Oral Nutrition Supplementation in the Health Dynamics of Dialysis Patients

Intra-dialytic hypotension

The National Kidney Foundation recommends an ideal intradialytic weight gain of 1.5-2 kg. An improper diet with excess salt and fluid could primarily lead to excess intradialytic weight gain. A higher ultrafiltration rate to remove this excess fluid may not be tolerated by some patients, as the rapid fluid removal may cause low blood pressure (hypotension) and cramping. This could lead to inappropriate fluid removal.³ Dietary adherence to fluid and salt restriction needs to be followed to avoid complications. Sugary and salty food causes more thirst. Sodium in the diet should be <2 g per day. The patient’s water requirement varies by urine output.

The dietary energy and protein intake are less on dialysis days.⁴ Providing a meal or ONS during an HD session can reduce PEW. However, these meals should be individualized according to the patient’s nutritional requirements and risk profile for developing hypotension.⁵ High-protein snacks or ONS, rather than a full meal with high-carbohydrates, prevent intradialytic hypotension.

Muscle cramps

Muscle cramps among HD patients are multifactorial. Excess fluid removal during dialysis (as stated above), alternation of blood pH (metabolic acidosis/alkalosis), electrolyte imbalance, and carnitine deficiency are common causes.

Cardiovascular complications

Dietary modifications significantly help curtail cardiovascular complications in patients on dialysis. A meta-analysis confirms improved diastolic pressure (p value = 0.0001), triglycerides (p value = 0.01), and myeloperoxidase (p value = 0.0001) with consumption of plant-based diets rich in polyphenols.¹⁰ Supplementation of fermentable soluble fiber improved the lipid profile, oxidative, and inflammatory status in patients on HD.¹¹

Protein-energy wasting

Protein and fat wasting causes weakness and poor quality of life. A 11.95 ± 0.69 g amino acid (AAs) loss was observed per HD session.¹² This AA-loss coupled with inadequate food intake, can worsen muscle and fat wasting. Therefore, it becomes essential to ensure adequate protein (1.0 g-1.2 g/kg/day) and energy intake (30-35 kcal/kg ideal body weight) in dialysis patients.¹³ Protein powders and medium chain triglycerides can be added to food to enhance its protein and energy content.

Renal osteodystrophy

As kidney functions decline, hyperphosphatemia (Serum phosphorus > 4.5 mg/dL) occurs. Most high protein food sources are high in phosphorus. The phosphorus in diet should be < 800-1000 mg per day.¹⁴ The desirable phosphorus-to-protein ratio is <12 mg/g of protein.¹⁵ ONS are formulated with low phosphorus and high protein.

Gastrointestinal symptoms

Inadequate food intake may be caused due to gastroesophageal reflux disease, gastric intolerance, gastrointestinal inflammation, bloating, constipation, and dyspepsia. Studies have suggested a higher dyspeptic symptom prevalence in patient on HD when compared to the general population. It is defined as an upper abdominal pain or discomfort, bloating, early satiety, post prandial fullness, nausea with or without vomiting, anorexia, regurgitation, and belching.¹⁶

Constipation: Constipation is prevalent in 63% HD and 29% of peritoneal dialysis (PD) patients. Medications such as phosphate binders, antibiotics, water restrictions, and dietary restrictions on potassium (restrictions of fruits and vegetables) may exacerbate constipation.¹⁷ Sufficient whole grains, fiber-rich low-potassium fruits, and vegetables would aid in better bowel movement and help constipation treatment.

A structured resistance exercise program during HD sessions is a safe and effective intervention that helps improve physical performance, nutritional status, quality of life, anabolic response, and muscle strength.¹⁸

Benefits of oral nutrition supplementation in dialysis patients

Oral nutrition supplementation and dietary counseling significantly improves the nutritional status of patients on dialysis [Figure 2]. This improvement is reflected by parameters like serum albumin, pre-albumin, subjective global assessment (SGA) scores,²⁴ body composition (muscle mass),²⁵ Pittsburgh Sleep Quality Index (PSQI) score,²⁶ physical activity, quality of life,²⁷ body mass index, hand grip strength,²⁸ and malnutrition inflammation score.²⁹

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Figure 2:

ONS in MNT of dialysis patients. ONS: Oral nutrition supplement, MNT: Medical nutrition therapy, SGA: Subjective global assessment, MIS: Malnutrition inflammation score.

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Types of oral nutrition supplements and its implications

The ONS types in dialysis patient management have been presented in Table 2.

