Not foods, but easy to miss: salt substitutes, potassium tablets, phosphate laxatives, phosphate additives, protein powders, effervescent tablets… each with sources and a verification date.
Low-sodium salt / salt substitute (potassium chloride)
Potassium
Amount：Typical salt substitutes are ~50% KCl: 1 tsp (~6 g) can contain 1,000–1,500 mg potassium (≈3–4 bananas)
Why：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.
What to do：Check the label for "potassium chloride" and avoid. Restaurants, relatives' kitchens and "healthy salt" are the usual blind spots.
Sources: NKF: Potassium and Your CKD Diet · FDA: Sodium Reduction – Salt Substitutes · Verified 2026-10-13
Potassium supplements (KCl tablets / syrup)
Potassium
Amount：Slow-K 600 mg = 8 mEq ≈ 312 mg potassium per tablet; potassium citrate (for stones) also 5–10 mEq per tablet
Why：Often started with diuretics and never stopped as kidney function declines; potassium citrate for stones is also potassium.
What to do：Bring all medicines to each visit; when kidney function changes ask "do I still need this potassium?"
Sources: DailyMed: Potassium chloride ER labels · Verified 2026-10-13
Drugs that raise potassium (ACEi / ARB / K-sparing diuretics / tacrolimus / cyclosporine / trimethoprim)
Potassium
Why：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.
What to do：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.
Sources: KDIGO 2024 CKD Guideline (hyperkalemia management) · Prograf (tacrolimus) label §5 Hyperkalemia · Verified 2026-10-13
Sodium phosphate laxatives / enemas (Fleet)
Phosphorus
Amount：One Fleet enema (118 mL) contains ~4.4 g phosphate; oral bowel-prep courses deliver several grams of phosphorus
Why：FDA boxed warning: oral sodium phosphate bowel preps can cause acute phosphate nephropathy and severe hyperphosphatemia / hypocalcemia in renal impairment.
What to do：Before colonoscopy tell the doctor you have CKD / dialysis / a transplant and ask for a PEG prep; never self-buy phosphate enemas for constipation.
Sources: FDA Safety: Oral Sodium Phosphate (OSP) Products for Bowel Cleansing · Verified 2026-10-13
Phosphate food additives (E338–E343, E450–E452)
Phosphorus
Amount：Phosphate-enhanced processed meats carry 60–100% more phosphorus than fresh meat; one 355 mL cola ≈ 40–50 mg phosphorus as phosphoric acid
Why：Inorganic phosphate is ~90–100% absorbed, far more than plant (20–40%) or animal (40–60%) phosphorus, yet it rarely appears on nutrition labels.
What to do：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.
Sources: KDOQI 2020 Nutrition in CKD Guideline §4 Phosphorus · NKF: Phosphorus and Your Diet · Calvo & Uribarri, Am J Kidney Dis 2013 (phosphorus additives) · Verified 2026-10-13
Active vitamin D (calcitriol / alfacalcidol / paricalcitol)
Potassium & phosphorus
Why：Increases intestinal absorption of both calcium and phosphorus; excess doses raise serum phosphorus and calcium together.
What to do：A prescribed phosphorus-raising factor — never self-increase; when phosphorus runs high, this is often adjusted first.
Sources: KDIGO 2017 CKD-MBD Update · Verified 2026-10-13
Phosphate binders (phosphorus-lowering)
Phosphorus
Why：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.
What to do：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.
Sources: KDIGO 2017 CKD-MBD Update · Renvela label §7 Drug Interactions (mycophenolate) · Verified 2026-10-13
Potassium binders (potassium-lowering)
Potassium
Why：Exchange or adsorb potassium in the gut. Patiromer binds other oral drugs — separate by 3 hours.
What to do：A rescue and maintenance tool, not a licence to eat high-potassium foods freely.
Sources: Veltassa label §7 · Lokelma label · Verified 2026-10-13
Effervescent tablets / electrolyte powders / sports electrolytes
Potassium
Amount：Many electrolyte products contain 200–400 mg potassium per serving; WHO-formula ORS ≈ 780 mg potassium per litre
Why：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.
What to do：For diarrhoea or vomiting call your nephrology / dialysis unit first instead of drinking large amounts of sports drinks or ORS.
Sources: WHO ORS formulation · NKF: Potassium · Verified 2026-10-13
High-potassium herbal / folk remedies (noni juice, aojiru, coconut water, starfruit juice)
Potassium
Amount：Noni juice ≈ 56 mEq/L (~2,200 mg/L) potassium; one green smoothie easily exceeds 800 mg potassium
Why：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.
What to do："Natural" does not mean low in potassium; anything blended into juice is a concentrated potassium drink.
Sources: Mueller et al., Am J Kidney Dis 2000 — Noni juice hyperkalemia · Neto et al., Nephrol Dial Transplant 2003 — Star fruit intoxication · Verified 2026-10-13
Phosphorus-containing supplements (bone formulas, protein powders, mass gainers)
Phosphorus
Amount：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
Why：Protein naturally carries phosphorus (~12–15 mg per g protein) and many formulas use calcium phosphate as the calcium source.
What to do：If supplements are needed on dialysis, choose renal-specific formulas (low phosphorus / potassium, high protein) with a dietitian.
Sources: KDOQI 2020 Nutrition in CKD · USDA FDC 173180 / 174181 · Verified 2026-10-13
Phosphate-containing antacids
Phosphorus
Amount：K-Phos Neutral 250 mg phosphorus per tablet; Phospho-soda ≈ 0.6 g phosphorus per 5 mL
Why：Some antacids are aluminium phosphate; phosphate supplements (for hypophosphatemia) cause hyperphosphatemia in renal impairment.
What to do：Show the OTC package to the pharmacist and mention your kidney disease.
Sources: DailyMed: K-Phos Neutral · Verified 2026-10-13
Sesame / nut / multigrain "health powders"
Potassium & phosphorus
Amount：One bowl of black sesame paste (30 g powder) ≈ 190 mg phosphorus, 140 mg potassium; multigrain rice carries ~3× the phosphorus of white rice
Why：Whole grains, seeds and nuts are concentrated plant sources of phosphorus and potassium; as powders the portion creeps up unnoticed.
What to do：On dialysis, choosing white rice, white noodles and rice vermicelli is a deliberate low-phosphorus strategy, not an unhealthy one.
Sources: USDA FDC 170150 (sesame) / 169722 (wheat bran) · KDOQI 2020 Nutrition in CKD · Verified 2026-10-13