Cystic Fibrosis

By Barbara Gordon, RDN, LD
Child with cystic fibrosis | Cystic Fibrosis

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Most people with cystic fibrosis, or CF, are diagnosed by the age of two years old. CF is a genetic condition that causes mucus to collect in the lungs and around the pancreas. A buildup of mucus in the lungs can cause breathing problems. Lung infections are common for those with CF. In the digestive tract, the buildup of mucus affects digestion, which could lead to malnutrition. The mucus impacts a person's ability to absorb nutrients found in foods, especially fat and fat-soluble vitamins.

Individuals with CF need to pay careful attention to their eating patterns. During childhood, nutritional status is key for overall health and survival. Lung infections and difficulties absorbing nutrients affect growth. They may also make it challenging to maintain a normal body weight. A common goal for people with CF is to focus on weight gain or the prevention of weight loss. The doctor might also prescribe enzymes to take with meals and snacks that help to digest foods. 

Registered dietitian nutritionists, or RDNs, create meal plans for children and adults with CF. These recommendations are tailored to individual needs. Most individuals with CF need extra calories, sodium, protein and higher fat intakes than their peers without CF, as well as vitamin and mineral supplements. There are few restrictions on specific types of foods recommended.

Additional recommendations may be made to help manage other conditions which may develop such as diabetes or liver disease.

Extra Calories

RDNs calculate calories based on a person's age, sex, activity level and health status. In children, growth needs are also important considerations. For both children and adults with CF, calorie needs may be 10 percent to 100 percent higher than those of a similar person without CF. To help get enough calories, many people with CF may need to eat smaller more frequent meals and snacks or focus on foods that add a lot of calories in small amounts, such as whole fat dairy foods, healthy fats, and gravies.

High Fat

Getting enough fat may be challenging for individuals with CF. To help meet those needs, people with CF need to include foods high in fat every day.

For example:

  • Full-fat dairy products, which can be added in several ways:
    • Drinking whole milk or using it to make smoothies
    • Eating full-fat yogurt
    • Adding cheese to egg dishes, sandwiches, burgers and steamed vegetables
    • Mixing butter or cheese into mashed potatoes
    • Using cream to make sauces, puddings and desserts
    • Enjoying ice cream and milkshakes
    • Putting whipped cream on hot chocolate or other desserts
  • Sources of fats and oils—you can sneak in extra fat by:
    • Adding olive oil to pasta dishes or drizzling it over salads and grains, such as rice and quinoa
    • Dipping bread in olive oil
    • Choosing regular dressings instead of light, lite or diet salad dressings
    • Having bacon with your eggs or mixed into vegetable dishes
    • Selecting fatty fish, such as salmon or mackerel, when having seafood
    • Adding avocado to salads and sandwiches or smoothies
    • Eating chips with guacamole
    • Snacking on trail mix with a variety of nuts and seeds
    • Spreading toast with peanut, almond or cashew butter

Vitamins and Minerals

Vitamin and mineral needs are often different for people with CF. An RDN can design an eating plan that includes foods and beverages that help meet these needs.

For example:

  • Vitamins A, D, E and K. The inability to absorb foods high in fat can also lead to deficiencies in fat soluble vitamins. Fat soluble vitamins include vitamins A, D, E and K.
    • Dairy products, some fortified breakfast cereals, sweet potatoes and dark green leafy vegetables are all sources of vitamin A
    • Dairy products are also rich in vitamin D, eggs and fatty fish, such as salmon are also good sources
    • Vegetable oils, nuts, and seeds are packed with vitamin E
    • Green leafy vegetables are the best sources of vitamin K


  • Calcium: Individuals with CF are at a higher risk of osteoporosis, or the weakening of the bones. This can increase the risk of bone fractures. An RDN can provide a list of foods that are good sources of calcium such as:
    • Whole milk, yogurt, and cheese
    • Calcium-fortified 100% fruit juices and soy beverages
    • Salmon with soft bones
    • Collard greens and kale
  • Sodium: Sodium is an electrolyte needed for muscle and nerve function.Individuals with CF lose a higher than normal amount of sodium in their sweat. Seasoning foods with salt can help increase sodium intake.
  • Iron: Many factors can influence an iron deficiency, which is common in people with CF. Foods providing a good source of iron include fortified cereals, oysters, some types of beans and lentils and beef. Other foods that contain iron in smaller amounts include dark green leafy vegetables.
  • Zinc: Another mineral that may result in a deficiency and helps to fight infection and promote healing is zinc. It is found in some of the same foods as iron. For example, beans and legumes, shellfish and meats. Dairy products and eggs also may provide zinc.

Since an individual with CF may not be able to get all the vitamins and minerals needed, they may require a supplement in a formulation that is specific to CF. Be sure to check with a health care provider before taking an over the counter vitamin and mineral supplement.

Balanced Eating Plans

Even with all of these modifications, a regular eating pattern that includes three meals and two to three snacks per day is important for people with CF. A balanced eating plan includes a variety of vegetables and fruits, whole grains, dairy products and protein foods. Getting enough protein is very important for those with CF. The RDN can help you figure out how much protein you need and suggest foods that are good sources of protein such as meats, eggs, soy-based foods such as tofu and tempeh, seafood, nuts and beans.

The Academy of Nutrition and Dietetics has a searchable database of RDNs. Enter your zip code to find a list of RDNs in your area.

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