Cystic fibrosis (CF) or mucoviscidosis (lat. mucus [mucous] and viscidus [viscous, sticky]) is a genetically determined, autosomal recessive hereditary metabolic disorder, which is based on a disruption to the chloride channel. It is one of the most frequent metabolic disorders among white people with 5% of the population healthy carriers.
The incidence in North America and Europe is between 1:2500 and 1:1600 sufferers. In Asia the rate is only 1:100,000 and in Africa and Latin America it is 1:17,000.
The cause of the condition is a genetic error in chromosome 7 (locus 7q31.2) or the CFTR gene (Cystic Fibrosis Transmembrane Conductance Regulator). This regulates a protein which acts as a chloride channel in the cell membrane. The most frequent mutation (approx. 75%) of this gene is known as ΔF508 (lack of the amino acid phenylalanine (= F) at position 508 in the protein). To date, it has been possible to identify 1500 mutations in the CFTR gene.
The condition cannot currently be cured. However, there are numerous different treatment strategies which have considerably improved the prognosis and the quality of life of those with cystic fibrosis in recent years.
Daily respiratory physiotherapy, inhalation and medication that enlarges the bronchi and loosens mucous can help with coughing up the mucous. In addition, anti-inflammatory medication and antibiotics can be used to treat inflammation and bacterial infections in the lungs. Playing sport and keeping active also have a positive effect on the state of health of the patients.
Alongside physiotherapy and medical treatment, dietetic treatment plays a fundamental role in the treatment of the condition. The aim is to maintain or achieve a good nutritional status, which can improve the life expectancy and quality of life for patients.
A varied and balanced diet is advisable, with particular attention placed on the increased energy needs of patients with cystic fibrosis. They require between 120-150% more energy than that of a healthy person the same age and a high fat content of between 35-40% total calories is recommended. During fat oxidation, the production of carbon dioxide, which needs to be exhaled via the lungs, is lower than during carbohydrate oxidation. In many cases, a fat intolerance may occur due to an insufficient number of digestive enzymes. In addition to the administration of pancreas enzymes (approx. 1000–2000 IE lipase per g fat), MCT fats may replace normal. Use of MCTs is particularly advisable for patients for whom the coefficient of fat absorption is insufficient despite enzyme administration. For example, a low pH value in the intestinal tract prevents good efficiency of the pancreas enzyme administration.
Omega 3 fatty acids (α-linolenic acid) have a demonstrated positive effect on inflammation events, because they result in fewer eicosanoids (e.g. prostaglandins, thromboxanes, leukotrienes), which promote inflammation in comparison with Omega-6 fatty acids. They compete with the Omega-6 fatty acids for the same enzyme system. However, arachidonic acid (Omega-6) results in mediators which promote inflammation, which can be reduced by a sufficient supply of Omega-3 fatty acids (contained in linseed oil, soya oil, salmon, mackerel and tuna). In addition, studies have shown that the supply of fish oil has a positive effect on the lung function (improvement of pulmonary function parameters). This is particularly useful due to the frequent occurrence of lung inflammations and bronchitis in cystic fibrosis.
Hydration with 2–3 litres daily is important due to increased water losses through sweating, thin stools and coughing. Salt losses as a result of increased sweating, high temperatures, physical exertion and fever must also be monitored and balanced within the diet. Infants are particularly important as the salt content of infant foods is typical very low in salt compared to adults.