Non sono alimenti ma spesso sfuggono: sali iposodici, compresse di potassio, lassativi fosfatici, additivi fosfatici, proteine in polvere, compresse effervescenti… ciascuno con fonti e data di verifica.
Low-sodium salt / salt substitute (potassium chloride)
Potassio
Quantità:Typical salt substitutes are ~50% KCl: 1 tsp (~6 g) can contain 1,000–1,500 mg potassium (≈3–4 bananas)
Perché:Sodium chloride is replaced by potassium chloride; in CKD 4–5, dialysis, or with tacrolimus / ACEi / ARB / potassium-sparing diuretics the kidney cannot excrete it, causing hyperkalemia.
Cosa fare:Check the label for "potassium chloride" and avoid. Restaurants, relatives' kitchens and "healthy salt" are the usual blind spots.
Fonti: NKF: Potassium and Your CKD Diet · FDA: Sodium Reduction – Salt Substitutes · Verificato 2026-10-13
Potassium supplements (KCl tablets / syrup)
Potassio
Quantità:Slow-K 600 mg = 8 mEq ≈ 312 mg potassium per tablet; potassium citrate (for stones) also 5–10 mEq per tablet
Perché:Often started with diuretics and never stopped as kidney function declines; potassium citrate for stones is also potassium.
Cosa fare:Bring all medicines to each visit; when kidney function changes ask "do I still need this potassium?"
Fonti: DailyMed: Potassium chloride ER labels · Verificato 2026-10-13
Drugs that raise potassium (ACEi / ARB / K-sparing diuretics / tacrolimus / cyclosporine / trimethoprim)
Potassio
Perché:They contain no potassium but reduce renal potassium excretion: RAAS blockers and K-sparing diuretics suppress aldosterone; tacrolimus / cyclosporine impair tubular secretion; trimethoprim acts like amiloride; NSAIDs lower renal blood flow.
Cosa fare:With these drugs the "safe" amount of high-potassium food is lower than general leaflets suggest; tell any prescriber of Bactrim or NSAIDs that you have CKD / a transplant.
Fonti: KDIGO 2024 CKD Guideline (hyperkalemia management) · Prograf (tacrolimus) label §5 Hyperkalemia · Verificato 2026-10-13
Sodium phosphate laxatives / enemas (Fleet)
Fosforo
Quantità:One Fleet enema (118 mL) contains ~4.4 g phosphate; oral bowel-prep courses deliver several grams of phosphorus
Perché:FDA boxed warning: oral sodium phosphate bowel preps can cause acute phosphate nephropathy and severe hyperphosphatemia / hypocalcemia in renal impairment.
Cosa fare:Before colonoscopy tell the doctor you have CKD / dialysis / a transplant and ask for a PEG prep; never self-buy phosphate enemas for constipation.
Fonti: FDA Safety: Oral Sodium Phosphate (OSP) Products for Bowel Cleansing · Verificato 2026-10-13
Phosphate food additives (E338–E343, E450–E452)
Fosforo
Quantità:Phosphate-enhanced processed meats carry 60–100% more phosphorus than fresh meat; one 355 mL cola ≈ 40–50 mg phosphorus as phosphoric acid
Perché:Inorganic phosphate is ~90–100% absorbed, far more than plant (20–40%) or animal (40–60%) phosphorus, yet it rarely appears on nutrition labels.
Cosa fare:Scan ingredient lists for "phos" or E-numbers: ham, sausages, restructured meats, fish cakes, cheese slices, cola, creamers, frozen meals, instant noodles, baking powder and bottled teas are common carriers.
Fonti: KDOQI 2020 Nutrition in CKD Guideline §4 Phosphorus · NKF: Phosphorus and Your Diet · Calvo & Uribarri, Am J Kidney Dis 2013 (phosphorus additives) · Verificato 2026-10-13
Active vitamin D (calcitriol / alfacalcidol / paricalcitol)
Potassio e fosforo
Perché:Increases intestinal absorption of both calcium and phosphorus; excess doses raise serum phosphorus and calcium together.
Cosa fare:A prescribed phosphorus-raising factor — never self-increase; when phosphorus runs high, this is often adjusted first.
