Essential Amino Acid Profile in Parenteral Nutrition Mixtures: Does It Meet Needs?

BACKGROUND AND AIMS

The study compares the essential amino acid (EAA) composition of different parenteral nutrition (PN) mixtures with whey protein EAA profile and the theoretical daily EAA requirements (set by WHO/FAO/UNU or IAAO method). According to the individual EAA profile, the potential effect of several PN mixtures was evaluated on the skeletal muscle mass (SMM) of patients on home PN.

METHODS

Eight AA solutions and fifteen complete PN mixtures were considered. Twenty-nine clinically stable patients with short bowel syndrome on home total PN were retrospectively evaluated. SMM was estimated by bioelectrical impedance analysis.

RESULTS

The prescribed doses of EAA that showed a significant increase in home PN patients muscle mass were considerably greater than the theoretical ones, showing an EAA profile similar to whey protein. At the daily dose of 1 g of total AA s/kg body weight (BW), the considered PN mixtures mostly failed to improve SMM. Only prescribed doses which included more than 0.25 g/kg BW of total BCAA with at least 0.10 g/kg BW leucine, 0.08 g/kg BW isoleucine, and 0.06 g/kg BW methionine showed a significant increase in SMM.

CONCLUSIONS

The theoretical daily requirement for each EAA was met by all considered PN solutions when the prescribed daily dose of total AAs was set at 1 g/kg BW. Nevertheless, our data suggest that only an increase in total BCAA, also richer in single AA leucine, isoleucine, and methionine, is associated with the maintenance and/or increase of SMM. According to these preliminary observations, we support the prescription of an EAA composition of PN mixtures close to that of whey protein for the preservation of SMM in patients on long-term total PN.

Prediction of Renal Acid Load in Adult Patients on Parenteral Nutrition

Metabolic acidosis and metabolic bone disease are frequent complications in patients on parenteral nutrition (PN). A common contributor to these complications could be a daily high renal acid load. This study aims to find a method for predicting the potential total acid load (PTAL) and the pH of the compounded parenteral nutrition mixtures. The pH and titratable acidity (TA) of fifty compounded mixtures were measured. The potential metabolic acid load (PMAL) was calculated by considering the amount of nutrients that are acid producers and consumers. The PTAL of the TPN mixtures was calculated by adding TA to PMAL. Multiple linear regression analyses were used to develop a predictive model for the TA and pH of the compounded mixtures. The predicted TA and pH values of the analyzed mixtures agreed with those measured (Passing-Bablok analysis). The PTAL was >50 mmol/day for 82% of the mixtures, >75 mmol/day for 40% of the mixtures, and >100 mmol/day for 22% of the mixtures. The prediction of the renal acid load in patients on long-term PN could allow more appropriate acid-base balancing. Moreover, predicting the pH of such mixtures could be useful to pharmacists to assess the stability and compatibility of the components in the compounded mixtures.