Law on nutrition of children with phenylketonuria. Phenylketonuria (PKU)
Phenylketonuria is one of the hereditary diseases, in the fight against which Special attention focus specifically on diet therapy. Nutrition in this case plays a very important role. Sometimes it is the only method of treatment, especially in cases where this pathology was identified during the first three months of the baby’s life. Since this pathology is accompanied by a significant increase in the level of phenylalanine in the blood serum, it is clear that nutrition in this case should include minimal consumption of products that contain this component. As a result, patients with this pathology are recommended to reduce to a minimum the amount of all high protein foods. This applies to both baked goods and meat, cottage cheese, peas, and liver. Nuts, eggs, chocolate, fish, cottage cheese, cereals, milk - all these are also food products that must be avoided during this period of time. As for fruits and vegetables, they can be given to the baby selectively. In this case, parents need to count the amount of phenylalanine in each fruit and vegetable separately. The child is given only those fruits that contain the smallest amount of this substance.
A well-known fact is that any protein contains approximately five to eight percent phenylalanine. Fifty to fifteen milligrams of this component per kilogram of body weight can enter a child’s body per day, depending on the age of the baby. How older child, the less phenylalanine should enter his body. It should also be noted that permissible quantity of this substance is determined for each patient with phenylketonuria separately. In fact, everything depends on individual tolerance to this component, which can only be identified during the course of therapy. Children under the age of six months can be given no more than forty percent protein per day. Children aged six months to one year - only twenty-five percent protein, children over one year old - fifteen percent protein. On average, patients are given from three and a half to eight grams of protein daily.
The amount of fat in such a diet should be no more than thirty to thirty-five percent. In this case, children are given fish oil, vegetable oil, and butter. It is possible to enrich the body of a sick child with the necessary amount of carbohydrates through fruits, vegetables, food products that contain starch, and also sugar. Certain mineral components such as iron and calcium can be obtained through certain medications. Today, special products are produced for children suffering from phenylketonuria. protein products, which are based on cereal starch. These include confectionery products such as cakes and cookies, as well as bread, which does not contain protein, as well as pasta and cereals.
If, with such a diet, the amount of phenylalanine in the blood serum of a sick child remains within 4-8 mg%, it means that the baby develops much better both physically and mentally. It turns out that the tactics were chosen correctly. If these indicators cannot be achieved, then the baby’s daily diet requires some changes.
Phenylketonuria (phenylpyruvic oligophrenia) is a hereditary disease of the group of fermentopathies associated with impaired metabolism of amino acids, mainly phenylalanine. Accompanied by the accumulation of phenylalanine and its toxic products, which leads to severe damage to the central nervous system, manifested in the form of impaired mental development.
Types of phenylketonuria
There are types I, II and III phenylketonuria, which differ in terms of manifestations and treatment methods.
- Phenylketonuria type I is the most common classical form of the disease (98% of cases). The occurrence of this form of phenylketonuria is based on a deficiency of the enzyme phenylalanine-4-hydroxylase, which ensures the conversion of the amino acid phenylalanine into tyrosine.
- Phenylketonuria type II is much less common (1-2%) and is characterized by a deficiency of the enzyme dihydropteridine reductase. In this form of the disease, severe mental retardation, convulsions. Type II phenylketonuria progresses very quickly and leads to the death of a child at 2-3 years of age.
- Phenylketonuria type III is caused by a deficiency of tetrahydrobiopterin. The course of this type of phenylketonuria resembles the course of type II disease, and also includes a decrease in brain volume (microcephaly).
Causes of phenylketonuria
The main causes of phenylketonuria are as follows:
- Consanguineous marriages increase the likelihood of having a child with phenylketonuria;
- Change (mutation) of a gene localized on chromosome 12;
Symptoms and signs of phenylketonuria.
Babies born with phenylketonuria are no different from healthy newborns. Their appearance during the first few weeks of life is completely normal. Let's say more, all children with this disease are born on time. At the same time, they note normal weight bodies, as well as growth corresponding to their age. Their only difference is considered to be very light skin, blonde hair and blue eyes. Agree, children with blue eyes and fair skin can be completely healthy.
The very first symptoms of this pathology can make themselves felt just a few weeks after the birth of the baby. It all starts with vomiting, which in most cases is mistaken for a symptom of pyloric stenosis, that is, a condition in which there is a narrowing of the outlet of the stomach. Obvious signs of phenylketonuria appear in most cases only at two to six months. It is at this age that parents begin to notice the baby’s obvious retardation not only physically, but also in mental development.
Another manifestation of this disease is considered to be excessive sweating, as a result of which a special specific smell emanates from the child. Most often it is compared to the smell of a mouse or the smell of mold. There are other signs of this disease that make themselves felt a little later. These include: excessive irritability, as well as lethargy, drowsiness, constant tearfulness, lack of interest in the entire world around us, causeless anxiety. Very often such children have seizures, delayed teething, reduction in head size. Children suffering from phenylketonuria often experience various skin changes such as dermatitis, eczema and so on.
The longer this pathology remains undetected, the more the physical structure of the body changes. So, for example, after a few months a child may develop a specific posture. One of these poses is the “tailor” pose. With her the child upper limbs The elbows are constantly bent, but the baby keeps his lower limbs tucked in. A constant sign of this disease is hand tremors.
The fact that the child is also lagging behind in his mental development can be noticed after six months of his life. Such children cannot make sounds; they begin to hold their heads up, sit up, crawl, and stand on their own legs very late.
Diagnosis of phenylketonuria
To diagnose phenylketonuria, the level of phenylalanine and its derivatives in the blood, urine and cerebrospinal fluid, as well as the level of phenylalanine hydroxylase, dihydropteridine reductase or tetrahydrobiopterin synthetase, are determined.
