Sodium: Safety Assessment

The European food safety authority (EFSA) was unable to derive a safe maximum daily intake for sodium because of insufficient data.

The DGE (German Nutrition Society) considers an intake of 6 g (6,000 mg) of table salt per day to be acceptable. This amount is equivalent to 2,400 mg of sodium, which is about 4 times the DGE intake recommendation for sodium.

A high intake of sodium tends to be considered unfavorable with respect to the prevention of hypertension (high blood pressure) and osteoporosis (bone loss) and is not associated with any health benefits. In terms of adverse effects, high sodium intake is more critical than low sodium intake.

Excessive sodium intake via conventional (mainstream) foods, i.e., even consumption of a diet very high in sodium chloride, does not lead to adverse effects in healthy individuals because excess amounts of sodium are excreted in the urine. The LOAEL (Lowest Observed Adverse Effect Level) – the lowest dose of a substance at which adverse effects were just observed – is 2.3 g of sodium per day (equivalent to 5.8 g of table salt). An increase in blood pressure was observed as an adverse effect.

Adverse effects of excessive sodium intake

Excessive intake of 4.6 g of sodium daily is associated with an increased risk of hypertension (high blood pressure). However, an increase in blood pressure has also been observed with amounts as low as 2.3 g of sodium.

There is no clear indication of the amount above which sodium or table salt leads to increased blood pressure. In this context, different salt sensitivity in the population is also discussed, i.e. some people react more sensitively to salt than others. In salt-sensitive people, hypernatremia (excess sodium) and hypertension occur earlier, while less sensitive people can tolerate a high sodium intake without side effects.

Furthermore, a permanently increased sodium intake can lead to edema (water retention).

Accidental overdose of table salt has resulted in symptoms of poisoning such as vomiting in both infants and adults. The acute toxic level of table salt is reported to be 35 to 40 g (equivalent to 14 to 16 g of sodium). Adverse side effects of acutely excessive sodium intake include severe thirst, vomiting, motor agitation, tremors up to coma, and heart failure at extremely high doses.

Long-term risks of high sodium or salt intake include hypertension, heart failure (cardiac insufficiency), increased risk of apoplexy and myocardial infarction (risk of stroke and heart attack), and increased risk of nephrolithiasis (kidney stones), osteoporosis (bone loss), gastric carcinoma (stomach cancer) and duodenal ulcers.

Contradictory results are provided by studies regarding the relationship between high salt intake and the incidence of bronchial asthma and the intensity of symptoms in individuals. Animal studies show that high sodium intake leads to increased contraction of bronchial muscles.

High consumption of table salt in combination with consumption of processed meats can trigger migraine. However, the mechanism of action is not yet known.

A recently published study describes a possible link between increased consumption of table salt and rising rates of autoimmune diseases (the immune system attacks healthy tissue). In their research, the researchers showed that table salt promotes the formation of special T-helper (TH) cells, TH17 cells, which are involved in the initiation and maintenance of autoimmune diseases. In experiments on mice, an early onset of the autoimmune disease multiple sclerosis (MS) occurred under a high-salt diet. The extent to which these findings translate to humans remains to be explored.