A Guide on How to Remove Phosphorus from Lentils for Better Kidney Health

November 2, 2025 •

4 min read

While plant-based phosphorus is less absorbed by the body than animal-based phosphorus, individuals with chronic kidney disease (CKD) often need to take extra steps to manage their intake. Learning how to remove phosphorus from lentils can make this nutritious legume a safe and beneficial addition to a renal diet.

Quick Summary

This guide explores effective culinary techniques, including soaking, boiling, and sprouting, to reduce the phosphorus content in lentils. It details the steps for each method and explains why these preparation techniques are crucial for managing mineral intake on a kidney-friendly diet.

Key Points

Soaking and Boiling: The most effective way to reduce phosphorus in dried lentils is to soak them for at least 12 hours, discard the water, and then cook them in a large pot of fresh water.
Sprouting for Bioavailability: Sprouting lentils can significantly reduce phytic acid, the compound that binds phosphorus, making the remaining minerals more bioavailable.
Less-Absorbed Phosphorus: Phosphorus from plant sources like lentils is poorly absorbed by the body compared to animal-based phosphorus or artificial additives.
Check for Additives: Always check food labels for words containing “phos,” as these indicate highly-absorbable phosphate additives, which should be avoided on a kidney diet.
Opt for Canned and Rinsed: For convenience, canned lentils can be used, but must be drained and rinsed thoroughly to remove excess sodium and minerals.
Portion Control is Key: Even with proper preparation, controlling portion sizes of lentils is important for managing phosphorus intake on a kidney diet.

Understanding Phosphorus in Lentils

Lentils are a nutritional powerhouse, packed with protein, fiber, and essential vitamins and minerals. However, for people with compromised kidney function, the mineral content, specifically phosphorus, can be a concern. High phosphorus levels in the blood can be harmful to bones and blood vessels. A key factor is the difference in how the body absorbs phosphorus from various food sources. Phosphorus from plant-based foods like lentils is primarily stored as phytic acid (or phytate), which the body absorbs poorly compared to the phosphorus in animal products or food additives. Despite this, specific preparation methods can further reduce the total phosphorus and phytic acid, making lentils a safer choice for those on a strict kidney diet.

Method 1: The Soaking and Boiling Technique

The most common and effective technique for reducing mineral content in legumes like lentils is a combination of soaking and boiling. This two-step process helps to leach water-soluble minerals like potassium and, to a lesser extent, phosphorus, out of the legumes.

Step-by-step guide to soaking and boiling lentils:

Rinse Thoroughly: Start by rinsing your dried lentils under cool, running water. Remove any debris or damaged lentils.
Initial Soaking: Place the lentils in a large bowl and cover them with a generous amount of water. For best results, use a water-to-lentil ratio of at least 5:1. Let them soak for a minimum of 12 hours, or overnight.
Discard Soaking Water: Drain the lentils completely and discard the soaking water. This is crucial as the minerals leach into this water. Rinse the lentils again with fresh water.
Boil in Fresh Water: Put the rinsed lentils in a pot and add a large volume of fresh, low-mineral water. Bring the water to a boil.
Cook and Drain: Continue to boil until the lentils are tender, which typically takes 20-30 minutes, depending on the variety. Once cooked, drain the lentils completely and discard this second batch of water as well.

Method 2: The Sprouting Technique

Sprouting is another excellent method for reducing phytic acid and making nutrients more bioavailable, though it does change the lentil's texture and flavor. Sprouting involves germinating the seeds, which activates enzymes that break down phytic acid.

How to sprout lentils to reduce phytic acid:

Soak: Start by soaking the lentils for 8-12 hours, similar to the first method.
Drain and Rinse: Drain the soaking water and rinse the lentils thoroughly.
Sprout: Place the lentils in a sprouting jar or colander. Rinse and drain them with fresh water twice a day. The sprouts will typically appear within 1-3 days.
Harvest: Once the sprouts reach your desired length, rinse them one last time and dry them before use.

