What Is Phosphorus?

Phosphorus is a mineral found in bones and teeth. It is also involved in cell maintenance and helps in the production and storage of energy in the body.

When kidneys are working, they filter excess phosphorus from the blood through the urine to keep the right amount in the blood.

Normal Phosphorus levels in the blood are 2.5-4.5mg/dL and for anyone receiving dialysis, the phosphorus goal is 3.5-5.5mg/dL.

Why is it important to keep Phosphorus levels in range?

Higher levels that are out of range will send signals in the body to balance calcium and phosphorus in the blood so calcium is then pulled from the bones. Over time this activity will make bones weaker and more prone to fractures and breaks.

Where does the calcium go?

The calcium that has been pulled out of the bones is then circulating in the blood with nowhere to go so it starts to deposit in soft tissue including bone joints, skin, arteries, etc. Calcium deposits can cause pain and stiffening in soft tissues where it doesn’t belong and makes blood flow in those areas difficult.

Recommended dietary intake is 800-1000mg of Phosphorus per day.

Meats and dairy sources tend to be higher in phosphorus. The type of phosphorus in your food is important to know because of how much can be absorbed when digested.

There are two types of phosphorus organic and inorganic.

Organic Phosphorus is found in foods naturally (farm to table) that go through little to no processing. These foods contain phosphorus without chemicals. The absorption of phosphorus from plant-based foods and seeds is low, usually less than 50%, while up to 60% of phosphorus found in animal foods may be absorbed.

These foods contain phosphorus naturally:

• Fresh fruits
• Nuts
• Seeds
• Legumes
• Fresh vegetables
• Minimally processed grains
• Meats from the butcher
• Dairy

Leaching Phosphorus Through Cooking

Place meats/chicken/turkey/pork/seafood, etc. in a pot, cover with water and bring to a boil. Pour out the water and then use other cooking or preparation methods as usual to finish the cooking process including baking, grilling, sautéing, stir-frying, etc. It is best to avoid breading these meats using flour, egg and bread crumbs because they will add phosphorus to the finished product.

Inorganic phosphorus or phosphate is added in processing to many commercially prepared foods such as hot dogs, bacon, sausage, deli meats or cold cuts, processed cheese, prepackaged ready to eat convenience foods and snacks, frozen meals, bottled or canned beverages and baked goods. More than 90% of inorganic phosphorus can be absorbed by the body.

Phosphorus additives are used in adding color, improving flavor and increasing the shelf life of processed foods.

Phosphorus additives (chemical phosphorus) in foods can be found in the ingredients list on a food label:

• Dicalcium phosphate
• Disodium phosphate
• Monosodium phosphate
• Phosphoric acid
• Sodium hexameta-phosphate
• Trisodium phosphate
• Sodium tripolyphosphate
• Tetrasodium pyrophosphate

Added phosphorus in prepared foods adds to the amount that kidneys need to filter out to maintain a balance in the blood. When kidneys aren’t working well, less phosphorus is removed from the blood so the levels are then out of balance. Over time higher phosphorus levels will cause damage to the body such as seizures, bone disease, and secondary hyperparathyroidism.

There are medications that may be prescribed to help bind some of the phosphorus in a meal. Known as phosphorus binders, these medications are most effective when taken with a meal. The medication works like a magnet or a sponge attracting extra phosphorus in the stomach and intestines before it is absorbed into the bloodstream. The extra phosphorus bound by the medication is then eliminated out of the body though the colon with a bowel movement. If taken on an empty stomach, some discomfort or upset stomach may occur. As with many other medications it is recommended to take as prescribed.

The main goals for someone receiving dialysis is to stay healthy, feel good and have a good quality of life. The best way to do this is to follow the renal diet for the dialysis modality, either hemodialysis or peritoneal dialysis, take prescribed medications consistently, go to every scheduled dialysis session, stay the full treatment time and continue to see a primary care physician and any other healthcare providers as scheduled.

If kidney transplant is the main goal then the best candidates do all of the above and go to their scheduled transplant team appointments as well.

Professionals such as Dietitians are part of the healthcare team and are specially trained to help patients follow the renal diet. The renal diet can be combined with other diets for preexisting conditions such as diabetes or heart disease and can be adjusted for other dietary needs. Speak with your Dietitian or ask your physician for a referral to a Dietitian to start making dietary changes that will allow you to meet your healthcare goals.

Credit: Marisol Kramer, RD., Pure Life Renal of Stoughton

Educational materials can be found through these accredited sources:

National Kidney Foundation:

https://www.kidney.org/atoz/atozTopic_Brochures

https://www.kidney.org/atoz/content/dietary_hemodialysis

American Kidney Fund:

https://kitchen.kidneyfund.org/

Dialysis Patient Citizens:

https://www.dpcedcenter.org/staying-healthy/nutrition/nutritional-guidelines/

References:

https://www.kidney.org/atoz/content/phosphorus

Organic Phosphorus Versus Inorganic Phosphorus: Empowering Adult Kidney Patients With Nutrition Education Michelle Bump, MS, RD, CSR, LD Journal of Renal Nutrition, Vol 26, No 5 (September), 2016: pp e31-e33

Photo Sources:

https://sites.google.com/site/faiqyosefchem10hp2/role-of-phosphorus-in-the-body?tmpl=%2Fsystem%2Fapp%2Ftemplates%2Fprint%2F&showPrintDialog=1

http://drwolgin.com/osteoporosis/

http://www.nutrientsreview.com/minerals/phosphorus-phosphate.html

What Causes Mineral & Bone Disorder?

