Zinc and its physiological role in Cystic Fibrosis

The physiological role of zinc

Zinc is an essential trace element that participates in multiple processes. It is a vital cofactor for the function of many proteins and these zinc-dependent proteins play numerous indispensable roles within cells, such as transcriptional regulation, DNA repair and apoptosis. 

Zinc-dependent proteins are involved in metabolism and play an important role in antioxidant defence. 

Zinc is also involved in the regulation of growth hormones and plays a key role in regulating the immune system. 

This trace element appears to be important for health due to its critical roles in growth and development, in bone metabolism, in the central nervous system, in immune function and in wound healing. Cells with a rapid turnover rate, such as those of the immune system, the gastrointestinal system and the skin, are particularly vulnerable to zinc deficiency, which can cause: dermatitis, diarrhoea, alopecia and loss of appetite.

Zinc and Cystic Fibrosis 

Zinc deficiencies are common in Cystic Fibrosis and are mainly attributable to impaired intestinal absorption. Zinc deficiencies in Cystic Fibrosis are associated with a significant number of clinical symptoms, such as retardation in growth and in sexual maturation, increased susceptibility to infections, visual disturbances, anorexia and loss of taste. 

In the epithelium of the airways, zinc is important for the ciliary function and, thanks also to its antioxidant properties, it exerts an anti-inflammatory action in the airways. 

Recent publications show that a high proportion of patients with CF (about 41%) would be at high risk of zinc deficiency and that these deficits must be corrected with adequate dietary supplementation, particularly in children and adolescents who show delays in growth weight and height and in subjects who are deficient in Vitamin A or with steatorrhoea. 

Blood zinc monitoring should be carried out regularly and at least once a year to verify any deficiencies and correct them promptly in the most appropriate way.

References:

• Challenges with optimizing nutrition in cystic fibrosis, Carla Colomboa, Rita Maria Nobili and Gianfranco Alicandro - EXPERT REVIEW OF RESPIRATORY MEDICINE - doi.org/10.1080/17476348.2019.1614917 – 2019 
• Zinc Nutritional Status in Patients with Cystic Fibrosis, M. F. Escobedo Monge et al. – MDPI - doi:10.3390/nu11010150 – 2019 
• Plasma zinc in adults with cystic fibrosis: Correlations with clinical outcomes, V. Damphoussea et al. - Journal of Trace Elements in Medicine and Biology - dx.doi.org/10.1016/j.jtemb.2013.10.003 – 2014 
• Pulmonary dysfunction in cystic fibrosis is associated with oxidative stress, R.K. Brown, H. Wyatt, J.F. Price, F.J. Kelly - European Respiratory Journal - DOI: 10.1183/09031936.96.09020334 - 1996