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Archivos Argentinos de Pediatria Feb 2022Lactose is the main carbohydrate present in human milk. It is a disaccharide made up of glucose and galactose. It is produced in the mammary glands, regardless of... (Review)
Review
Lactose is the main carbohydrate present in human milk. It is a disaccharide made up of glucose and galactose. It is produced in the mammary glands, regardless of maternal diet. In addition to providing energy, it is the only source of dietary galactose, necessary for macromolecule synthesis, including oligosaccharides, glycoproteins, and glycolipids. It favors calcium, magnesium, and zinc absorption and retention. Its digestion by lactase and subsequent absorption occurs in the small intestine. Lactase deficiency may be classified into congenital primary (very rare), late-onset primary or secondary due to an injury of the intestine; it may cause intolerance with pain, abdominal distension, abdominal gas, and diarrhea. In the colon, it may be hydrolyzed by bifidobacteria and lactobacilli. The nutritional management of intolerance should always preserve breastfeeding. Lactose reduction or elimination should be transient, and eliminated food should be replaced with other similar in calorie, protein, mineral, and vitamin content.
Topics: Diet; Humans; Lactase; Lactose; Lactose Intolerance; Milk, Human
PubMed: 35068123
DOI: 10.5546/aap.2022.eng.59 -
Annals of Nutrition & Metabolism 2018Lactose intolerance primarily refers to a syndrome having different symptoms upon the consumption of foods containing lactose. It is one of the most common form of food... (Review)
Review
Lactose intolerance primarily refers to a syndrome having different symptoms upon the consumption of foods containing lactose. It is one of the most common form of food intolerance and occurs when lactase activity is reduced in the brush border of the small bowel mucosa. Individuals may be lactose intolerant to varying degrees, depending on the severity of these symptoms. When lactose is not digested, it can be fermented by gut microbiota leading to symptoms of lactose intolerance that include abdominal pain, bloating, flatulence, and diarrhea with a considerable intraindividual and interindividual variability in the severity of clinical manifestations. These gastrointestinal symptoms could be similar to cow's milk allergy and could be wrongly labeled as symptoms of "milk allergy." There are important differences between lactose intolerance and cow's milk allergy; therefore, a better knowledge of these differences could limit misunderstandings in the diagnostic approach and in the management of these conditions.
Topics: Abdominal Pain; Animals; Cattle; Diagnosis, Differential; Humans; Lactase; Lactose Intolerance; Milk Hypersensitivity
PubMed: 30783042
DOI: 10.1159/000493669 -
Large-scale association analyses identify host factors influencing human gut microbiome composition.Nature Genetics Feb 2021To study the effect of host genetics on gut microbiome composition, the MiBioGen consortium curated and analyzed genome-wide genotypes and 16S fecal microbiome data from...
To study the effect of host genetics on gut microbiome composition, the MiBioGen consortium curated and analyzed genome-wide genotypes and 16S fecal microbiome data from 18,340 individuals (24 cohorts). Microbial composition showed high variability across cohorts: only 9 of 410 genera were detected in more than 95% of samples. A genome-wide association study of host genetic variation regarding microbial taxa identified 31 loci affecting the microbiome at a genome-wide significant (P < 5 × 10) threshold. One locus, the lactase (LCT) gene locus, reached study-wide significance (genome-wide association study signal: P = 1.28 × 10), and it showed an age-dependent association with Bifidobacterium abundance. Other associations were suggestive (1.95 × 10 < P < 5 × 10) but enriched for taxa showing high heritability and for genes expressed in the intestine and brain. A phenome-wide association study and Mendelian randomization identified enrichment of microbiome trait loci in the metabolic, nutrition and environment domains and suggested the microbiome might have causal effects in ulcerative colitis and rheumatoid arthritis.
