What Foods Increase Calcium in Urine? A Nutritional Guide

October 16, 2025 •

4 min read

Did you know that up to 50% of calcium kidney stone formers have hypercalciuria, or excessive urinary calcium excretion? Understanding what foods increase calcium in urine is crucial for managing your dietary intake and reducing your risk of kidney stone formation.

Quick Summary

This guide explores which dietary factors elevate urinary calcium, including high sodium and animal protein. It explains the complex roles of oxalates, phosphorus, and vitamin D, and offers strategies for making better food choices to manage kidney health.

Key Points

Excessive Sodium: High sodium intake significantly increases urinary calcium excretion, often from processed, canned, and fast foods.
Animal Protein's Impact: Excessive animal protein raises urinary calcium and lowers citrate, a natural stone inhibitor.
Phosphorus Additives: Processed food additives containing phosphorus can combine with urinary calcium, forming crystals.
Balancing Calcium and Oxalates: Pair calcium-rich foods with high-oxalate items to bind oxalates in the gut and prevent them from reaching the kidneys.
Vitamin D Supplementation: High doses of vitamin D supplements can increase urinary calcium, especially in susceptible individuals.
Prioritize Hydration and Moderation: The best approach is a balanced diet, ample water intake, and a focus on whole foods over strict elimination of single items.

The Link Between Diet and Urinary Calcium

The kidneys play a vital role in filtering waste and maintaining a balance of minerals in the body. When this balance is disrupted, excessive calcium can be excreted in the urine, a condition known as hypercalciuria. While genetic and metabolic factors can contribute, diet is a major, and often controllable, influence. Several dietary habits, not just single foods, can increase the risk of hypercalciuria and subsequent calcium-containing kidney stones. By understanding these factors, you can make informed choices to protect your kidney health.

The Primary Dietary Culprits for High Urinary Calcium

Excessive Sodium Intake

One of the most significant dietary factors influencing urinary calcium is sodium. High sodium intake directly correlates with increased calcium excretion in the urine. The kidneys regulate the reabsorption of both sodium and calcium. When you consume high amounts of sodium, the kidneys excrete more of it, and this process also causes more calcium to be flushed out. The effect is particularly pronounced in individuals already prone to hypercalciuria.

Common high-sodium foods to watch out for include:

Processed and packaged foods: Canned soups, frozen dinners, and convenience meals.
Fast food and restaurant meals: These often contain very high levels of hidden sodium.
Cured and deli meats: Bacon, ham, and sausages.
Salty snacks: Chips, pretzels, and salted nuts.
Condiments: Ketchup, soy sauce, and salad dressings.

High Animal Protein

Eating large amounts of animal protein, such as red meat, poultry, fish, and eggs, has been shown to increase urinary calcium excretion. This is due to the acid load produced when these proteins are metabolized. The body uses calcium from the bones to neutralize this acid, and the excess calcium is then excreted in the urine. Furthermore, a diet high in animal protein can decrease levels of citrate in the urine. Citrate is a natural inhibitor of kidney stone formation, and its reduction allows calcium crystals to form more easily.

Phosphorus Additives

While phosphorus is an essential mineral, the type of phosphorus found in processed foods can be problematic. Inorganic phosphorus additives, used to enhance flavor, color, and act as a preservative, are much more readily absorbed by the body than natural phosphorus. This can increase the amount of phosphorus in the urine, where it can combine with calcium to form calcium phosphate stones.

Foods with phosphate additives often contain words including "phos" on the ingredient list. Sources include:

Some colas and bottled iced teas.
Processed cheeses and spreads.
Fast food items like chicken nuggets and fries.

The Complex Role of Oxalates and Vitamin D

High Oxalate Foods

Oxalates are naturally occurring compounds in many plant foods. When oxalates are high in the urine, they can bind with calcium to form calcium oxalate crystals, the most common type of kidney stone. However, the relationship is nuanced: eating calcium-rich foods with oxalate-rich foods allows the calcium and oxalate to bind in the gut, preventing the oxalate from being absorbed and reaching the kidneys. A low-calcium diet can actually increase oxalate absorption and contribute to higher stone risk.

