Guide
Special diets and medical nutrition
In metabolic diseases, the diet is the treatment itself. This guide explains in plain language how diets are monitored, SGK (Social Security Institution) payment for medical formulas, sick days and tube feeding.
Why is diet part of the treatment?
In some metabolic diseases, what you eat is a treatment as important as medicine.
What is a metabolic disease, and what does the diet do?
In metabolic diseases, the body cannot break down some components of food. These substances build up in the blood and can harm the brain, the liver or other organs. The diet limits how much of these substances enters the body. That is why the diet is not a choice but the treatment itself. How much restriction is needed varies from person to person; the metabolic team decides this.
Source: MedlinePlus Genetics – Phenylketonuria · MedlinePlus Genetics – Tyrosinemia
Phenylketonuria (PKU)
In PKU, the body cannot break down a substance called phenylalanine. Phenylalanine is found in all proteins. So protein-rich foods such as meat, milk, eggs and nuts are limited. The sweetener aspartame also contains a lot of phenylalanine. In Türkiye, all babies are screened for PKU free of charge with a heel-prick blood test. With early diagnosis and diet, delays in intellectual development can be prevented.
Source: MedlinePlus Genetics – Phenylketonuria · MedlinePlus – Phenylketonuria (tedavi bölümü) · Sağlık Bakanlığı HSGM – Yenidoğan Tarama Programı broşürü
Maple syrup urine disease (MSUD)
In MSUD, three amino acids cannot be broken down. These amino acids are building blocks of protein. So a lifelong diet low in these three amino acids is needed. Babies use a special formula. A crisis can happen at times of stress such as infection or fasting. During a crisis, fluids and sugar may be given into a vein in hospital.
Tyrosinemia type 1
In this disease, tyrosine and its by-products build up. If untreated, the liver and kidneys can be damaged. Treatment combines medicine with a low-protein diet. Tyrosine and phenylalanine are limited in the diet; the missing protein is made up with a special amino acid mixture. One study found a strong link between following the diet and blood tyrosine levels.
Source: MedlinePlus Genetics – Tyrosinemia · Nutrients 2020;13(1):134 – Hepatorenal Tyrosinaemia: Impact of a Simplified Diet (PMC)
Glycogen storage disease type 1
In this disease, the main goal is to prevent blood sugar from dropping. Frequent, carbohydrate-containing meals are needed through the day. Older children and adults may take uncooked starch by mouth. Some children are tube-fed through the night. Fruit sugar and milk sugar are also not broken down well. The doctor and the dietitian decide which plan to follow.
Source: MedlinePlus – Von Gierke disease · MedlinePlus Genetics – Glycogen storage disease type I
Metabolic dietitian and regular blood monitoring
The diet is often readjusted according to blood results and growth.
The metabolic team and the dietitian
In metabolic diets, a dietitian and a doctor follow the person closely. The dietitian adjusts which formula is given and how much, based on blood results and weight. Needs change as the child grows, so appointments continue throughout childhood. The family and the child sticking to the diet is also part of the treatment.
Source: MedlinePlus – Phenylketonuria (tedavi bölümü) · NHS England (GOV.UK) – PKU: detailed information
How often are blood tests done?
In the PKU and MSUD guidelines in England, blood levels are checked every week in the first year. Families are taught to collect a drop of blood from a finger or heel at home. The card is sent to the laboratory. In one tyrosinemia study, young children had blood taken every 2–3 months. In Türkiye, frequency and method may vary by center; you can ask your team.
Source: NHS England (GOV.UK) – PKU: detailed information · NHS England (GOV.UK) – MSUD: detailed information · Nutrients 2020;13(1):134 (PMC)
Pregnancy in women with PKU
If a mother with PKU does not follow the diet during pregnancy, high phenylalanine can harm the baby. The risk of delayed intellectual development, low birth weight and heart defects in the baby increases. That is why it is recommended that the diet starts before pregnancy and continues throughout it. If you are thinking about pregnancy, you can talk to your metabolic team about it in advance.
Source: MedlinePlus Genetics – Phenylketonuria · MedlinePlus – Phenylketonuria (tedavi bölümü)
SGK payment for medical formulas and special products
SGK pays for some medical formulas and special products with a specialist report; the rules are set out in the SUT (Health Implementation Communiqué, SGK’s reimbursement rules).
Formulas for metabolic diseases (SUT Article 4.2.16)
Special formulas used in inborn metabolic diseases are covered in Article 4.2.16 of the SUT. This includes protein breakdown disorders. For children, the report is written by a pediatric metabolism, pediatric endocrinology or pediatric gastroenterology specialist. For adults, an endocrinology or gastroenterology specialist writes it. If these specialists are not available, a pediatrician or an internal medicine specialist can write it. The report is valid for 3 years. Any doctor can write the prescription.
