Why Salt Works for Respiratory, Skin Disorders
Sodium chloride (NaCl), more commonly known as salt, is found in abundance in nature and is without a doubt the most frequently used condiment around the globe. Its use as a seasoning, as a preservative, and for medicinal purposes has been documented in almost every civilization.
Salt is an essential part of daily life, and this is reflected in several language derivations. In fact, the word “salary,” which comes from the Latin “salarium,” denotes money that was paid to Roman soldiers so they could buy salt rations.1 Likewise, the Austrian city of Salzburg literally translates as the “salt fortress” and derives its name from the barges carrying salt on the Salzach river.1
Regular consumption of salt is necessary for proper functioning of the nervous system, as well as for the regulation of water balance in cells.2
Salt is found in a variety of forms. Sea salt is so abundant that there has been no scientific discussion of reserves.3 Other salt deposits are scattered around the world in areas thought to have once been ancient oceans that evaporated, leaving large salt deposits. The total world production of salt is estimated to be 290 million tons, with the United States being the largest producer at more than 44 million tons.3 In folk medicine, warm saltwater gargles for sore throats and salt poultices for soft-tissue infections are two of many commonly used salt therapies.4
The majority of clinical trials researching the efficacy of salt therapy target respiratory conditions. Therapeutic methods range from spending time in a natural salt cave to breathing aerosolized hypertonic salt water.
In the respiratory tract, salt's mechanism of action is multifaceted. Because salt particles are smaller than most particulate matter in the air, they can be inhaled deeper into the airways. Once in the respiratory tract, salt triggers a cascade of therapeutic events.
Salt acts as a mucolytic, allowing natural ciliary action to improve: it decreases bronchial edema; it is an antimicrobial; and, due to these properties as well as an anti-inflammatory action, salt suppresses bronchial hyperreactivity.5
Aerosolized hypertonic saline has been studied as a treatment for cystic fibrosis. Researchers randomized 24 cystic fibrosis patients to receive either nebulized hypertonic saline (5 ml of 7% NaCl) four times a day with or without pretreatment with amiloride (Midamor), a mild diuretic. Treatments were continued for two weeks with pulmonary function and mucus clearance measured at baseline and periodically during therapy.
At the end of the trial, the study group that used only nebulized saline showed a twofold improvement in both immediate and sustained mucus clearance, and nearly a 7% improvement in pulmonary function (as measured by forced expiratory volume in one second [FEV1]). The hypothesis for the dramatic difference in the two groups was that by allowing the natural water-retaining action of the salt to function uninhibited by diuresis, the mucolytic action was much more effective.6
A study of the effect of dry salt aerosol on lung function focused on 393 patients with severe obstructive pulmonary disease. Participants were assigned to traditional therapy (aimed at bronchodilatation) alone or to traditional therapy coupled with aerosol salt therapy. After one hour, the patients receiving dual therapy showed an increase of 6.5% in oxygen saturation levels and a 26% reduction in respiratory rate compared with only 3% and 19%, respectively, in the standard-therapy group.7
Dermatology is another emerging area for salt therapy. About 2% to 3% of the world's population is afflicted with psoriasis. In a phase 3 trial, researchers randomized 367 psoriaris patients to either traditional ultraviolet light therapy (UVT) alone or UVT and bathing in a Dead Sea hypertonic salt solution. After 35 treatments, the combination group showed a 46% greater symptom improvement than the UVT-only group.8
Salt also may relieve atopic dermatitis in children with severe disease. Researchers compared topical therapies of traditional emollient cream with therapies utilizing cream enriched with Dead Sea salts. Eighty-six children were randomized, and at the end of 12 weeks, participants receiving the Dead Sea salt-enriched cream showed significant improvement in all symptom areas.9