What are food additives and why are they sneaky?
How much phosphate does a human being need?
The human body actually only needs about 800 mg of phosphate per day, depending on body size. Such an amount can usually be easily covered with a balanced diet. In practice, however, people nowadays eat significantly more.
In kidney disease, your body can no longer adequately regulate the phosphate level in your body. For this reason, a maximum level of phosphate between 800 and 1,000 mg per day is often recommended.
Where is phosphate actively used?
Nowadays, phosphate is used industrially in a wide variety of areas. It is mainly extracted from phosphorous rock, which is mainly found in North Africa, China, Russia and the USA. It has even been on the EU's list of critical raw materials since 2014. In some countries, sewage treatment plants are now obliged to recover a certain proportion of phosphate from the sewage sludge and recycle it.
Most phosphate is used in the fertilizer industry. As an excellent mineral fertilizer, it accelerates plant growth. However, phosphate is also a major problem in water bodies. The fertilizers enter the water cycle and lead to a collapse of ecosystems there due to extreme algae growth.
Similarly, phosphates are used in households to make water softer. Even though the proportion of these is declining, phosphate is still used in detergents and dishwashing products.
In the food industry, phosphates are used, among other things, to enhance flavour and extend shelf life. For example, they are used in the meat industry as a preservative, are an important ingredient in the production of processed cheese, or prevent pudding or coffee powder from clumping.
Are additives harmful to health?
Phosphate-containing additives are harmful not only to the health of people with kidney disease. In larger amounts, they also cause problems for people with healthy kidneys. They can accelerate the progress of kidney disease, or cause cardiovascular problems. This is partly because phosphate from additives is absorbed better than animal phosphate or plant-based phosphate in fruits, vegetables and grains. Phosphate from additives can be absorbed almost 100% from the intestines into your bloodstream. Some also speak of 100% bioavailability. In comparison, the bioavailability of plant-based phosphate is usually well below 50%, that from animal phosphate below 60-70%.
What are E-numbers?
Since phosphate-containing additives, as well as others, can sometimes be quite a chemical bombs, they must be labelled on packaging in Europe by E-numbers (e.g. E339 sodium phosphate). This EU-wide regulation applies to several hundred food additives. Unfortunately, companies are only obliged to indicate the E-number. Most products do not have a name or dosage, which makes it very difficult to understand the amount of phosphate added.
In organic foods, only calcium phosphate (E341) is allowed among the phosphate-containing additives. Therefore, in principle, you are usually on the safer side when eating predominantly organic foods.
Which additives contain phosphate?
Not all additives contain phosphate. Some can also contain potassium or sodium -- which you should usually only consume in moderation. A few examples of food additives that contain phosphate are:
E101a -- Riboflavin-5-phosphate
E338 -- Phosphoric acid
E339 -- Sodium phosphate
E340 -- Potassium phosphate
E341 -- Calcium phosphate
E343 -- Magnesium phosphate
E442 -- Ammonium phosphatide
E450 (a, b, c) -- Diphosphate
E451 -- Triphosphate
E452 -- Polyphosphate
E540 -- Dicalcium diphosphate
E541 -- Aluminium phosphate
E543 -- Calcium sodium polyphosphate
E544 -- Calcium polyphosphate
E1410 -- Phosphate starch
E1412 -- Distarch phosphate
E1413 -- Phosphated distarch phosphate
E1414 -- Acetylated distarch phosphate
E1442 -- Hydroxypropyl distarch phosphate
As you can see, some of these additives are also real tongue twisters. They don't necessarily sound too healthy either. We're working on making it possible for you to look up all the E-numbers in the Miku app's food search as soon as possible to check exactly what they contain.
Which food groups contain which additives?
Of course, you can't make a blanket statement like that. But here you can find an overview of food groups and which phosphate-containing additives they regularly contain:
Bread, baked goods: E340, E341, E343, E450, E451, E452, E541, E1410, E1412, E1413, E1414
Confectionery, snacks & creams, desserts: E340, E450, E451, E452, E1410, E1412, E1413, E1414, E1442
Dairy products: E338, E339, E1412
Processed cheese & sliced cheese: E339, E450, E451, E452, E1414
Dry food (=powder like meat sauces or soups): E343, E450, E451, E452, E1410, E1412, E1413, E1414, E1442
Ready-to-eat processed products, instant soups & instant products: E322, E1410, E1412, E1413, E1414
Did you know…?
that coke drinks would be pitch black without the added phosphates? Coke owes its dark brown colour to phosphate. According to European guidelines, a litre of coke may contain up to 700 mg of phosphate. In practice, the average is only 500 mg per litre, but even that is about half the daily guideline value for dialysis patients. Coca cola and the like are therefore a rather difficult topic from the point of view of phosphate and dialysis.
E-numbers in processed products may contain phosphate and their dosage does not have to be specified by manufacturers.
Since the phosphate in additives can be absorbed particularly well by the body, they are particularly dangerous.
It is best to know the most common E-numbers containing phosphate (and potassium) by heart -- even better: buy organic products to be on the safer side.
- Gesundheitsrisiko durch Phosphatzusätze in Nahrungsmitteln; Dtsch Arztebl Int 2012; 109(4): 49-55; DOI: 10.3238/arztebl.2012.0049 (Ritz, Eberhard; Hahn, Kai; Ketteler, Markus; Kuhlmann, Martin K.; Mann, Johannes)
- Phosphorus homeostasis in normal health and in chronic kidney disease patients with special emphasis on dietary phosphorus intake; Semin Dial. 2007 Jul-Aug;20(4):295-301. doi: 10.1111/j.1525-139X.2007.00309.x. PMID: 17635818. (Uribarri J.)
- Köstlich Essen: Nierenerkrankungen; Barbara Börsteken, TRIAS Verlag 2019 (3. Auflage)
- Ikizler TA, Burrowes JD, Byham-Gray LD, Campbell KL, Carrero JJ, Chan W, Fouque D, Friedman AN, Ghaddar S, Goldstein-Fuchs DJ, Kaysen GA, Kopple JD, Teta D, Yee-Moon Wang A, Cuppari L. KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update. Am J Kidney Dis. 2020 Sep;76(3 Suppl 1):S1-S107.