Nutrition Diet: Does citrus make urine alkaline?

November 1, 2025 •

3 min read

Despite tasting highly acidic, a metabolic conversion process means citrus fruits actually have an alkalizing effect on urine, increasing its pH. This surprising fact challenges common dietary myths and highlights the complex relationship between a food's initial chemistry and its effect on the body.

Quick Summary

Citrus fruits are metabolically converted into alkaline byproducts that increase urine pH, contrary to their initial acidic nature. The kidneys then filter this alkali load to maintain the body's tightly regulated acid-base balance.

Key Points

Metabolic Conversion: Citrus fruits have an alkalizing effect on urine due to the body's metabolic conversion of their citric acid into alkaline bicarbonate.
Urine vs. Blood pH: The alkaline effect only impacts urine pH, not blood pH, which the body tightly regulates to maintain a narrow, healthy range.
Health Benefits for Kidneys: Increasing urine alkalinity is beneficial for preventing certain types of kidney stones, specifically uric acid and cystine stones.
Citrate is Key: The citrate in citrus binds to calcium, increasing its solubility and inhibiting crystal formation, which is another mechanism against stone development.
Different Citrus Effects: The magnitude of the alkalizing and citraturic effect can vary between different citrus fruits, with some studies showing orange juice has a stronger effect than lemonade.
Dietary Context: The overall balance of a diet rich in fruits and vegetables, rather than isolated food items, has the most significant and positive impact on urinary pH and kidney health.

The Metabolic Switch: How Citrus Becomes Alkaline-Forming

It seems counterintuitive that something so distinctly sour and acidic could produce an alkaline effect within the body. The resolution of this paradox lies in the process of metabolism. A food's effect on the body's acid-base balance, specifically measured by its potential renal acid load (PRAL), is determined not by its taste or raw pH, but by the mineral compounds left behind after digestion.

The Role of Citrate

The key to this process is citrate, a salt of citric acid found in high concentrations in citrus fruits. When consumed, citrate undergoes metabolism in the liver, converting into bicarbonate. This alkaline bicarbonate is then processed by the kidneys and excreted, raising urine pH.

Urine pH vs. Blood pH

While diet can alter urine pH, it has minimal effect on blood pH. The body maintains blood pH within a narrow healthy range of 7.35–7.45 using buffering systems involving the kidneys and lungs. Deviations indicate serious medical conditions. Kidneys regulate systemic pH by filtering excess acid or alkali into urine.

Health Implications, Particularly for Kidney Stones

The alkalizing effect of citrus on urine can be significant for those prone to certain kidney stones, such as uric acid and cystine stones, which form in acidic urine. By raising urine pH, citrus can help prevent these stones. Citrate also binds with calcium, improving the solubility of calcium-based stones and inhibiting crystal formation. The effectiveness varies between different citrus fruits and preparations.

Comparing Different Citrus Juices

Research indicates that various citrus juices have different effects on urine alkalinity and citrate levels.


Feature	Lemon Juice/Lemonade	Orange Juice	Grapefruit Juice	Potassium Citrate Supplement (for comparison)
Metabolic Effect	Metabolized to bicarbonate, increasing urine pH and citrate.	Metabolized to bicarbonate, increasing urine pH and citrate.	Metabolized to bicarbonate, increasing urine pH and citrate.	Directly provides alkali load and citrate.
Effect on Urine pH	Increases urine pH, but less significantly than orange juice in some studies.	{Link: Dr.Oracle https://www.droracle.ai/articles/311745/does-lemon-alkaline-or-acidify-the-urine-}.	Can increase urine pH, but with varied study results.	Very effective at increasing urine pH to a targeted level.
Effect on Urinary Citrate	{Link: Dr.Oracle https://www.droracle.ai/articles/311745/does-lemon-alkaline-or-acidify-the-urine-}.	Increases urinary citrate significantly, sometimes more so than lemonade.	Can increase urinary citrate, but studies are mixed on overall stone risk.	Most effective at increasing urinary citrate levels.
Potential Negative Effects	Contains citric acid which can erode tooth enamel.	High sugar content can contribute to weight gain and potentially increase urinary calcium.	Mixed epidemiological evidence regarding stone formation risk, possibly due to other components or sugar content.	Can cause gastrointestinal side effects and requires careful dosing.

A Broader Nutritional Perspective

Many fruits and vegetables have alkalizing properties. A diet emphasizing high intake of fruits and vegetables is recommended for overall health and beneficial effects on urine pH. The DASH diet, rich in fruits, vegetables, and whole grains, is associated with reduced kidney stone risk.

Alkalizing Foods (High in potassium, calcium, magnesium):

Fruits (e.g., apples, bananas, most berries)
Vegetables (e.g., spinach, broccoli, carrots)
Legumes
Nuts (e.g., almonds)

Acidifying Foods (High in protein, phosphorus, sulfur):

Meat, fish, poultry
Most grains
Cheese and dairy products
Processed foods

Conclusion

In summary, citrus makes urine alkaline due to the metabolic conversion of citrate into bicarbonate, not its initial acidity. This effect is important for those managing certain kidney stones. A diet rich in fruits and vegetables supports a healthy acid-base balance.

Frequently Asked Questions

When consumed, the citrate in citrus is metabolized by the liver into bicarbonate, an alkaline compound. The kidneys excrete this excess alkali, raising urine pH.

No, diet has minimal effect on blood pH. The body's systems, including kidneys and lungs, maintain blood pH in a tight, healthy range (7.35–7.45). Deviations indicate serious medical conditions.

Some studies show orange juice may have a stronger alkalizing effect on urine than lemonade. Both are effective, but individual results vary.

Increasing urine pH with citrus helps prevent stones like uric acid and cystine stones that form in acidic urine. Citrate also inhibits calcium-based stone formation.

Urine pH strips measure only urine pH, not overall body or blood pH. Urine pH fluctuates based on recent diet as kidneys regulate systemic pH.

No, the effect varies based on the type of citrus, citrate content, and preparation (e.g., sugar content).

Most fruits and vegetables are alkalizing (e.g., apples, spinach). A diet high in plant-based foods is generally more alkalizing than diets high in meat, dairy, and grains.