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Sticking to a Low Phosphorus Diet

One of the biggest concerns that my kidney patients always have is phosphorus and how to stick to a low phosphorus diet. So, let's dig in.

What is Phosphorus and What Does it Do?

Phosphorus is an essential mineral found in protein-rich foods like meat, eggs, poultry, fish, dairy, nuts, legumes, and grains - so, most foods. It is mostly stored in the bones and teeth, but is also distributed through the soft tissues of the body and in blood.

It has a lot of roles, but it plays a big part in keeping our bones healthy and strong, helping our cells to replicate, energy metabolism, and pH balance(1). It does a lot of things.

Kidney Disease and High Phosphorus Side Effects

When the kidneys stop working well, they aren’t able to get rid of extra phosphorus. When this happens, CKD-Mineral and Bone Disorder occurs (CKD-MBD). This can cause an imbalance in phosphorus, calcium, and vitamin D and the bone and mineral cycles.

One of the most significant side effects of hyperphosphatemia (high phosphorus in the blood) is the deposit of minerals into the blood vessels. This can cut off the supply of blood and nutrients to soft tissues in the organs and muscles causing tissue death and poor wound healing(2).

High phosphorus doesn’t usually cause problems immediately (like a high potassium can), but it causes really bad long term problems.

This is why we watch your phosphorus so closely and why your healthcare team gets so serious about it. We’ve seen the awful side effects that develop from having a high phosphorus. And no one wants that for you.

Bioavailability of Phosphorus

Bioavailability is the ability of certain minerals to be absorbed in the body. We may eat a great deal of something, but our bodies may not absorb all of it if it isn't very bioavailable.

Phosphorus Additives

Many additives contain phosphorus to make products more shelf-stable, to improve texture and taste, and to keep powders from caking. Phosphorus additives are found in dark colas (as phosphoric acid) and convenience foods (as varying phosphates). The phosphorus found in these is not bound to anything to keep it from being absorbed. So it is absorbed at about 90%(3).

These products also tend to have a great deal of phosphorus in them. So, not only are they phosphorus-rich, but the phosphorus is very bioavailable. Making them, what I like to call, double-whammy foods.

Animal Based

Phosphorus that comes from animal sources like meat, poultry, fish, dairy, and eggs is bound to protein. This type of phosphorus is a bit harder for the body to absorb, but not impossible. It’s absorbed at about 40-60% Which means that we can expect to absorb about half of the phosphorus that exists in things like milk or chicken(3).

Salmon, avocado, nuts, and eggs sit on a table top.
Minimally processed foods have phosphorus that is less bioavailable and can be part of a healthy renal diet.
Plant Based 

However, much of the phosphorus that exists in plant based foods like beans, nuts, peas, and seeds is in the form of phytic acid. Humans don’t make the enzyme needed to break this acid down. Remaining phosphorus is still not well absorbed by the gut. It is estimated that less than 50% of phosphorus from plant sources is absorbed by humans(3)


Your doctor may have started you on a medication called a phosphorus binder. You may also just hear them called “binders”. Phosphorus binders work by literally binding to the phosphorus in the food that you’ve eaten. Once the medication has been bound to phosphorus in the gut, it passes into the stool without being absorbed. Yay!

The important things to remember about phosphorus binders:

  • Binders only work when you take them. So, let your doctor know if you’re having a hard time tolerating them. There are several different kinds on the market, but your doctor can’t know that you're not tolerating them if you don't say so! 

  • All of the binders in the world can’t make up for a poor diet. The binders can only bind to so much phosphorus. So, phosphorus doesn’t stop mattering just because you have a binder. It’s still important to limit overall phosphorus intake if your doctor has asked you to do so.

So, that's my spiel about phosphorus for this week. It's a pretty complex topic, so if you'd like to know more, just leave me a comment and I'll be happy to elaborate!

And because phos is such a complex topic, I wanted to leave you guys with a little gift! There is a High Phosphorus Foods PDF embedded in this article! Just click on the image above and download it!


Brandy Winfree, RDN smiling at the camera.

I'm Brandy Winfree, RDN.

When I was working in dialysis, I saw so many patients who had no idea that diet plays a HUGE role in kidney health.

I decided then that I needed to pass my knowledge onto people with kidney disease BEFORE they went into kidney failure. Not after.

That's why I became a board Certified Specialist in Renal Nutrition and why I started this blog. 

You deserve to take care of the kidneys that you have now and I want to share my knowledge with you to make that happen.

Are they any topics that you'd like to hear my thoughts on?

Shoot me a message here.

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