Phosphorus is an important mineral that is absorbed through the diet as phosphate. Together with calcium, it ensures the strength of bones and teeth, plays a role in energy production, in the construction of cell walls and as a buffer substance in the blood. Phosphorus has numerous functions in the human body, and its importance has been known since the beginning of the 20th century. Phosphorus is significantly involved in the mineralization of bone substance. In addition, it plays an important role – as a component of the energy carrier adenosine triphosphate – in energy storage and energy supply.
Phosphorus: occurrence and functions in the body
Phosphorus is needed for the construction of cell walls and, as a component of nucleic acids in the genetic material (DNA), is partly responsible for its structure. Another function is as a buffer in the acid-base balance – it helps stabilize the pH of the blood. The amount of phosphorus in the body is about 600-700 g; about 90% of it is bound in the bones. It is excreted mainly in the urine, less in the stool. In the event of a calcium deficiency in the blood, the parathyroid gland secretes a hormone (parathyroid hormone) that dissolves calcium from the bone, and phosphorus is then released at the same time.
Supply of phosphorus through the diet
The recommended daily intake of phosphorus is 700 mg. This daily dose of phosphorus is contained in the diet, for example, in the following foods:
- 55 g wheat bran
- 120 g soybeans
- 120 g Gouda (30% fat)
- 160 g oil sardines
- 170 g lentils
- 180 g white beans
- 350 g mixed bread
- 390 g roast pork
- 760 g yogurt (3.5% fat)
- 1400 g kohlrabi
Phosphorus is found in almost all foods. Particularly good sources of phosphorus are protein-containing products, nuts, legumes, fruits and vegetables.
Deficiency symptoms of phosphorus
Phosphorus is present in virtually every food, so deficiency symptoms are unlikely to occur in adults with a sensible diet and are most likely to occur with artificial diets. Other causes of phosphorus deficiency include kidney dysfunction, hyperparathyroidism, and vitamin D deficiency. If blood phosphate levels fall below a certain level, bone softening may occur (called rickets in children).
Phosphorus overdose
Normally, the body excretes excess phosphorus in the urine. Hyperphosphatemia. i.e., an excessively high level of phosphate in the blood, occurs only in cases of renal dysfunction and hypothyroidism. The fact that a very high phosphorus intake combined with a low calcium intake leads to bone formation disorders is nowadays rather denied. It is possible that there is a connection between an excessively high phosphorus intake and the hyperactivity of many children (ADHD).
Phosphates in foods
Phosphoric acid and phosphates are widely used as food additives in industrial food production. For example, they serve as antioxidants, leavening agents, acidity regulators, and preservatives, among other things. Phosphate is also present in relatively high doses in cola drinks, soft drinks, brightly colored foods and sweets such as gummy bears. Together with sodium benzoate, it is said to cause an increase in hyperactivity in children.
