# Nutrition in cystic fibrosis
Energy requirements and caloric intake
People with cystic fibrosis typically have increased energy requirements compared to peers without this condition. This is because chronic lung infections and inflammatory processes consume more energy, and digestion is less efficient.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Adequate caloric intake is important for growth, weight maintenance and strength, especially because being underweight can weaken resistance to lung infections. This is usually discussed with the treatment team, as requirements vary from person to person and can change with age and disease activity.
Fat absorption and pancreatic function
In approximately 85–90% of people with cystic fibrosis, pancreatic function is impaired (pancreatic insufficiency). This means the body absorbs fats and certain vitamins from food less effectively. Because of this absorption disorder, certain nutrients — especially the fat-soluble vitamins A, D, E and K — are harder to obtain, even if they are present in food.
ProveniIncluded in official guidelines, or approved by EMA or FDA
This is usually supported by replacement therapy (enzymes prescribed by the doctor), but dietary choices can also help with this. For more information about how this works and which adjustments are relevant for you, discuss this with your dietitian or gastroenterologist from your treatment team.
Salt balance and fluid balance
Because the sweat glands in cystic fibrosis lose too much salt, reducing salt intake can have the opposite effect. Particularly during physical exertion, hot weather or fluid loss (from diarrhea or vomiting), the body may need extra sodium to function properly. This varies greatly depending on the situation and the individual.
ProveniIncluded in official guidelines, or approved by EMA or FDA
For someone with cystic fibrosis, "healthy" eating (with little salt) may not always be appropriate. This requires individual adjustment with your treatment provider.
Nutrition and lung function
There is increasing attention to how dietary patterns can affect inflammation status and lung function. Recent research focuses on how dietary choices may alter inflammatory processes in the body, but the practical significance of this for daily eating in cystic fibrosis is not yet fully clear.
ResearchediPositive results in clinical studies, not yet standard treatment
Some nutrients (such as certain fatty acids, certain vitamins and minerals) theoretically play a role in immunity and inflammation regulation, but concrete recommendations for specific dietary patterns have not yet been established. This remains an area of research.
Gastrointestinal tract and nutritional absorption
The digestive system is affected in several ways in cystic fibrosis: thick, sticky mucus in the intestines can lead to constipation or — in younger children — to a type of ileus (bowel obstruction). Acid reflux and inflammatory reactions are also common.
ProveniIncluded in official guidelines, or approved by EMA or FDA
This can make eating more difficult: many people feel full more quickly, experience abdominal pain or irregularities in their bowel movements. These symptoms can affect what you can comfortably eat. Regular collaboration with your treatment team (including dietitian and gastroenterologist) helps find personalized adjustments.
Blood sugar regulation and CF-related diabetes
As lung disease progresses, the islets in the pancreas (which produce insulin) can also become affected. This can lead to CF-related diabetes (a form in which insulin is scarce). This occurs in approximately 20–40% of adults with cystic fibrosis, depending on the severity of lung damage.
ProveniIncluded in official guidelines, or approved by EMA or FDA
When someone develops CF-related diabetes, dietary choices around carbohydrates and sugars become more relevant, although this pattern differs from classic type-2 diabetes. Specific dietary adjustment for this is discussed with a dietitian or endocrinologist.
Micronutrients and supplementation
Because fat absorption is impaired, many members of the treatment team regularly see deficiencies in vitamins (A, D, E, K) and sometimes also B12, iron and zinc. This can prevent you from getting them through food alone, even if you eat a lot.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Supplementation is usually planned based on blood values and clinical concerns. You do not determine dosages and schedules yourself, but this happens through your doctor or dietitian. Food can also help: for example, iron-rich products or vitamin-D-containing foods can play a supporting role, but do not replace medical supplementation.
Probiotic-prebiotic approach
There is ongoing research into the role of gut bacteria (microbiome) in cystic fibrosis. Some studies suggest that certain bacterial strains in CF may be different than in people without cystic fibrosis, and that this affects digestion and immunity.
ResearchediPositive results in clinical studies, not yet standard treatment
From this perspective, researchers are looking at nutritional interventions (such as fermentable dietary fibres, certain dairy products or special bacterial preparations), but hard recommendations for daily eating do not yet exist. This remains experimental territory.
Nutrition and fluid balance
Given the chronic coughing and inflammation, adequate fluid intake is important, both for mucus production and for overall health. At the same time, many people with cystic fibrosis become dehydrated easily because of sweat loss. This sometimes requires more fluid than is typical for others.
ProveniIncluded in official guidelines, or approved by EMA or FDA
How this works in practice (types of drinks, amounts, timing) you discuss with your treatment provider, especially since some drinks (for example high sugar or caffeine) can affect your digestion or diabetes risk.
Eating behaviour and psychosocial aspects
Eating is not just nutrition; it is also a social and emotional experience. With cystic fibrosis, chronic fatigue, abdominal pain, taste changes (from medication or chronic infection) or stress can prevent eating from being pleasant. Recent research signals that attitudes towards body, nutrition and self-care among young people with cystic fibrosis are shifting, partly thanks to better treatments.
ResearchediPositive results in clinical studies, not yet standard treatment
This does not mean there is one right way to eat. What is for you personally full, healthy, pleasant and feasible is central — and that can be very different from traditional advice.
Interactions between nutrition and medication
Certain medications (for example antibiotics, anti-inflammatory agents or enzymes) can affect nutrition or vice versa. Some foods can reduce or enhance the effectiveness of medications; others can cause digestion problems.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Always inform your treatment provider about nutritional choices you want to change significantly, so they can check whether there are interactions with your treatment.
Practical tips for nutrition choices
- Working factors are individual and change over the course of life: what is pleasant today does not have to work tomorrow.
- A dietitian with experience in cystic fibrosis can help adapt nutrition to your absorption, symptoms and preference.
- Caloric density (more energy in less volume) can be advantageous, but does not have to be "unhealthy": for example, add nuts, oil or whole grain products, not just sweets.
- Regular monitoring of weight, blood values and nutrition-related symptoms helps with good coordination.
_This information never replaces a doctor's judgment. Always discuss your situation with your own healthcare provider._