Does Soybean Have Phosphorus? Understanding Mineral Content and Bioavailability

November 14, 2025 •

3 min read

Approximately 70% of the phosphorus in soybeans is bound up as phytate, a compound that significantly impacts how much your body can absorb. While soy is a natural source of phosphorus, the available amount depends heavily on preparation methods and the form of the soy product consumed.

Quick Summary

Soybeans contain phosphorus, but its absorption is reduced by naturally occurring phytic acid. The bioavailability and total amount vary across different soy products, such as edamame, tofu, and fermented items.

Key Points

Yes, Soy Has Phosphorus: Soybeans are a natural source of phosphorus, a key mineral for human health.
Bioavailability is Key: A large portion of soybean phosphorus is bound by phytic acid (phytate), which reduces how much the body can absorb.
Processing Matters: Techniques like soaking, sprouting, and fermenting soy products can increase phosphorus bioavailability by breaking down phytates.
Content Varies by Product: The amount of phosphorus differs significantly between various soy products, with soy protein isolate and concentrate being very high and tofu and soy milk containing less.
Consider Health Needs: People with chronic kidney disease should monitor their phosphorus intake from soy, as excess can be harmful.
Crucial for Plants: Phosphorus is vital for the growth and yield of the soybean plant itself, with deficiency causing stunted growth and discolored leaves.

What is Phosphorus and Why Does It Matter?

Phosphorus is a crucial mineral for the human body, playing a central role in numerous biological processes. As a major component of bones and teeth, it is essential for maintaining a strong skeletal structure. It is also integral to energy production, helping the body convert food into energy through molecules like adenosine triphosphate (ATP). Additionally, phosphorus is part of DNA and cell membranes, and it helps regulate pH balance within the body. Most of the phosphorus in the Western diet comes from dairy, meat, and processed foods, but plant-based sources like soybeans offer a valuable alternative.

The Unique Challenge of Plant-Based Phosphorus: Phytic Acid

When considering if soybean has phosphorus, it's important to understand the role of phytic acid. Phytic acid, or phytate, is a compound in many plant seeds that binds to minerals like phosphorus, iron, and zinc in the digestive tract, reducing their absorption. This means that although a plant food may contain a high amount of phosphorus, the body might not be able to use all of it, a concept known as bioavailability. In soybeans, roughly 70% of the phosphorus is stored as phytate.

How to Increase Phosphorus Bioavailability

Several processing techniques can help reduce phytic acid and improve mineral availability in soy products.

Soaking: Soaking soybeans can activate phytase, an enzyme that breaks down phytic acid.
Germination (Sprouting): Sprouting increases natural phytase activity, which degrades phytates and releases phosphorus.
Fermentation: Fermenting soy into products like tempeh and natto effectively breaks down phytic acid, increasing the amount of bioavailable phosphorus.
Cooking: Boiling can also lower phytate levels, though often less effectively than other methods.

Phosphorus Content in Common Soy Products

The phosphorus content can vary significantly based on how soybeans are processed. The following table shows the approximate phosphorus levels in some common soy items.


Soy Product	Phosphorus Content (per 100g)	Notes on Bioavailability
Soy Protein Concentrate	839mg	Bioavailability varies with processing.
Soy Protein Isolate	776mg	High concentration in processed form.
Tempeh	266mg	Improved bioavailability due to fermentation.
Mature Soybeans	245mg	Absorption can be enhanced through cooking.
Edamame (Immature Soybeans)	169mg	Lower concentration than mature soybeans.
Firm Tofu	121mg	Relatively lower content, impacted by processing.
Soy Milk	Less than 15% DV/serving	Significantly less than other soy products.

The Health Implications of Soybean Phosphorus

For most healthy individuals, consuming phosphorus from soybeans is part of a balanced diet. However, those with specific health conditions, particularly chronic kidney disease (CKD), should manage their intake. In CKD, the kidneys are less able to remove excess phosphorus, which can lead to health complications by affecting calcium balance and hormones. Some processed soy products may contain added phosphate additives, so reading nutrition labels is important for those managing phosphorus intake. Even with lower bioavailability, plant-based phosphorus contributes to total phosphorus load, emphasizing the need for moderation in at-risk individuals. The National Kidney Foundation offers valuable resources on managing phosphorus for kidney health.

Phosphorus in Soybeans: An Agricultural Perspective

Phosphorus is vital for the growth and development of soybean plants. It's crucial for root development in early stages. The plant's need for phosphorus is highest during later vegetative and reproductive phases, with phosphorus moving from leaves to seeds. Signs of phosphorus deficiency in soybean plants include:

Stunted growth and small leaves.
Dark green, bluish, or purple leaf discoloration, starting with older leaves.
Delayed blooming and maturity.
Reduced nitrogen fixation in root nodules. Proper phosphorus fertilization is necessary for optimal crop yield.

Conclusion: The Final Word on Soybean and Phosphorus

Yes, soybeans contain phosphorus, and they can be a useful source, especially for plant-based diets. However, phytic acid affects how much phosphorus is absorbed. Processing methods like fermentation and sprouting improve bioavailability. While generally beneficial, individuals with conditions like kidney disease should be mindful of their intake. Understanding the variations in phosphorus content and bioavailability across different soy products helps in making informed dietary choices.

For more information on mineral absorption, the National Institutes of Health provides resources on essential minerals like phosphorus(https://ods.od.nih.gov/factsheets/Phosphorus-HealthProfessional/).

Frequently Asked Questions

Yes, soy milk contains phosphorus, but the amount is typically lower compared to whole soybeans or fermented products like tempeh and natto.

Yes, much of the phosphorus in soybeans is bound to phytic acid, making it less bioavailable than the phosphorus found in animal sources.

Yes, processing methods like soaking, germinating, and fermenting can help reduce phytic acid, thereby increasing the amount of absorbable phosphorus.

Phosphorus content varies greatly among soy products. Processed items like soy protein concentrates often have higher levels, while tofu and soy milk are generally lower.

Yes, individuals with chronic kidney disease should monitor their intake of high-phosphorus foods, including some soy products, as excess phosphorus can be harmful.

Phytate is a compound found in many plant seeds, including soybeans, that binds to minerals like phosphorus and limits their absorption in the body.

Fermentation, used to make products like tempeh, can break down phytic acid, making more of the phosphorus readily available for absorption.