Phosphorus is the second most abundant mineral in the human body after calcium. It is found throughout the body, essential for the health of every cell and present in tissues like bones, teeth, and blood.
Essential Functions of Phosphorus
Roughly 85% of phosphorus resides in bones and teeth, where it works with calcium to provide structural strength. Beyond skeletal health, phosphorus is a component of adenosine triphosphate (ATP), the body’s main energy-generating molecule. This links it directly to energy production and the metabolism of carbohydrates, fats, and proteins.
The mineral also forms cell membranes as a component of phospholipids. These structures are important for maintaining cell integrity and function. Phosphorus is also involved in the synthesis of genetic material, DNA and RNA, the blueprints for cellular activity. Its functions extend to nerve signaling and muscle contraction, aiding their correct operation. Phosphorus also acts as a buffer, helping to maintain the body’s delicate acid-base balance, important for physiological stability.
Dietary Sources of Phosphorus
Phosphorus is widely available in many foods, making deficiency rare for most healthy individuals. Dairy products are a good source, including milk, cheese, and yogurt. Protein-rich foods also provide significant amounts of this mineral.
Meat, poultry, fish, and eggs are examples of animal-based sources. Specific fish like salmon contain high levels of phosphorus. Plant-based sources include nuts and seeds, such as cashews, along with legumes like lentils. Whole grains also contain phosphorus, though its absorption can be affected by the presence of phytate.
Phytate, or phytic acid, is a compound found in plant foods like whole grains, beans, nuts, and seeds, where it stores phosphorus. The human digestive system lacks the enzyme phytase, which is needed to break down phytate and release phosphorus for absorption. However, food processing methods like fermentation, sprouting, cooking, and baking can help reduce phytate content and increase mineral bioavailability. While processed foods and soft drinks can contain added phosphorus, obtaining it from natural, whole food sources is preferred for overall nutrition.
Maintaining Healthy Phosphorus Levels
For most healthy adults, the recommended daily allowance (RDA) for phosphorus is 700 milligrams per day. Children and adolescents aged 9 to 18 years require a higher intake, around 1,250 milligrams daily. The body tightly regulates phosphorus levels, with normal blood concentrations ranging from 2.5 to 4.5 milligrams per deciliter (mg/dL) in adults.
Low phosphorus levels, known as hypophosphatemia, are uncommon but can cause symptoms like muscle weakness, bone pain, fatigue, and joint stiffness. Severe cases can result in rickets in children or osteomalacia in adults, often linked to vitamin D deficiency that impairs phosphorus absorption. Conversely, excessive phosphorus intake, or hyperphosphatemia, is rare in healthy individuals but poses risks, especially for those with kidney disease. High levels can lead to calcium deposits in soft tissues, including blood vessels, heart, and kidneys, potentially increasing cardiovascular risk. Conditions like severe kidney disease or excessive use of phosphate-containing laxatives can contribute to hyperphosphatemia.