For more information about the health effects, please refer to the background paper by Suvi T. Itkonen and Christel Lamberg-Allardt (Itkonen & Lamberg-Allardt, 2023).
Dietary sources and intake. Phosphorus occurs widely in foodstuffs, but the highest content is found in protein-rich foods, including meat, fish, eggs, dairy, legumes, whole-grain cereals, nuts and seeds. Various phosphate compounds are also used as food additives. The average phosphorus intake ranges from 870 to 1800 mg/d (Lemming & Pitsi, 2022).
Main functions. Phosphorus-containing compounds are involved in e.g., ATP synthesis, signal transduction, cell structure, cellular metabolism, regulation of subcellular processes, acid-base homeostasis and in bone mineralization (Itkonen & Lamberg-Allardt, 2023). About 85% of the body’s phosphorus is in bones and teeth, and phosphorus homeostasis is closely linked to that of calcium because of the actions of calcium-regulating hormones, such as parathyroid hormone (PTH) and 1,25-dihydroxy-vitamin D (1,25(OH)2D), at the level of the bone, the gut and the kidneys.
Indicator for recommended intake. Due to tight homeostatic control, no reliable indicator for recommended intake is available. Serum inorganic phosphate reflects short term intake after meal. Surrogate markers such as FGF23 or PTH are also influenced by other nutrients.
Main data gaps. Effects of phosphorus on health may depend on the source from which it is ingested, but methods by which phosphorus bioavailability can be taken into account are lacking. Data on bioavailability and total phosphate content (including additives) in foods is missing and there is a need to conduct studies on phosphorus intake and health outcomes.
Deficiency and risk groups. Phosphorus deficiency is related to metabolic disorders. Although vitamin D deficiency or resistance decreases phosphorus absorption, hypophosphatemia due to low intestinal absorption is rare and only becomes apparent when phosphorus deprivation has continued for a long time, such as in the case of diarrhoea (Itkonen & Lamberg-Allardt, 2023).
Dietary reference values. An AI is set to 520 mg/day (females and males), based on the RI for calcium, as calcium and phosphorus metabolism is closely linked, considering a whole-body molar ratio of calcium to phosphorus of 1.4:1. Provisional AR is set to 420 mg/day (females and males). Values are based on AIs set by EFSA, scaled to the RI for calcium in NNR2023 (EFSA, 2015f). UL for phosphorus is 3,000 mg/d (NNR2012).