Natural phosphate esters are found mainly in protein-rich foods and are broken down slowly in the gut before they are reabsorbed into the body. However, phosphate additives are also present at high levels in many processed foods, including meat products, soft cheeses, flavoured soft drinks, baked goods and canned or frozen vegetables, and these are thought to be absorbed more rapidly.
Intakes of phosphate-containing food additives are estimated to have doubled in the past 20 years, from just under 500 mg a day to 1000 mg a day.
Researchers writing in the journal Deutsches Ärzteblatt International last year called for a ‘traffic light’ labelling system for phosphate additives, considering that its presence in food not quantified on labels, but simply indicated by an E number (E 338 – 442).
They said there is a known correlation between phosphate consumption and organ calcification in renal patients, and a correlation between high blood phosphate levels and cardiovascular disease in healthy people.
“In view of the known connection between dietary phosphate and organ calcification in patients with renal failure, as well as the growing realization that phosphate can damage health even in persons with normal kidneys, one may ask whether concrete interventions in health policy ought to be taken now, even though such steps cannot yet be supported by any findings from prospective interventional trials,” the authors wrote.
In response to this article, the European Commission has requested technical assistance from EFSA by the end of September to assess whether the current maximum tolerable daily intake (MTDI) of 70 mg per kilo of bodyweight, expressed as phosphorus, is still relevant. Current exposure to phosphates is considered to be below this level.
Phosphate-containing additives can legally be added to food as preservatives, acidifying agents, acidity buffers, and emulsifying agents, and phosphate salts are also used in foods to intensify flavours.