IN last years in order to early diagnosis Phenylketonuria patients carry out mass examination (screening) of newborns. To make a diagnosis of phenylketonuria, blood is taken from all newborns in maternity hospitals (from the heel, 1 hour after feeding the baby) for examination: from a full-term baby on the 4th day of life, from a premature baby on the 7th day. If the concentration of phenylalanine in the blood is more than 2.2 mg%, parents and the child are called to the genetic center to examine and re-test the child’s blood.
There may be cases when the content of phenylalanine in the blood does not exceed high performance, but slightly exceeds the norm (4-5 mg%). Such children are monitored during the first month of life and repeated checks of phenylalanine levels in the blood are carried out.
In a child with phenylketonuria, the level of phenylalanine in the blood can reach 20-30 mg%.
There are also genetic methods for diagnosing a gene defect in phenylketonuria, which examine blood cells (lymphocytes), fetal amniotic fluid cells (amniocytes) or cells of the outer germinal membrane (chorion). These examination methods make it possible to identify the mutant gene and accurately determine the form of phenylketonuria.
Basic principles of diet for phenylketonuria
The main and only method of treating phenylketonuria today is diet therapy. Specific diet for phenylketonuria it should be observed for a long time (more than 10 years from the date of confirmation of the diagnosis). Treatment with diet begins when the level of phenylalanine in the blood is 15 mg% or higher.
Phenylalanine (PA) is an exogenous essential amino acid necessary for normal growth and development, which is supplied to the body with food. In patients with PKU, the dose of phenylalanine is limited to an amount that depends on the individual's tolerance to PA.
A low-protein diet allows you to maintain the concentration of FA in the patient’s blood serum at a level that is safe for the central nervous system. This level is determined for each age group. For infancy, FA should be at a level of 2-4 mg%; the level of FA concentration in the patient’s blood serum is checked once a week until the 6th month of life.
Phenylalanine is found in all foods containing protein. Therefore food with high content protein should be eliminated from the diet of patients with phenylketonuria. However, it is impossible to completely eliminate the entry of phenylalanine into the body due to its significant role in the process of growth and development.
In order for the phenylalanine content to be at a certain “safe” level, the diet must consist of medicinal drugs with low or no phenylalanine content (which meet the protein requirement by 70-80%), and such an amount natural products to satisfy the body's needs for protein, mineral components, vitamins and phenylalanine, taking into account the basic age-related needs of the child.
The only effective treatment for patients with PKU is specialized diet therapy from the moment of diagnosis. The diet for PKU is:
- Reducing the dose of phenylalanine according to individual phenylalanine tolerance, which means reducing the dose of natural protein in the daily diet
- Providing an appropriate dose of protein for normal development (additional protein without phenylalanine) from PKU medical food products
- Providing an appropriate dose of energy using special low-protein foods
- Provide adequate doses of vitamins, macro- and microelements - mainly from PKU preparations and other sources.
Diet with limited (reduced) phenylalanine content in to a large extent limits the choice of natural food products:
| Prohibited | Allowed in strictly limited quantities | Allowed |
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In patients with PKU, the amount of protein consumed from natural products cannot exceed the established norm. In this regard, in young children and older people, the predominant part of the need for protein, i.e. about 80% should be repaid with mixtures that do not contain phenylalanine, enriched with mineral ingredients.
Diet infant with PKU is based on mixtures (preparations) without phenylalanine, which are the main sources of protein, vitamin, micro- and macroelements. Breast milk and infant formula supplement this diet with phenylalanine, which is essential for growth.
The amount of PKU drug, breast milk or formula should be systematically adjusted depending on individual phenylalanine tolerance, as well as the needs of the growing body. During the first year of life, phenylalanine tolerance changes rapidly, constantly decreasing, and therefore the concentration of phenylalanine in the blood must be monitored at certain intervals and the diet modified.
Starting from the second year of life, the therapeutic amino acid mixture PKU without phenylalanine is gradually replaced by mixtures without phenylalanine with an increased protein content. The composition of these formulas is designed to meet the essential nutritional requirements of healthy children in appropriate age groups, with the exception of phenylalanine: only a mixture of amino acids ("protein equivalent") combined with vitamins and minerals.
The required amount of phenylalanine-free protein enters the body from low-energy drinks: fruit juices, fruit and vegetable juices. Such a change in diet and regimen can affect amino acid metabolism. Optimal use of free amino acids from the mixture for the synthesis of one’s own protein is possible only by consuming the appropriate amount of calories at one time in the daily diet, since every synthesis process in the human body is carried out using energy.
Due to the fact that phenylalanine-free mixtures contain few calories, and the diet must be balanced, i.e. meet certain ratios of fat and carbohydrates (the main sources of energy) in such a way as to fully satisfy daily requirement body in energy, it becomes advisable to enrich daily ration other high-energy food products. This is made possible by the availability of a large number of specialized low-protein and partially phenylalanine-free products on the market.
The daily dose of PKU mixture depends on the child's age, body weight, general health and individual daily phenylalanine tolerance. It is very important that the recommended daily amount of the mixture is not given in one dose, e.g. in the morning. This method of delivering the mixture may lead to fluctuations in amino acid balance or symptoms of drug intolerance. The daily dose of the mixture should be divided into 3-4 doses throughout the day. The drug should be taken with meals.
Daily intake of phenylalanine from food products should be limited to such an amount that the controlled level of phenylalanine concentration in the blood serum does not exceed the “safe for the central nervous system” level, i.e. 2-4 mg/dl, this is the individual daily phenylalanine tolerance. In order to fully meet the needs of a child with phenylketonuria, and maintain acceptable level When eating natural protein and phenylalanine, all foods should be measured and weighed, and foods with the lowest phenylalanine content should be selected.
