Are Olives Bad for Your Kidneys?

Spanish green Manzanilla olives: ~1,800 mg sodium per 100 g. Kalamata: ~1,500–2,000 mg per 100 g. Black ripe olives (Californian style): ~750–1,500 mg per 100 g. Olives stuffed with anchovy or feta: even higher (~2,500 mg per 100 g). Olives packed in extra virgin olive oil (drained): ~400–700 mg per 100 g — the most renal-friendly option.

Olives are 12–15% monounsaturated fat (oleic acid), which is heart- and kidney-friendly. They also contain polyphenols (hydroxytyrosol, oleuropein) studied for anti-inflammatory effects. The Mediterranean diet — which includes moderate olives — is associated with slower CKD progression in observational studies (PREDIMED, Bonaccio et al.).

• Limit to 30 g (~6–8 olives) per serving.
• Drain and rinse brined olives under cold water for 30 seconds.
• Choose olives in olive oil over olives in brine.
• Avoid stuffed olives (anchovy, feta, blue cheese) — extra sodium.
• Avoid olive tapenade — usually 1,000–1,500 mg sodium per 100 g.
• Pair with lower-sodium dishes to balance the salt budget.

Olive tapenade, olive bread, and Greek salad with feta are all sodium-heavy combinations. A single slice of olive ciabatta plus 4 olives plus 30 g feta can deliver 1.5–2 g salt — a quarter to a third of the NHS 6 g daily limit. Build Mediterranean meals around fresh tomato, cucumber, herbs and olive oil, with olives as an accent.

Extra virgin olive oil is the real Mediterranean staple and is essentially sodium-free. 1 tbsp provides the same heart-healthy oleic acid as 10 olives, without the brine. For CKD, lean on olive oil for cooking and dressings, and treat brined olives as an occasional flavour accent.