Collagen is a type of protein found throughout your body’s connective tissue, including your bones, skin, joints, and ligaments (1).

It’s also found in a variety of protein-rich foods, including meat, fish, and poultry.

Finally, it’s widely available in supplement form and often used to improve skin elasticity, relieve joint pain, and protect against bone loss (2, 3).

However, many people are unsure whether collagen can harm their kidney health or increase their risk of kidney stones.

This article looks at the evidence to determine whether collagen supplements can cause kidney stones.

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Kidney stones are a type of mineral deposit that forms in the kidneys, causing symptoms like pain, nausea, and vomiting (4).

Although several types of kidney stones exist, calcium oxalate kidney stones are the most common (4).

Oxalate is a compound found in many plant foods, including some fruits, vegetables, nuts, and grains (5).

When you eat oxalate-rich foods, the oxalate in them binds to calcium in your digestive tract and is excreted through your stool or urine.

However, large amounts of oxalate passing through to your kidneys can lead to the formation of kidney stones (5).

Inadequate fluid or calcium intake may also contribute to the development of kidney stones by increasing oxalate absorption (5).

summary

Calcium oxalate kidney stones are caused when high amounts of oxalate build up in the kidneys. Consuming more fluids or calcium-rich foods may reduce the risk of kidney stones by decreasing oxalate absorption.

Like other types of animal protein, collagen contains a type of amino acid called hydroxyproline (6).

Hydroxyproline is converted into oxalate in your body, which may increase levels of oxalate excretion in urine (7).

In one older study, consuming 30 grams of gelatin derived from collagen increased urinary oxalate excretion by 43% after 24 hours compared with a control group (8).

Several animal studies also show that consuming high amounts of hydroxyproline could increase oxalate levels in the urine, and therefore, may harm kidney health (9, 10).

Other test-tube and animal studies suggest that these effects could be amplified in those with primary hyperoxaluria, a genetic disorder that affects oxalate metabolism and increases the risk of recurrent kidney stones (11, 12, 13).

However, keep in mind that most of these studies used concentrated amounts of hydroxyproline.

Therefore, it’s unclear how the collagen found in meat or supplements may affect urinary oxalate excretion and kidney stone formation when consumed in normal amounts.

summary

Collagen contains hydroxyproline, which may increase urinary oxalate excretion if consumed in high amounts.

In general, collagen supplements aren’t recommended for those at a high risk of developing kidney stones. That said, consuming collagen in moderation as part of a healthy diet is unlikely to cause kidney stones for most people.

In fact, studies show that reducing your intake of oxalates is not always necessary to prevent kidney stones.

Most research suggests that increasing your calcium intake may be a more effective approach to reduce oxalate absorption and protect against the formation of kidney stones (14, 15).

Ideally, try to consume at least 1,000–1,200 mg of calcium per day to reduce the risk of developing kidney stones (16).

Ensuring that you’re drinking enough fluid each day may also lower your risk of developing kidney stones (17).

However, if you’re prone to developing kidney stones or have a condition like primary hyperoxaluria, you may want to avoid consuming high amounts of collagen from foods and supplements.

To avoid adverse health effects, it’s also a good idea to talk with your healthcare provider before starting to supplement with collagen or making any dietary changes.

summary

Although collagen supplements are unlikely to cause kidney stones for most people when used in moderation, those at a higher risk of developing kidney stones may need to limit their intake.

Collagen is a type of protein found in many foods and supplements.

It contains hydroxyproline, a type of amino acid that’s converted into oxalate in your body, which may increase urinary oxalate excretion.

For those prone to developing kidney stones, it may be better to avoid consuming high amounts of collagen from foods or supplements.

However, for most adults, consuming moderate amounts of collagen as part of a healthy diet is unlikely to cause kidney stones.