Opinion of the Scientific Panel on Dietetic Products, Nutrition and Allergies on a request from the Commission related to the Tolerable Upper Intake Level of Phosphorus

Phosphorus as phosphate is an essential nutrient involved in many physiological processes, such as the cell's energy cycle, regulation of the whole body acid-base balance, as a component of the cell structure (as phospholipids), in cell regulation and signalling, and in the mineralisation of bones and teeth (as part of the hydroxyapatite). Estimates of habitual dietary intakes in European countries are on average around 1000-1500 mg/day, ranging up to about 2600 mg/day. The contribution of food supplements to phosphorus intake is low. Adverse effects of excessive phosphorus intake, such as hyperphosphatemia, leading to secondary hyperparathyroidism, skeletal deformations, bone loss, and/or ectopic calcification have been reported in animal studies. However, such effects were not observed in studies in humans, except in patients with end stage renal disease. Although in acute or short term loading studies an increase in serum parathyroid hormone (PTH) levels has been found, no significant changes could be demonstrated in longer term studies with dosages up to 3000 mg/day (for 6 weeks). In these studies no evidence was found for effects on markers of bone remodelling and the Panel does not consider these to be adverse effects. Similarly, the Panel found no convincing evidence to support suggestions that high phosphorus diets would aggravate the effects of a state of secondary hyperparathyroidism induced by inadequate calcium intakes, or an inadequate vitamin D status. Gastrointestinal symptoms, such as osmotic diarrhoea, nausea and vomiting, have been seen in some healthy subjects taking phosphorus (phosphate) supplements with dosages >750 mg/day. The Panel considered that these are not a suitable basis to establish an upper level for phosphorus from all sources. The Panel concludes that the available data are not sufficient to establish an upper level for phosphorus. The available data indicate that normal healthy individuals can tolerate phosphorus (phosphate) intakes up to at least 3000 mg/day without adverse systemic effects. In some individuals, however, mild gastrointestinal symptoms have been reported if exposed to supplemental intakes >750 mg phosphorus per day. There is no evidence of adverse effects associated with the current dietary intakes of phosphorus in EU countries.