What Does Phosphoric Acid in Soda Do to the Body?

November 10, 2025 •

4 min read

According to research, excessive soft drink consumption has been associated with lower bone mineral density (BMD), raising concerns about what does phosphoric acid in soda do to the body. This additive's impact extends beyond bones to affect kidney function and dental health, especially with frequent, high-volume intake.

Quick Summary

Phosphoric acid in soda affects the body primarily through its impact on bone mineral density, kidney function, and dental enamel. Excessive intake disrupts calcium balance, potentially leading to weakened bones and kidney strain over time. The acidity also accelerates tooth decay and erosion.

Key Points

Bone Demineralization: High intake of phosphoric acid can disrupt the calcium-phosphorus balance, potentially weakening bones over time due to mineral loss.
Kidney Strain: Excessive consumption of sodas containing phosphoric acid is linked to an increased risk of kidney stones and chronic kidney disease, placing extra burden on the kidneys.
Dental Erosion: The high acidity from phosphoric acid softens tooth enamel, making teeth more vulnerable to erosion, sensitivity, and cavities.
Moderation is Crucial: The potential harm of phosphoric acid is primarily tied to chronic, high consumption, so moderation is key to mitigating risks.
Healthy Alternatives: Sparkling water, kombucha, and naturally flavored water are healthier beverage options that provide fizz without the harmful additives.
Dietary Balance: Ensuring adequate calcium intake is vital, as excessive phosphorus from soda can disrupt the body's mineral homeostasis.
Diet vs. Regular Soda: Both diet and regular sodas containing phosphoric acid can contribute to dental erosion due to their high acidity.

The Function of Phosphoric Acid in Soft Drinks

Phosphoric acid, often labeled as E338, is a colorless, odorless mineral acid used widely in the food and beverage industry. In many sodas, particularly colas, it serves two main purposes:

Flavor Profile: It provides a sharp, tangy taste that effectively balances the high sugar content, preventing the beverage from tasting overly sweet or syrupy.
Preservative Qualities: By creating an acidic environment, it inhibits the growth of mold and bacteria, thereby extending the product's shelf life.

While approved for use by regulatory agencies, the health implications of consuming large quantities of this additive have been a subject of concern and research.

The Direct Impact on Bone Health

One of the most concerning potential health risks associated with high intake of phosphoric acid from soda is its effect on skeletal health. The body maintains a delicate balance of minerals, primarily calcium and phosphorus, to build and maintain strong bones.

Disruption of Calcium-Phosphorus Balance: When excessive amounts of inorganic phosphorus are consumed, it can interfere with the body’s ability to absorb and utilize calcium. To correct this mineral imbalance, the body may release calcium from the bones into the bloodstream.
Reduced Bone Mineral Density (BMD): Over time, this process can lead to a reduction in bone mineral density. Several observational studies have found correlations between high cola consumption and lower BMD, particularly in adolescent girls and postmenopausal women. Some research also suggests an increased risk of fractures in heavy soda drinkers.
Confounding Factors: It is important to note that many studies point out that this effect is likely compounded by the fact that individuals who drink a lot of soda often consume less milk and other calcium-rich beverages.

Potential Strain on Kidney Function

Healthy kidneys are very efficient at filtering excess phosphorus from the blood. However, a constant, excessive load of phosphorus from a diet rich in sodas and other processed foods can place a significant burden on these organs.

Risk of Kidney Disease: Studies have linked the consumption of two or more colas per day with an increased risk of developing chronic kidney disease (CKD). Both sugar-sweetened and diet versions containing phosphoric acid have been implicated.
Kidney Stone Formation: The phosphoric acid can cause urinary changes that promote the formation of kidney stones. The combination of high fructose and phosphoric acid in sodas is thought to encourage this process.

Harmful Effects on Dental Health

Dental enamel, the protective outer layer of the teeth, is highly susceptible to acid erosion. Sodas are notoriously acidic, and phosphoric acid is a key contributor to their low pH levels.

