The Claim

Malic acid supplementation at 1200 mg/day for 7 days in healthy adults does not significantly reduce ionized calcium or calcium oxalate supersaturation, despite increases in urinary citrate and pH, indicating that the net effect on stone-forming potential is uncertain.

Source: Malic Acid Supplementation Increases Urinary Citrate Excretion and Urinary pH: Implications for the Potential Treatment of Calcium Oxalate Stone Disease

What the research says

Supports is higher

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

Supports
30score
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.

Description
1 study reviewed
In plain English

Taking 1200 mg of malic acid daily for 7 days in healthy adults does not lower ionized calcium or calcium oxalate supersaturation, even though urinary citrate and pH increase, so the overall impact on kidney stone risk is not clearly reduced or increased.

See the scientific wording

Malic acid supplementation at 1200 mg/day for 7 days in healthy adults does not significantly reduce ionized calcium or calcium oxalate supersaturation, despite increases in urinary citrate and pH, indicating that the net effect on stone-forming potential is uncertain.

Why this might work

When malic acid is consumed, it gets processed in the body to make the blood slightly less acidic. This causes the kidneys to release more citrate into the urine and make the urine less acidic. Citrate binds to calcium in the urine, which should reduce the chance of calcium oxalate stones forming. However, despite this binding, the amount of free calcium and the tendency for calcium oxalate to form crystals in the urine do not drop significantly, meaning the overall risk of stone formation does not decrease.

Supported mechanismbased on 1 study

What the research says

1 study

  1. Study: Malic Acid Supplementation Increases Urinary Citrate Excretion and Urinary pH: Implications for the Potential Treatment of Calcium Oxalate Stone Disease

    Malic acid made urine less acidic and increased a chemical that usually stops kidney stones, but it didn’t reliably lower the actual substances that form calcium oxalate stones. So we still don’t know if it helps prevent them.

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

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