Lactase deficiency
The content of the article:
- Causes and risk factors
- Forms of the disease
- Symptoms of lactase deficiency
- Diagnostics
- Treatment of lactase deficiency
- Potential consequences and complications
- Forecast
- Prevention
Lactase deficiency is a congenital or acquired deficiency in the activity of the enzyme lactase, which causes a violation of the breakdown and absorption of lactose and manifests itself as digestive disorders in the form of enzymatic chronic dyspepsia.
Hereditary lactase deficiency is a widespread pathology. So primary lactose intolerance is noted in 100% of American Indians, 80% of Jews, representatives of the Negroid race, indigenous people of the Mediterranean and Asia, 5% of the inhabitants of Northern and Central Europe.
Acquired lactase deficiency is no less widespread. About 50% of children with chronic dyspepsia are diagnosed with this form of fermentopathy.
Lactase deficiency in children, especially in the first year of life, is an urgent task in pediatrics. This is due to the fact that lactose is a disaccharide found in large quantities in milk, which, in turn, serves as the basis for baby food.
Causes and risk factors
Lactose, or milk sugar, is a complex carbohydrate consisting of two monosaccharide residues and is one of the main sources of carbohydrates in the human diet. In the small intestine, under the influence of the enzyme lactazoflorizine hydrolase (lactase), the lactose molecule is split into monosaccharides galactose and glucose, which are absorbed into the systemic circulation by means of the villous apparatus and are carried throughout the body.
Further, galactose is used in the synthesis of galactolipids, which are necessary for the normal development and functioning of the central nervous system, and glucose serves as the main energy resource in the body.
In the case of insufficient activity or complete absence of lactazoflorizine hydrolase, lactose does not break down in the small intestine, and it enters the large intestine unchanged. Here, under the influence of intestinal microflora, fermentation of milk sugar occurs, which is accompanied by increased secretion of water, gas formation, and a decrease in the pH of intestinal contents.
The development of congenital lactase deficiency is usually caused by a defect in the LCT gene (LAC), localized on the second chromosome and responsible for the synthesis of lactase. Pathology is inherited in an autosomal recessive manner, that is, it is not related to sex and for the development of the disease, the child must receive a pathologically altered gene from both the father and the mother. In this case, the parents themselves can only be carriers of the mutated gene and not have any clinical signs of milk sugar intolerance.
With age, lactase activity gradually decreases, which becomes the reason for some people intolerance to dairy products rich in lactose. In this case, they talk about the development of a constitutional form of lactase deficiency.
Lactase deficiency is more often diagnosed in premature babies. This is due to the fact that lactase activity increases in the last weeks of intrauterine development of the fetus and reaches a maximum by the 39-40th week of gestation.
In some diseases of the small intestine (enteritis, giardiasis, rotavirus and other acute intestinal infections, resection of a section of the intestine), its mucous membrane is damaged, as a result of which the secretion of lactase is disrupted and lactase deficiency develops.
Forms of the disease
Based on the reasons for the occurrence of lactase deficiency in adults and children, it is divided into primary and secondary. The primary forms of the disease include:
- congenital (hereditary) lactase deficiency (hereditary intolerance to disaccharides, alactosia);
- transient lactase deficiency of premature babies;
- hypolactasia of the adult type.
Secondary lactase deficiency is associated with damage to enterocytes caused by pathologies of the small intestine.
By the nature of the flow, transient (transient) and persistent (permanent) lactase deficiency are distinguished.
Depending on the severity of enzyme deficiency, there are:
- alactasia - observed against the background of a complete absence of lactase;
- hypolactasia - lactase is synthesized by cells of the small intestine, but in an insufficient amount or its activity is reduced.
Some authors distinguish galactosemia as a separate form of lactase deficiency, but most experts do not agree with this.
Symptoms of lactase deficiency
Clinical manifestations of lactose intolerance occur after the consumption of dairy products and, above all, whole milk. The main symptom of lactase deficiency is fermentative diarrhea. The frequency of bowel movements can reach 10-12 times a day. The stool is watery, frothy, with a characteristic sour odor. They are accompanied by abdominal pain of the type of intestinal colic, flatulence. In very rare cases, lactase deficiency in adults and children can manifest itself not with diarrhea, but, on the contrary, with constipation.
Source: deteylechenie.ru
In newborns, symptoms of lactase deficiency, in addition to those listed, include frequent regurgitation and skin rashes.
