Kidney stones form in the kidneys. Pain occurs when stones move into ureters, thin tubes that allow urine to pass from kidneys to bladder.
This large, prospective, cohort study found that consumption of red meat and poultry increased risk of kidney stones, while fresh fruit decreased risk.
Diet And Risk Of Kidney Stones In The Oxford Cohort Of The European Prospective Investigation Into Cancer And Nutrition (EPIC), Nutritional Epidemilogy, 2014
In conclusion, compared to meat-eaters, vegetarians are at a lower risk of being hospitalised for kidney stones. Among meat-eaters, increasing meat intake is associated with a higher risk of developing kidney stones. Conversely, a high intake of fresh fruit, fibre and magnesium may reduce the risk.
Also:
There were no associations between dietary intake of sodium or calcium and kidney stone risk.
Mechanism:
It has been proposed that metabolism of a high protein diet may result in an increased stone risk by producing an acid load that increases urinary calcium and oxalate levels and decreases levels of citrate (an inhibitor of calcium stone formation).
I suspect the mechanism is ingestion of animal collagen and its unique modified amino acid hydroxyproline.
Holmes et al, 2007. Origin of urinary oxalate. In Renal Stone Disease (Vol. 900, pp. 176-182).
“A 10-fold differential in the amounts of glycolate and oxalate formed from hydroxyproline and glycine apparently occurs regardless of the subcellular compartmentation of the site of glyoxylate formation (mitochondria for hydroxyproline and peroxisome for glycine).
The metabolism of hydroxyproline can potentially make an important contribution to oxalate synthesis as collagen turnover leads to the metabolism of 240 to 420 mg of hydroxyproline each day. Hydroxyproline may be also ingested either as collagen in meats and meat products or as gelatin. We have recently shown that the ingestion of gelatin leads to significant increases in urinary oxalate and glycolate excretion.”
Gelatin! From Wikipedia:
That’s a lot of foods. It makes it worth scanning the ingredient list.