Fonti: KDIGO 2017 CKD-MBD Update · Verificato 2026-10-13
Phosphate binders (phosphorus-lowering)
Fosforo
Perché:The opposite of a phosphorus source: binds dietary phosphorus in the gut so it leaves in stool. Only works if taken WITH phosphorus-containing meals; on an empty stomach it does nothing.
Cosa fare:Match the dose to the meal's phosphorus; carry one for phosphorus-rich snacks. Sevelamer reduces mycophenolate absorption — transplant recipients should separate by 2 hours.
Fonti: KDIGO 2017 CKD-MBD Update · Renvela label §7 Drug Interactions (mycophenolate) · Verificato 2026-10-13
Potassium binders (potassium-lowering)
Potassio
Perché:Exchange or adsorb potassium in the gut. Patiromer binds other oral drugs — separate by 3 hours.
Cosa fare:A rescue and maintenance tool, not a licence to eat high-potassium foods freely.
Fonti: Veltassa label §7 · Lokelma label · Verificato 2026-10-13
Effervescent tablets / electrolyte powders / sports electrolytes
Potassio
Quantità:Many electrolyte products contain 200–400 mg potassium per serving; WHO-formula ORS ≈ 780 mg potassium per litre
Perché:Designed to replace potassium and sodium in people with normal kidneys; during diarrhoea CKD / dialysis patients are at higher hyperkalemia risk because renal perfusion falls.
Cosa fare:For diarrhoea or vomiting call your nephrology / dialysis unit first instead of drinking large amounts of sports drinks or ORS.
Fonti: WHO ORS formulation · NKF: Potassium · Verificato 2026-10-13
High-potassium herbal / folk remedies (noni juice, aojiru, coconut water, starfruit juice)
Potassio
Quantità:Noni juice ≈ 56 mEq/L (~2,200 mg/L) potassium; one green smoothie easily exceeds 800 mg potassium
Perché:Concentrates many raw fruits and vegetables, no boiling, and is drunk 300–500 mL at a time — far more potassium than one fruit serving; starfruit is additionally neurotoxic in CKD.
Cosa fare:"Natural" does not mean low in potassium; anything blended into juice is a concentrated potassium drink.
Fonti: Mueller et al., Am J Kidney Dis 2000 — Noni juice hyperkalemia · Neto et al., Nephrol Dial Transplant 2003 — Star fruit intoxication · Verificato 2026-10-13
Phosphorus-containing supplements (bone formulas, protein powders, mass gainers)
Fosforo
Quantità:Whey powders ≈ 150–400 mg phosphorus per 30 g scoop; standard (non-renal) nutrition shakes ≈ 250–300 mg phosphorus and 350–450 mg potassium per 237 mL
Perché:Protein naturally carries phosphorus (~12–15 mg per g protein) and many formulas use calcium phosphate as the calcium source.
Cosa fare:If supplements are needed on dialysis, choose renal-specific formulas (low phosphorus / potassium, high protein) with a dietitian.
Fonti: KDOQI 2020 Nutrition in CKD · USDA FDC 173180 / 174181 · Verificato 2026-10-13
Phosphate-containing antacids
Fosforo
Quantità:K-Phos Neutral 250 mg phosphorus per tablet; Phospho-soda ≈ 0.6 g phosphorus per 5 mL
Perché:Some antacids are aluminium phosphate; phosphate supplements (for hypophosphatemia) cause hyperphosphatemia in renal impairment.
Cosa fare:Show the OTC package to the pharmacist and mention your kidney disease.
Fonti: DailyMed: K-Phos Neutral · Verificato 2026-10-13
Sesame / nut / multigrain "health powders"
Potassio e fosforo
Quantità:One bowl of black sesame paste (30 g powder) ≈ 190 mg phosphorus, 140 mg potassium; multigrain rice carries ~3× the phosphorus of white rice
Perché:Whole grains, seeds and nuts are concentrated plant sources of phosphorus and potassium; as powders the portion creeps up unnoticed.
Cosa fare:On dialysis, choosing white rice, white noodles and rice vermicelli is a deliberate low-phosphorus strategy, not an unhealthy one.
Fonti: USDA FDC 170150 (sesame) / 169722 (wheat bran) · KDOQI 2020 Nutrition in CKD · Verificato 2026-10-13