Given the fact that the diet of patients with PKU should include limiting the dose of phenylalanine to an amount safe for the central nervous system, it is very important to simultaneously ensure the supply of the main nutritional ingredients: protein, carbohydrates, fats, as well as vitamins, micro- and macroelements, energy and fluid volume according to the recommendations for certain age groups.
Reasons for increasing the level of phenylalanine concentration in a child’s blood serum
Very often, an increase in the concentration of phenylalanine in a child’s blood serum means that the amount of phenylalanine consumed by the child significantly exceeds the recommended daily dose. It may also be due to a problem with PKU drug use. Chronic lack of energy, as well as a lack of protein, accelerate the process of destruction of the body's own proteins (catabolic processes).
Protein breakdown and increased phenylalanine concentrations may be caused by infectious process, which occurs with increased body temperature, vomiting, diarrhea, decreased appetite, surgical operations (intensification of catabolic processes, increased energy needs). In such cases, the amount of energy entering the body should be increased.
During a child’s illness, you should pay attention to the amount of calories consumed, since energy deficiency is the main reason for the acceleration of protein catabolism, and as a result, the level of phenylalanine increases. For infections, energy intake should be increased by 20–30%. At high temperatures, it is necessary to increase the amount of energy by 12% for every 1 degree of temperature. If you have diarrhea or vomiting, you should abandon the PKU diet for 1-2 days, and gradually return to it after recovery.
If a child gains rapid weight, there may be a need for an additional portion of food or medication. Inattention to these needs and failure to comply with basic dietary requirements can negatively affect the level of phenylalanine in the patient's blood.
Parents should constantly update their knowledge about PKU and use it in their daily diet practices. When teaching a child the rules of proper nutrition, parents should emphasize the importance of systematic food intake and eating only approved foods. The child needs to be systematically explained in an accessible form the need to avoid high-protein foods. It is also important that the child can refuse treats from peers and be able to identify similarities and differences in food choices.
Based on website materials.
Phenylketonuria (PKU) - genetic disease, characterized by disorders of phenylalanine metabolism. Occurs with a frequency of 1 in 8,000-15,000 newborns. There are four forms of PKU; There are over 400 different mutations and several metabolic phenotypes of PKU.
Definition, pathogenesis, classification
Phenylketonuria is a hereditary aminoacidopathy associated with impaired phenylalanine metabolism, resulting in mutational blockade of enzymes leading to persistent chronic intoxication and damage to the central nervous system with a pronounced decrease in intelligence and neurological deficit.
Of primary importance in the pathogenesis of classical PKU is the inability of phenylalanine hydroxylase to convert phenylalanine to tyrosine. As a result, phenylalanine and the products of its abnormal metabolism (phenylpyruvic, phenylacetic, phenyllactic acids) accumulate in the body.
Other pathogenetic factors include disturbances in amino acid transport across the blood-brain barrier, disturbances in the cerebral pool of amino acids with subsequent disruption of the synthesis of proteolipid proteins, disturbances in myelination, and low levels of neurotransmitters (serotonin, etc.).
Phenylketonuria I (classic or severe) is an autosomal recessive disease caused by a mutation in the phenylalanine hydroxylase gene (long arm of chromosome 12); 12 different haplotypes were identified, of which about 90% of PKU are associated with four haplotypes. The most common mutations in the phenylalanine hydroxylase gene: R408W, R261Q, IVS10 nt 546, Y414C. The disease is based on a deficiency of phenylalanine 4-hydroxylase, which ensures the conversion of phenylalanine to tyrosine, which leads to the accumulation of phenylalanine and its metabolites in tissues and physiological fluids.
A special group consists of atypical variants of PKU, in which the clinical picture resembles the classical form of the disease, but in terms of development indicators, despite dietary therapy, no positive dynamics are noted. These PKU variants are associated with deficiencies of tetrahydropterin, dehydropterin reductase, 6-pyruvoyltetrahydropterin synthase, guanosine 5-triphosphate cyclohydrolase, etc.
Phenylketonuria II (atypical) is an autosomal recessive disease in which the gene defect is localized in the short arm of chromosome 4 (section 4p15.3), characterized by dehydropterin reductase deficiency, leading to impaired recovery active form tetrahydrobiopterin (cofactor in the hydroxylation of phenylalanine, tyrosine and tryptophan) in combination with a decrease in folate in the blood serum and cerebrospinal fluid. The result is metabolic blocks in the mechanisms of conversion of phenylalanine into tyrosine, as well as precursors of neurotransmitters of the catecholamine and serotonin series (L-dopa, 5-hydroxytryptophan). The disease was described in 1974.
Phenylketonuria III (atypical) is an autosomal recessive disease associated with deficiency of 6-pyruvoyltetrahydropterin synthase, which is involved in the synthesis of tetrahydrobiopterin from dihydroneopterin triphosphate (described in 1978). Tetrahydrobiopterin deficiency results in disorders similar to those in PKU II.
Primapterinuria is an atypical PKU in children with mild hyperphenylalaninemia, in whom primapterin and some of its derivatives are present in the urine in large quantities in the presence of normal concentrations of neurotransmitter metabolites (homovanillic and 5-hydroxyindoleacetic acids) in the cerebrospinal fluid. The enzymatic defect has not yet been identified.
Maternal PKU is a disease accompanied by a decrease in the level of intelligence (to the point of mental retardation) among the offspring of women suffering from PKU and not receiving a specialized diet in adulthood. The pathogenesis of maternal PKU has not been studied in detail, but the leading role of chronic intoxication of the fetus with phenylalanine and the products of its abnormal metabolism is assumed.