Method 3: Choosing Lower-Phosphorus Lentil Varieties

Some research suggests that certain types of lentils and processing methods result in naturally lower levels of antinutrients like phytic acid. Hulled lentils, for instance, have significantly less phytic acid. Red lentils, which are often sold hulled, are noted in some sources as a lower phosphorus and potassium choice. Cooking hulled lentils can further reduce their phytic acid content and cooking time.

Cooking Methods Comparison

To help you decide the best approach for your needs, here is a comparison of the primary methods for reducing phosphorus.


Method	Effectiveness on Phosphorus	Time Commitment	Impact on Texture/Use	Best For	Considerations
Soaking & Boiling	Moderate reduction; helps leach minerals into water.	Medium (12+ hour soak + cooking).	Softer texture, ideal for soups, stews, and dals.	Cooking with dried lentils for softer results; also helps with potassium.	Requires discarding soaking and cooking water to remove minerals.
Sprouting	Significant reduction of phytic acid.	Long (1-3+ days).	Crunchy, raw texture, suitable for salads and sandwiches.	Maximizing mineral bioavailability and for recipes where a raw texture is desired.	Changes the flavor profile and is not suitable for all recipes.
Using Canned Lentils	Lower initial mineral content due to processing.	Very Low (ready-to-eat).	Consistent texture, ready for immediate use.	Quick meals where time is a factor. Rinsing further reduces minerals.	Check labels for added salt and phosphate additives.

Considerations Beyond Preparation

Reducing phosphorus isn't just about how you prepare legumes; it's a holistic dietary strategy. For individuals with CKD, consulting a registered dietitian is vital to ensure all nutritional needs are met without overburdening the kidneys. It is especially important to focus on minimizing or avoiding processed foods, which often contain highly absorbable phosphate additives.

Dietary tips for managing phosphorus:

Read Labels Carefully: Search ingredient lists for words containing “phos,” such as phosphoric acid or sodium phosphate, which indicate added phosphorus.
Choose Fresh Over Processed: Opt for fresh, unprocessed foods whenever possible, as they are free of artificial phosphate additives.
Control Portion Sizes: Even after preparing lentils to reduce phosphorus, moderation is key. A dietitian can help determine the appropriate serving size for your specific needs.
Rinse Canned Products: If using canned lentils, drain the liquid and rinse them thoroughly with fresh water to remove excess sodium and some minerals.

Conclusion

While lentils naturally contain phosphorus, they are not off-limits for most individuals on a kidney-friendly diet. By employing simple culinary techniques like soaking and boiling, you can effectively reduce the mineral content. Understanding the different absorption rates of plant-based versus additive-based phosphorus also helps contextualize the dietary approach. Combining proper preparation with careful food selection and portion control empowers individuals to enjoy the significant nutritional benefits of lentils while managing their phosphorus intake safely. As always, for personalized advice, a consultation with a healthcare professional or registered renal dietitian is highly recommended.

Authoritative Source

For more information on managing diet with chronic kidney disease, refer to the National Kidney Foundation's guide on phosphorus.

Frequently Asked Questions

No, soaking does not completely remove phosphorus. It is very effective for removing potassium, but phosphorus is less water-soluble. However, soaking and then cooking in fresh water does help to reduce the overall mineral content.

For healthy individuals, the phytic acid in lentils is not a major concern. The body has natural mechanisms to regulate phosphorus levels. The issue is specific to those with impaired kidney function who cannot effectively excrete excess minerals.

Yes, but you should always drain the liquid from the can and rinse the lentils thoroughly under running water. This removes added sodium and some of the minerals that leached out during processing.

Some sources suggest that red lentils, which are often sold hulled, might be a lower-phosphorus option. Processing like decortication (dehulling) can significantly reduce phytic acid content.

Phytic acid is a compound found in many plant seeds, including lentils. It binds to minerals like phosphorus and iron, which reduces their absorption by the body. Soaking and sprouting can help break down this phytic acid.

Sprouting increases the bioavailability of certain nutrients, including phosphorus, by breaking down phytic acid. While this makes them healthier in general, it is important for individuals on a kidney diet to consider the overall mineral content and portion sizes.

Check the ingredient list on the food packaging for words containing “phos,” such as phosphoric acid, calcium phosphate, or sodium phosphate. These additives are a significant source of highly-absorbable phosphorus.