Have you heard about the low phosphorus diet? If you have kidney disease, chances are you have. Phosphorus is something that can be very difficult to control when the kidneys aren’t functioning well. But what exactly is a low phosphorus diet? What is allowed? What’s not allowed?
Let’s talk all about phosphorus and the low phosphorus diet!
Table of Contents
What is Phosphorus?
Phosphorus is an organic compound. It is an essential nutrient for our bones, teeth, DNA, and RNA. It is also required for the cell membrane structure and is part of the body’s main energy source.
Interestingly, phosphorus is also considered a uremic toxin. A review in 2021 identified the connection between phosphorus and a healthy (or unhealthy) gut.
How Does Kidney Disease Affect Phosphorus?
Phosphorus is one of the considerations in discussing a renal diet and kidney disease.
This is because as kidney function declines, so does its ability to safely manage phosphorus levels. In later stages of CKD, phosphorus can tend to rise.
This is for several reasons. One is that the parathyroid hormone (PTH) can increase with kidney disease. It pulls both calcium and phosphorus from the bones and into the bloodstream.
Another reason is that many people with kidney disease eat foods that are, unknowingly, high in phosphorus. For this reason, a low phosphorus diet may be advised.
Phosphorus Levels in the Blood
For kidney disease stages 3 and 4, phosphorus levels should be around 2.5 – 4.5 mg/dL (you can find this in your renal function panel).
For those on dialysis, the goal range has traditionally been to aim for 3.0 – 5.0 mg/dL. However, many people struggle with reaching this goal due to the heavy pill burden that can come with phosphorus binders.
How Much Phosphorus do I Need?
The U.S. Institute of Medicine determined the Estimated Average Requirement (EAR) for adults to be 580 milligrams per day. The Recommended Dietary Intake (RDI) is 700 milligrams per day for adults. For pregnant women and children without kidney disease, it’s recommended to consume 1,250 milligrams of phosphorus daily.
While this may seem high, it’s not. The average American diet is nearly 200% of phosphorus needs.
For those with kidney disease, it’s recommended phosphorus intake is between 700-1,200 milligrams per day. However, what’s most important is where the phosphorus comes from.
What Happens if Phosphorus Gets Too High?
Symptoms of high phosphorus (aka hyperphosphatemia) can include;
- Joint pain
- Muscle pain
- Rash/bumps on the skin
- Red, itchy eyes
What Happens if Phosphorus Gets Too Low?
Symptoms of low phosphorus (aka hypophosphatemia) can include:
- Loss of appetite
- Bone pain
- Fragile bones/Fractures
- Joint pain
- Muscle weakness
But don’t worry about not getting enough. It is rare to have a phosphorus deficiency.
Phosphorus is so commonly found in our diet, it’s a much bigger concern to have too much phosphorus rather than not enough.
Some studies are suggesting even with fully functioning kidneys, the American diet is providing too much phosphorus. This increases the risk of cardiovascular disease, kidney disease, and bone disease.
Phosphorus Absorption Rates
Before we dive into the low phosphorus diet, it’s important to understand the different phosphorus absorption rates.
How much phosphorus is absorbed will depend on what type of phosphorus it is. It will also depend on where the phosphorus comes from. This term is also known as phosphorus bioavailability.
There are two types of phosphorus in the diet: organic and inorganic.
Organic phosphorus is found naturally in foods. You will generally not find this phosphorus listed on the nutrition label as it is not required.
However, some food companies do choose to list it if it is a high source of phosphorus.
Inorganic phosphorus is added to foods, typically as a preservative. Some of the most common phosphorus additives are;
- Phosphoric acid
- Trisodium phosphate
- Dicalcium phosphate
- Disodium phosphate
- Monosodium phosphate
- Sodium hexameta-phosphate
- Sodium tripolyphosphate
- Tetrasodium pyrophosphate
Inorganic phosphorus is absorbed over 80% into the bloodstream. And while you won’t find the milligrams of phosphorus of these foods, it won’t matter as they are highly absorbed regardless.
Phosphorus in Plants, Animals, and Additives
Phosphorus absorption will be different between plants, animals, and additives. With plants, phosphorus is absorbed by less than 40% due to the phytates that are in plants. This prevents phosphorus breakdown and absorption.
With animal foods, phosphorus that is naturally found. This is similar to the human body!
Who Should be on a Low Phosphorus Diet?
Those who are on dialysis will most likely need to follow a low phosphorus diet. Dialysis does help in removing some phosphorus, but not enough.