R. Koch et al. (2008) during an autopsy of the brain of an infant whose mother had PKU (without adequate control over the level of phenylalanine in the blood), found a number of pathological changes: low weight brain, venticulomegaly, hypoplasia white matter and delayed myelination (without signs of astrocytosis); chronic changes V gray matter no brain was found. It is assumed that disturbances in the development of white matter of the brain are responsible for the formation of neurological deficits in maternal PKU.
For practical purposes, medical genetic centers of the Russian Federation use a conditional classification of PKU based on the levels of phenylalanine in the blood serum: classical (severe or typical) - phenylalanine level above 20 mg% (1200 µmol/l); average - 10.1-20 mg% (600-1200 µmol/l), as well as the level of phenylalanine 8.1-10 mg%, if it is stable against the background physiological norm protein intake in the diet; mild (hyperphenylalaninemia that does not require treatment) - phenylalanine level up to 8 mg% (480 µmol/l).
Clinical manifestations and diagnosis
At birth, children with PKU I appear healthy, although more often they have a specific habitus (blond hair, blue eyes, dry skin). In the absence of timely detection and treatment of the disease during the first two months of life, they develop frequent and intense vomiting and increased irritability. Between 4 and 9 months, a pronounced lag in psychomotor development becomes apparent.
Patients are distinguished by a specific (“mouse”) odor skin. Expressed neurological disorders They have rare but characteristic features of hyperactivity and autism spectrum disorders. With absence timely treatment IQ level is< 50. Судорожные приступы, характерные для детей с выраженным интеллектуальным дефицитом, чаще дебютируют в возрасте до 18 месяцев (могут исчезать спонтанно). В раннем возрасте приступы нередко имеют форму инфантильных спазмов, впоследствии трансформируясь в тоникоклонические припадки .
From diagnostic methods(in addition to determining the levels of phenylalanine and tyrosine in the blood), the Felling test, Guthrie test, chromatography, fluorimetry, and search for a mutant gene are used. EEG and MRI studies are widely used.
EEG reveals abnormalities, mainly in the form of a pattern of hypsarthymia (even in the absence of seizures); Single and multiple foci of spike and polyspike discharges are typical.
MRI findings are usually abnormal regardless of treatment/untreated PKU: T2-weighted image shows increased signal intensity in periventricular and subcortical white matter posterior sections hemispheres. Although children may have cortical atrophy, there are no detectable signal changes in the brainstem, cerebellum, or cortex. The described changes in MRI studies do not correlate with IQ level, but depend on the level of phenylalanine in the blood.
For phenylketonuria II in patients clinical symptoms appears at the beginning of the second year of life. Despite dietary therapy prescribed after detection of elevated levels of phenylalanine in the blood during the neonatal period, a progressive course of the disease is observed. There is severe mental retardation, signs of increased excitability, convulsions, muscular dystonia, hyperreflexia (tendinous) and spastic tetraparesis. Often, by the age of 2-3 years, death occurs.
Clinical picture phenylketonuria III resembles that of PKU II; it includes the following triad of symptoms: profound mental retardation, microcephaly, spastic tetraparesis.
Prevention
Necessary timely detection PKU using appropriate screening tests in maternity hospitals, as well as genetic counseling. Expectant mothers with PKU are advised to strictly follow a diet low in phenylalanine to prevent fetal damage before conception and throughout pregnancy, maintaining phenylalanine levels.< 4 мг% (< 242 мкмоль/л). Потомство матерей с легкой ФКУ (фенилаланин < 6,6 мг% или < 400 мкмоль/л) не страдает .
New treatments
Currently, several types are being intensively developed. alternative therapy PKU. Among them: the so-called “large neutral amino acids” method ( large neutral amino acids), enzyme therapy with phenylalanine hydroxylase, phenylalanine ammonia lyase; treatment with tetrahydrobiopterin (Sapropterin).
There is information about successful treatment patients with moderate or mild PKU using tetrahydrobiopterin (10-20 mg/kg/day).
D. M. Ney et al. (2008) showed that the use of dietary glycomacropeptides in PKU (with limited subsidy) essential acids) reduces phenylalanine concentrations in the blood plasma and brain, and also promotes adequate physical development. An experimental treatment for PKU is to inject the phenylalanine hydroxylase gene directly into the affected liver cells. In the Russian Federation, these methods are not currently used.
Diet therapy
It is the therapeutic diet that is most effective in preventing intellectual deficits in severe (classical) PKU. The age of the patient at the time of starting diet therapy is of greatest importance (IQ decreases by approximately 4 points for each month from birth to the start of treatment). Approaches to dietary therapy for PKU in different countries differ somewhat, but their principles themselves are consistent.
Dietary restrictions are not indicated for infants whose blood phenylalanine levels are between 2-6 mg% (120-360 µmol/L). The basis of the diet for PKU is the prescription of diets low in phenylalanine, the source of which is protein food. This diet is prescribed to all patients in the first year of life. It should be prescribed to children with diagnosed PKU before 8 weeks of age; its application in more late age much less effective.
general characteristics diets for PKU. The therapeutic diet for PKU is represented by three main components: medicinal products (mixtures of amino acids without phenylalanine), natural foods (selected), low-protein starch-based products.
Animal products high in protein (meat, poultry, fish, dairy products, etc.) are excluded from the diet for PKU. Breast milk is limited in the first year of life (previously it was completely abolished). Among formulas (breast milk substitutes), preference is given to those containing less protein.