Topics: Adolescent; Adult; Bifidobacterium; Child; Child, Preschool; Cohort Studies; Female; Gastrointestinal Microbiome; Genetic Variation; Genome-Wide Association Study; Humans; Lactase; Linkage Disequilibrium; Male; Mendelian Randomization Analysis; Metabolism; Quantitative Trait Loci; RNA, Ribosomal, 16S
PubMed: 33462485
DOI: 10.1038/s41588-020-00763-1 -
Asia Pacific Journal of Clinical... 2015Lactose is the main carbohydrate in infant feeding, but its impact decreases as the child gets older and consumes less milk and dairy products. Congenital lactose... (Review)
Review
Lactose is the main carbohydrate in infant feeding, but its impact decreases as the child gets older and consumes less milk and dairy products. Congenital lactose intolerance is a very rare condition. However, lactase activity may be low and need to mature during the first weeks of life in many infants. However, the evidence that unabsorbed lactose is causing infantile crying and colic is contradictory. Unabsorbed lactose has a bifidogenic effect and improves calcium absorption. Lactose malabsorption may occur secondary and thus temporally to other etiologies such as infectious gastroenteritis, cow's milk allergy and celiac disease. One the cause is treated, lactase activity will gradually return to normal. The vast majority of Asian children will develop late onset congenital lactase deficiency. However, this entity only exceptionally causes symptoms before the age of 4-5 years. Symptoms are abdominal cramps, flatulence and watery, acid stools, and decrease the quality of life but lactose intolerance is not associated with "true disease". The diagnosis is made on clinical grounds and confirmed with a lactose breath test, if needed. These patients need to have a lifetime long reduced lactose intake to improve their quality of life.
Topics: Animals; Asian People; Breath Tests; Carbohydrate Metabolism, Inborn Errors; Cattle; Celiac Disease; Child; Child, Preschool; Gastroenteritis; Humans; Intestinal Absorption; Intestines; Lactase; Lactose; Lactose Intolerance; Milk Hypersensitivity
PubMed: 26715083
DOI: 10.6133/apjcn.2015.24.s1.02 -
Nutrients Sep 2015Lactose intolerance related to primary or secondary lactase deficiency is characterized by abdominal pain and distension, borborygmi, flatus, and diarrhea induced by... (Review)
Review
Lactose intolerance related to primary or secondary lactase deficiency is characterized by abdominal pain and distension, borborygmi, flatus, and diarrhea induced by lactose in dairy products. The biological mechanism and lactose malabsorption is established and several investigations are available, including genetic, endoscopic and physiological tests. Lactose intolerance depends not only on the expression of lactase but also on the dose of lactose, intestinal flora, gastrointestinal motility, small intestinal bacterial overgrowth and sensitivity of the gastrointestinal tract to the generation of gas and other fermentation products of lactose digestion. Treatment of lactose intolerance can include lactose-reduced diet and enzyme replacement. This is effective if symptoms are only related to dairy products; however, lactose intolerance can be part of a wider intolerance to variably absorbed, fermentable oligo-, di-, monosaccharides and polyols (FODMAPs). This is present in at least half of patients with irritable bowel syndrome (IBS) and this group requires not only restriction of lactose intake but also a low FODMAP diet to improve gastrointestinal complaints. The long-term effects of a dairy-free, low FODMAPs diet on nutritional health and the fecal microbiome are not well defined. This review summarizes recent advances in our understanding of the genetic basis, biological mechanism, diagnosis and dietary management of lactose intolerance.
Topics: Adult; Dairy Products; Diet, Carbohydrate-Restricted; Digestion; Fermentation; Gastrointestinal Absorption; Gastrointestinal Microbiome; Gastrointestinal Tract; Genetic Predisposition to Disease; Humans; Lactase; Lactose; Lactose Intolerance; Phenotype; Predictive Value of Tests; Risk Factors; Treatment Outcome
PubMed: 26393648
DOI: 10.3390/nu7095380 -
American Family Physician May 2002Persons with lactose intolerance are unable to digest significant amounts of lactose because of a genetically inadequate amount of the enzyme lactase. Common symptoms... (Review)
Review
Persons with lactose intolerance are unable to digest significant amounts of lactose because of a genetically inadequate amount of the enzyme lactase. Common symptoms include abdominal pain and bloating, excessive flatus, and watery stool following the ingestion of foods containing lactose. Lactase deficiency is present in up to 15 percent of persons of northern European descent, up to 80 percent of blacks and Latinos, and up to 100 percent of American Indians and Asians. A sizable number of adults believe they are lactose intolerant but do not actually have impaired lactose digestion, and some persons with lactase deficiency can tolerate moderate amounts of ingested lactose. A diagnosis of lactose intolerance can usually be made with a careful history supported by dietary manipulation. If necessary, diagnosis can be confirmed by using a breath hydrogen or lactose tolerance test. Treatment consists primarily of avoiding lactose-containing foods. Lactase enzyme supplements may be helpful. The degree of lactose malabsorption varies greatly among patients with lactose intolerance, but most of them can ingest up to 12 oz of milk daily without symptoms. Lactose-intolerant patients must ensure adequate calcium intake.
