Cystic fibrosis (CF) is a genetic disorder impacting epithelial cells, disrupting salt and water balance, leading to thick mucus buildup in the lungs and digestive system. This mucus obstructs the lungs, causing infections and breathing difficulties, and interferes with pancreatic enzyme function, impairing food digestion. Effective nutritional strategies, particularly adequate protein intake, are crucial for managing CF, maintaining lung function, physical performance, and overall survival.
Understanding Cystic Fibrosis and Its Nutritional Impact
Cystic fibrosis affects the body's epithelial cells, found in sweat glands, lungs, and the pancreas. The body responds by making thick mucus, which blocks the lungs and sometimes other ducts and passageways, causing infections and breathing problems. CF often leads to pancreatic insufficiency, where enzymes that digest fat, carbohydrates, and protein do not reach the intestines properly, hindering normal digestion and potentially causing problems with growth and weight gain. Individuals with pancreatic insufficiency might experience frequent, foul-smelling bowel movements and require prescribed enzymes with meals and snacks to aid digestion and maintain a healthy weight.
The Evolving Dietary Recommendations for CF
Historically, a high-calorie, high-fat, and high-salt diet was recommended for individuals with cystic fibrosis. However, with new therapies extending life expectancy and making weight gain more manageable, the focus is shifting towards a more balanced diet that supports long-term health and prevents conditions like heart disease and cancer. Current recommendations include:
- Consuming five servings of fruits and vegetables daily.
- Including protein with meals and snacks.
- Prioritizing whole grains over refined grains.
- Avoiding sugary drinks.
- Eating more homemade meals and fewer fast food or restaurant meals.
Determining a Healthy Weight
A healthy weight for teens with cystic fibrosis is different for each person. Body mass index (BMI) is used to measure if you are at a healthy weight by comparing your weight to your height. The goal for all teens with CF is to reach a healthy weight that supports healthy lungs.
Special Nutritional Needs in CF
Individuals with CF have unique nutritional requirements, including:
Read also: CF Diet for Adults
- Salt: Due to increased salt loss in sweat, adding extra salt to foods, consuming salty snacks, and drinking sports drinks during exercise or hot weather is often recommended.
- Fat-soluble vitamins (A, D, E, and K): These vitamins are crucial for immune function, growth, and healing. Since fat absorption is often impaired in CF, a CF-specific multivitamin may be necessary.
- Calcium: To mitigate the risk of osteopenia or osteoporosis, adequate calcium intake is essential. Dairy products are good sources of calcium and fat. Calcium-fortified milk alternatives can be considered for those who do not consume cow's milk.
- Calories: Some teens with CF need more calories than their peers. The extra calories should come from a well-balanced, healthy diet.
Strategies to Increase Calorie Intake
For teens with CF who need more calories than their peers, the best way to meet these calorie needs is by eating a well-balanced diet, but adding extra calories with added fat; add extra butter or oil to pasta, rice, potatoes, or cooked vegetables; pair raw vegetables with salad dressing or hummus; top salads and sandwiches with avocados or guacamole; grill sandwiches in butter or margarine; add a splash of heavy cream to milk, oatmeal, smoothies, or cream-based soups; focus on high-calorie snacks such as trail mix, peanut butter and banana sandwiches, full-fat yogurt with granola, or cheese crackers.
When Are Nutrition Supplements or Tube Feedings Necessary?
Some teens with CF may have trouble gaining weight from a high-calorie diet alone. A doctor or dietitian may recommend adding nutrition supplements to your diet. Nutrition supplements are calorie-rich drinks that also have protein, vitamins, and minerals. For some teens, this added source of calories is enough to improve weight gain. If a high-calorie diet and nutrition supplements are not enough, a doctor or dietitian may recommend tube feedings. These feedings, done through a tube into the stomach, are often given at night for extra calories. These overnight feedings leave teens with CF free to enjoy normal meals and activities during the day.
The Crucial Role of Protein in CF
Protein is essential for building and repairing tissues, supporting immune function, and maintaining overall health. For individuals with CF, protein plays an especially vital role in maintaining muscle mass, which is closely linked to lung function and survival. About 15 to 20 percent of your calories should be from protein. Eat foods like meat, fish, eggs, cheese, soy and nuts.
