Patients on maintenance hemodialysis (MHD) may be able to decrease inflammation and improve physical function by drinking soy or whey protein beverages prior to each dialysis session, according to a new study.
Investigators led by Kenneth R. Wilund, PhD, of the University of Illinois in Urbana, randomly assigned 38 MHD patients to supplementation with a whey protein (11 patients), soy protein (12 patients), or placebo (15 patients) beverage. Patients consumed the drink (27 g of protein or placebo mixed with 4 oz water) within 15 minutes before the start of every dialysis session for 6 months. The drinks were in addition to patients’ regular diet, and over time, increased their daily protein intake. None of the patients were considered malnourished.
Acute protein loss may occur both during and immediately after dialysis treatment due in part to inflammation, adding up to a loss of lean muscle mass from 1 to 3 kg/year, according to the researchers.
The investigators chose whey protein for supplementation because its higher leucine content may influence physical performance and body composition. Soy protein, although potentially less anabolic than whey, may reduce inflammation via isoflavone compounds.
The investigators measured markers of blood inflammation (interleukin 6 [IL-6] and C-reactive protein [CRP]) at baseline and 6 months. They also assessed patients’ physical function (via gait speed and shuttle walk test) and body composition (via x-ray absorptiometry).
According to results published in the Journal of Renal Nutrition (2015;25:276-283), the protein drinks significantly reduced pre-dialysis levels of IL-6, and there was a trend for reduction in CRP. Both gait speed and shuttle walking significantly improved in patients who drank the protein supplements. Although the researchers observed no changes in body composition, alkaline phosphatase—a marker of bone turnover—decreased in the protein groups.
“Intradialytic protein supplementation induced modest favorable changes in functional outcomes and could represent a low-cost therapeutic treatment strategy for this critically ill population,” the researchers concluded. Intradialytic nutrition is somewhat controversial due to concerns related to hemodynamic stability, they added.