Diagnostics
The preliminary diagnosis of lactase deficiency is based on the characteristic clinical picture. In the future, it must be confirmed by the results of laboratory studies and functional tests.
In clinical practice, the method of dietary diagnosis is widely used. The patient is prescribed a lactose-free diet, which leads to the cessation of diarrhea, elimination of flatulence. The introduction of dairy products into the diet promotes the resumption of symptoms of the disease. Attention is drawn to the fact that after a lactose load, the concentration of methane and hydrogen in the air exhaled by patients increases, which can be detected using special laboratory tests.
In infants with lactase deficiency, a decrease in fecal pH to 5.5 or less is determined, and in adults, a high lactose content is found in feces.
Currently, the gold standard for the diagnosis of lactase deficiency in adults is the determination of lactase activity in a biopsy specimen of the small intestine. In pediatric practice, this method is not widely used due to its invasiveness and complexity.
In case of primary lactase deficiency, a genetic study is indicated - lactase genotyping.
Treatment of lactase deficiency
The approach to the treatment of lactase deficiency in patients of different ages has certain characteristics. The basic therapy scheme is based on the following principles:
- diet therapy;
- improvement of the lactose breakdown process;
- prevention of the development of complications (polymineral and multivitamin deficiency, malnutrition).
For children of the first year of life, enzyme replacement therapy is shown, which allows you to preserve breastfeeding. If children are artificially fed, they are transferred to soy milk or special lactose-free nutritional formulas.
Source: cdn.azbyka.ru
When introducing complementary foods, products that do not contain lactose are used: red meat, poultry, fish, vegetables, fruits, cereals.
From the diet of older children and adults with lactase deficiency, condensed and whole milk, sour cream, processed cheeses, ice cream, yogurt, and some medicines (in particular, probiotics) should be completely excluded. Lactose is often used in the food industry as a sweetener in instant breakfast and baked goods. Such foods should also be excluded from the menu.
In some cases, patients tolerate foods with a low lactose content (butter, hard cheeses, cottage cheese) well. Their assimilation depends on the severity of lactase deficiency. With good tolerance, a small amount of such products in the diet is allowed.
To determine the effectiveness of the diet therapy, the carbohydrate content in the feces is regularly determined.
Potential consequences and complications
In the absence of treatment, lactase deficiency can lead to the development of a number of complications and, above all, dehydration due to diarrhea and malnutrition.
Prolonged intake of undigested lactose into the large intestine changes the pH of the intestinal contents, which in turn causes changes in the qualitative and quantitative composition of microflora, that is, the development of intestinal dysbiosis.
Lactase deficiency in children in the absence of timely and adequate therapy is often accompanied by damage to the central nervous system, the development of which is caused by the following factors:
- endogenous intoxication of the body as a result of long-term fermentation processes in the large intestine;
- deficiency of minerals and vitamins;
- violation of nutritional status.
Lesions of the central nervous system in children with lactase deficiency are manifested by a lag in psychomotor development, sleep disorders, irritability, hyperexcitability.
Lactase deficiency in children is often combined with other pathological conditions (attention deficit hyperactivity disorder, vitamin D-deficiency rickets, convulsions, muscle hypotension).
Forecast
Patients with hereditary lactase deficiency should follow a diet low in lactose and / or take lactase throughout their lives.
Transient lactase deficiency in premature babies usually passes by the third or fourth month of life, which is explained by the maturation of the body's enzyme systems.
After the relief of the underlying disease of the small intestine, the signs of secondary lactase deficiency are eliminated on their own.
Children with lactase deficiency should be monitored by a gastroenterologist and pediatrician. The criteria for effective therapy are:
- disappearance of dyspeptic syndrome;
- a decrease in the content of carbohydrates in the feces;
- psychomotor development appropriate for age;
- weight gain corresponding to the age norm.
Prevention
There are no measures to prevent the occurrence of primary lactase deficiency. If family members have cases of lactose intolerance, genetic counseling is recommended to spouses at the stage of pregnancy planning.
Prevention of secondary lactase deficiency is based on timely diagnosis and active therapy of diseases of the gastrointestinal tract.
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Elena Minkina Doctor anesthesiologist-resuscitator About the author
Education: graduated from the Tashkent State Medical Institute, specializing in general medicine in 1991. Repeatedly passed refresher courses.
Work experience: anesthesiologist-resuscitator of the city maternity complex, resuscitator of the hemodialysis department.
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
