Nitrogen balance trials with cystic fibrosis patients.

Preliminary nitrogen balance trials have been carried out with six patients known 
to have pancreatic insufficiency to investigate the utilisation of protein from 
a general diet; protein from a general diet plus exogenous pancreatic 
extract; and pre-digested protein, comprising 85% of dietary nitrogen intake, in 
the absence of a pancreatic supplement. In all cases, the addition 
of pancreatic supplement to the general diet improved protein digestibility and 
utilisation. Substituting 85% of the dietary protein with the enzymic casein 
hydrolysate resulted in further improvement in nitrogen balance (but not digestibility) 
for five of the patients. Urinary nitrogen levels of the casein 
hydrolysate diet tended to be lower, which accounts for the finding 
above. With the acid-hydrolysed protein, urinary nitrogen was higher when compared 
with the excretion from the partial casein hydrolysate and provided smaller 
positive nitrogen balances. These preliminary findings indicate that, for some patients 
with pancreatic insufficiency, partial hydrolysates have greater potential for nitrogen retention 
than the administration of exogenous pancreatic extracts with intact protein. It 
is suggested that a daily supplement of pre-digested protein might be 
advantageous for CH children to ensure that minimum protein requirements are 
met. 