“In all ages salt has been invested with a significance far exceeding that inherent in its natural properties…Homer calls it a divine substance. Plato describes it as especially near to the gods, and we shall presently note the importance attached to it in religious ceremonies, covenants and magical charms. That this should have been so in all parts of the world and in all times shows that we are dealing with a general human tendency and not with any local custom circumstance or notion.” Ernest Jones, 1912
Salt has been the subject of controversy in recent years, and has increasingly been blamed for a number of poor health outcomes, such as high blood pressure, heart disease and stroke. (1) Salt is ubiquitous in our modern diet, with Americans consuming an average of 10 grams of salt per day. Of this amount, about 75% is derived from processed food; only about 20% is naturally occurring or from discretionary salt use, such as that added in cooking or at the table (the rest comes from sources such as water treatment and medications). (2, 3) Most of what we read and hear about salt these days is telling us that salt consumption needs to be reduced, and it has even been referred to as “the single most harmful substance in the food supply”. (4)
However, until recently, salt had maintained an extremely high level of value for thousands of years of human history. As Mark Kurlansky explains in his book, A World History of Salt, “salt is so common, so easy to obtain, and so inexpensive that we have forgotten that from the beginning of civilization until about 100 years ago, salt was one of the most sought-after commodities in human history.” (5) So how did we develop this insatiable taste for salt, and why is it that we now fear salt as being dangerous for health? And furthermore, what role does salt truly play in our health and wellbeing?
In this first part of my series on salt, I will cover the historical significance of salt and its role in the evolution of humanity.
The development of human civilization is intricately linked to the pursuit of salt: wild animals wore paths to salt licks, men followed these animals and built settlements near the salt deposits. (6) These settlements became cities and nations. The human obsession with salt has spanned thousands of years of human history, across many different contexts and continents. Nearly every society in existence has some level of salt use not only in their cuisine, but also in their medicine, their politics, their economies, and even their religious practices.
Kurlansky’s A World History of Salt (7) explains the incredible role that salt has played in the development of humanity over thousands of years. In Judaism and Christianity, salt is a symbol of the covenant between God and the ancient Hebrews. Ancient Egyptians, Greeks, and Romans included salt in their sacrifices and offerings. Muslims believe that salt protects against the evil eye. During the Middle Ages, the spilling of salt was considered ominous, and the spiller had to cast a pinch over his left shoulder. (8)
As civilization and agriculture spread, salt became one of the first international commodities of trade, its production was one of the first industries, and a number of the greatest public works were motivated by the need to obtain salt. Salt trade routes traversed the globe, between Africa, Asia, the Middle East, and Europe. Salt was often used as money, and was desperately coveted, hoarded, searched for, traded for, and even fought over.
Salt has even made its way into our language as a metaphor for value: hardworking people are known to be “worth their salt”, and the most worthy amongst us are known as “the salt of the earth”. The root word “sal-” is of Latin origin and refers to salt. Words that have been historically based on humanity’s high value for salt include “salubrious”, which means “health-giving”, and “salary”, which is derived from the Latin salarium, the money allotted to Roman soldiers for purchases of salt. (9)
“Salus” is the Roman goddess of health and prosperity. (10) Even the word “salad” originated from the Italian salata, as the Romans often ate dishes of assorted raw vegetables with a brined dressing, hence the name which is short for herba salata or “salted vegetables”. (11) Nearly four pages of the Oxford English Dictionary are taken up by references to salt, more than any other food. (12) Clearly, the high value placed on salt in many cultures around the world has greatly contributed to the developmental course of human history.
But what about human pre-history?
There is no evidence that Paleolithic people engaged in salt extraction or sought out inland salt deposits, and the current estimate of Paleolithic intake is similar to that of chimpanzees. (13) Preagricultural humans are estimated to have consumed only 768 mg of sodium each day (about 1950 mg of salt), which is much lower than our current intake. (14) The mining, manufacture, and transportation of salt originated in the Neolithic Period, when agriculture was developed.
The question is, what drove Neolithic man to begin the inevitable search for salt? Not surprisingly, the move from a hunting-and-gathering diet to one consisting largely of grains and vegetables necessitated the procurement of supplemental dietary salt. (15) Humans, like many carnivores, can meet their salt needs by eating meat and seafood, provided they do not sweat excessively. (16) For example, the Masai, nomadic cattle herders in East Africa, can easily obtain adequate dietary salt by drinking the blood of their livestock. In modern and historic hunter-gatherer societies, it has generally been found that hunting tribes do not make or trade salt, unlike agricultural tribes, and once humans began cultivating crops, their dietary need for salt increased. (17)
Based on what we know about Paleolithic consumption of salt and how it compared to Neolithic and modern-day intake, where does this leave us in terms of our own salt consumption? Is it ideal to completely avoid salt and simply eat enough animal products to meet our needs? Or can added dietary salt play a role in optimal health and wellbeing, despite its theorized absence from the original Paleo diet?
In Part 2 of my series on salt, I will be discussing the physiological roles of salt in the human body, and what the evidence says (or doesn’t say) about our need for dietary salt.