The Claim

Higher protein intake (above 0.8 g/kg body weight/day) is associated with increased urinary calcium excretion by approximately 25 mg/24 hours in healthy adults, and there is no convincing evidence that this increase is linked to a higher risk of kidney stone formation over short-term observation periods.

Source: Protein intake and risk of urolithiasis and kidney diseases: an umbrella review of systematic reviews for the evidence-based guideline of the German Nutrition Society

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
53score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

Eating more protein than 0.8 grams per kilogram of body weight per day increases the amount of calcium lost in urine by about 25 mg per day in healthy adults, but this increase does not appear to raise the risk of kidney stones in the short term.

See the scientific wording

Higher protein intake (above 0.8 g/kg body weight/day) is associated with increased urinary calcium excretion by approximately 25 mg/24 hours in healthy adults, but no convincing evidence links this to higher risk of kidney stone formation over short-term observation periods.

Why this might work

Eating more protein causes the kidneys to filter more blood, which pushes more calcium into the urine. At the same time, the protein breaks down into acids that trigger bones to release calcium into the blood, adding even more calcium for the kidneys to remove. The kidneys handle this without damage, and the extra calcium in urine does not lead to kidney stones in the short term.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Protein intake and risk of urolithiasis and kidney diseases: an umbrella review of systematic reviews for the evidence-based guideline of the German Nutrition Society

    Eating more protein makes your kidneys flush out a bit more calcium in your urine, but this doesn’t mean you’re more likely to get kidney stones — at least not within two years.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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