- Note the report’s validity period and renewal date.
- Ask your doctor and pharmacy whether the product is on the SGK list.
Source: SGK Sağlık Uygulama Tebliği (SUT), madde 4.2.16 (mevzuat.gov.tr)
Which products are paid for? (EK-4/B list)
SGK publishes a list of products for these diseases. It is called the Hastalığa Özel Diyet Ürünleri ile Tıbbi Mamalar Listesi (List of Disease-Specific Dietary Products and Medical Formulas, EK-4/B). Products not on this list are not paid for. Ordinary infant formulas count as food and are not on this list. The list is updated from time to time.
Source: SGK Sağlık Uygulama Tebliği (SUT), madde 4.2.16 fıkra 1 ve 8 (mevzuat.gov.tr)
Starch products in glycogen storage disease
Special starch products used in glycogen storage disease are also covered in the SUT. These products are paid for patients aged 2 and over. The health board report must include at least one pediatric metabolism or gastroenterology specialist. The report states the product name and daily amount. Up to four boxes a month can be prescribed.
Source: SGK Sağlık Uygulama Tebliği (SUT), madde 4.2.16 fıkra 2-c (mevzuat.gov.tr)
Low-protein flour and products
For protein breakdown disorders, SGK pays a monthly amount for special flour and products made from it. Pasta, vermicelli and cookies are examples. This requires the specialist report described above. The amount varies by age group and is updated often. SGK announces separately how the payment is made. You can ask SGK or your doctor about the current amount and procedure.
Source: SGK Sağlık Uygulama Tebliği (SUT), madde 4.2.16 fıkra 3 ve 9 (mevzuat.gov.tr)
Tube or gastrostomy feeding (SUT Article 4.2.8)
Enteral nutrition products are ready-made feeds given through the stomach or intestine. Under the SUT, these are generally paid for if there is malnutrition. This condition does not apply to children with inborn metabolic diseases or to people fed by tube or gastrostomy. In this case, a 6-month health board report is needed; for neurological diseases, the period is 1 year. The report states weight, height and daily amount. A single prescription can cover at most 30 days.
Source: SGK Sağlık Uygulama Tebliği (SUT), madde 4.2.8.A (mevzuat.gov.tr)
Nutrition on sick days
Fever, vomiting or fasting can trigger a crisis in some metabolic diseases; on these days, the plan your doctor gives you is what counts.
Why are sick days risky?
During illness or long fasting, the body starts to break down its own tissues. In some metabolic diseases, this causes harmful substances to build up quickly. This is called a metabolic crisis. Irritability, excessive sleepiness, poor feeding and breathing difficulty can be signs of a crisis. A crisis can be serious; spotting it early is important.
Source: NHS England (GOV.UK) – MCADD: detailed information · MedlinePlus – Maple syrup urine disease
Emergency (sick-day) regimen
In many metabolic diseases, the team gives the family a written sick-day plan. This plan is usually energy-rich feeding given at frequent intervals, day and night. The dietitian teaches what to give, how much and how often. The plan is personal. Do not use someone else’s plan or recipes from the internet; follow your own team’s plan.
Source: NHS England (GOV.UK) – MSUD: detailed information · NHS England (GOV.UK) – MCADD: detailed information
When to go to the hospital?
Guidelines recommend contacting the metabolic team on the first day of illness. Fever, vomiting, diarrhea or the child not being their usual self are among these signs. If the child cannot take the feeds in the plan or is getting worse, go to the hospital immediately. You can ask your doctor for the thresholds in writing. In an emergency, call 112.
Source: NHS England (GOV.UK) – MSUD: detailed information · NHS England (GOV.UK) – MCADD: detailed information
What to take to the hospital
When going to the hospital, bring your sick-day plan and treatment information. Also bring the special formula and its scoops. The emergency department doctor may not know the disease; written information makes their job easier. You can also fill in the emergency card on the disease page and carry it in your bag.
Source: NHS England (GOV.UK) – MCADD: detailed information · NHS England (GOV.UK) – MSUD: detailed information
Swallowing difficulties, weight monitoring and tube feeding
For someone who cannot swallow or eat enough, nutrition can be supported in other ways.
Signs of swallowing difficulty
Coughing or choking while eating can be a sign of swallowing difficulty. Food coming back up and a gurgling sound after eating may also occur. Over time, weight loss, dehydration and frequent chest infections can happen. If you notice these signs, you can talk to your doctor. A speech and language therapist and a dietitian can help.
