Salt intake and kidney stone risk
What it found
Higher salt intake is linked to more calcium in urine, a key risk factor for kidney stones, and cutting salt may lower that risk.
The evidence comes from population studies, lab work and diet trials in people.
What they found
Studies in people
Salt raises urinary calcium
Many studies in people show that eating more salt increases the amount of calcium in urine. A rise of 6 g/day in salt intake may increase urinary calcium by 40 mg/day in healthy people and by 80 mg/day in stone formers.
Stone formers eat more salt
People who form calcium stones tend to eat more salt and salty foods like sausages and ham than healthy people. Those with idiopathic hypercalciuria eat even more salt than stone formers with normal calcium excretion.
Salt lowers urinary citrate
A rise in salt intake from 2.9 to 14.5 g/day lowered urinary citrate in a small group of healthy volunteers. Citrate helps prevent stones.
Cutting salt lowers calcium
Intervention studies in people found that reducing salt intake lowers urinary calcium. In one study, a 7.7 g/day reduction in salt intake cut calcium excretion by 109 mg/day after only 3 days.
Less stone recurrence
A 5-year trial in men with idiopathic stones found that a low-salt, low-animal-protein diet led to fewer stone recurrences than a low-calcium diet with unrestricted salt.
Animal and lab studies
Salt-sensitivity in animals
Studies in Dahl rats showed that the calcium response to salt is influenced by salt-sensitivity only in females, suggesting gender-related factors may affect how the kidneys handle calcium.
What the authors conclude
- They conclude that most scientific evidence suggests excessive salt intake is associated with a higher risk for hypercalciuria and thus for idiopathic nephrolithiasis onset or recurrence.
- They advise that limiting salt intake may be an effective preventive measure.
- They call for further research to address open issues and to raise awareness of the harmful effects of salt in this setting of human pathology.
How it was done
The authors wanted to review what is known about how salt intake affects the formation and recurrence of kidney stones, and to address the main controversies in this area.
They reviewed epidemiological studies, laboratory experiments and intervention trials that looked at salt intake, urinary calcium and other stone risk factors. They also analysed urine from 1952 patients at their kidney stone clinic and compared stone formers with healthy controls.
What it can’t tell you
- Many of the studies in people followed them over time or asked about their diets, so they can show a link between salt and stones but not prove that salt causes stones.
- The animal studies cannot show what happens in people.
- The review notes that the complex interplay between salt and other dietary factors is far from fully understood.
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 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error