Diet therapy in the first year of life. Equivalent replacement for protein and phenylalanine is made using the “portion” method of calculation: 50 mg of phenylalanine is equal to 1 g of protein (for adequate replacement of products for protein and phenylalanine). Since phenylalanine is an essential amino acid, a minimum requirement must be met to ensure normal development of a child with PKU. During the first year of life, the permissible amount of phenylalanine is from 90 to 35 mg/kg child.
For children with PKU under the age of 12 months, the following medicinal products of foreign and domestic production are currently available in the Russian Federation: Aphenilac (Russian Federation), MD mil PKU-0 (Spain) and HR Analogue LCP (Netherlands-UK).
Diet therapy begins when the level of phenyl-alanine in the blood is from 360-480 mmol/l and above. It is the indicator of its content in the blood that is considered the main criterion for diagnosis and evaluation of the effectiveness of treatment.
Introduction of complementary foods and additional foods. After three months, the diet begins to expand through the use of juices (fruit and berries), prescribing them with 3-5 drops, with a gradual increase in volume to 30-50 ml, and by the end of the first year of life - up to 100 ml. Basic juices: apple, pear, plum, etc. Fruit purees are prescribed, increasing their amount in the diet in the same way as that of the administered juice.
In the period from 4-4.5 months, the first complementary foods are introduced into the diet in the form of vegetable puree prepared independently (or canned fruits and vegetables for feeding infants - the latter without the addition of milk). Next, the 2nd complementary food is sequentially prescribed - porridge (10%) from ground sago or protein-free grains. Industrially produced dairy-free porridges based on corn and/or rice flour can be used, containing no more than 1 g of protein per 100 ml of ready-to-eat product.
After 6 months, you can introduce jelly and/or mousses (protein-free), which are prepared using amylopectin swelling starch and fruit juice, protein-free drink with milk flavor Nutrigen or low-protein milk drink PKU “Loprofin”.
From 7 months, a child with PKU can receive low-protein Loprofin products, for example, spirals, spaghetti, rice or protein-free noodles, and from 8 months - special protein-free bread.
Diet therapy in children over one year of age. Features of the preparation of therapeutic diets for patients older than 12 months are the use of products based on mixtures of amino acids without phenylalanine and/or protein hydrolysates with a small amount of it (exceeding that in products for children with PKU in the first year of life), which contain complexes of vitamins, macro - and microelements. The proportion of protein equivalent gradually increases as children grow, and the quota of fat and carbohydrate components, on the contrary, decreases (later completely eliminated), which subsequently makes it possible to significantly expand the patient’s diet through selected natural products.
The amount of phenylalanine that children of various ages is allowed to be obtained through nutritional means when following a therapeutic diet, gradually reduced from 35 to 10 mg/kg/day.
In diet therapy for children over one year old, it is customary to use specialized medicinal products (based on mixtures of amino acids without phenylalanine): Tetrafen 30, Tetrafen 40, Tetrafen 70, MD mil PKU-1, MD mil PKU-3 (Spain).
The products of “Nutrition” (Netherlands-Great Britain) are distinguished by their special variety and proven quality over the years: P-AM 1, P-AM 2, P-AM 3, Isifen (ready-to-use product), as well as XP Maxamade and XP Maxamum with neutral and orange flavors.
It is recommended to make a gradual transition from a specialized formula (for infants) to products for older children gradually (over 1-2 weeks). In this case, the volume of the previous mixture is reduced by 1/4-1/5 part and an amount of the new product equivalent in protein is added. New medicinal product(the amount of which is calculated depending on body weight and age-appropriate amounts of phenylalanine) it is preferable to give the child fractionally, 3-4 times a day, offering to wash it down with juices, water or other drinks.
The range of products for children with PKU is significantly limited. During the period of maximum strict adherence to the diet (infancy and early childhood), the use of specialized medicinal products is mandatory. The purpose of their use in PKU is to replace protein sources in full compliance with the standards for consumption of basic nutrients by children (taking into account age and specific clinical situation). Some medicinal products contain polyunsaturated fatty acid(omega-6 and omega-3) in a ratio of 5:1-10:1; such food sources are preferred.
From special products dry amino acid mixtures are used, devoid of phenylalanine, with a subsidy of protein equivalent - its artificial analogue (in quantities corresponding to the age of patients with PKU).
Other low-protein foods available in the Russian Federation for dietary therapy of PKU include sago, special bread, vermicelli and other types of therapeutic foods. These medicinal products (amylophens) are based on starches that do not contain difficult-to-digest carbohydrates and minerals. They are represented by pasta, cereals, sago, special flour, bakery products, instants for preparing jelly, mousse, etc. Vitamin supplements increase the nutritional value of low protein foods.
There are also foreign-made low-protein products, Loprofin (Netherlands-Great Britain), based on starches (wheat, rice, potato, corn, etc.), including pasta, cereals for making porridges, special types of bread (tapioca, wheat and rice starch), cookies, crackers, crackers, as well as flour, various desserts, seasonings and sauces with an attractive taste, a significant range of drinks (including milk, cream and coffee substitutes), etc.
Calculation and preparation of diet. The following formula is used: A = B + C, where A is the total protein requirement, B is protein natural food, C - protein provided by medicinal foods.
Enrichment of diet with tyrosine. Some researchers suggest supplementing a low-phenylalanine diet with tyrosine, although there is no statistically significant evidence of improved intellectual development with a PKU diet.
Organoleptic properties diets. The taste properties of almost all artificial medicinal products for patients with PKU are specific. To mask organoleptically unpleasant qualities therapeutic diet for PKU, various flavorings(devoid of protein) and special recipes. The sweetener aspartame should not be used as it breaks down into phenylalanine, methanol and aspartate.
