliminated the enhanced digestion of lactose , reduced the inherent lactase activity of the yogurt by 10-fold and reduced cell counts by 100-fold . Interestingly , eight of nine subjects fed cultured milk experienced gastrointestinal distress , whereas all subjects fed pasteurized yogurt were symptom free , even though the amount of malabsorbed lactose was similar The relative effectiveness of five milk products with various levels of lactose reduction [ 0 % , 50 % , 80 % ( # 1 ) , 80 % ( # 2 ) , and 95 % ] was evaluated in six subjects with lactose malabsorption .  Breath hydrogen was measured for 4 h after consumption of 300 mL of each product in a single-blind , r and omized design . The mean + /- SEM maximum breath-hydrogen rise ( ppm ) after the 0 % , 50 % , 80 % ( # 1 ) , 80 % ( # 2 ) , and 95 % lactose-reduced ( LR ) milks was 31 + /- 6 , 7 + /- 3 , 5 + /- 3 , 5 + /- 2 , and 8 + /- 3 , respectively . The difference between whole milk and the LR milks was statistically significant ( P less than 0.05 ) but there was no difference between any of the LR milks . Whole milk provoked symptoms in most subjects whereas 95 % LR milk produced none . Only one of six subjects reacted to the 50 % and 80 % LR milks . The results suggest that a 50 % level of lactose reduction in milk may be adequate to relieve the signs and symptoms of milk intolerance in the majority of healthy adults with lactose malabsorption Lactose digestion from and tolerance to flavored and frozen yogurts , ice cream , and ice milk were evaluated ( 20 g lactose/meal ) in lactase-deficient subjects by use of breath hydrogen techniques . Unflavored yogurt caused significantly less hydrogen production than milk ( 37 vs 185 delta ppm X h , n = 9 ) . Flavored yogurt was intermediate ( 77 delta ppm X h ) . Subjects were free of symptoms after consuming flavored and unflavored yogurts . Of seven commercial yogurts tested , all contained significant levels of microbial beta-galactosidase ( beta-gal ) . In addition , eight subjects were fed meals of milk , ice milk , ice cream , and frozen yogurts with and without cultures containing high levels of beta 
    Output:
    
Moderate- quality evidence indicated that 12 to 15 g of lactose ( approximately 1 cup of milk ) is well tolerated by most adults .
Evidence was insufficient that  lactose-reduced solution  or milk with a lactose content of 0 to 2 g , compared with greater than 12 g , is effective in reducing symptoms of lactose intolerance .
Most individuals with presumed lactose intolerance or malabsorption can tolerate 12 to 15 g of lactose .