Nutrition strategies for cystic fibrosis

May 3, 2003 in Healthy Eating

Nutrition strategies for cystic fibrosis

Cystic fibrosis is a progressive, potentially fatal, inherited disorder that affects the glands in the body that produce sweat and mucus. Approximately one in every 2,500 children born in North America has the disease.

To be born with cystic fibrosis, a child must inherit two defective cystic fibrosis genes, one from each parent. Most people have two normal genes. However, approximately 5 percent of all Caucasians who don't show any signs of cystic fibrosis are carriers of the disease. That means they are born with one normal gene and one defective cystic fibrosis gene.

The defective cystic fibrosis gene produces an abnormal protein that interferes with the ability of the body to move sodium chloride (salt) and water through the cells. This causes the exocrine glands (the glands that produce sweat, saliva, mucus and tears) to malfunction. The fluids or secretions from the exocrine glands are used as lubricants in the body and are normally quite thin and slippery. The defective cystic fibrosis genes cause the glands to produce secretions that are abnormally thick and sticky.

The problems caused by cystic fibrosis are most evident in the respiratory and digestive systems. The thick secretions block the passages of the lungs, clogging the airways and creating an ideal environment for infection-causing bacteria to flourish. Breathing difficulties, recurrent infections and permanent lung damage are typical symptoms of cystic fibrosis.

The sticky mucus also blocks the ducts of the pancreas, which prevents digestive enzymes from reaching the intestinal tract. As a result of this mucus buildup, the body is unable to break down and absorb adequate nutrition from food. Chronic diarrhea, abdominal pain and nutritional deficiencies are common problems associated with cystic fibrosis.

People with cystic fibrosis tend to lose excessive amounts of salt through their sweat and saliva. This salt loss can upset the mineral balance in the body and may cause abnormalities in heart rhythms or shock. Cystic fibrosis also affects the reproductive system of both men and women. Men with the disease are usually infertile and women may have difficulty conceiving or may have more complications during pregnancy.

The severity of cystic fibrosis varies from person to person and usually depends on the degree of lung damage caused by the disease. Improved treatments have postponed some of the lung damage associated with cystic fibrosis and many people with the disorder now have a life expectancy of 30 years or more. Research into gene therapy is promising and may eventually prevent the progression of cystic fibrosis. However, at this time there is no cure for cystic fibrosis and the disorder inevitably leads to death, usually as a result of lung disease and heart failure.


Who's at risk?

Approximately one in 25 North Americans carry the defective gene responsible for cystic fibrosis. Cystic fibrosis occurs mainly in Caucasians, especially those with a Northern European heritage. The disease affects both boys and girls equally. Long-term survival is better in males, in people without pancreatic problems, and in people who only have digestive problems in the early stages of the disease.

Most babies are diagnosed with the disease before they are one year old. In some cases symptoms of the disease may not become apparent until the child is a teenager or even an adult.


Dietary Approaches

High calorie diet. The impaired digestion of cystic fibrosis causes weight loss and may failure to grow properly in children. When food isn't digested properly, calories and nutrients are lost. For normal growth, people with cystic fibrosis often require 50 to 100 percent more calories than if they were healthy. These calories should come from fat, protein and carbohydrate. A registered dietitian who specializes in cystic fibrosis can help develop a diet with adequate calories for both children and adults.

Essential fatty acids. Many studies have reveled that patients with cystic fibrosis are deficient in both alpha-linolenic and linoleic acid due to poor absorption of dietary fat and faulty metabolism of these fatty acids. A deficiency of these essential fatty acids can contribute to kidney complications, lung damage and liver disease seen in cystic fibrosis.

Children and adults should consume at least two tablespoons of oil rich in essential fatty acids (your dietitian will determine how much fat is required for an optimal calories intake). Flaxseed oil, walnut oil, canola oil are good sources. A commercial product called Udo's Choice Ultimate Oil Blend is available in health food stores. Udo's Oil contains a balance of both alpha-linolenic and linoleic fatty acids from organic flaxseed, sesame and sunflower seeds, wheat germ, rice germ and oat germ. Flaxseed oil, walnut oil and Udo's oil should not be used for saut'ing or frying since their essential fatty acids are easily destroyed by heat. Store them in the refrigerator and use in salad dressings, dips, smoothies or add to foods like pasta sauces and soups after cooking.

Supplements of essential fatty acids may help correct imbalances that occur in cystic fibrosis. One study found that borage oil which contained the fatty acid gamma-linolenic acid, taken daily for four weeks, improved essential fatty acid levels in patients with the disease. While borage oil and evening primrose oil supplements may help, it is very important to get healthy oils in your daily diet to provide extra calories.

To supplement with evening primrose oil (contains gamma-linolenic acid), take 1000 to 1500 milligrams twice daily. Buy a product standardized for 9% gamma-linolenic acid.

Identify food sensitivities. Some children continue to have diarrhea and fail to thrive despite adequate dietary treatment. These children should be evaluated for possible food allergies. Studies have found that when these children are tested and allergenic foods are removed from their diet, diarrhea stops and weight gain occurs. Your doctor should consider the possibility of food allergies if improvement does not occur with standard treatment. Ask for a referral to an allergy specialist for testing.


Vitamins and Minerals

Multivitamin/mineral. Due to impaired absorption of nutrients, people with cystic fibrosis should take a multivitamin and mineral supplement twice daily with meals. This supplement will provide many of the nutrients that are commonly depressed in cystic fibrosis -- vitamins A, D, E, C, beta-carotene, zinc and copper.

