Salt Questions · Health & nutrition
How does salt intake affect kidney function?
Short answer
Your kidneys control the body's sodium balance. A high-sodium diet raises blood pressure, which over time damages the small blood vessels in the kidneys, and is linked to more protein in the urine, a sign of kidney stress. People with chronic kidney disease are usually advised to limit sodium to protect their kidneys and control swelling and blood pressure.
How excess salt can strain the kidneys
- 1High-sodium diet
- 2Blood pressure rises
- 3Kidney blood vessels are damaged over time
- 4Less filtering capacity; more protein in urine
What the kidneys do with sodium
The kidneys filter blood and decide how much sodium to keep and how much to excrete. With a high-salt diet, they must work to excrete the excess, and the body holds more water while they do.
How too much salt can harm them
- High blood pressure is a leading cause of kidney disease, and sodium is a major driver of high blood pressure.
- High sodium intake is associated with more protein leaking into the urine.
- In people with kidney disease, excess sodium worsens swelling, fluid build-up and blood pressure.
If you have kidney disease
The National Kidney Foundation advises limiting sodium and using herbs and spices instead. Be careful with potassium salt substitutes, which can be dangerous in kidney disease; ask your care team first.
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Cite this page
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The Salt Almanac. (2026, November 8). How does salt intake affect kidney function. https://saltalmanac.com/answers/how-does-salt-intake-affect-kidney-function
“How does salt intake affect kidney function.” The Salt Almanac, 8 Nov. 2026, saltalmanac.com/answers/how-does-salt-intake-affect-kidney-function. Accessed [today's date].
“How does salt intake affect kidney function.” The Salt Almanac. Last modified November 8, 2026. https://saltalmanac.com/answers/how-does-salt-intake-affect-kidney-function.
Original sources
- National Kidney Foundation. Sodium and your CKD diet. https://www.kidney.org/kidney-topics/sodium-and-your-ckd-diet-how-to-spice-your-cooking
- American Heart Association. How much sodium should I eat per day? https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/sodium/how-much-sodium-should-i-eat-per-day