Monitoring the effectiveness of diet therapy. It is based on regular monitoring of phenylalanine content in the blood (it should be in the average range of 3-4 mg% or 180-240 µmol/l).
In the Russian Federation it is used next diagram monitoring the content of phenyl-alanine in the blood in patients with PKU: up to 3 months of age - 1 time per week (until receiving stable results) and then at least 2 times a month; from 3 months to 1 year - 1 time per month (if necessary - 2 times per month); from 1 year to 3 years - at least 1 time every 2 months; after 3 years - once every 3 months.
The nutritional status of the patient, his physical and intellectual, emotional and speech development. If necessary, medical specialists are involved in examining the patient, psychological and defectological testing and a number of studies are carried out (ultrasound internal organs, ECG, EEG, MRI of the brain, general blood and urine analysis, blood proteinogram, according to indications - glucose, cholesterol, creatinine, ferritin, serum iron, etc.). A general blood test is performed once a month, biochemical research blood - according to indications.
Nutrition for infectious diseases. In case of intercurrent diseases with hyperthermia, intoxication and/or dyspeptic symptoms, it is possible to temporarily stop diet therapy (for several days) with the replacement of medicinal products with natural ones (with a low protein content). At the end of the acute period of the disease, the medicinal product is reintroduced into the diet, but over a shorter period than at the beginning of diet therapy.
Discontinuation of diet therapy. The age at which diet therapy can be discontinued in patients with PKU continues to be controversial.
There is evidence that when diet therapy was discontinued at 5 years of age, one third of children with PKU experienced a decrease in IQ level by 10 points or more over the next 5 years. In patients over 15 years of age, breaks in diet therapy are often accompanied by progressive changes in the white matter of the brain (according to MRI).
Diet therapy for patients with classic PKU should be lifelong.
In the Russian Federation, in accordance with the law, special dietary therapy must be provided to the patient free of charge, regardless of the degree of disability and the patient’s age. Strict, mandatory dietary treatment for PKU is usually carried out until the age of 18, followed by an expansion of the diet. Adult patients are advised to avoid consuming high-protein products of animal origin (the total amount of protein should not exceed 0.8-1.0 g/kg/day).
Literature
- Blau N. et al. Phenylketonuria // Lancet. 2010. No. 376. P. 1417-1427.
- Medical nutrition at hereditary disorders exchange (E70.0-E74.2). In the book: Clinical Dietetics childhood/ Ed. Borovik T. E., Ladodo K. S. M.: “MIA”. 2008. pp. 330-383.
- Harding C.O. et al. Advances and challenges in phenylketonuria // J. Inherit. Metab. Dis. 2010. V. 33. P. 645-648.
- Lord B. et al. Implications of resolving the diagnosis of PKU for parents and children // J. Pediatr. Psychol. 2008. V. 33. P. 855-866.
- Koch R. et al. Neuropathology of a 4-month-old infant born to a woman with phenylketonuria // Dev. Med. Child. Neurol. 2008. V. 50. P. 230-233.
- Van Spronsen F. J. et al. Large neutral amino acids in the treatment of PKU: from theory to practice // J. Inherit. Metab. Dis. 2010. V. 33. P. 671-676.
- Harding C.O. New era in treatment for phenylketonuria: pharmacologic therapy with sapropterin dihydrochloride // Biologics. 2010. V. 9. P. 231-236.
- Ney D. M. et al. Dietary glycomacropeptide supports growth and reduces the concentrations of phenylalanine in plasma and brain in a murine model of phenylketonuria // J. Nutr. 2008. V. 138. P. 316-322.
- Singh R.H. et al. BH4 therapy impacts the nutrition status and intake in children with phenylketonuria: 2-year follow-up // J. Inherit. Metab. Dis. 2010. V. 33. P. 689-695.
- Trefz F. K. et al. Sapropterin dihydrochloride: a new drug and a new concept in the management of phenylketonuria // Drugs Today. 2010. V. 46. P. 589-600.
- Webster D. et al. Tyrosine supplementation for phenylketonuria // Cochrane Database Syst. Rev. 2010. V. 8: CD001507.
V. M. Studenikin,
T. E. Borovik, doctor medical sciences, Professor
T. V. Bushueva, Candidate of Medical Sciences
SCCD RAMS, Moscow
The basis of the hereditary disease is the absence of the enzyme phenylanine-4-hydroxylase, which normally ensures the conversion of one of the amino acids, phenylalanine, into the amino acid tyrosine.
The only treatment is the use of a special diet with low, controlled or completely devoid of phenylalanine. These are mixtures based on protein hydrolyzate, from which phenylalanine has been removed: “Aponti-40”, “Lofenalak”, “Phenyl-done”, “Aphenilak”. They are a type of human milk substitute containing, in addition to protein hydrolysate, fats, carbohydrates, vitamins and minerals. For older children, mixtures “Phenyl-free” and “Aponti-80” are used.
Formulas for children with celiac disease
Celiac disease is based on insufficient production of enzymes that break down the plant protein gluten, found in some grains (wheat, rye, oats, barley). The basis of treatment is a gluten-free diet with the exclusion of products from semolina, wheat, pearl barley, barley, oatmeal and rye.
Mixtures based on protein hydrolysates are used: “Nutramigen”, as well as “Nutrilon Pepti TSC”, “Alimentum”, “Pregestimil”. Special porridges are prescribed: Nestlé rice, vegetable, Danone banana, buckwheat, Heinz rice, Humana special porridge, etc. The absence of gluten in the product is indicated by a special icon on the label - a crossed out ear. (See pages 30-31).