Source: NHS – Dysphagia (swallowing problems) · MedlinePlus – Swallowing Disorders
Thickening and food texture
For swallowing difficulty, soft food and thickened drinks may be recommended. Under the SUT, thickening products can be paid for in children over 1 year of age with a swallowing disorder. This requires a health board report that includes the relevant specialists. The report states the product name and daily amount.
Source: NHS – Dysphagia (swallowing problems) · SGK Sağlık Uygulama Tebliği (SUT), madde 4.2.8.A fıkra 3 (mevzuat.gov.tr)
Weight and height monitoring
Weight and height show whether nutrition is adequate. In the SUT, malnutrition in children is defined by weight-for-age or body mass index. So regular measurements are needed for the report. Keeping the measurements in a notebook makes the team’s work easier.
Source: SGK Sağlık Uygulama Tebliği (SUT), madde 4.2.8.A fıkra 1 (mevzuat.gov.tr)
Daily life with a gastrostomy
A gastrostomy is a feeding route opened from the abdomen into the stomach. The skin around it is cleaned with soapy water one to three times a day and dried well. If there is redness or discharge, or if the tube comes out, call your team. Once the wound has healed, bathing is possible; ask the team about swimming. Going to school is usually possible; school staff can be taught tube care.
Source: MedlinePlus – Gastrostomy feeding tube - bolus · NHS (Cambridge University Hospitals) – PEG tubes in children
Eating at school and away from home
A special diet can become harder outside the home; a written plan and open communication help.
A written health plan at school
In England, a survey was carried out with families of children with PKU. Most children were unsupervised at lunch. Access to foods not allowed at school was also common. Children with a written individual healthcare plan had better supervision and communication with the school. This plan can list the foods the child can and cannot eat, as well as sick-day signs.
- Meet the teacher and school management in person.
- Give the food list and the team’s contact details in writing.
- Clarify where the formula will be stored and who will give it.
Eating out
In a survey of 254 people in England, people with PKU found eating out difficult. The biggest barrier was the lack of suitable low-protein options. Menus also often had no protein information. Many people felt anxious before going into a restaurant. Calling ahead to ask and, if needed, bringing your own food can be options.
Source: Poole ve ark. Nutrients 2022;14(3):626 – Hungry for Change (PMC)
Dietary supplements and natural cure claims
Be careful with supplements and natural products that claim to treat disease.
Claiming that a food treats disease is prohibited
Under Article 7 of the Türk Gıda Kodeksi Etiketleme Yönetmeliği (Turkish Food Codex Labeling Regulation), a food may not be claimed to prevent or treat a disease. The Tarım ve Orman Bakanlığı (Ministry of Agriculture and Forestry) also states that selling supplements as curative is against the law. The ministry also reports that hidden drug ingredients have been found in some illegal supplements. Phrases like “completely natural” or “no side effects” are no guarantee.
Source: Resmî Gazete 26.01.2017/29960 (Mükerrer) – Türk Gıda Kodeksi Gıda Etiketleme ve Tüketicileri Bilgilendirme Yönetmeliği, md. 7 · Tarım ve Orman Bakanlığı – Takviye Edici Gıdalar Soru-Cevap
Signs of fake treatments
The US drug agency, the FDA, lists six warning signs. Claiming that one product helps with many diseases is one of them. Promises of quick results, and words like miracle or secret formula, are others. Personal success stories are not scientific evidence. A claim that the government or companies are hiding the cure is also a sign.
Source: FDA – 6 Tip-offs to Rip-offs: Don't Fall for Health Fraud Scams
Ask your team before starting
Supplements are not tested the way medicines are. Some can interact with medicines. On a metabolic diet, a supplement may secretly contain a restricted substance. So ask your doctor and dietitian about every product first. Tell them about all the supplements you use.
Source: MedlinePlus – Dietary Supplements · FDA – 6 Tip-offs to Rip-offs
Questions to ask your doctor
You can print this list, take it to your appointment and note the answers below each question.
- Which foods are restricted in my child’s condition, and which are allowed?
- How often will blood levels be checked? Can we collect a drop of blood at home?
- Can you give us our sick-day plan in writing? When should we come to the hospital?
- Is the formula we use on SGK’s EK-4/B list? Which specialist will write the report, and when will it be renewed?
- How can we benefit from SGK payment for low-protein flour and products?
- How often should we measure weight and height?
- Could you prepare an information note or health plan for school?
- Is a referral to a speech and language therapist needed for swallowing difficulties?
- Could this supplement or natural product interfere with our diet?
This guide is for information only and does not replace medical or legal advice. If you notice missing or incorrect information, please write to us.