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Sodium

Plays vital role in regulation of fluid balance and blood pressure. Restriction is essential for compliance in fluid restricted patients.

Guidelines for general population= max 6g NaCl per day - but this is much more than is essential. An estimated 75% of salt intake comes from processed foods. All renal patients advised on a 'No Added Salt' (NAS) diet: 80-100mmols/day.

• Avoid adding salt at the table
• Use small amount in cooking or none at all
• Reduce intake of salty foods (e.g., cheese, smoked food, savoury snacks)
• Limit intake of packet, processed & convenience foods
• But avoid salt replacements (e.g. Lo Salt) because of their potassium content
• Encourage use of pepper, herbs and spices as alternative flavourings

Protein

Essential for the growth and repair of body tissues

Protein-rich foods include: Meat, chicken, fish, eggs, cheese, yoghurts, nuts, pulses, meat substitutes (Note: some high protein foods contain high levels of phosphate and potassium)

Recommendation for protein varies according to stage of renal disease/ type of renal replacement therapy

Pre dialysis/ Conservative Management

Controlled protein intake (0.8-1g/kg/IBW)

• Helps to reduce phosphate load
• Prevents acidosis
• May reduce uraemic symptoms
• But must maintain nutritional status
• Use of low protein diets is controversial

Haemodialysis

Moderate protein requirements (1-1.2g/kg/IBW)

• Haemodialysis is a catabolic process
• Aim to replace protein lost during dialysis (~4g per session)

Peritoneal Dialysis

High protein requirements (1.1-1.5g/kg/IBW)

• Average peritoneal losses of 5-15g protein per day
• Increased losses in peritonitis

Energy

Adequate energy intake essential to optimise nutritional status

Pre dialysis/ Conservative Management

High energy requirements (30-35 kcal/kg/IBW)

• Can have raised metabolic rate

Haemodialysis

High-energy requirements (30-35 kcal/kg/IBW)

• Catabolic process raises metabolic rate

Peritoneal Dialysis

Moderate energy requirements (25-30/kg/IBW)

Account for calories absorbed from dialysis fluid (can be 70-270kcal/day)

 

Phosphate

Phosphate control essential for prevention and management of renal bone disease, arterial stiffening and vascular calcification.

Phosphate in the diet generally associated with intake of protein: Meat, fish, chicken, eggs, yoghurts, cheese, milk

Typical UK intakes of phosphate: - Men: 47mmol/day - Women: 36mmol/day

When GFR deteriorates to 25-30ml/min, phosphate retention can occur. Level of restriction depends on treatment mode, residual renal function, dietary intake, and biochemistry. Phosphate not very well dialysed - relatively large ion, with small gradient as plasma concentration low (1-2mmol/l).

Aim to maintain serum phosphate <1.8mmol/l. Control can be achieved via combination of:

Low phosphate diet

• Limit high phosphate foods (Cheese, yoghurt, eggs, nuts, milk, oily fish)
• May have to restrict phosphate intake to approx 30mmol/day.
• However, must maintain adequate protein intake

Phosphate binding medication:

Work in the stomach by binding the phosphate in foods - so should not be taken without food as will have no benefit

• Calcichew, Phosex (Calcium containing)
• Renagel, Alucap, Fosrenol, Lanthanum carbonate (Non-calcium containing)

Potassium

Average intakes in the UK: - Men 84mmol/day -Women 66mmol/day

Restriction often required in renal patients for prevention and management of hyperkalaemia. Level of restriction based on treatment mode, dietary intake and biochemistry.

• Aim approx 1mmol per kg/IBW (e.g. 5ft 8in male ~68mmol)
• Often no restriction required in peritoneal dialysis
• MUST RULE OUT NON-DIETARY CAUSES - Acidosis, ACE inhibitors, NSAID, K+ supplements, K+ sparing diuretics, salt substitute, uncontrolled diabetes

High Potassium Foods (more info on high potassium foods)

• Milk
• Potatoes and green vegetables (boiling reduces K+ content) , Potato crisps (Maize/corn better)
• Fruit (limit all fruit, fruit juice, dried fruit) and nuts
• Salt substitutes
• AND unfortunately: milk chocolate, coffee, toffee, liquorice, wine, beer, cider. But spirits are low in K+.

Fluid

Restriction may be needed to prevent excessive fluid retention, depending on urine output. Impossible if salt intake high. Must count foods with a high fluid content (e.g. soup, ice cream, custard, gravy, jelly) in allowance. Difficult; aim to give practical tips: using smaller cups, sucking ice-cubes

Pre-dialysis

• Ensure adequate fluid intake (2-2.5L per day)
• May require restriction when nearing ESRF

Haemodialysis

• Varies depending on residual renal function
• Usually 500mls + PDUO
• Intradialytic weight gains of >2kg indicate excessive fluid intakes

Peritoneal Dialysis

• Varies depending on residual renal function and ultra filtration
• Tends to be less restricted than in haemodialysis

Transplantation

Post-op

• Ensure adequate nutritional intake post-op
• Ensure adequate intake of fluid and electrolytes during polyuric phase
• Dietary restrictions can usually be relaxed as function improves

Education on discharge

• Healthy eating
• Food safety, drug interactions
• Adequate calcium for bone preservation
• Potential to develop obesity, hyperlipideamia and steroid induced diabetes.

Malnutrition

40-50% of HD and PD patients are malnourished. Affects morbidity and mortality rates. Very difficult to reverse once evident. Causes: