E339 – Sodium phosphates

General Information

Sodium phosphates (additive E339) are a group of inorganic compounds used in the food industry as acidity regulators, emulsifiers, stabilizers, and moisture-retaining agents. Additionally, additive E339 helps fix the color of products and enhances the action of antioxidants, making it indispensable in the production of various food products.

The term “sodium phosphates” is a general designation for salts formed by the reaction of sodium hydroxide with orthophosphoric acid. These compounds do not occur in pure form in nature and are produced synthetically. At the same time, phosphorus and its compounds, including phosphates, are natural components of all living organisms and are essential for metabolism, bone formation, and energy production. Physically, sodium phosphates are white crystalline or granular powders, highly soluble in water and thermally stable.

According to Regulation (EU) No. 231/2012, additive E339 is divided into several subtypes, allowing it to be used in different technological processes:

• E339(i) — monosodium orthophosphate, chemical formula NaH₂PO₄;
• E339(ii) — disodium orthophosphate, chemical formula Na₂HPO₄;
• E339(iii) — trisodium orthophosphate, chemical formula Na₃PO₄.

On an industrial scale, additive E339 is obtained by reacting orthophosphoric acid with sodium hydroxide or soda ash.

Effects on the Body

Benefits of Additive E339

Phosphates are natural components of all living organisms and are essential for normal cell function, bone formation, and energy metabolism. The body absorbs 80–90% of dietary phosphorus as free orthophosphate, which is excreted by the kidneys. According to the Food Additives and Flavourings Committee (FAF), moderate consumption of sodium phosphates is safe and supports physiological processes, including maintaining acid-base balance and digestive system function.

Risks of Additive E339

Excessive consumption of additive E339 may cause side effects. High phosphate intake can lead to disrupted mineral balance, reduced absorption of calcium and magnesium, and gastrointestinal disturbances.

Some studies indicate that excessive phosphate intake may be dangerous for people with impaired kidney function, leading to hyperphosphatemia and increased risk of cardiovascular diseases.

In healthy individuals, excess phosphate compounds may contribute to:

• Hyperphosphatemia
  Excess dietary phosphates accumulate in the blood, disrupting mineral balance and potentially causing systemic complications.
• Vascular and arterial calcification
  Phosphates promote calcium deposition in vessel walls, reducing elasticity and increasing risk of atherosclerosis and ischemic heart disease.
• Increased risk of cardiovascular disease
  High blood phosphate levels are associated with higher incidence of heart attacks and heart failure, even in individuals without kidney disease.
• Higher mortality
  Epidemiological studies show that even “high-normal” phosphate levels in the blood correlate with increased overall mortality, especially in people with cardiovascular conditions.
• Disturbed phosphate-calcium metabolism
  Excess phosphorus impairs calcium absorption and metabolism, potentially causing bone calcium deficiency and soft tissue overload.
• Increased kidney workload
  Excess phosphates force kidneys to work harder for excretion, posing risk to people with chronic kidney disease (CKD).
• Joint disorders
  Deposition of calcium pyrophosphate crystals in joints can cause inflammation and pain, a condition known as pyrophosphate arthropathy.
• Osteoporosis due to phosphorus-calcium imbalance
  Imbalance leads to calcium loss from bones, weakening their structure and increasing fracture risk.
• Increased LDL cholesterol (“bad” cholesterol)
  High phosphate intake may raise LDL cholesterol, promoting atherosclerotic plaque formation and increasing risk of stroke and heart attack.
• Impaired calcium absorption and kidney deposition
  Undigested phosphate-calcium complexes can accumulate in kidneys, forming stones and increasing risk of renal failure and osteoporosis.

At the same time, according to EFSA and JECFA, acute toxicity of phosphates is low, and genotoxicity and carcinogenicity have not been confirmed. However, in infants, young children, and adolescents, high intake (95th percentile) may exceed the acceptable daily intake.

The FDA considers phosphates safe ingredients but recommends moderation in use.

The acceptable daily intake (ADI) for the phosphate group, established by EFSA, is 40 mg/kg body weight per day in terms of phosphorus. The Food Additives Committee concluded that this level is safe for all age groups, including infants up to 16 weeks consuming formulas and medical nutrition products.

Uses

Additive E339 is used in the food industry as an acidity regulator, stabilizer, emulsifier, moisture-retaining agent, and melting salt. It improves structure and texture, enhances stability and color intensity. Sodium phosphates are used in:

• bakery and confectionery products (dough leavening);
• non-alcoholic beverages;
• dairy products, including powdered milk and cream;
• soups, broths, pastas, sauces;
• dry and instant teas;
• cheeses, including processed, as well as meat and fish products;
• instant and dietary products.

Sodium phosphates were also used in household laundry detergents, but since the 1960s their use has been gradually restricted due to environmental concerns related to water pollution.

Legal Status

The legal status of additive E339 depends on the country. In the European Union, it is permitted and listed in Regulation (EU) No. 1333/2008 with specified maximum use levels. In Ukraine and CIS countries, additive E339 is also allowed in the same product categories.

In the USA, phosphates are recognized as safe (GRAS) and widely used in the food industry. In Canada, additive E339 is permitted in several product categories. In Japan, phosphates are also used in food production.

The acceptable daily intake (ADI) in terms of phosphorus is 40 mg per kg of body weight per day and is considered safe for all population groups.