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What is Phosphorus?

Phosphorus is a mineral found in the natural world and the human body. The body needs phosphorus for many important functions. Most people obtain enough phosphorus from their diet, but some people can have a phosphorus deficiency, leading to low phosphorus levels or excess amounts of this mineral in their bodies. Both low and high phosphorus levels can cause health problems.

The Role of Phosphorus in the Natural World

Most of the phosphorus humans use comes from mining. About 70% of the world’s phosphate rock reserves are in Morocco in the earth’s crust, soils, and sedimentary rocks. It is used in fertilizers for food production and animal feed and to make phosphorus additives for human consumption.

Interesting Facts About Phosphorus

• After calcium, phosphorus is the second most abundant mineral in the body.

• About 85% of the body’s phosphorus is in the bones and teeth.

• A balance of calcium and phosphorus in your diet is necessary to maintain good health.

• Most people have sufficient dietary phosphate intake and don’t need to take dietary supplements for more phosphorus. 

• Too much phosphorus in the body can be toxic.

The Significance of Phosphorus in Bodily Functions

Phosphorus is a key component of the genetic building blocks in the human body. Alternating sugar and phosphate molecules form the structural framework of DNA and RNA molecules. DNA carries genetic information, which is passed on to the next generation. The information in DNA is read to make RNA and proteins for the human body to function. 

Phosphorus and Your Health

Phosphorus is one of the two main minerals — the other is calcium — needed to form hydroxyapatite, the substance that gives structural strength to bones. The body, therefore, needs phosphorus and calcium to build healthy bones and teeth. 

Phosphorus plays a key role in energy transfer across cell membranes in the body. It is an essential part of adenosine triphosphate (ATP). ATP is a source of readily available energy and energy storage at the cellular level. 

Other functions of phosphorus in the body include the following:

• Filter out waste in the kidneys. 

• Repair of tissues and cells.

• Reduce muscle pain after workouts.

• Balance other minerals and nutrients such as zinc, magnesium, iodine, vitamin D, and other vitamins.

Bone Health and Phosphorus: Why It’s Central to Calcium Absorption

Calcium and phosphorus levels in the body are tightly controlled and correspond closely with each other. In many Western diets, phosphorus intake is high, but calcium intake can be low. 

Studies have found that phosphorus has a dose-dependent effect on certain hormones like parathyroid hormone (PTH), meaning that the diet directly affects PTH levels. 

PTH is a hormone that leads to bone breakdown and calcium release from the bones. The intake of extra phosphorus reduces PTH levels when calcium levels are low. Therefore, very high phosphorus levels in the body can hurt bone health by decreasing bone formation and increasing bone breakdown. Learn more: Hypoparathyroidism: Symptoms, Causes, & Treatments.

The relationship between the two minerals is complex. Calcium from foods and supplements can bind to dietary phosphorus and prevent absorption. If calcium intake increases without a corresponding increase in phosphorus intake, phosphorus absorption decreases, which can lower phosphorus levels in the body.

Because of how phosphorus and calcium levels interact, it’s important to take phosphorus supplements only under the supervision of a healthcare provider.

How Much Phosphorus Do You Need?

The recommended dietary allowances (RDAs) for phosphorus are as follows:

• Age 0 to 6 months: 100 milligrams (mg) daily

• Age 7 to 12 months: 275 mg daily

• Age 1 to 3 years: 460 mg daily

• Age 4 to 8 years: 500 mg daily

• Age 9 to 18 years: 1,250 mg daily

• Age 19 years and older: 700 mg

According to the National Institutes of Health and Food and Nutrition Board, the tolerable upper intake level is 4,000 mg daily for adults up to age 70 and 3,000 mg daily for older adults (age 71 and above). The tolerable upper intake level is the maximum daily amount of phosphorus unlikely to cause harm.

Sources of Dietary Phosphorus: Where to Find This Crucial Mineral in Your Diet

Protein-rich foods are also good sources of phosphorus, for example:

• Meat (beef, pork)

• Fish (salmon)

• Poultry

• Eggs

• Dairy products (milk, yogurt, cheese)

• Nuts and seeds

• Legumes

• Whole grains

• Potatoes

• Dried Fruit 

• Garlic 

In addition, phosphorus is found in food additives, for example:

• Carbonated beverages, flavored waters, iced teas, bottled coffee drinks, sports drinks

• Processed foods such as baked goods, frozen foods, deli meats, sausages, bacon

Natural food sources contain organic phosphorus, which is incompletely absorbed by the gut. Phosphorus from animal foods is absorbed more efficiently than that from plant foods. 

