Phosphate

It’s found in the cheese that makes a burger so irresistible, in cola, and in instant pudding mixes: With artificial phosphate, the food industry makes its products last longer. Doctors, however, are sounding the alarm — this additive may increase the risk of cardiovascular disease.

Gobbledegook on the label: E339, E340, E341, E450, E451, E452. These codes stand for food additives — more precisely, for artificial phosphates permitted under EU legislation. But these phosphate additives are far from harmless. Physicians warn that people with chronic kidney disease in particular should be cautious with phosphate.

When kidney function is impaired, phosphate is no longer filtered out properly. As a result, its concentration in the blood rises sharply, placing excessive strain on the cardiovascular system. According to studies, this significantly increases the risk of death among people with kidney disease.

By now, medical experts are also warning healthy individuals about excessively high phosphate levels in the blood.

Even healthy people should be cautious with artificial additives, write physicians led by Eberhard Ritz from the Renal Centre at Heidelberg University Hospital in a review article recently published in the Deutsches Ärzteblatt. Ritz and his colleagues — Kai Hahn, Markus Ketteler, Martin Kuhlmann and Johannes Mann, all kidney specialists — analysed existing studies on phosphate additives and their association with cardiovascular risk.

The molecule of ageing

Back in 1997, the Japanese researcher Makoto Kuro-o discovered a new gene at the National Institute of Neuroscience in Tokyo — a gene that carries the blueprint for a protein called Klotho. In animal experiments, he observed the following: when the Klotho gene is switched off in mice, their phosphate levels rise sharply. They go on to develop vascular calcification, osteoporosis, damage to skin and lungs, become infertile, and face a markedly increased risk of death. For this reason, Kuro-o refers to phosphate as a “signalling molecule of ageing.”

Even if the metabolism of rodents cannot be transferred one-to-one to the human body, vascular calcification caused by excessive phosphate levels has now also been demonstrated in humans. In addition, a persistently elevated phosphate level has, since a US study published at the end of 2011, been suspected of triggering changes in the heart via specific signalling pathways. In this process, heart muscle cells are stimulated to grow in a pathological way. The result is what is known as left ventricular hypertrophy, which can partially impair the function of the left chamber of the heart.

It is true, emphasises medical professor Eberhard Ritz, that for these phosphate-related, premature ageing processes, “a direct cause-and-effect relationship for the general population has not yet been conclusively proven.” Nevertheless, given the existing body of research, he calls for “comprehensive labelling of phosphate additives.”

Phosphate levels in foods have doubled

According to Ritz, the risk stems from our modern way of eating. It has led to a situation in which the amount of phosphate-containing additives we consume every day has “doubled since the 1990s — from just under 500 milligrams to around 1,000 milligrams.” Even those who choose organic foods are not entirely protected. While only calcium phosphate is permitted in products bearing the organic label, Ritz explains, manufacturers are not required to state how much of the additive a product actually contains.

“The consumer — or the patient — therefore has no way of seeing how much phosphate a food actually contains,” says Ritz. One possible solution, he suggests, would be a traffic-light label printed on packaging, using red, yellow and green to signal whether a product delivers a high, moderate or low phosphate intake.

Phosphate plays a particularly important role in the meat industry as a preservative, and in cheese production as a melting salt. It is found in sterilised, ultra-heat-treated and condensed milk, as well as in milk powder. It keeps coffee and pudding powders free-flowing. As an acidifying agent, it lowers the pH value and thereby inhibits the growth of yeasts, fungi and bacteria in food. And by loosening the structure of proteins, it enables them to bind more water — improving texture and shelf life.

Particularly high amounts of phosphate are found, for example, in processed cheese and soft drinks. “Just one litre of cola already accounts for 50 to 75 per cent of the recommended daily phosphate intake for adults,” Ritz warns. But phosphate is not all the same. Natural phosphate compounds are found, for instance, in grains, nuts and legumes — and these are largely excreted by the body again.

Those most affected by excessive phosphate levels in food appear to be people on lower incomes. A US study published in 2010 by Orlando Gutiérrez and colleagues at the University of Alabama at Birmingham showed that phosphate levels are twice as likely to be elevated in people from socially disadvantaged backgrounds as in higher earners. Cheap fast food, in particular, often contains large amounts of phosphate — added, for example, as a preservative.

Source: https://www.spiegel.de/gesundheit/ernaehrung/phosphat-in-lebensmitteln-koennte-giftig-sein-a-839049.html