Poor dietary intake resulting in malnutrition is common among dialysis patients, and oral nutritional supplementation is often employed to address the problem of dietary inadequacy.
However, little is known about how effective whey protein supplementation is on malnutrition in continuous ambulatory peritoneal dialysis (CAPD) patients.
The whey to better health
As such, researchers in Malaysia conducted a multi-centre, parallel, open-label RCT to investigate the clinical efficacy of whey protein supplementation on 126 malnourished CAPD patients whose serum albumin levels were below 40g/L and BMI under 24kg/m2.
The patients were randomly assigned to two groups: 37 in the intervention group and 37 in the control group completed the study. Those in the intervention group each received 27.4g of protein powder daily for six months, as well as dietary counselling, whole those in the control group were given only dietary counselling.
The researchers assessed their anthropometry, biochemistry, malnutrition-inflammation score (MIS), dietary intake including dialysate calories, handgrip strength and quality of life at baseline and after six months.
Subsequently, they observed that in the intervention group, 59.5% of the patients achieved dietary protein intake adequacy of 1.2g/kg of ideal body weight. In contrast, only 16.2% of the patients in the control group managed a similar achievement, though the difference in dietary energy intake adequacy between the two groups was not significant.
The researchers stated that greater dietary protein intake was directly proportional to significant increases in serum urea and normalised protein catabolic rate in the intervention group, compared to the control group.
Based on changes in normalised protein catabolic rate, those in the intervention group saw a considerable improvement in their weight, BMI, skinfold measures and serum urea.
The researchers also wrote: "Although not significant, comparison for changes in post-dialysis weight and mid-arm circumference indicated trends favouring the intervention group over the control group."
In addition, the patients in the control group experienced a marked decline in their quality of life.
The pros of protein
The researchers stated that the patients in the intervention group "did not report any issues related to compliance with whey protein supplementation", despite peritoneal dialysis patients typically displaying poor compliance with nutritional supplementation.
For this reason, the researchers had intentionally assessed nutritional outcomes focused on compliance. They added that a longer period of supplementation might be required in order to achieve nutritional efficacy characterised by substantial improvement in body weight.
They concluded: "A six-month whey protein supplementation feeding improved markers of nutritional status in malnourished CAPD patients, with good compliance and tolerance to the product.
"The study provides evidence supporting the beneficial effects of the single-nutrient approach through whey protein supplementation provision to address negative nitrogen balance and achieve the high dietary protein intake recommendations for CAPD patients.
"However, additional calorie supplementation is warranted in patients with suboptimal energy intakes."
Source: Clinical Nutrition
"Clinical efficacy and feasibility of whey protein isolates supplementation in malnourished peritoneal dialysis patients: A multicenter, parallel, open-label randomized controlled trial"
Authors: Sharmela Sahathevan, et al.