Formulas for children with cystic fibrosis
Patients have impaired function of the pancreas and other organs of the gastrointestinal tract. (See page 31).
Diet therapy is combined with enzymes. Special medicinal mixtures containing fats in the form of medium chain triglycerides are used. Mixtures “Nutrilon Pepti TSC”, “Pregestimil”, “Hipp H.A.”, “Alfare”.
JUSTIFICATION OF OPTIMAL DATES FOR COMPLEMENTARY FEEDING INTRODUCTION
According to modern concepts, complementary feeding is understood as food of a denser concentration with a gradually more complex composition and a higher energy value compared to breast milk.
Transitional power- the process of gradually reducing the share of mother’s milk and increasing the volume and range of non-dairy food products in the child’s diet. This period is extremely difficult and problematic. Complementary feeding products must guarantee overcoming all forms of intolerance: mechanical, enzymatic, allergic, psychological. In the first year of life, inadequate nutrition is associated primarily with the choice or formulation of complementary foods, dysadaptation of the digestive system or immunity.
The introduction of other food products into the diet in addition to dairy will mark the second period of feeding a child in the first year of life - mixed.
An analysis of foreign literature on the timing of the introduction of new products indicates a clear trends towards revision of the timing of introduction of complementary foods and moreits late introduction.
This is due to the morpho-functional characteristics of the child’s gastrointestinal tract, the immaturity of enzyme systems and functional state kidneys, imperfect immune response in the first months of life. Early introduction of complementary foods is accompanied by a decrease in lactation in nursing mothers, which reduces the contraceptive effect of breastfeeding. The child is provoked by the occurrence of intestinal disorders, allergic reactions and food intolerance.
Too late introduction of complementary foods leads to a deficiency of protein and micronutrients and low energy value of the diet, as well as to malnutrition and growth retardation. In addition, the development of important physiological skills such as chewing and swallowing is delayed. The correct “eating behavior” of the child in relation to new types of food and new flavors is not formed in a timely manner and is not fully developed, and a lag in social development occurs.
By 4 months of life in children who are on breastfeeding, micronutrient reserves are depleted. To prevent deficiency, infants should be introduced to foods containing iron from 4 months of age. In the 5th month, complementary foods are needed to replenish Zn and Si.
New foods must be introduced gradually one after another in order to identify food allergies at intervals of 3-5 days. The amount of added salt, sugar, and spices must be strictly controlled. Up to 5 months, one milk feeding is replaced. The second - at 6 months of age, the third - at 8-9 months.
cereals - energy contribution to food, iron;
meat - high quality protein, iron in the form of topic;
juices - water, vitamin C, potassium, mineral salts;
fruits/vegetables - vitamins, mineral salts, taste, density, plant fibers.
Based on the clinical experience of Russian scientists and literature data, the following conclusions were made:
1. The optimal age for introducing complementary foods is 4-6 months. (Table 7). Signs indicating the need to introduce complementary foods are low weight gain in the absence of illness or the rapid appearance of hunger in the child after breastfeeding.
2. The fruit component (juices and purees) should be introduced into the child’s diet during natural feeding at 4-4.5 months. This is due to the revealed unsatisfactory tolerance of the fruit component (atopic dermatitis, dyspeptic disorders). In addition, the introduction of a fruit component up to 3 months. life affects the absorption of iron, leading to iron deficiency and iron deficiency anemia.
Fruit juices and purees, characterized by a liquid or semi-liquid consistency, are most suitable for transitioning a child to new dairy-free foods. Preferably canned juices and purees should be used. varying degrees softening: homogenized from 4 months, pureed from 6 months. and older. They guarantee quality and safety for children under 1 year of age.
Among the domestic ones there are unclarified juices (with pulp), which contain plant fibers, large amounts of potassium, iron, other mineral salts and vitamins. They are introduced from 7-8 months.
The priority feature of juices and purees for baby food is the absence of any food additives, stabilizers and preservatives, minimal introduction or absence of forming agents (starch, pectin, flour).
3. Cereal-based complementary feeding products should be recommended taking into account the range of cereals they contain, but not earlier than 4.5-5 months of life, both with artificial and natural feeding. The scheme lasts 5.5-6.5 months (porridge). In connection with the anatomical, physiological and functional features The gastrointestinal tract of a child adapted in the first 4 months of life to receiving only liquid food ( breast milk or mixtures), early use of cereal complementary foods (especially wheat) in the diet leads to allergic and gastrointestinal manifestations in children.
Complementary feeding cereal products include dry flour for baby food(semolina, rice, oatmeal), dry milk porridges and more modern dry fortified porridges (“Kolobok”, “Malyshka”, “Krupinka”, imported porridges). The most convenient and modern porridges that do not require cooking are Hipp, Heinz, Nestle, Beach-Nat, Gerber, Danone. Cereals should be fortified with iron.
Previously 5.5 months. It is advisable to introduce porridge into the diet of children with a slow increase in body weight, later - from 6.5 months. - in the nutrition of children with a tendency to paratrophy. Rice or buckwheat porridge, practically free of gluten, is used as the first cereal complementary food (according to modern ideas, it can induce the development of celiac disease in children in the first months of life). Semolina porridge contains gluten.
4. It is not advisable to introduce yolk into a child’s diet before 6 months. life and cottage cheeseearlier than 5 months with natural and 7 and 6, respectively, with artificial feeding.
Yolk often leads to allergic reactions. Protein is not recommended until 12 months.
Earlier introduction of cottage cheese is unjustified due to the occurrence of allergies to cow's milk proteins in 70-80% of all food sensitizations. Protein deficiency with natural feeding or the use of adapted milk formulas is quite rare.
