Phosphorus is located in every cell of the body and is vitally concerned with many metabolic processes, including those involving the buffers in body fluids. Phosphorus is the most abundant element after the calcium in the body. In the human body it is approximately 1% of its total body weight. It is present in every cell, but the most of it is in the bones and teeth (about 85% of total phosphorus).

Physiological role of phosphorus

The roles of phosphorus in the human body:

Building bones and teeth; Use of carbohydrates (sugar) and fat; Protein synthesis; Growth, maintenance and healing of cells and tissues; Serves as a source of energy (in the molecule adenosine triphosphate - ATP and creatine phosphate); Muscle contractions; Kidney function; Regulation of heart rate; Transmission of nerve impulses; Reduces muscle soreness after hard work; Production of genetic material (DNA, RNA); Maintains balance and helps in the utilization of other vitamins and minerals (vitamins of the B group, vitamin D, iodine, magnesium, zinc); Part of the cell membrane (within the phospholipid); Necessary in all the metabolic pathways in the body (energy production, cell division, etc.); A part of many enzymes and hormones; Maintain normal acid-base balance in the body (pH).

Metabolism

Phosphorus enters the body through diet and is absorbed in the small intestine. Any excess of phosphorus is ejected from the body through the kidneys. Regulation of calcium and phosphorus in the blood is regulated by parathyroid hormone (PTH) and vitamin D. Slight decrease of calcium in blood (e.g. in the case of an insufficient intake of calcium in the body) causes the parathyroid glands to increase the secretion of PTH. PTH stimulate translation of vitamin D in the kidney to its active form. Increased levels of calcium in the blood leads to increased intestinal absorption of calcium and phosphorus. Stimulation of PTH leads to reduced excretion of calcium in the urine and an increased excretion of phosphorus.

Food sources of phosphorus

Phosphorus is present in the high-protein foods such as meat, poultry, fish, eggs, dairy products (especially cheese), nuts, beans, bread, chokeberry. Besides them there are grains, potatoes, dried fruit, garlic, soybeans, etc.. Fruits contain mostly small amounts of phosphorus. Phosphorus is also present in a soft drinks but is not balanced with calcium, so soft drinks are not a good source of this element.

Recommended daily allowance

Phosphorus deficiency

Although phosphorus is enough in food its deficiency is mainly due to certain diseases such as diabetes, starvation, and alcoholism. In addition, some diseases can reduce the digestibility of phosphorus (Crohn's disease, celiac disease). Also the lack of phosphorus can be affected by certain drugs (eg, diuretics).

Symptoms of phosphorus deficiency are: Loss of appetite; Anxiety, mental confusion; Bone pain; Brittle bones; Stiff joints; Irregular breathing; Irritability; Numbness; General body weakness; Changes in body weight; Fatigue, exhaustion; Anaemia; Problems with speech; Susceptibility to infections.

In children, occurring more: Slow growth; Poor development of the bone; Weak growth and tooth decay.

Overdose

High phosphorus intake is associated with increased mortality in a healthy United States population. Excess phosphorus in the body occurs frequently and may be more concerned than the lack of it. The excess is most commonly caused by kidney disorders, consuming excessive amounts of phosphorus in food and soft drinks, and if the diet does not have enough calcium. Larger amounts of phosphorus in the body and cause a greater need for calcium.

A high intake of phosphorus leads to: Cardiovascular disease; Non-skeletal calcification of tissues (especially the kidneys, where it creates a kidney stone); Diarrhoea; Poor digestibility of iron, calcium, magnesium and zinc.

Phosphorus in medicine

Due to its side effects of phosphorus can be taken only by the preparation in consultation with a doctor. In fact, too much phosphorus in the body can be toxic and cause various disorders.

Nutritionists recommend a balanced intake of calcium and phosphorus, as excessive intake of phosphorus in comparison to calcium causes the body draws calcium from the bones, leading to osteoporosis and deterioration of the gums and teeth.

Preparations of phosphorus are applied in cases of hypophosphatemia, hypercalcemia and for the treatment of kidney stones (of calcium origin).

Phosphorus products are not recommended (without prior consultation with a doctor) in cases of alcoholism and entering many drugs (e.g. lowering cholesterol, steroids, insulin, potassium preparations, diuretics, drugs to regulate blood pressure, cyclosporine, cardiac glycosides, heparin, ibuprofen and many others).

References

Calvo M.S. and Tucker K.L., 2013, “Is phosphorus intake that exceeds dietary requirements a risk factor in bone health?,” Annals of the New York Academy of Sciences; 1301(1): 29-35. [Web Reference]

Chang A.R., et al., 2014, “High dietary phosphorus intake is associated with all-cause mortality: results from NHANES III,” The American Journal of Clinical Nutrition; 99(2): 320-327. [Web Reference]

Hays V.W. and Swenson M.J., 1985, “Minerals and Bones,” In: Dukes’ Physiology of Domestic Animals, 10^th Ed. p. 449-466.

Malhotra V.K., 1998, “Biochemistry for Students. 10^th Ed,” Jaypee Brothers Medical Publishers (P) Ltd, New Delhi, India. [Web Reference]

Soetan K.O., Olaiya C. O. and Oyewole O.E., 2010, “The importance of mineral elements for humans, domestic animals and plants-A review,” African Journal of Food Science; 4(5): 200-222. [Web Reference]

Takeda E., et al., 2012, “Dietary phosphorus in bone health and quality of life,” Nutrition Reviews; 70(6): 311-321. [Web Reference]