Topics: Calcium, Dietary; Family Practice; Humans; Lactase; Lactose Intolerance; beta-Galactosidase
PubMed: 12018807
DOI: No ID Found -
Current Drug Metabolism 2016Digestive enzymes are able to break down proteins and carbohydrates and lipids, and their supplementation may play a role in the management of digestive disorders, from... (Review)
Review
BACKGROUND
Digestive enzymes are able to break down proteins and carbohydrates and lipids, and their supplementation may play a role in the management of digestive disorders, from lactose intolerance to cystic fibrosis. To date, several formulations of digestive enzymes are available on the market, being different each other in terms of enzyme type, source and origin, and dosage.
METHODS
This review, performed through a non-systematic search of the available literature, will provide an overview of the current knowledge of digestive enzyme supplementation in gastrointestinal disorders, discussion of the use of pancreatic enzymes, lactase (β-galactosidase) and conjugated bile acids, and also exploring the future perspective of digestive enzyme supplementation.
RESULTS
Currently, the animal-derived enzymes represent an established standard of care, however the growing study of plant-based and microbe-derived enzymes offers great promise in the advancement of digestive enzyme therapy.
CONCLUSION
New frontiers of enzyme replacement are being evaluated also in the treatment of diseases not specifically related to enzyme deficiency, whereas the combination of different enzymes might constitute an intriguing therapeutic option in the future.
Topics: Animals; Bile Acids and Salts; Dietary Supplements; Gastrointestinal Agents; Gastrointestinal Diseases; Humans; beta-Galactosidase
PubMed: 26806042
DOI: 10.2174/138920021702160114150137 -
Nutrients May 2020Lactose intolerance (LI) is characterized by the presence of primarily gastrointestinal clinical signs resulting from colonic fermentation of lactose, the absorption of... (Meta-Analysis)
Meta-Analysis
Lactose intolerance (LI) is characterized by the presence of primarily gastrointestinal clinical signs resulting from colonic fermentation of lactose, the absorption of which is impaired due to a deficiency in the lactase enzyme. These clinical signs can be modified by several factors, including lactose dose, residual lactase expression, concurrent ingestion of other dietary components, gut-transit time, and enteric microbiome composition. In many of individuals with lactose malabsorption, clinical signs may be absent after consumption of normal amounts of milk or, in particular, dairy products (yogurt and cheese), which contain lactose partially digested by live bacteria. The intestinal microbiota can be modulated by biotic supplementation, which may alleviate the signs and symptoms of LI. This systematic review summarizes the available evidence on the influence of prebiotics and probiotics on lactase deficiency and LI. The literature search was conducted using the MEDLINE (via PUBMED) and SCOPUS databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and included randomized controlled trials. For each study selected, the risk of bias was assessed following the Cochrane Collaboration methodology. Our findings showed varying degrees of efficacy but an overall positive relationship between probiotics and LI in relation to specific strains and concentrations. Limitations regarding the wide heterogeneity between the studies included in this review should be taken into account. Only one study examined the benefits of prebiotic supplementation and LI. So further clinical trials are needed in order to gather more evidence.
