Improved diagnosis and treatment has extended cystic fibrosis (CF) patients’ life expectancy into adulthood.
CF-related impaired bone health becomes increasingly common as these patients move into middle age. Meanwhile, poor skeletal strength increases patient mortality.
In patients who eventually need, qualify for, and accept the risks associated with lung transplants, skeletal compromise worsens organ transplantation success. Exocrine pancreatic insufficiency (reduced secretion of pancreatic digestive enzymes) causes malabsorption of fat-soluble vitamins (A, D, E, and K) and contributes to low bone density. Patients need adequate consumption of calcium, vitamins A, D, and K, zinc, magnesium, phosphorus, fluoride, and protein for bone health.
Now, an article published ahead-of-print in Clinical Nutrition indicates that CF patients experience vitamins D and K deficiencies despite fat-soluble vitamin supplementation.
CF patients often have vitamin D intakes and levels lower than the general population’s. Vitamin D deficiency leads to osteopenia and osteoporosis, as well as worsened respiratory function. This fat-soluble vitamin is critical for muscle strength and antimicrobial peptide and cytokine production.
Vitamin K deficiency occurs in CF patients due to both malabsorption and changes in gut flora. Vitamin K is crucial for the synthesis of bone mineralization proteins. Supplementation with as little as 1 mg/day can stave off the effects of vitamin K deficiency.
Cross-sectional dietary surveys have found that vitamin A and E serum levels are at least adequate in CF patients receiving supplements. Vitamin A is anti-inflammatory, and vitamin E prevents blindness, muscle weakness, and other neurologic damage.
Fat-soluble vitamins can accumulate to toxicity over time. Vitamin A toxicity includes hepatotoxicity, impaired bone health, and increased birth defects. Excessive vitamin E supplementation rarely causes toxicity, but when it does, it causes increased bleeding.
Pharmacists should note that medications often used in CF patients can cause mineral deficiencies. Aminoglycoside antibiotics and calcineurin inhibitors for post-transplantation patients may promote renal wasting of magnesium, while proton-pump inhibitors may increase magnesium loss or impair absorption in the gastrointestinal tract.
CF patients are at high risk for impaired bone and respiratory health due to deficiencies of vitamins D and K. The effect of CF on bone health is increasingly important as life expectancy advances.
Providers should proactively supplement all 4 fat soluble vitamins (A, D, E, and K) in CF patients to protect patients’ bones.