When phosphorus is added to processed food, the additive is inorganic phosphorus, which is completely absorbed. 

Signs and Symptoms of Phosphorus Imbalance

Normal Serum Phosphorus Concentration

Normal blood phosphorus levels are between 2.5 and 4.5 milligrams per milliliter (mg/dL). Levels below 2.5 mg/dL are called hypophosphatemia (low phosphorus levels). Levels above 4.5 mg/dL are called hyperphosphatemia (high phosphorus levels).

Note: Most of the phosphorus in the body is stored in bone and teeth. Therefore, blood phosphate levels do not reflect the total amount of phosphorus in the body. 

Low Levels of Phosphorus: Causes, Symptoms, and Management

Causes

The most common causes of phosphorus deficiency are:

• Kidney problems that cause excess phosphorus elimination through urine.

• Hyperparathyroidism (excess parathyroid hormone PTH), which decreases the retention of phosphorus in the kidneys.

• Overuse of antacids that bind phosphorus.

• Refeeding syndrome in people with severe malnutrition, where the sudden reintroduction of nutrients and calories results in rapid changes in electrolytes and fluids.

Symptoms

Symptoms of a phosphorus deficiency can include:

• Poor appetite

• Signs of anemia or low red blood cells (weakness, tiredness, problems concentrating, headaches, irritability)

• Muscle weakness

• Bone pain

• Weak bones

• Confusion

• Falling sick frequently due to an increased risk of infections

Management

The management of low phosphorus depends on the severity of the condition. To correct phosphate levels, your healthcare provider may recommend eating foods high in phosphorus. A high-phosphorus diet is usually enough to ensure adequate intake for most people. However, some people may be prescribed phosphate supplements or IV (intravenous or into the vein) phosphate replacement for severe hypophosphatemia.

High Levels of Phosphorus: Understanding the Risk Factors and Prevention

Causes

Hyperphosphatemia (high blood phosphorus levels) is not common. In healthy people with normal kidney function, excess phosphorus leaves the body through the urine. 

Hyperphosphatemia can potentially occur due to taking too many phosphorus supplements. If taken correctly, the amount of phosphorus in dietary supplements is unlikely to cause toxicity for generally healthy people, so read supplement labels carefully.

Symptoms 

Some people with high phosphorus don’t have any symptoms. In others, it can lead to calcium leaking from the bones, weakening them. High phosphorus levels can also result in calcium deposits in the blood vessels, heart, lungs, eyes, and soft tissues. Over time, this can increase the risk of heart attack, stroke, and death. 

Management

If your phosphate levels are high, your doctor may prescribe medications called phosphate binders to take with meals and snacks. These medications reduce the amount of phosphorus absorbed by your body from food. Phosphate binders come in the form of pills, chewable tablets, liquids, and powders. Some of the phosphate binders also contain calcium. 

The Impact of Kidney Function on Phosphorus Levels

Phosphorus levels in the body are closely related to kidney function. In healthy people, the kidneys remove extra phosphorus from the body. In people with chronic kidney disease, the kidneys are unable to do so properly, leading to high phosphorus levels in the body.

Managing Phosphorus Intake: Strategies for Balancing Your Diet

Foods High in Phosphorus: Identifying Rich Sources

If you have high phosphorus, your doctor may recommend dietary phosphorus restriction (limiting the maximum daily phosphorus intake through diet). Remember that phosphate additives are common in fast food and other processed foods, such as ready-to-eat meals as well as canned foods. Beverages such as dark colas, chocolate drinks, and canned iced teas also have high phosphorus content. These foods also contain saturated fat and are bad for your health overall. Avoiding these unhealthy foods can help to lower your daily phosphorus intake. Look for sodium phosphate, sodium polyphosphate, phosphoric acid, and phytic acid on the nutrition labels.

Phosphorus Supplements: When Are They Necessary?

Most people have sufficient dietary phosphate intake. However, some people with low phosphorus may need to take dietary supplements. Always check with your doctor before starting any nutrient intake in the form of supplements. As explained above, phosphorus and calcium metabolism are interrelated, and too much or too little phosphorus can cause electrolyte disorders and health problems. 

