Lactase is high in the newborn intestine, allowing him to digest the high amounts of lactose present in breastmilk. From weaning, lactase is genetically programmed to decrease, reaching residual levels in the adult. This situation occurs in 75% of the world population and is known as "adult primary hypolactasia" while the remaining 25% is "lactase persistent" i.e. maintains in adulthood lactase values similar to these of newborns. In subjects with hypolactasia, the intake of milk products can produce digestive symptoms, making that the affected individuals spontaneously reduce the consumption of these products and, therefore, their intake of calcium and proteins. In addition to lactose-free milk and exogenous lactase, a strategy for the intolerant subjects to continue consuming dairy products is, for example, to consume yogurt, due to the fact that the lactase of the yogurt bacteria continues to function in the intestine of the consumer, hydrolyzing lactose and decreasing the development of digestive symptoms. Similarly, many probiotic strains, such as L. acidophilus NCFM, L. casei CRL431, B. longum 401 and B. bifidum Orla Jensen 1424, express β-galactosidases that hydrolyze lactose, preventing its fermentation and the production of gases. The acute administration of these strains improves lactose tolerance. In addition, a recent study reported that dietary supplementation of intolerant subjects for 4 weeks with L. casei Shirota and B. breve Yakult reduced digestive symptoms and breath hydrogen excretion not only at the end of the period of administration of the probiotics but also 3 months after having discontinued the use of probiotics. Based on this background, the aim of this study is to determine whether the regular consumption of an ice cream with the strain B. bifidum 900791 improves lactose intolerance in hypolactasic subjects, even after the suspension of the consumption of the product. To determine if this effect is due to the adaptation of the microbiota, the investigators will also evaluate changes in the composition of the microbiota and the generation of volatile fatty acids.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
50
One portion (50g) of an ice-cream containing the probiotic B. bifidum 900791 (\>10(exp7)/g) every day for 4 weeks
One portion (50g) of an ice-cream without probiotic every day for 4 weeks
Area under curve (AUC) of hydrogen in the HBT
Acute effect of the probiotic on hydrogen excretion after lactose ingestion
Time frame: Day 15
Area under curve (AUC) of hydrogen in the HBT
Chronic effect of the probiotic on hydrogen excretion after lactose ingestion
Time frame: Day 43
Area under curve (AUC) of hydrogen in the HBT
Remanent effect of the probiotic on hydrogen excretion after lactose ingestion after one month without probiotic ingestion
Time frame: Day 71
Fecal microbiota alpha-diversity
Shannon Index
Time frame: Days 15
Fecal microbiota alpha-diversity
Shannon Index
Time frame: Day 43
Fecal microbiota alpha-diversity
Shannon Index
Time frame: Day 71
Relative abundancies of the bacterial taxa forming the the fecal microbiota
Relative abundancies of the different bacterial taxa detected by high throughput sequencing
Time frame: Day 15
Relative abundancies of the bacterial taxa forming the the fecal microbiota
Relative abundancies of the different bacterial taxa detected by high throughput sequencing
Time frame: Day 43
Relative abundancies of the bacterial taxa forming the the fecal microbiota
Relative abundancies of the different bacterial taxa detected by high throughput sequencing
Time frame: Day 71
Fecal counts of B. bifidum 900791
B. bifidum 900791 counts in fecal samples
Time frame: Days 15
Fecal counts of B. bifidum 900791
B. bifidum 900791 counts in fecal samples
Time frame: Days 43
Fecal counts of B. bifidum 900791
B. bifidum 900791 counts in fecal samples
Time frame: Days 71
Fecal beta-galactosidase activity
Determination of the microbial beta-galactosidase activity in fecal samples (expressed as U/g)
Time frame: Days 15
Fecal beta-galactosidase activity
Determination of the microbial beta-galactosidase activity in fecal samples (expressed as U/g)
Time frame: Days 43
Fecal beta-galactosidase activity
Determination of the microbial beta-galactosidase activity in fecal samples (expressed as U/g)
Time frame: Days 71
Fecal short chain fatty acids concentrations
Determination of short chain fatty acids concentrations in fecal samples
Time frame: Days 15
Fecal short chain fatty acids concentrations
Determination of short chain fatty acids concentrations in fecal samples
Time frame: Days 43
Fecal short chain fatty acids concentrations
Determination of short chain fatty acids concentrations in fecal samples
Time frame: Days 71
Scores of gastrointestinal symptoms: bloating, abdominal distention, abdominal pain, borborygms and flatulence, during the HBT
Determination of gastrointestinal symptoms (bloating, abdominal distention, abdominal pain, borborygms and flatulence) using a previously validated questionnaire on a scale of 0 (none), 1 (mild), 2 (moderate), 3 (severe). We will define clinically relevant ymptoms as a composite score of 3 or more during the HBT.
Time frame: Days 15
Scores of gastrointestinal symptoms: bloating, abdominal distention, abdominal pain, borborygms and flatulence, during the HBT
Determination of gastrointestinal symptoms (bloating, abdominal distention, abdominal pain, borborygms and flatulence) using a previously validated questionnaire on a scale of 0 (none), 1 (mild), 2 (moderate), 3 (severe). We will define clinically relevant ymptoms as a composite score of 3 or more during the HBT.
Time frame: Days 43
Scores of gastrointestinal symptoms: bloating, abdominal distention, abdominal pain, borborygms and flatulence, during the HBT
Determination of gastrointestinal symptoms (bloating, abdominal distention, abdominal pain, borborygms and flatulence) using a previously validated questionnaire on a scale of 0 (none), 1 (mild), 2 (moderate), 3 (severe). We will define clinically relevant ymptoms as a composite score of 3 or more during the HBT.
Time frame: Days 71
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