Breathing in large quantities of salt particles has just the same effect on blood pressure as eating a salty diet

Workers in salt factories, who inhale large amounts of salt particles, are at risk of high blood pressure due to the increased salt intake.

A study published today in the Open Access journal Environmental Health shows for the first time that breathing in large quantities of salt particles has just the same effect on blood pressure as eating a salty diet. Wearing face masks and plastic eyeglasses is enough to protect workers who are highly exposed to salt from salt-related high blood pressure.

A high consumption of salt has been shown to be directly linked to high blood pressure and the development of cardiovascular and kidney diseases, which are major causes of mortality worldwide. The European Food Safety Authority recently issued an opinion stating that current salt intakes in Europe far exceed nutritional requirements and may cause adverse health effects.

The present study, conducted by Kripa Haldiya and colleagues from the Desert Medicine Research Centre in Jodhpur, India, provides new data suggesting that inhaling large amounts of salt particles has the same effect as consuming a salty diet and increases blood pressure considerably, thus putting workers in salt factories around the world at risk of high blood pressure. This study represents the first demonstration of an occupational hazard linked to table salt.

Haldiya et al. measured the blood pressure of workers in two salt milling factories in Rajasthan, India. They divided the workers in two groups: one group worked close to the salt milling plant and was directly involved in crushing, grinding, milling and packing salt; the other group worked far away from the salt milling plant and was much less exposed to salt particles. The results of the study show that the first group of workers had a mean systolic blood pressure of 122.1 mmHg, which is significantly higher than the mean systolic blood pressure of 118.8 mmHg measured in the second group. In addition, workers from the first group had an incidence of hypertension of 12.2%, compared with an incidence of 7.0% in the second group. Wearing face masks and plastic spectacles for four days caused the mean systolic blood pressure of workers from the first group to drop significantly from 127.8 mmHg on the first day to 117.5 mmHg on the fourth day.

"This is a new observation, though it is in line with the hypothesis that, after being inhaled, salt may be absorbed from respiratory tract or […] the gastrointestinal tract. Consequent increases in plasma sodium may be responsible for increases in the blood pressure", explain the authors.

Their findings also suggest that workers in factories such as the ones studied could easily protect themselves from the negative effects of exposure to salt particles by wearing face masks and plastic glasses.