Enamel Erosion: The frequent exposure of teeth to the low pH of soda can cause demineralization, softening and wearing away the enamel. This leaves the underlying, more sensitive dentin exposed.
Increased Sensitivity and Cavities: Eroded enamel can lead to increased tooth sensitivity and, combined with the sugar in regular sodas, creates a perfect storm for bacteria to thrive and cause cavities.

Phosphoric Acid vs. Carbonation vs. Citric Acid


Aspect	Phosphoric Acid	Carbonation (Carbonic Acid)	Citric Acid
Source	Added as an acidulant (E338).	Result of dissolved carbon dioxide gas.	Added acidulant, common in fruit-flavored drinks.
Effect on Bones	Associated with decreased BMD in high doses.	Not directly linked to bone harm in moderation.	Not significantly linked to bone issues.
Dental Acidity	Contributes significantly to low pH and enamel erosion.	Contributes to acidity and enamel wear.	High acidity, contributes to dental erosion.
Flavor Profile	Sharp, robust, and tangy.	Adds a slight tang and effervescence.	Tart, sour, and fruity.
Prevalence in Sodas	Dominant in colas.	Present in all carbonated drinks.	Common in citrus-flavored sodas.

Mitigating the Risks of Phosphoric Acid Consumption

Reducing the health risks associated with phosphoric acid is a matter of moderation and mindful choices. The following strategies can help:

Switch to Healthier Beverages: Consider alternatives like naturally sparkling mineral water, plain water with fresh fruit, kombucha, or coconut water.
Reduce Overall Soda Intake: For most people, occasional soda consumption is not a major health concern. The key is to limit frequent, high-volume intake, as chronic exposure is the primary issue.
Prioritize Calcium Intake: Ensure your diet includes sufficient calcium-rich foods like dairy, fortified plant-based milks, and leafy greens to support bone health.
Protect Your Teeth: Use a straw to minimize direct contact of soda with your teeth. Rinse your mouth with water after drinking soda to help neutralize the acid.

Conclusion

Phosphoric acid plays a functional role in sodas by balancing flavor and acting as a preservative. However, its over-consumption can have significant consequences for the body, particularly affecting bone health through mineral imbalance, increasing the risk of kidney strain and stone formation, and causing dental erosion. While moderate intake is generally safe for healthy individuals, reducing or replacing high-phosphoric acid beverages with healthier alternatives is a prudent strategy for long-term well-being. Being aware of the risks allows for more informed dietary decisions and better health outcomes.

Resources for Further Reading

National Kidney Foundation: Phosphorus and Your CKD Diet
Medical News Today: Soda and kidney stones: Effects and risks
PubMed Central: High Consumption of Soft Drinks Is Associated with an Increased Risk of Fracture: A Prospective Cohort Study in Chinese Adults
ResearchGate: The Impact of Soft Drink Consumption on Bone Health
Fusion Dental & Braces: How Soda Erodes Tooth Enamel

Frequently Asked Questions

Phosphoric acid at the low concentrations used in sodas is not considered toxic. However, it can have adverse health effects over time, especially with excessive consumption, due to its cumulative impact on mineral balance.

Excessive dietary phosphorus, such as that from phosphoric acid, can alter the body's calcium-to-phosphorus ratio. In an effort to maintain proper blood calcium levels, the body may mobilize calcium from the bones.

Sodas with high levels of phosphoric acid, particularly colas, are most commonly associated with adverse effects on bone health. The impact is more significant with high and frequent consumption, especially when it displaces other calcium sources.

While not common, excessive consumption of products with high phosphoric acid content can cause gastrointestinal irritation and stomach upset in some individuals. Those with digestive issues like acid reflux should be mindful of their intake.

While the sugar in regular soda significantly impacts blood sugar, the phosphoric acid itself has a complex relationship with glucose metabolism, often studied in the broader context of metabolic syndrome. Studies on this are complex and inconclusive.

For most healthy individuals, moderate intake as part of a balanced diet is not considered a significant risk. The issue arises from chronic, high consumption, which can disrupt mineral balance and put a strain on the body.

The most effective way is to limit or eliminate sodas, especially colas. Look for healthier beverage alternatives like sparkling water or kombucha and be mindful of other processed foods, like some cheeses and baked goods, that also contain phosphate additives.