Despite the individual characteristics of the protein composition, each woman’s milk is adequate to the physiological and biochemical characteristics and meets the needs of her child up to 4-5 months of life.
Additional introduction of protein and minerals with cottage cheese, especially in the first half of life, can contribute to the occurrence of metabolic disorders and cause a load on kidney function.
5. Breastfeeding is recommended for a child until he is 1-2 years old. In this case, whole pasteurized milk is administered if necessary - the absence or lack of breast milk - after 9 months, for “artificial babies” - after 8 months. under the same conditions in
6. Other types of complementary foods: vegetable purees - at 4.5-5.5 months: vegetable oil and butter - at 4.5-5.5 months; with artificial feeding, creamy from 6 months. Rusks, cookies - from 6 months; wheat bread - from 8 months. Meat puree introduced into the diet from 7 months, fish - from 8-9 months. for any type of feeding.
It is advisable to use canned vegetables, domestic or imported (Hipp, Heinz, Nestlé, Baby, Beach-Nat) as vegetable puree. Meat broths are currently not recommended for children and are not included in the diet during the first year.
Meat puree is produced in homogenized or finely ground form (for the earlier and older periods of the 1st year of life) domestic, “Gerber”, “Beach-Nat”, Hipp. Canned meat and vegetables containing up to 20-30% meat, vegetables and grains are produced: Hipp, Beach-Nut, Nestle, Gerber. Coarsely ground products are intended for children from 1 to 3 years old.
Of course, only industrially prepared products can ensure a high degree of safety of complementary feeding products in children’s diets.
There is a misconception that diet only helps with diseases of the gastrointestinal tract. In fact, strict restriction and shifting the balance of the diet in favor certain type products are prescribed by doctors for many pathologies. For example, in case of allergic reactions or developmental disorders, genetic abnormalities. By controlling the menu, you can improve the condition of internal organs, normalize metabolism and help the endocrine system produce necessary hormones. Therapeutic nutrition helps to overcome diseases such as histidynamia, phenylketonuria and galactosemia.
General information about the disease phenylketonuria
This disease is a rare genetic pathology characterized by a disorder of amino acid metabolism in the body. The patient’s digestive system cannot independently break down phenylalanine, which leads to slow intoxication nervous system and the development of dementia.
Girls born in European countries are more likely to be at risk. Fortunately, the incidence in Russia is quite low. According to statistics, only one case per 10,000 births is recorded in our country (for comparison in the UK this number is 1:5000).
It is important to know that a genetic disease can be completely neutralized. Therapy consists of strict control of diet and regulation of work digestive system with the help of diet. Nutritional therapy for patients with phenylketonuria (PKU) is the only way for normal development.
Symptoms and treatment methods
Get genetic disorder only possible from both parents. That is why the disease is quite rare. As a result of intolerance to certain nutrients, the concentration of phenyllactic and phenylpyruvic acid in the blood increases, which subsequently causes a deficiency of neurotransmitters and failures of fat metabolism in the brain. That is why you have to limit yourself by choosing therapeutic nutrition and abstinence.
The main danger of such a pathology is asymptomatic early stages. The baby is born absolutely healthy, and the first obvious manifestations of the disease become noticeable only at 5-6 months of life. The child moves little, does not smile, reacts poorly to external stimuli. Such symptoms are difficult to correctly recognize even for an experienced pediatrician.
Treatment of phenylketonuria is based on a properly balanced menu. There are no other effective ways to influence altered genes yet. Research is being conducted on the use of plant enzymes, which will act as phenylalanine breakers, and artificial infection with a virus that can change cells. But for now these developments are at the project stage.
Principles and features of therapeutic nutrition for phenylketonuria
Therapeutic nutrition for phenylketonuria completely excludes proteins of animal origin. This restriction helps prevent poisoning and negative impact toxins on the brain. It is very important to control the diet from the first days of life. This will protect the baby's nerve cells.
If treatment is started late, then the diet can only stop negative changes. It is impossible to reverse the process; destroyed cells are lost to the body irretrievably. In any case, you will have to follow a strict diet until you are 16-18 years old.
For feeding infants, special formulas are used, which are provided free of charge in medical institutions. This food is almost completely free of lactose and is produced on the basis of other components (milk protein hydrolysate). Breastfeeding in the early stages is possible, but the mother must follow the strict recommendations of the attending physician.
It is necessary to understand that proteins are a necessity for a growing organism. This element cannot be completely excluded. In our country they produce such mixtures as “Aponti”, “Aphenilak”, “Analogue-SP”, which are saturated with peptides and free amino acids that help gastrointestinal tract digest food.
Permitted and prohibited products
Medical nutrition for patients with phenylketonuria is developed by specialized specialists taking into account individual characteristics patient, age, gender. It is important to remember that without good nutrition normal development body is impossible. Therefore, the diet of children and adolescents must be saturated with vitamins (B6, B1, C) and amino acids.
Due to protein restriction, daily menu should be increased by 20-30% and saturated with products containing magnesium, calcium, iron, folic acid. A small person should receive all these elements from special complexes and additional medications.
Sample menu for a child's day over 5 years old:
- breakfast: mixed vegetables, sweet tea, juice;
- morning snack: sago pudding, mineral water;
- lunch: vegetarian cabbage soup, mashed potatoes With vegetable oil, plum juice;
- afternoon snack: sweet fruits;
- dinner: vinaigrette, corn bread, honey, tea.
This diet is not suitable for all sick children. Therapeutic nutrition for pheniketonuria is developed by a nutritionist based on individual indicators. But even from our example it is clear that compiling varied menu Maybe. Restrictions are necessary, but proper therapy the disease is highly treatable.