One hemodialysis (HD) treatment will remove anywhere from 250 to 1,000 milligrams of phosphorus. That means one treatment will only remove at most a days’ worth of phosphorus. This will not be enough as HD is performed three to four times each week.
In peritoneal dialysis, only about 1,300-1,900 milligrams of phosphorus are removed in a week.
For late stages of kidney disease (4-5) not on dialysis, a low phosphorus diet can be helpful. As with many areas of the renal diet, “eating according to your labs” is very much the case.
Who Doesn’t Need to be on a Low Phosphorus Diet?
There are no studies for those in the early stages of kidney disease (1-3) to show a low phosphorus diet is necessary.
The likelihood that those in later stages of kidney disease and following a low-protein diet or very-low protein diet is very low that a low phosphorus diet would also be required. However, as mentioned above, some in the late stages may still need a low phosphorus diet.
After a kidney transplant, a common issue is low phosphorus levels. Many are recommended to eat more foods that are high in organic phosphorus. It’s important to discuss your phosphorus needs with your doctor and transplant team.
Foods High in Phosphorus
Here are some food categories that are higher in organic and inorganic phosphorus.
Foods that are packaged and/or ready-to-eat have a higher chance of containing phosphate additives.
Examples of packaged foods that can include phosphorus are;
- Pastries and baked goods
- Non-dairy creamers
- Jarred sauces
- Puddings (also high in PRAL!)
Many drinks, including sodas, are high in phosphorus. The additive phosphoric acid is commonly added to these sugary beverages. These are often the drinks that cause the most issues with phosphorus because they are so high.
Drinks that are high in phosphorus include:
- Cola sodas including Coke ® products, Pepsi ® products, and RC ® products
- Dr. Pepper ® / Diet Dr. Pepper ®
- AMP Energy Drink®
- Crystal Light®, Classic Orange
- Hawaiian Punch® products
- Starbucks® Doubleshot Energy Drinks
- Lipton® Brisk Iced Sweet Tea, Lemon Tea, and Raspberry Tea
- Vitamin Water ®, Revive Fruit Punch
- Vitamin Water Zero ®, Squeezed Lemonade
- Fruitworks ® beverages
- Mountain Dew ® Code Red
Animal-based foods will include high levels of organic phosphorus and are absorbed anywhere from 60-80%. Examples include;
- Game meats
- Eggs (whole)
These types of foods can also include inorganic phosphorus when enhanced. Some of these examples can include;
- Deli meats
- Frozen meats (like chicken nuggets or meal kits)
- Seasoned/marinated meats
Dairy is another group that can include both organic and inorganic phosphorus. The phosphorus found in dairy products is typically absorbed by about 60-80%.
The foods in this group that have the highest phosphorus content come from hard and processed cheeses.
While considered lower, even an 8-ounce glass of low-fat milk has approximately 250 milligrams of phosphorus.
Cottage cheese is another product that is often encouraged due to its protein content. However, it also comes with 326 milligrams of phosphorus per cup.
Bread that requires leavening from baking powder will be higher in phosphorus than other grains like cereals, rice, and flatbreads.
Baking powder is made with sodium aluminum phosphate. Because of this, bread and bread products that include baking powder will have a higher absorption of phosphorus.
If you use baking soda at home, check out this two-ingredient Homemade Phosphorus-Free Baking Powder from DaVita. Beware of looking for just aluminum-free baking powder as they can contain different phosphorus additives.
Low Phosphorus Diet
Below are the groups and foods that can be included in the low phosphorus diet.
Fruits and Vegetables
In general, fruits and vegetables are not a source of phosphorus. Rather than listing out all the fruits and vegetables you can include in a low phosphorus diet, check out the Renal Diet Grocery List article.
(It may be helpful to see the Low Potassium Diet article if a potassium restriction is part of your diet.)
While whole grains are typically demonized in regards to phosphorus, it’s one of the lowest absorbable phosphorus sources in our diet.
Examples of low phosphorus whole grains include:
- Brown rice
- Wild rice
- Whole wheat bread, bagels, and buns
- Wheat berries
Plant Proteins in the Low Phosphorus Diet
As mentioned above, animal meats and dairy products have a higher phosphorus absorption than plants do.
Since plants are low in phosphorus, this can be a great way to get in protein without the additional phosphorus.
Examples of plant proteins include:
Keep in mind that nuts and seeds are high in nutrients. Generally, a serving of nuts is ¼ cup, and seeds and nut butter are 2 Tbsp. Eating larger amounts of these foods may result in higher phosphorus levels.
Egg whites, when compared to yolks, have a much lower phosphorus content and can still provide protein. These are often encouraged for those on dialysis to provide more protein while keeping phosphorus levels down.
