What is salt? Technically, it is what you get when an acid reacts with a base. However, when it comes to salt in our diet, it is synonymous with sodium chloride, NaCl. It is the compound you get when hydrochloric acid reacts with sodium hydroxide (the base).
Salt was used by humans long before its chemical composition was known. Before sophisticated analytical technologies, like spectroscopy and mass spectrometry were invented to identify the chemical composition of substances, humans had to use their senses to discern different substances. Ayurveda, a healthcare system that originated in India over 5000 years ago, talks about the salt taste as one of the six essential tastes that is necessary in the human diet to support health.
As with pretty much everything else, we have choices when it comes to salt; from the common table salt, to the pretty pink Himalayan salt, to the less visually appealing black salt. All all salts equal when it comes to our health? This article will delve into the nature, types, and nutritive impact of salt as described in Ayurveda, with some chemistry juxtaposition.
Salt taste in Ayurveda
One of the fundamental properties of substances as described in Ayurveda is Rasa, translated as "taste" in English. There are six tastes: sweet, sour, salt, pungent, bitter, and astringent. Since everything that was known to humans was perceived through the senses, Ayurveda describes the properties of substances in terms of five perceivable elements called Panchamahabhoota viz. space, wind, fire, water, and earth. The salt taste has the properties of Fire and Water elements and has the following effect on the body:
There are over ten types of salt that are referenced in the Brihat Trayi, the three authoritative works on Ayurveda. Of these, five types are referenced in all three which indicates they were probably more commonly used. These are Saindhava, Samudra, Sauvarchala, Vida, and Aubhida.
1. Saindhava salt is referenced in all three texts as being the best type of salt. This is currently understood to be rock salt. Contrary to other types of salts, this salt is cooling and beneficial for the eyes. The excellent review on salts in Ayurveda by N. S. Mooss explains the possible origins and composition of this salt:
4. Vida salt is described as being "sharp, and alkaline, and dark red in color". This variety of salt is also currently shrouded in confusion as to the chemical composition. It is a salt that seems to be synthesized using organic material, probably alma. It is unlikely that there are authentic commercial forms of this salt available today.
5. Aubhida salt is described as "sharp, hot, bitter, pungent, and alkaline". The origin of this salt seems to be in current Punjab. Mooss postulates that the composition of this salt is similar to Souvarchala salt based on the similarity in properties described.
Iodine in salt
Iodine was introduced in salt in the US in the 1920s when goiter, a disease that causes enlargement of the thyroid gland due to iodine deficiency, plagued a significant percentage of the US population. Natural food sources of iodine are plants that absorb the nutrient from the soil, seaweed, fish, and dairy. However, there are some areas where the soil is depleted of iodine, such as the Great Lakes region in the US. This area was part of the "goiter belt" that catalyzed the introduction of iodized salt.
Iodine is not found naturally in cow's milk, but industrialization of the dairy industry, particularly, using iodine for sanitation and in feed, have resulted in dairy products becoming a significant, albeit highly variable, source of iodine.
So this begs the question: do we need iodized salt?