Is Gravy Bad for Your Kidneys?

Gravy granules and stock cubes are designed to deliver intense flavour quickly — which means concentrated salt. A single teaspoon of granules can contain 300–500 mg sodium. Most people use 2–4 teaspoons per meal. In addition, manufacturers add phosphate salts (E339–E452) to improve texture, colour and shelf stability. For people with CKD, this double hit of sodium and absorbable phosphate is problematic.

A single standard stock cube (dissolved in 500 ml water) contains 1,500–2,500 mg sodium. Many home cooks use a whole cube in a gravy serving 2–4 people, and then add granules on top. The result is a gravy that can exceed an entire day's renal sodium allowance in one meal. 'Reduced salt' stock cubes are better but still deliver 800–1,200 mg sodium per cube.

Phosphate additives are used in gravy granules, stock cubes and instant gravy mixes to prevent caking, improve flow and enhance browning. These inorganic phosphates (sodium or potassium phosphates, E339–E452) are absorbed at 80–100% in the intestine. In CKD, where phosphate excretion is impaired, this accelerates vascular calcification and secondary hyperparathyroidism. The simplest solution is to avoid all instant gravy products.

1. Roast your meat on a rack so juices collect in the tray.
2. Remove the meat and skim excess fat from the juices with a spoon or fat separator.
3. Place the roasting tray on the hob over medium heat.
4. Add a splash of hot water and scrape the browned bits (fond) from the tray.
5. Mix 1–2 teaspoons of cornflour with cold water to a thin paste.
6. Stir the cornflour mixture into the juices and simmer until thickened.
7. Season with black pepper, fresh rosemary, thyme or a splash of red wine (cooked for 1–2 minutes).
8. Do not add salt, stock cubes or granules.
9. Strain if desired and serve immediately.

• Red wine reduction: simmer red wine with meat juices until syrupy (alcohol cooks off).
• Onion gravy: slowly cook sliced onions in a little olive oil until caramelised, add meat juices and thicken with cornflour. The onions provide sweetness without salt.
• Mushroom gravy: sauté sliced mushrooms, add meat juices and cornflour.
• Apple gravy: add a grated cooking apple to meat juices for natural sweetness — excellent with pork.
• Cranberry sauce (home-made, no added salt): a tart alternative to gravy with turkey.

Restaurant gravy and ready-meal gravies are almost always made with stock cubes, bouillon powder or instant mixes. A typical pub Sunday roast with 'chef's gravy' can contain 1,000–2,000 mg sodium from the gravy alone. If eating out, ask for gravy on the side and use sparingly, or ask if a low-salt homemade gravy is available. Better yet, choose a dry-cooked meat (roast chicken, grilled steak) with a side of mustard or cranberry instead.