Nutrition Support Traineeship
We are just starting to have cooler Fall temperatures here in Charlottesville, so the trainees were treated to great weather this time; the rain even held-off for much of the week! Our trainees this month were from Altoona, PA and Owensboro, KY.
Our article this month adds some science to an area of nutrition that traditionally has been guided more by myth, legend, and folklore, than by evidence. It is from the July 2004 issue of Journal of Hepatology.
This study randomized 30 patients with “cirrhosis and clear signs of episodic encephalopathy” to receive either tube feedings with a normal protein content (1.2 gm/kg ideal weight) or a low-protein content (0 protein X 3 days, 12 gm X 3 days, 24gm X 3 days, 48gm X 3 days, then 1.2 gm/kg X 2 days). Both groups were expected to receive 30 calories/kg during the entire 14-day study. All participants had their encephalopathy treated with a lactulose enema X 1, then received neomycin for the duration of the study (3gm/day X 3 days, then 1 gm/day thereafter).
The primary outcomes of this study were:
The authors reported that there was no significant difference in median encephalopathy scores between the two groups, but reported that protein breakdown was significantly increased in the low-protein group on day 2 of the study.
This study has several strengths, including the fact that it is a double-blind study; the subjects, the researcher, and caregivers did not know which group assignment until the trial was completed. This investigation also addresses one of the flaws of other encephalopathy trails, in that the low-protein group received adequate calories throughout the study – both groups received > 80% expected.
There are however, some significant limitations to this study. The foremost of these limitations is the small sample size – only 10 patients in each group completed the study, and analysis was done only on these patients. In addition, the authors only provide the median results. The analysis of protein metabolism was done on day 2 and day 14 of the study. There is a difference in the group’s protein metabolism on day 2, when the low-protein group was receiving absolutely no dietary protein, but no comparison of protein metabolism again, until both groups were receiving identical nutrition on day 14. It would be valuable to document the detrimental effects of prolonged low-protein diets in this population that is all too frequently malnourished.
There is also no mention of the group’s plasma ammonia levels, except those measured at the end of the trial, when they were receiving identical nutrition. This is not to say that elevated ammonia is an absolute outcome, because encephalopathy is a clinical diagnosis. In fact, it would have been a valuable addition to our body of knowledge if they had been able to document improvements in mental status irrespective of the serum ammonia.
Take home message:
Overall, the group considered this a valuable study, despite its limitations. There are precious few that have investigated the question of appropriate protein intake in the setting of encephalopathy. This study does document that there is no obvious disadvantage to feeding normal protein levels to patients with encephalopathy. In addition, there was no obvious advantage to a low-protein intake in terms of encephalopathy, but there IS a potential disadvantage to low-protein diet in relation to protein metabolism and nitrogen balance. There is need for a larger study that would document outcomes in this population, to help counter the practice of “protein starvation” that has never been documented to have a clinical advantage, and is still all too frequently practiced in hospitals across the country.
I reserve the right to be smarter tomorrow than I am today.
- Winston Churchill
Latest Practical Gastro article is up on the website:
Kelly D., Nadeau J. Oral Rehydration Solution: A “Low-Tech” Oft Neglected Therapy. Practical Gastroenterology 2004;XXVIII(10):51.
Joe Krenitsky MS, RD
PS – Please feel free to send this on to friends and colleagues.