Salt intake and kidney stone risk in people
What it found
Higher salt intake was linked to more calcium in urine and a greater chance of kidney stones in people.
Cutting back on salt lowered urinary calcium and reduced stone recurrence.
What they found
Studies in people
Calcium in urine
Adding 6 g of salt per day raised urinary calcium by about 40 mg in healthy people. In stone formers, the same extra salt raised it by 80 mg per day.
Citrate in urine
Raising salt intake from 2.9 to 14.5 g per day lowered urinary citrate in a small group of healthy volunteers. Citrate normally helps prevent stones from forming.
Stone risk in women
A large American study following more than 90 000 middle-aged women found that higher salt intake raised the chance of developing stones. Women eating over 10.3 g of salt daily had the highest risk.
Cutting salt lowers recurrence
Male stone formers who followed a low-salt, low animal protein diet for 5 years had about half the rate of new stones compared with those on a low-calcium diet. Cutting salt alone by about 8 g per day corrected high urinary calcium in hypertensive people over 3 months.
Animal and lab studies
Salt sensitivity in rats
Studies in Dahl rats showed that being sensitive to salt changed how the kidneys handled calcium after a salt load, but only in females. This suggests gender may play a role in how salt affects the kidneys.
Other findings
Salt sources in food
In a typical Western diet, processed foods supply 70 to 80 percent of salt. Only under 10 percent comes from salt added at the table or during cooking.
What the authors conclude
- They state that most evidence links high salt intake to a greater risk of kidney stones through increased calcium in urine.
- They suggest that limiting salt may be a useful way to help prevent stones from forming or returning.
- They call for more research into why some people respond differently to salt and how salt affects other conditions that cause kidney stones.
How it was done
Salt is widely known to affect heart health, but its role in kidney stones is less well known. The authors wanted to gather the evidence linking salt to kidney stones and address ongoing debates.
The authors gathered and examined population studies, lab research and diet trials about salt and kidney stones. They also analysed urine test results from 1952 patients at an Italian clinic over 25 years. Some of the trials they reviewed followed people for up to 5 years.
What it can’t tell you
- Population studies that follow people over time can show a link between salt and stones, but cannot prove salt causes them.
- Trials testing lower salt often changed other parts of the diet too, making it hard to separate the effect of salt alone.
- Findings from rats cannot directly show what happens in people.
Who paid
- Authors work at
- University of Parma, Italy; Parma University Hospital, Italy; University of Texas Southwestern Medical Center, USA
The paper
- Title
- Salt and nephrolithiasis
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Ticinesi A, Nouvenne A, Maalouf NM, Borghi L, Meschi T (2016). Salt and nephrolithiasis. Nephrology, dialysis, transplantation. doi:10.1093/ndt/gfu243Free full textPubMed 25031016DOI
Summary written 1 Oct 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error