Some high-oxalate foods include:

Vegetables: Spinach, rhubarb, beets, potatoes.
Nuts and Seeds: Almonds, cashews, peanuts.
Legumes: Navy beans, soy products.
Other foods: Chocolate, cocoa powder, wheat bran.

Vitamin D Supplementation

While vital for bone health, excessive intake of vitamin D, particularly through high-dose supplements, can increase intestinal calcium absorption and lead to higher urinary calcium excretion, especially in predisposed individuals. In fact, some studies show a significant increase in urinary calcium in patients receiving vitamin D supplements, though results vary depending on the individual's baseline vitamin D levels. For most, a balanced intake from food and moderate supplementation is sufficient without causing issues.

Dietary Strategies to Reduce Urinary Calcium Excretion

Stay Well-Hydrated: The most effective strategy is to drink plenty of fluids, primarily water, to dilute the substances that can form stones.
Moderate Animal Protein: Limit high-animal protein meals and consider incorporating more plant-based protein sources like beans, lentils, and tofu.
Increase Urinary Citrate: The citrate in citrus fruits like lemons and oranges helps inhibit stone formation. Potassium citrate supplements may also be prescribed for some.
Reduce Sodium and Processed Foods: Read nutrition labels to limit sodium intake, especially from highly processed or fast food.
Balance Calcium and Oxalate: Do not cut out dietary calcium. Instead, pair high-oxalate foods with a source of dietary calcium (e.g., cheese with a spinach salad) to help bind oxalate in the gut.

Comparison of Dietary Factors and Their Effects on Urinary Calcium


Dietary Factor	Effect on Urinary Calcium	Effect on Urinary Citrate	Primary Impact on Kidney Stone Risk
High Sodium	Significantly increases	Neutral	Increased risk due to higher urinary calcium
High Animal Protein	Increases	Decreases	Increased risk from higher calcium and lower citrate
High Oxalates (without calcium)	Indirectly contributes to stones	Neutral	Binds with calcium in the kidneys to form stones
Phosphorus Additives	Increases	Neutral	Forms calcium phosphate crystals in the urine
Adequate Fluid Intake	Dilutes	Neutral	Lowered risk due to dilution of stone-forming substances

Conclusion: Prioritizing a Balanced Approach

Understanding what foods increase calcium in urine is not about eliminating single items, but rather adopting a balanced, holistic dietary approach. Focusing on overall eating patterns, such as the DASH or Mediterranean diets, which prioritize fruits, vegetables, and whole foods while limiting processed items and excess animal protein, is more effective than strict elimination. For individuals with a history of kidney stones or other risk factors, consulting with a doctor or dietitian is essential for a personalized prevention plan based on lab results, including a 24-hour urine collection.

For more information on kidney stone prevention, consult the National Kidney Foundation's guide: Calcium oxalate stones.

Frequently Asked Questions

No, drinking milk does not cause kidney stones. In fact, consuming adequate dietary calcium from sources like milk, yogurt, and cheese can help prevent kidney stones by binding to oxalates in the intestines before they can cause problems in the kidneys.

When you consume high amounts of sodium, your kidneys excrete more of it. As the kidneys flush out sodium, they also increase the amount of calcium that is excreted into the urine, which can lead to higher calcium levels and increase stone risk.

Not necessarily. For most people, a strict low-oxalate diet is not required and can be difficult to maintain. A better strategy is to ensure you eat a calcium-rich food with any high-oxalate food to allow the calcium and oxalate to bind in the gut.

A diet low in animal protein often results in lower urinary calcium levels and higher urinary citrate levels, which helps inhibit stone formation. Plant-based protein alternatives like beans, lentils, and tofu are often recommended.

Large doses of vitamin C supplements (over 500-1000 mg/day) may increase the body's production of oxalate, potentially increasing the risk of calcium oxalate stones. It is best to obtain vitamin C from fruits and vegetables rather than high-dose supplements.

Staying well-hydrated is the most important step for preventing kidney stones. Sufficient fluid intake, especially water, helps dilute the minerals in your urine, making it harder for calcium and other substances to crystallize and form stones.

Look at the ingredient list on food labels for words containing "phos," such as calcium phosphate, sodium phosphate, or phosphoric acid. Foods like soda, some dairy products, and processed meats are common sources of added phosphorus.