Chronic kidney disease causes mineral and bone disorder because the kidneys have lost the ability to balance the mineral levels in the body.  The kidneys stop activating calcitriol (Vitamin D).  These low levels of Vitamin D create an imbalance of calcium in the blood.  The kidney also loses the ability to remove excess phosphorous in the blood resulting in high levels of phosphorus.  This extra phosphorus pulls calcium from the bones, causing them to weaken.  In response to these high levels of phosphorus, the parathyroid gland releases the parathyroid hormone (PTH) in order to pull calcium from the bone and raise calcium levels.  This continuous cycle robs the bones of the much needed calcium, causing them to become weak and brittle.

• Itchy skin
• Bone pain
• Weak bones that break easily
• Blocked blood vessels
• Heart problems
• Anemia
• Nerve problems
• Difficulty fighting off germs 

How do I know if I have mineral and bone disorder?

• You will have blood tests to check your blood levels of calcium, phosphorus, PTH, and vitamin D. These levels are important markers for Mineral & Bone Disorder and once you have started dialysis, will be done on a monthly basis
• Your doctor may order a Bone biopsy. A bone biopsy is a procedure that removes a piece of bone tissue for examination with a microscope. This test shows whether a person’s bone cells are building normal bones.
• Your healthcare provider may order an X-Ray which can show if there is extra calcium in the blood vessels.

Possible Treatment(s) may include:

• Changes to your diet in order to control minerals.  Reducing dietary intake of phosphorus is one of the most important steps in preventing bone disease.
• Vitamins, supplements, and medicines may be prescribed.  Your body also has problems releasing certain hormones, like “active” vitamin D and parathyroid hormone (PTH). “Active” vitamin D helps your kidneys, bones, and intestines balance phosphorus and calcium. Healthy kidneys change the vitamin D you get from sunlight and the foods you eat into “active” vitamin D. But with mineral and bone disorder, your kidneys can’t change vitamin D into “active” vitamin D.
• Also, treatment to control parathyroid hormone (PTH) may be needed. If the parathyroid glands are over-active, they make too much PTH. These glands can be made less active with medicine. In some cases, surgery may be needed if other treatments are not effective. This surgery (parathyroidectomy) removes the parathyroid glands that make PTH.

 Common medicines used to treat mineral and bone disorder are:

• Phosphate binders:  If a lower-phosphorus diet does not control your blood phosphorus, you may need a medicine called a phosphate binder.
• Active vitamin D:  If your vitamin D level is low, you may need a prescription form of active vitamin D.  
• Calcimimetrics:  Your healthcare provider may prescribe another medicine called a calcimimetric to help control mineral and bone disorder. It works differently from phosphate binders and vitamin D.  It is often used when PTH, calcium, and phosphorus levels are too high.

Most people with mineral and bone disorder need a phosphate binder. If you have high levels of phosphorus, your healthcare provider will talk to you about the pros and cons of using phosphate binders and which phosphate binder might be best for you.

Phosphate binders are not all alike. There are many different types and therefore finding the right and most affordable binder should be discussed with your healthcare team.

To work best, your phosphate binders should be taken with food or within 10 to 15 minutes of eating. However, if you forget, be sure to take them even if you are a little late.

You should take phosphate binders as instructed by your healthcare provider or dietitian. Using phosphate binders does not take the place of your lower phosphorus diet. Making low-phosphorus food choices is important.

Note:  This list is not complete and it is important that you get in the habit of reading food labels.  Processed foods and many beverages often contain phosphate additives to enhance quality and increase shelf life. They can contribute large amounts of phosphorus to your diet.  Phosphate additives are almost 100% absorbable.

Foods with phosphate additives tend to raise blood phosphorus levels because this type of phosphorus is easier for your body to absorb than the phosphorus found naturally in foods. Phosphorus additives are in most processed and fast foods. Avoiding these foods will help control your blood phosphorus level.

Keep these tips in mind:

• Many foods have phosphorus.
• Canned foods, frozen foods, or foods that come in boxes may have added phosphorus.
• Read food labels to see if they contain phosphorus additives. You may see words like “sodium phosphate” or “pyrophosphate.” Ask your healthcare provider about any ingredients with “phos” in it.

Special occasions and eating out:

• Ask for sauces and dressing on the side. 
• Limit foods that are “creamed,” “scalloped,” or “au gratin.”
• Choose drinks that are not “colas.”
• Eat smaller amounts.