The low phosphorus diet has changed a lot since I first started working as a Renal dietitian more than 10 years ago. And it’s so much better now! The renal diet can be a restrictive diet because there are so many factors that are at play- protein, fluids, sodium, potassium, phosphorus. You’re certainly juggling a lot when following a renal diet.
Fortunately, there are new guidelines pertaining to phosphorus which has opened up many food options than previously recommended. In this article we will discuss what phosphorus is, who needs to follow a low phosphorus diet, and what foods to choose when following a low phosphorus diet.
Table of Contents
What is Phosphorus?
Phosphorus is a mineral that is found in various foods. The body stores phosphorus in your bones to keep them strong and healthy. It also helps regulate nerve and muscle function and plays a role in gene formation. Your body uses phosphorus along with calcium and vitamin D to keep bones healthy.
Low Phosphorus Diet and Kidney Disease
People with chronic kidney disease through dialysis (Stage 3-5) need to be mindful of phosphorus in their diet. When kidney function declines, the kidneys can’t remove extra phosphorus to help keep levels normal and phosphorus builds up in the blood.
When there is excess phosphorus in the blood, it causes an imbalance of hormones and pulls calcium from the bones. Without the right amount of calcium in the bones they can become weak and easily breakable.
The calcium that is pulled from the bones is deposited in the soft tissues in the body such as the heart, blood vessels, skin, eyes, and lungs. This causes the tissues to become stiff and blocks blood flow.
This imbalance of minerals and hormones is called CKD Bone and Mineral Disorder. Over time this can cause major health problems such as heart attack, stroke, and broken bones. The good news is you can manage this with diet!
What is a Normal Blood Level for Phosphorus?
A normal blood level for phosphorus 2.8-4.5 mg/dL. You may want to ask your doctor the next time you have labs to draw phosphorus levels and review the results. Sometimes phosphorus isn’t a routine blood test for people in early stages of CKD or it’s not drawn often.
Symptoms of High Phosphorus Levels
Some people don’t have any signs or sypmtoms while phosphorus levels are high. Others may have signs and symptoms, but these may not occur until the disorder has been going on for a long time. Signs and symptoms of high phosphorus levels are:
- Joint and bone pain
- Redness in the whites of eyes
- Itchy skin or rash
- Sores on skin
- Muscle cramps
- Weak bones
How much Phosphorus to Eat?
People with CKD need to consume 800-1,000 mg of phosphorus per day.
Phosphorus Food Sources
There are two types of phosphorus. Foods that contain natural sources of phosphorus are called organic. Foods that have phosphorus added to them are called inorganic.
The phosphorus in these foods contain phytate. Our bodies don’t have the ability to break down and absorb phytate efficiently. About 50% of the phosphorus in these foods will be absorbed in the body causing less of an impact on your phosphorus levels.(2)
Foods that contain organic phosphorus are:
- Beans and legumes
- Whole grains
- Fresh Meats
- Dairy Products
The old low phosphorus diet recommended to avoid some of these foods with organic phosphorus. Since the phosphorus in these foods have low bioavailability, meaning the body absorbs a little bit of this type of phosphorus, they are now great choices! They provide good sources of protein, fiber, and healthy fats as well.
It’s important to note that plant sources of protein and phosphorus like beans, whole grains, nuts, and seeds are less absorbed (10-30%) than animal products like meats and dairy products (40-60%). (1)
This type of phosphorus is added to enhance the foods color, flavor or shelf stability. You can find inorganic phosphorus in processed foods. When they are added to foods, your body has the ability to absorb 90% or more of this type of phosphorus. Inorganic phosphorus will significantly impact on your phosphorus blood levels.
Foods that contain inorganic phosphorus are:
- Bottled teas
- Some sweetened beverages
- Fast foods
- Frozen, breaded foods
- Sports drinks
- Processed cheese- cheese whiz, American Cheese, Velveeta
- Processed Deli meats- bologna, salami, pepperoni, sausage
You can find out if a food has inorganic phosphorus by looking at the ingredients list on the food label. The following are phosphorus additives to avoid. (3)
- Disodium phosphate
- Dicalcium phosphate
- Monosodium phosphate
- Phosphoric Acid
- Sodium hexameta-phosphate
- Sodium Tripolyphosphate
- Tetrasodium pyrophosphate
- Trisodium phosphate
While it’s important to avoid inorganic phosphorus foods, sometimes it’s necessary to take medications with food to help keep your phosphorus levels in range. These medications are phosphate binders. Take phosphorus binders with meals and snacks to help absorb phosphorus in the foods, even the organic phosphorus.
Talk with your doctor to see if these medications are right for you. If you are in the early stages of CKD (Stage 1-3) you may be able to control your phosphorus levels with diet alone. Many people that are in the later stages of CKD (stage 4-5) or receiving dialysis treatments may need to use phosphate binders to keep levels in range.
Some phosphate binders are:
Phosphate binders when taken with food will act like a sponge and absorb the phosphorus found in the food so your body doesn’t absorb it.
The current low phosphorus diet opens up a lot of food choices for those following a renal diet. Choosing fresh, less processed foods will help you keep your phosphorus levels in check. Plant sources of phosphorus have less absorbability than animal and dairy products.
Reading the food label to make sure there are no added phosphates in the foods you’re consuming is important as these foods will impact your phosphorus levels more. Taking phosphorus binders can help keep your phosphorus levels in range for those that need it.