A Case for Nutritional Supplements

A Case for Nutritional Supplements

Debra Blair, MPH, RD, CSRFebruary 02 2009

They may benefit dialysis patients whose dietary intake is not sufficient to meet nutrient needs

Malnutrition is common in stage 5 CKD patients, especially those who are just beginning dialysis. A recent study by Kaysen and colleagues (J Ren Nutr. 2008;18:323-331) examined the trends and outcomes associated with serum albumin concentration among 840,348 incident dialysis patients in the United States from 1995-2004. The findings indicate that hypoalbuminemia is strongly associated with poor prognosis and is becoming more prevalent despite efforts by renal health professionals. New strategies to prevent and treat malnutrition are key to improving outcomes in the dialysis population. Although many factors are known to impact albumin levels, medical nutrition therapy remains the cornerstone of treatment.

When dietary intake is not sufficient to meet nutrient needs, oral nutritional supplements (ONS) may provide benefit. Because adherence to supplement recommendations is often inconsistent, administering ONS to patients during dialysis sessions is an approach receiving new attention. Results of recently published studies demonstrate that the intradialytic use of enteral supplements in maintenance hemodialysis (MHD) patients may be associated with improvements in nutrition-related parameters (i.e., serum albumin, body weight), particularly in those without intercurrent illness or other non-nutritional factors, such as liver disease, recent surgery, or malignancy.

Demonstrating the potential of intradialytic ONS to improve protein homeostasis is a study by Pupim et al (J Am Soc Nephrol. 2006;17:3149-3157). The authors compared the nutritional effects of ONS, intradialytic parenteral nutrition (IDPN), and no intervention during dialysis on eight malnourished MHD patients. Subjects received either IDPN (59 g protein, 26 g fat, 197 g carbohydrate) or equivalent ONS or no oral intake during three separate dialysis treatments. Based on whole-body (WB) and skeletal-muscle (SM) protein balance measurements, the authors concluded that intradialytic ONS “is similarly effective as IDPN in preventing HD-associated net WB and SM protein catabolism and has the additional benefit of persistent anabolic effects in the SM after the HD procedure is complete.”

To assess the effect of ONS on serum albumin and other nutrition-related markers, Kalantar-Zadeh et al (J Ren Nutr. 2005;15:318-331) provided hypoalbuminemic MHD patients (serum albumin less than 3.8 g/dL) with a four-week trial of supplements (830 kcal, 31.5 g protein) given thrice weekly during dialysis. Supplements consisted of a renal-specific formula along with a product containing anti-inflammatory and antioxidant components. In the ONS group, which included 21 patients, mean serum albumin increased significantly (3.44 to 3.68 g/dL) compared with a group of 20 controls (3.46 to 3.47 g/dL). Mean hematocrit and total iron-binding capacity also showed statistically significant improvement with ONS. Most patients tolerated supplementation without adverse effect, although three reported diarrhea and one had higher blood sugar levels.

Similar improvements in serum albumin with intradialytic ONS (~500 kcal, 15 g protein) were reported in an earlier study by Sharma et al (J Ren Nutr. 2002;12:229-237) that compared the nutritional effect and acceptability of providing a home-prepared (HP) or commercial (CNS) high-calorie/protein supplement at dialysis vs. diet counseling alone. Supplements were provided thrice weekly for one month after HD treatment in addition to daily dietary recommendations of 1.2 g/kg protein and 35-45 kcal/kg. Subjects receiving ONS, either HP (16 patients) or CNS (10 patients), achieved significantly improved mean serum albumin (3.4 to 4.0 and 3.9 g/dL, respectively) compared with 14 controls (3.4 to 3.5 g/dL). Dry weight and BMI increased in the HP and control groups and remained stable with CNS. Mean phosphorus increased for all groups, significantly with CNS. Functional scores (Karnofsky index) increased significantly with ONS vs. control, and ONS was rated acceptable with no adverse effects.

Although results seem to support using dialysis as an opportunity to provide patients with nutritional supplementation, studies are generally small and short term, and they differ with respect to the type of supplement used and how it is provided. Generalizability of results is limited by exclusion of patients with common non-nutritional factors related to hypoalbuminemia and weight loss in MHD patients, as well as singularity of race in the study by Pupim and colleagues in which subjects were solely African American. Also, the study by Sharma et al excluded patients with diabetes, a comorbidity found in almost 50% of incident dialysis patients. While study results show promise, there is thus far a lack sufficient follow-up to detect impacts of ONS on morbidity and mortality.

Generally, as a means of addressing malnutrition, intradialytic ONS is well tolerated and may improve serum albumin in otherwise stable MHD patients and assist in achieving National Kidney Foundation Kidney Disease Outcomes Quality Initiative nutrition recommendations for a daily intake of 1.2 g/kg of protein and 30-35 kcal/kg.

Further study is needed with randomized controlled trials of larger sample size and longer duration to determine the optimal ONS composition and delivery (i.e., intradialytic vs. home use) as well as potential effects on overall health outcomes in MHD patients.

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