Vitamins A, D, E and K. These fat-soluble vitamins are poorly absorbed in cystic fibrosis. As a result, deficiencies are common and can have important implications for the long-term health of people with the disease. Vitamin A levels should be monitored routinely in adults with cystic fibrosis who drive cars since a deficiency causes night blindness. Inflammatory lung flare-ups may also increase the risk for vitamin A deficiency. The best food sources of vitamin A include liver, oily fish, milk, cheese, butter, and whole eggs. Your doctor will take blood tests to determine if vitamin A supplements are necessary.

Vitamin D is necessary for bone health and a deficiency can increase the risk of bone loss and osteoporosis, two conditions often seen in people with cystic fibrosis. Children with low vitamin E levels, teens and adults with cystic fibrosis should get regular blood tests to evaluate their vitamin D status. If a deficiency exists, your doctor will recommend a daily 400 to 800 IU vitamin D supplement. Good food sources of vitamin D include milk, oily fish, margarine, butter and whole eggs.

Vitamin E levels are often reduced in cystic fibrosis primarily from poor absorption. This antioxidant vitamin plays an important role in scavenging harmful free radical molecules whose damage can reduce lung function and increase the risk of heart disease. In cystic fibrosis, levels of many antioxidant nutrients are depressed (E, C, beta-carotene) and levels of free radicals are increased by inflammatory reactions of the disease. As a result, people with cystic fibrosis may have inadequate antioxidant defences to protect their health. Studies in patients with the disease have found that vitamin E supplements improve vitamin E levels and prevent free radical damage to blood cholesterol. To supplement, take water-soluble vitamin E, 100 to 400 IU per day. The best food sources of vitamin E include wheat germ, nuts, seeds, vegetable oils, whole grains and leafy greens.

Vitamin K status may also be impaired due to impaired fat absorption. Vitamin K is essential for blood clotting and health bone growth. Regular blood tests will detect a vitamin K deficiency and your doctor may recommend supplements. Good food sources include green peas, broccoli, spinach, leafy green vegetables, Brussels sprouts, Romaine lettuce, cabbage, and liver.

Beta-carotene. Studies show that people with cystic fibrosis tend to be deficient in beta-carotene. This nutrient is found in orange and dark green produce including carrots, sweet potato, winter squash, broccoli, collard greens, kale, spinach, apricots, cantaloupe, peaches, nectarines, mango, and papaya can also help provide the body with vitamin A. Once consumed, some beta-carotene is converted to vitamin A. Beta-carotene also acts as an antioxidant and can help protect the body from oxidative stress. To get additional beta-carotene, choose a multivitamin and mineral supplement with the nutrient added.

Vitamin C. Ensuring an optimal intake of vitamin C can help to prevent some of the free radical damage that occurs in cystic fibrosis. Researchers have found that patients who did not take a multivitamin supplement have low blood vitamin C levels and higher markers of inflammatory processes. In patients who took low dose vitamin C from a multivitamin pill, vitamin C levels were normal and markers of inflammation were much lower. Vitamin C rich foods include citrus fruit and juices, cantaloupe, kiwi, mango, strawberries, broccoli, Brussels sprouts, cauliflower, red pepper and tomato juice. To supplement, take 500 or 600-milligrams, once or twice daily.

Calcium. Many adults and adolescents with cystic fibrosis have evidence of bone loss. Low bone mass and osteoporosis are caused by a deficiency of vitamin D and poor intake of calcium. It is very important to ensure an adequate intake of calcium since critical periods of bone growth occur throughout childhood and adolescence. Calcium rich foods include milk, yogurt, cheese, fortified soy and rice beverages, fortified orange juice, tofu, salmon (with bones), kale, bok choy, broccoli, and Swiss chard. To supplement take 300 milligrams of calcium citrate with added vitamin D, one to three times daily. Your dose will depend on how much calcium your diet provides.

Zinc. Getting more zinc may help people with cystic fibrosis fight bacterial lung infections. This mineral is needed to activate thymulin, a hormone that enhances the immune system. Zinc is also needed for proper growth and development. Research suggests that zinc metabolism is altered in cystic fibrosis and that people with the disease may have lower blood levels of the mineral. Zinc rich foods include oysters, seafood, red meat, poultry, yogurt, wheat bran, wheat germ, whole grains, and enriched breakfast cereals. Most adult multivitamin and mineral supplements provide 10 milligrams (children's formulas do not have zinc). Take single zinc supplements in the advice of your doctor only. Too much zinc taken for long periods of time has toxic effects and may suppress the immune system.


Other Natural Health Products

Digestive Enzymes. In cystic fibrosis, insufficient amounts of digestive enzymes enter the intestine due to mucus-blocked ducts from the pancreas. As a result, carbohydrates, proteins and fats are not completely broken down and nutrients cannot be absorbed into the bloodstream. Taking a digestive enzyme supplement with each meal can help the body digest food and increase nutrients available for absorption.

When you buy digestive enzymes, the amount is expressed in activity units rather than milligrams. This refers to the enzyme's potency. Dosage will vary depending on the type of enzymes found in the product so follow the manufacturers' directions. Buy a broad based enzyme supplement that contains protease (digest proteins), amylase (digests starch) and lipase (digests fat).


Recommended Websites

Canadian Cystic Fibrosis Foundation

The Cystic Fibrosis Foundation

National Heart, Lung and Blood Institute
NHLBI Health Information Network


The above  an excerpt from "Leslie Beck's Nutrition Encyclopedia" (Penguin Canada, 2001/2003), available at bookstores across the country. The following is copyrighted and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form or means - electronic, mechanical, photocopying, or likewise.

All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.