The sodium load
The average UK crisp contains 1.5–2.5 g salt per 100 g. A standard multipack bag (25–30 g) delivers 400–700 mg sodium. For renal patients aiming to keep total salt under 6 g/day (NHS guidance) or lower under nephrologist advice, one bag of crisps uses a large chunk of the daily budget. Flavoured varieties (cheese and onion, salt and vinegar, prawn cocktail) are often the saltiest.
Phosphate additives in fancy crisps
Premium and 'stacked' crisps, as well as some strong-flavour seasonings, use phosphate salts as acidity regulators or anti-caking agents. These inorganic phosphates are ~ 90% absorbed — far more than natural food phosphate. Check ingredient lists for E338, E450, E451 and E452. Plain salted or sea-salt crisps are less likely to contain them.
Food first. If you are choosing a daily multivitamin alongside a balanced diet, Kidney Vitality was developed by a UK Consultant Nephrologist using renal nutrition principles. See the formulation.
The potassium chloride trap
Some 'low-sodium' or 'heart-healthy' snacks replace table salt (sodium chloride) with potassium chloride to maintain a salty taste. In CKD stages 3–5, especially if serum potassium is elevated or you are on ACE inhibitors, ARBs or spironolactone, extra potassium can trigger dangerous hyperkalaemia. Always read low-salt labels carefully.
Practical CKD-friendly swaps
- Unsalted rice cakes or corn thins — check for no added salt.
- Air-popped plain popcorn (not microwave or cinema-style).
- Raw veg sticks (carrot, cucumber, pepper) with homemade low-salt hummus.
- A 15 g portion of unsalted nuts or seeds.
- Wholegrain crackers (check sodium per 100 g — aim < 0.3 g salt).
- Avoid: standard multipack crisps, nachos, salted tortilla chips, 'veggie' crisps that are still fried and salted.