Foods and Substances That Affect Phosphorus Absorption

Large amounts of calcium in foods and supplements can bind to dietary phosphorus and prevent its absorption. In addition, drug interactions can affect how the body absorbs phosphorus from foods:

• Alcohol can pull phosphorus from bones and cause low levels.

• Antacids can bind to phosphate and prevent the absorption of this mineral from the gut. 

• Anticonvulsants can increase the levels of an enzyme called alkaline phosphatase, which removes phosphate from the body. 

• Bile acid sequestrants can decrease the absorption of phosphates from diet and supplements. 

• Corticosteroids can increase phosphorus elimination in urine.

• Insulin can lower phosphorus in people with a condition called diabetic ketoacidosis.

• Angiotensin-converting enzyme (ACE) inhibitors (blood pressure medications) can lower phosphorus levels. 

• Other drugs can lower phosphorus levels, including the immunosuppressant drug cyclosporine, heart medications such as digoxin (Lanoxin), blood thinners like heparin, nonsteroidal anti-inflammatory drugs (NSAIDs), and salt substitutes containing potassium.

Taking phosphorus supplements with potassium supplements or potassium-sparing diuretics can result in hyperkalemia (too much potassium in the blood). High potassium can lead to life-threatening heart rhythm abnormalities. 

The Risks Associated with Phosphorus: Deficiency and Excess

Chronic Kidney Disease and Phosphorus: How They Are Connected

Kidneys regulate phosphorus in the body. When adequate amounts of the mineral are present, the kidneys get rid of extra phosphorus through urine. In people with chronic kidney disease (CKD), the kidneys are unable to eliminate extra phosphorus, which can result in blood phosphorus levels rising to harmful levels. 

Studies have found that higher phosphate blood levels can make the progression of CKD more rapid. High serum phosphorus is also associated with an increased risk of cardiovascular disease, bone disorders, and death. 

Nonetheless, it is unclear if lowering phosphate blood levels can improve health outcomes in CKD patients. Health professionals may make dietary recommendations depending on the severity of CKD and blood phosphorus levels. They may prescribe medications such as phosphate binders to reduce the amount of phosphorus absorbed from food in the gut.

Phosphorus Deficiency and Its Effects on the Body

A phosphorus deficiency in the body can occur in certain health conditions such as alcoholism, diabetes, and malnutrition. It can also be seen in people with conditions that make it hard for the body to absorb gut nutrients, such as Crohn’s disease and celiac disease. Low phosphorus is also common in preterm infants. Rarely, genetic disorders that affect the body’s ability to absorb or store phosphorus can result in low levels of this mineral. Your doctor can diagnose a deficiency of phosphorus with a blood test. They may order further tests to find out the cause.

Left untreated, low phosphorus levels can lead to weak bones (rickets in children and osteomalacia in adults). Other symptoms in phosphorus-deficient individuals may include loss of appetite, anemia, muscle weakness, increased infection risk, numbness and tingling, poor balance, and confusion.

Dangers of Excess Phosphorus: From Cardiovascular Risks to Bone Health

Extra phosphorus in the body can be dangerous. It can result in calcium leaking out of the bones, resulting in weak bones. Excess phosphorus can bind to calcium and form deposits in various tissues in the body, including the blood vessels and heart. Deposits can lead to an increased risk of heart attack, stroke, and cardiovascular mortality.

Conclusion: A Balanced Approach to Phosphorus

The Importance of Phosphorus in a Healthy Diet

Phosphorus is an essential mineral that is key to many bodily functions. Too little or too much phosphorus in the body can cause serious health problems. Dietary calcium and other medications can affect how phosphorus is absorbed in the gut. 

The recommended dietary allowance for most adults is 700 mg daily of phosphorus. Most people have sufficient phosphorus intake in their food supply. The mineral is present in both plant and animal proteins. Generally speaking, Western diets tend to be high in phosphorus. However, some people may need to take phosphorus supplements, which should always be under the supervision of a healthcare provider. 

Tips for Maintaining Optimal Phosphorus Levels

If you have early-stage or moderate chronic kidney disease (CKD), your healthcare provider may recommend limiting your intake of dietary phosphorus. You can accomplish this by choosing natural whole foods rather than processed foods that typically have high amounts of food additives, including phosphorus additives.

Further Research and Consultation with Healthcare Providers

A registered dietician can create a meal plan that will help you meet your phosphorus needs based on the recommended dietary guidelines for your age, health status, and personal preference. A meal plan can ensure you get all the nutrients you need while following your doctor’s recommendations for dietary phosphorus intake.