A disorder of phosphorus metabolism caused by a lower than normal concentration of phosphate in the circulating blood. Also known as hypophosphatemia. Manifestations include hemolysis, lethargy, weakness, and convulsions. Causes include fasting, prolonged use of aluminum hydroxide, magnesium hydroxide or aluminum carbonate binding agents, glycolysis and alkalosis, hyperthyroidism, vitamin D deficiency, certain renal tubular diseases (e.g., Fanconi’s syndrome), alcoholism and anti-vitamin D rickets (familial hypophosphatemia). Treatment can be intravenous rehydration and phosphate supplementation, as well as treatment for the cause. Phosphorus is also widely present in food. Rich sources of phosphorus are cocoa powder, cottonseed flour, fish flour, peanut flour, zucchini seeds, pumpkin seeds, rice bran, soybean flour, sunflower, and wheat bran. Good sources are beef, cheese, fish, seafood, lamb, liver, nuts, peanut butter, pork, poultry, and whole grain flour. Fair sources are bread, cereals, dried fruits, eggs, ice cream, milk, most vegetables (vegetable foods) and white flour. Trace sources are fats, oils (oil foods), fruit juices, beverages, fresh fruits (fruit foods), and sugar. Phosphorus is absorbed and excreted in the body in much the same way as calcium (calcium food). The phosphorus in dietary cereals and vegetables is in the form of phytic acid, and the human intestine lacks lactase, so the utilization of phytic acid is low. Therefore, normal adults can absorb about 43% to 46% of the dietary phosphorus, especially in the case of rice as a staple food. When rice and dairy products or rice and small fish as the main food, the absorption rate can be higher, about 47% to 64%. The net absorption rate of phosphorus in the intestine of milk-fed infants is 65% to 75%. Human milk-fed people are more than 85%; the absorption rate of low-phosphorus diets can reach a maximum of 90%. If a large number of cereals are consumed for a long time, adaptations to plant phosphorus formation can increase the absorption rate of phytate phosphorus to varying degrees. Fermentation of pasta facilitates the absorption of phosphorus. The form of phosphorus present in food is not closely related to the phosphorus requirement. Phosphorus in food is present in both inorganic and organic forms, with organic phosphorus including phosphoproteins, phosphose and phospholipids. The amount of inorganic and organic phosphorus varies from one type of food to another. In the case of milk, 70% is inorganic phosphorus. Animal tissues, on the other hand, are dominated by organic phosphorus. Ingested phosphorus, whether in the form of organic phosphorus or inorganic phosphorus, is absorbed in the gastrointestinal tract. Most of the organic phosphorus compounds are absorbed after hydrolysis in the gastrointestinal tract. If food provides sufficient inorganic phosphorus, the body itself can synthesize it into organic phosphorus. Seventy percent of dietary phosphate intake is absorbed in the small intestine, with the greatest absorption occurring in the midsection. Phosphorus absorption requires the presence of both sodium and calcium ions and sufficient metabolic energy. Phosphorus absorption also requires vitamin D. When vitamin D is deficient, inorganic phosphate in the serum decreases. The phosphorus content of different types of food varies. Foods rich in protein, such as meat, fish, eggs, cow’s milk, cheese and hard shelled fruits, contain more phosphorus. Rice supplies about 12 percent of phosphorus. In addition to bone, meat, poultry and fish contain 15 to 20 times more phosphorus than calcium. Only milk, natural cheese, dark green broadleaf vegetables and bone have higher calcium than phosphorus content. Both calcium and phosphorus are higher in cow’s milk than in human milk, and their calcium-phosphorus ratios are very different. The ratio of calcium to phosphorus in cow’s milk is 1.3:1 compared to 2.3:1 in human milk. non-dairy and dairy common foods have a calcium to phosphorus ratio between 0.3 and 0.9. Therefore, the ratio of milk and dairy products in food can affect the calcium and phosphorus ratio of the entire diet. A calcium and phosphorus ratio that is too low can affect the absorption of calcium and too high can affect the absorption of phosphorus. In general, there is no dietary phosphorus deficiency because phosphorus is present in all natural foods.