Kidney Diet Tips

Is Everyone Being Phosphatized by too Much Phosphorus?

You are a phosphorus expert! Right? If you doubt me, identify one person in your family who knows more about high phosphorus foods than you. Phosphorus is part of the kidney education plan. So, don’t be surprised if friends and family start asking you about foods high in phosphorus to limit and avoid.

Phosphorus and Healthy People

There have been a couple of articles in the news about the dangers of too much phosphorus –for everyone! Remember when the low carb diet hit the media or trans fats were a concern? The same thing is about to happen with phosphorus!

Everyone needs some phosphorus in their diet. It helps the body store and use energy, assists with normal bone growth and development, and keeps all of our cells working properly.

However, there is evidence that too much phosphorus may cause health problems in everyone, even those with healthy kidneys.1, 2

Sources of Phosphorus 

Phosphorus naturally occurs in many foods, especially high protein foods like milk products, chicken, beef, eggs, pork. It is also in plant-based foods like beans, nuts and whole grains. These are organic sources of phosphorus. A person with healthy kidneys is able to digest and metabolize organic sources of phosphorus, without difficulty. Part of that phosphorus is absorbed into the blood. The part that is not digested is passed out through the gi tract. Then, healthy kidneys remove extra phosphorus from the blood through the urine.

Another source of phosphorus is phosphoric acid. Phosphoric acid (inorganic phosphorus)  and other phosphorus containing additives are a man-made form of phosphorus. It is absorbed more quickly and at a greater concentration than organic phosphorus.

Phosphate Additives

Phosphoric acid and other phosphate additives are added to baked goods, canned soups and sauces, processed cheese, and thousands of other processed foods. They are even injected into fresh meats like chicken and pork. These additives are used to improve flavoring and color of many foods. The more processed and/or packaged the food, the more phosphate additives it may contain. The problem is that we have increased the amount of processed and packaged foods in our diet. We also eat out more often than ever, and get phosphate additives from restaurant and fast foods. For these reasons, most individuals consume much higher amounts of phosphate additives than they did a decade ago. The biggest increase is from phosphate additives, not from the naturally occurring organic phosphorus.

Let’s consider biscuits as an example. Freezer biscuits are amazing! They are perfectly shaped, bake golden brown and rise to the perfect height. The downside is they contain a lot of additives (phosphoric acid). It is one of the reasons they look and taste perfect.

Biscuit mixes require a little more work but also produce great biscuits. Biscuit mixes include phosphorus containing additives preservatives to keep them stable on the shelf for a year, or more. They also contain baking powder, which is high in phosphorus.

Home-made biscuits require time and effort, but with practice, are just as delicious and perfect as the processed biscuits. The advantage to home-made biscuits is that they are lower in phosphorus compared to frozen or biscuit mixes. However they do contain baking powder, so your dietitian may suggest limiting the number of biscuits you eat.

Limiting Phosphorus

The more food made at home, from scratch, the less phosphorus consumed. We are learning that decreasing phosphorus intake may be important for EVERYONE, not just people with chronic kidney disease or end stage kidney disease.

Experts are concerned about the connection between higher phosphorus blood levels in individuals with healthy kidneys. This is because of an increase in cardiac events including calcification and hardening of arteries. These are high phosphorus problems we used to only see in people with kidney disease. Now we are seeing them more frequently in individuals without kidney disease. In addition, cardiovascular disease is a risk factor for kidney disease.

As you know, phosphorus is a common mineral found in food and in our bodies. Healthy kidneys help get rid of the extra phosphorus consumed, but when kidneys are not working correctly or are unable to get rid of the phosphorus, it begins to build up in the blood and becomes toxic.

We don’t know the total impact of increased phosphorus in people with healthy kidneys, but we can be pretty confident that it is a good idea for everyone to cut back on pre-packaged, convenience foods. In addition, prepare most meals at home using the least processed ingredients possible, and stick to natural organic phosphorus sources!

References:

Serum Phosphorus Levels Associate with Coronary Atherosclerosis in Young Adults; Robert N. Foley, Allan J. Collins, Charles A. Herzog, Areef Ishani, Philip A. Kalra; J Am Soc Nephrol. 2009 Feb; 20(2): 397–404.

Levels of Serum Phosphorus and Cardiovascular Surrogate Markers: A Population-Based Cross-Sectional Study; Jinwei Wang, Fang Wang, Shengyong Dong, Qiang Zeng, Luxia Zhang; Journal of Atherosclerosis and Thrombosis. Vol. 23 (2016) No. 1 p. 95-104.

Shelley Munch, MBA, RDN, LD

Shelley Munch, MBA, RDN, LD

Shelley has been a registered dietitian for many years with over 15 years in renal (Acute, CKD 3-5, Dialysis, Transplant). She is an adjunct professor at Park University and teaches Human Nutrition and Nutrition for Health Sciences for undergraduates. She loves helping people connect what they eat with how they feel. Shelley has a husband and two daughters that keep her running.