Why Protein Needs Are Higher in CF
The RDA for dietary protein is likely insufficient for individuals with cystic fibrosis (CF) because individuals with CF use a lot of energy to breathe and fight infections. But protein and fat digestion problems mean there are fewer nutrients for the body to use. Individuals with CF need more protein than those without CF because of the increased work of breathing, chronic inflammation and exacerbations.
Several factors contribute to increased protein needs in CF:
Read also: Children's CF Diet Tips
- Malabsorption: Exocrine pancreatic insufficiency, present in 85-90% of CF patients, impairs the digestion and absorption of nutrients, including protein.
- Increased energy expenditure: Individuals with CF often have increased energy needs due to the increased work of breathing and chronic inflammation.
- Chronic inflammation: Systemic inflammation is common in CF and is correlated with the severity of lung disease and nutritional depletion.
- Muscle wasting: Low muscle mass is consistently associated with pulmonary decline, bone mineral loss, and poor survival in CF.
Assessing Protein Intake and Diet Quality
A study assessing dietary intake in adults with cystic fibrosis (awCF) before and after elexacaftor/tezacaftor/ivacaftor (ETI) therapy, compared with healthy controls, found that both healthy controls and CF patients at baseline had a higher mean daily protein intake than the protein RDA of 0·75g·kg-1·day-1. However, there was a significant reduction in daily protein intake in the CF group at follow-up, with levels below the alternative suggested dietary intake of ≥ 1·2 g·kg-1·day-1. This emphasizes the importance of ensuring appropriate dietary protein intake to promote healthy ageing in adults with CF.
Optimizing Protein Digestion and Absorption
Impaired protein digestion capacity reduces the anabolic potential of a meal, and leads to high loads of undigested proteins in the colon and production of harmful toxins by gut bacteria and diarrhea. Studies have shown that protein digestibility is severely reduced in both children and adults with CF. Protein digestibility normalized after intake of pancreatic enzymes, albeit with a severe delay. Strategies to improve protein digestion and absorption include:
- Pancreatic enzyme replacement therapy: Taking prescribed enzymes with meals and snacks helps improve the digestion and absorption of protein and other nutrients.
- Choosing easily digestible protein sources: Changing the source of proteins into more slowly digested proteins, hydrolyzed proteins or free dietary amino acids is a way to get around the impaired protein digestibility in CF while still on pancreatic enzyme replacement therapy.
- Amino acid mixtures: Amino acids are the main nutrients responsible for acute stimulation of muscle protein synthesis, and essential amino acids (EAA) are solely responsible for the amino acid induced stimulation of muscle protein anabolism in healthy individuals and insulin-resistant states.
Protein Supplementation
For individuals with CF who struggle to meet their protein needs through diet alone, protein supplements can be a valuable tool. A dose-response effect on protein synthesis was observed in stunted children with stable CF when protein is provided at 1.5, 3 and 5 g protein kg/d for 4 days. PS was 30% higher in the high compared to the low-protein group which resulted in more protein anabolism, and a trend towards higher plasma insulin concentrations were observed with increasing protein intake. This indicates that large amounts of protein are required to increase protein anabolism in patients with CF.
Practical Strategies to Increase Protein Intake
Incorporating more protein into the diet can be achieved through various strategies:
- Choose protein-rich foods: Include foods like meat, fish, eggs, cheese, soy, and nuts in your diet.
- Add protein to meals and snacks: Sprinkle grated cheese on soups, sauces, casseroles, vegetables, mashed potatoes, rice, noodles, or meat loaf. Spread peanut butter on bread products or use it as a dip for raw vegetables and fruit.
- Use enriched milk: Use whole milk, half and half, cream, or enriched milk in cooking or beverages. Enriched milk has nonfat dry milk powder added to it.
- Consider protein supplements: If dietary intake is insufficient, consider using protein supplements to meet daily requirements.
Monitoring Nutritional Status and Body Composition
Regular monitoring of nutritional status and body composition is crucial for individuals with CF. While BMI has improved the past decades, the prevalence of FFM loss is still high in CF. Body composition assessment and achieving protein balance in the routine care in CF is important to prevent muscle loss and further improve clinical and overall outcome of these patients.
Read also: CF Nutrition Guide
The Importance of Exercise
Besides the right diet, exercise can help support better lung health, mood, and quality of life. When you exercise, you burn additional calories. You may need to add an extra snack (or two) to make up for the calories lost during exercise. It's also important to do weight-bearing exercises, that work against gravity like walking, hiking, jogging, climbing stairs, tennis or dancing.
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