Vegetable protein powder

Plant-based diets reduce the obesity, high blood pressure, and diabetes risk.³¹ A study on patients supplemented with soy protein found an inverse relationship between inflammatory marker CRP levels and serum isoflavone levels (P < 0.02) and positive correlation between Δ-isoflavone and albumin variation (R = 0.522, P = 0.05) and insulin-like growth factor-1 (R = 0.518, P < 0.05).³²

Whey protein

Whey protein isolates used in patients on PD showed improved dietary protein intake and increased serum urea (P = 0.002) and normalized Protein catabolic rate (n PCR) (P < 0.001). The body weights, BMIs, skin-fold measures, and serum urea of positive responders increased.³³

Balanced tube feeding ONS

The protein sources are a combination of whey and casein protein. ONS given to dialysis patients decreased MIS scores in 38% (p value 0.04) and improved serum albumin (p value = 0.02).³⁴

High protein diet with proteolytic enzyme

Proteolytic enzymes are used to improve protein digestion. Using proteolytic enzymes with a protein-rich diet was beneficial in dialysis patients for better protein assimilation thereby reducing PEW. There was a significant improvement in dry weight and CRP reduction (p value < 0.05).³⁵

Protein supplement with hydroxymethylbutyrate (HMB) helps in muscle protein synthesis by stimulating the mammalian target of rapamycin.³⁶ However, no significant HMB effects on dialysis patients with regard to body composition, bone density, strength, physical function, fall risk, quality of life, or blood parameters were seen.³⁷

Egg albumin protein

Egg albumin-based supplement significantly improved serum albumin, n(PNA), triceps skinfold, mid-arm muscle circumference (MAMC), and calorie protein intake compared with the controls who received diet counseling only (p value < 0.05). The malnutrition percentage reduced by 28% in the study group compared with the control group (6%).³⁸

Collagen peptides

Administration of oral collagen peptide was beneficial in PD patients. It significantly increased protein intake (p value = 0.05) and serum urea levels (p value = 0.003). However, there was no significant serum albumin improvement.³⁹

Branched chain amino acid (BCAA) level was low in malnourished HD patients. Supplementing BCAAs significantly improved the serum albumin, plasma BCAA, oral calorie and protein intake, and anthropometric indices (p value < 0.05).⁴⁰

Factors considered while recommending ONS

ONS are recommended for malnourished patients or those not meeting nutritional requirements. Malnutrition could be diagnosed using nutrition assessment tools like malnutrition inflammation score (MIS)⁴¹ and SGA.⁴²

Malnourished patients are recommended to take ONS twice or thrice a day based on their nutrition deficit. Consumption is recommended between the main meals to avoid interference with normal kitchen-based food quantity. Proteolytic enzymes are advised immediately after a high-protein meal. The ONS recommended for patients on dialysis should adhere to fluid, sodium, potassium, and phosphorus restrictions. ONS with the lowest phosphorus-to-protein ratio (< 12) are preferred. ONS with additional benefits on fiber, probiotics, and carnitine are preferred. Protein from egg, whey, BCAA, and collagen can be considered.

A balanced oral nutrition formula is recommended for reduction in overall intake. The recommended guidelines for patients include: total fat ≤ 30% of energy intake, reducing saturated fat (<10% of total energy), monounsaturated fat (≤20% of total energy), polyunsaturated fat (≤10% of total energy), and cholesterol intake (<200  mg/d). Daily carbohydrate intake should reach 45% to 65% total energy and fiber intake ≥20 g/d.⁴³

Proteins with neutral flavors are available. These types are used when patients resist commercial preparations with different flavors. Patients prefer routine food without flavor. It could be mixed into food. Micronutrient supplementation should be individualized based on nutrient levels indicated by blood test investigation. Formulas with high in Vitamin A & E should be avoided as they could be toxic.⁴⁴

Vegetable-source protein supplements could be recommended for patients having high phosphorus values (>4.5 mg/dL), as the phosphorus in vegetable protein is less bioavailable. The taste and flavor preferences of the patient should also be considered while planning ONS.

ONS mixing & Administration: ONS should be mixed in lukewarm water for better miscibility. Medications should not be mixed in ONS as they can interfere with nutrient absorption.

Economic constraints of patients: The patients’ financial constraints and consent should be considered before planning ONS. Kitchen-based protein-rich snacks could be included in the diet of patients having financial constraints.

Dialysis-associated complications should be efficiently managed by implementing the appropriate nutritional intervention. Dietary modification and suggesting suitable ONS as per guidelines would safeguard patients from malnutrition and provide a better quality of life.