Topics: Abdominal Pain; Animals; Databases, Factual; Diarrhea; Diet; Flatulence; Food, Fortified; Gastrointestinal Microbiome; Humans; Lactase; Lactose; Lactose Intolerance; Milk; Prebiotics; Probiotics; Vomiting
PubMed: 32443748
DOI: 10.3390/nu12051487 -
Journal of Translational Medicine Jun 2020Worldwide, 70% of the adult population has limited expression of lactase enzyme with a wide variation among different regions and countries. Lactase deficiency may lead... (Review)
Review
Worldwide, 70% of the adult population has limited expression of lactase enzyme with a wide variation among different regions and countries. Lactase deficiency may lead to lactose intolerance (LI). Depending both on the amount of lactose ingested and on the lactase activity, people who suffer from lactose malabsorption might experience numerous gastrointestinal and extra-intestinal symptoms and manifestations. Treatment of LI mainly consists of reducing or eliminating lactose from the diet until the symptoms disappear as well as supplementing lactase, and inducing colon microbiome adaptation by probiotics. Cow's milk is one of the major source of calcium and several other vitamins and minerals. Thus, a complete exclusion of dairy products may favor the development of bone diseases such as osteopenia and osteoporosis. Therefore, the dietetic approach has a crucial role in the management of LI patients. Additionally, the use of lactose and milk-derived products in non-dairy products (e.g., baked goods, breakfast cereals, drinks, and processed meat) has become widespread in the modern industry (the so-called "hidden lactose"). In this regard, a strict adherence to the lactose-free diet becomes challenging for LI patients, forced to continuous check of all products and food labels. In fact, lactose-free product labeling is still controversial. Considering that nowadays a specific cut-off value establishing "lactose-free" labeling policy is lacking and that there is no universal law regulating the production and commercialization of "delactosed" products, identification of specific safe and suitable products with a well-recognized lactose-free logo might help consumers. This narrative review aims to identify the dietary management for lactose intolerant people, avoiding symptoms and nutrients deficiencies, helped by the use of specific labelling to guide them to choose the safer product on the market.
Topics: Adult; Animals; Cattle; Diet; Female; Food Labeling; Humans; Lactase; Lactose; Lactose Intolerance
PubMed: 32590986
DOI: 10.1186/s12967-020-02429-2 -
Asia Pacific Journal of Clinical... 2015"Lactose intolerance (LI)" is considered a common problem in Asians, and in many parts of the world. Its prevalence and age of manifestation varies between by Asian... (Review)
Review
"Lactose intolerance (LI)" is considered a common problem in Asians, and in many parts of the world. Its prevalence and age of manifestation varies between by Asian country, for possible genetic or cultural reasons. Studies in Indonesian children 3-15 years old (y) are available within the past two decades, using a pure lactose tolerance test. The prevalences of lactose malabsorption (LM) in pre-elementary (3-5 y), elementary (6-11 y), and junior high (12-14 y) school-children were 21.3%, 57.8%, and 73%, respectively. An increasing trend for LM prevalence was seen within the pre-elementary group, from 9.1% at 3 y to 28.6% at 5 y. The most frequent symptoms of LI in junior high school (JHS) group were abdominal pain (64.1%), abdominal distention (22.6%), nausea (15.1%), flatulence (5.7%), and diarrhea (1.9%), mostly within one hour of lactose ingestion. In children with regular and irregular milk drinking, LM occurred in 81.2% and 69.6%; LI was found in 56.2% and 52.1%, respectively. Most JHS children with dairy-associated recurrent abdominal pain (RAP) symptoms proved to be malabsorbers. Dairy products most related to RAP were milk and yogurt. LI was found in 81% of RAP children with abdominal pain most frequently, followed by nausea, bloating, diarrhea, borborygmi, and flatulence. Symp-tom onset occurred 30 minutes after lactose ingestion, especially nausea, bloating, and abdominal pain. In RAP children LI symptoms mostly found in breath hydrogen concentration>20 ppm. More LI symptoms were found in lactose malabsorbers, but symptoms were mild and generally disappeared in 7 hours, and in most by 15 hours.
Topics: Abdominal Pain; Adolescent; Age Factors; Animals; Child; Child, Preschool; Dairy Products; Diarrhea; Diet; Flatulence; Humans; Indonesia; Lactase; Lactose; Lactose Intolerance; Milk; Nausea; Yogurt
PubMed: 26715082
DOI: 10.6133/apjcn.2015.24.s1.06