Egg whites may be a part of a renal diet before starting dialysis but will depend on your stage and kidney function. (For example, for someone with late-stage kidney disease on a low protein diet, egg whites likely will not be a daily food.)
Low Phosphorus Drinks
As mentioned above, many drinks are quite high in phosphorus. However, there are absolutely beverages that are low in phosphorus.
Low phosphorus drinks include:
- Black coffee
- Brewed tea
- Certain kinds of milk
- Ginger ale and ginger beer
- Sprite ® / Diet Sprite ®
- Orange soda
- Barq’s ® Root beer
- Cream soda
- Fruit juices
- Nestea ® Diet Lemon, Honey Lemon Green Tea, Lemon Sweet, and Raspberry Teas
- Mello Yello ®
- Minute Maid ® bottled beverages
- Fanta ® beverages
- Mountain Dew ®
- 7up ®
How to Read Labels for Phosphorus
When reading the ingredients list on the back of a food label, look for P-H-O-S, as highlighted above.
The higher it is on the list, the more there is in that item. But that doesn’t mean you can ignore it if it’s at the bottom!
Hard to read the ingredient list? They can be small, long, and tough to get through. Try starting from the bottom of the list and working your way up. Phosphates are not the main ingredient, so they’ll usually be seen towards the bottom.
Tips and Tools for Phosphorus Label Reading
While label reading can be tough, here are some tips to help make it easier and faster!
Use Your Smartphone
Can’t read the list of ingredients? Use your camera on your phone! Snap a quick picture of the ingredients, then zoom in on the picture.
Did you know that renal dietitian Greta Hensler of Lorelei Nutrition has made an app that helps find phosphorus in foods?
While only available for Apple right now, it should soon be available for Android! Click here to download.
Computer Search Feature
Lookup a food online first, then hit either CONTROL and the F key (on a PC) or COMMAND and the F key (on a Mac). Type in those key letters – PHOS – and let your computer look for you!
I talk a bit more about how to do this in my Fast Food That’s Okay for Kidney Disease article.
But what about when I go out to eat?
Phosphorus is rampant in fast food and restaurant meals. It’s here that the most caution is advised. But there are ways to make fast food more kidney-friendly and to even follow a low phosphorus diet.
Read more details and examples in my article about fast food and kidney disease.
Does boiling work to lower the phosphorus of food?
Boiling can reduce the phosphorus content of food, similar to the way it reduces potassium. A study from the Journal of Renal Nutrition found that phosphorus reduction is seen in the chart below.
|Type of Food||Phosphorus Reduction Range after Boiling|
|Meats||38.5% (+/- 22.5%)|
|Flours||70.5% (+/- 13.5%)|
It’s important to note that many of the vegetables tested in this study did not have phosphorus levels checked. Of the 16 vegetables tested, only 7 had phosphorus reductions noted. (The primary focus in the vegetables was potassium reduction.)
Boiling meats may be an option to help lower both phosphorus and potassium. However, this method is extremely time-consuming and labor-intensive. This may not be a long-term solution in a low phosphorus diet.
What if My Phosphorus is Still High Even with a Low Phosphorus Diet?
Depending on your kidney disease stage, you may need to talk with your doctor about a phosphorus binder.
This is a prescribed medication that works in your stomach and GI tract to bind to the phosphorus in your meal and is excreted in your feces. Therefore, it is not absorbed into your blood and keeps your limits lowered.
Phosphorus binders can come in capsules, tablets, chewable, liquid, and powder forms. Talk with your doctor and dietitian about which phosphorus binder is best for you.
The Bottom Line
Low phosphorus is not necessary for the early stages of kidney disease but can be important for later stages. If following a low protein diet, your phosphorus levels may already be better controlled as many foods high in protein are also high in phosphorus.
Those on dialysis will likely need to follow a low phosphorus diet, but it doesn’t mean staying away from foods like peanut butter!
Include fruits, vegetables, and whole grains which are all naturally low in phosphorus. Nuts, seeds, and even plant proteins like tofu can also be included in a low phosphorus diet.
Limit high phosphorus foods like processed foods, animal products, and some bread and baked goods. Work with your dietitian to include your favorite foods while still keeping phosphorus levels controlled.
If you cannot keep your phosphorus levels below 4.5 mg/dL, ask your doctor about phosphorus binders to take with meals. This can help protect your bones, heart, and brain.
It’s Your Turn!
Take a look at your pantry, fridge, and freezer. Are you finding foods with added PHOSphates? Help yourself and others stick to a low phosphorus diet! Comment below to share your finds.