FUNDAMENTALS OF FUNCTIONAL NUTRITION COURSE THE ROLE OF SUGAR AND SALT M o d u l e 6 FUNDAMENTALS OF FUNCTIONAL NUTRITION COURSE Lesson 2 Salt: historical perspective, science, and nutritional roles in the human body. The significance of salt throughout history Salt has played a major role in the development of our civilisation. It has been used as money, to flavour food, in religious proceedings, to enhance the libido, and to ward off evil. Below we will explore a ‘snap-shot’ of the significant role that salt has played in the history of the world. The following reference 1 was used in this section as it provides an easy digestible account of this long history. Stone Age: During this period people hunted and therefore obtained their salt from red meat. Ten thousand BC: People began to farm the land, cultivating rice, wheat, barley, and millet, and reduced their red meat consumption. Thus, people required salt in their diets and to for the preservation of foods such as hams and salted fish. The cattle they kept on their farms also required salt. Neolithic period: Settlements flourished around salt springs and caravans transported salt across the desert trading it for gold – ounce for ounce. Six thousand BC: Northern China’s Lake YunCheng was documented as the first place people harvested and produced salt. Ancient Egyptians 3000 BC: The Old Kingdom was preserving fish and meat with salt. They also used salt to preserve mummies. The Egyptians obtained salt by evaporating water from the Mediterranean Sea and buying it from nearby Libya, Sfax, Tunisia, and Nubia. Chinese 800 BC: The Chinese produced salt by filling clay jars with sea water and boiling the water until only salt remained. Others who used evaporation to produce salt included the Etruscans of Italy, the early Romans, and the Carthaginians in North Africa. Indo-European Celts 700 BC: The Celts were mining salt underground in what is now Austria, Hungary, South Germany, and Poland. Ancient Greeks: sold their slaves in exchange for salt. MODULE 6 LESSON 2 V2.1 2019 PAGE 2 FUNDAMENTALS OF FUNCTIONAL NUTRITION COURSE Lesson 2 As Napoleon was retreating from Moscow, many of his troops died because of the lack of salt. Europeans in America: The first Europeans in America had great commercial success because they learned to salt the fish they caught in order to transport it to their home markets. The Erie Canal in the United States was built primarily to transport salt. The symbolic value of salt The history of salt has both positive and negative connotations. According to an Arabic proverb; ‘salt is not worm-eaten’. Salt is white, immaculate, incorruptible, and imperishable” 2. Salts durability and its immunity to decay made it an emblem of immortality. Salt also served as a recognition of loyalty, as illustrated by the ancient custom to share one’s bread and salt with the guest 2. As a reflection of its anti-bacterial properties, salt was also considered to have healing strength 2. Salt was said to promote health. The Latin words for health and healthy, salus and saubris are actually derived from sal (salt) 2. Although salt was thought to be essential for health, the Chinese were sceptical. The famous Yellow Emperor wrote approximately 3000 BC ‘If too much salt is used in food, the pulse hardens, tears make their appearance and the complexion changes’2. Salt was a precious commodity, often used as the equivalent of money. For example, in ancient Rome soldiers and officials were paid in the form of a ‘salarium’; salt money, from which the word salary comes from 1,2. The symbol of salt also had some negative connotations. In biblical times, defeated and destroyed cities during war had salt spread over their territory 2. It was thought that salt belonged to the realm of evil, the deadly desert, and the land of sin. Even now, farmers in Bavaria still put salt into the brim of their hats to ward off evil 2. The lack of salt Salt hunger is well known in the animal kingdom. As early as 1884, Manley wrote: The ‘universal existence of an appetite for salt surely indicates that the substance serves more important functions that that of merely gratifying the palate’ 2. In fact, it has been suggested that one of the reasons why some species of wild MODULE 6 LESSON 2 V2.1 2019 PAGE 3 FUNDAMENTALS OF FUNCTIONAL NUTRITION COURSE Lesson 2 animals could be domesticated into human settlements were because they were attracted by the salt content of human urine 2. Salt deficiency occurs usually in remote regions a long way from the sea. It is not noted in carnivorous animals (which get a supply of salt from their prey’s blood and meat), but occurs in herbivores 2. Salt deficiency poses a serious risk in selection: speed and endurance are diminished when animals are trying to escape predators, thermoregulation is disturbed, and fertility is reduced 2. In humans, lack of salt contributed to the development of the slave trade. In Africa, salt was traded for gold and it has been documented that natives even gave their wives and children away in exchange for salt 2. Adding salt to food: how was this need met? When did the need to add salt to food arise? Addition of salt to food by the hunters and gatherers was unknown, and is supported by more recent anthropological studies in New Guinea 2. The need to add salt arose when agriculture was introduced which led largely to a vegetarian diet. How was the need for salt met? Some populations satisfied their need for salt by cannibalism, others by drinking milk or animal blood and urine 2. Apart from these sources, salt was obtained by three main techniques. 1. Sea salt obtained by the evaporation of sea water, 2. Mining of rock salt, and 3. Heating of the brine of salterns (area for making salt). Production of salt and its role in the beginnings of modern industry and capitalism Salterns were the forerunners of industrial production and capitalistic organisations in Europe. At the end of the 16th century, salterns were faced with growing economic and ecological problems. For example, the use of wood to fuel the salterns became uneconomical because it had to be transported over great distances. Likewise, an ecological crisis arose because the forests were cleared to make way for new salterns. This was not surprising because 1 tonne of salt required 1.5 tonnes of wood2. Salt was also the driving force behind the MODULE 6 LESSON 2 V2.1 2019 PAGE 4 FUNDAMENTALS OF FUNCTIONAL NUTRITION COURSE Lesson 2 construction of roads and canals around the world, and the expansion of cities (e.g. Venice) 3. Salt today Salt today is produced on an enormous scale. For example, in 2010, an estimated 270 million tonnes of salt was produced, a quantity far greater than the production of ammonia and sulphuric acid 3. So what do we do with all this salt? Well, we don’t eat most of it. It is estimated that only 2% of the salt produced each year goes to human or livestock consumption 3. In contrast, approximately 20% goes to salting roads in the winter months, and the vast remainder goes to the chemical industry 3. ☺ We all love a bit of salt, which may explain why it has been called the “primordial narcotic.” We tend to put it on everything even when it is not needed. For example, there are two camps of people when it comes to barbecues. The first say you should salt your meat before cooking – that way the salt can be absorbed into the meat and bring out the flavour. The second camp says that you should add salt after cooking; the argument goes that salting beforehand removes the juices from the meat by osmosis and it dries out. The second group is correct, but for the wrong reason. The structure of meat is such that osmosis does not occur, but the juices that are lost during cooking simply wash away any salt that was added to the surface of the meat. So you can salt before you cook if you wish, but it’s a waste 3. Types of salt Most of the world’s salt comes from seawater which contains dissolved minerals, rocks, and soil containing sodium and chloride, and from massive underground salt deposits 1. Salt deposits were formed millions of years ago when large bodies of water evaporated leaving behind rock salt (halite) which formed the salt beds we find today 1. Salt is used for various purposes, the most common being added to food for flavour. It is also added as a food preservative because bacteria do not grow well in salt-rich environments. The reason salt often has bad press as being unhealthy (in large amounts) is that it binds to water in the blood and raises blood pressure. The great majority of salt in the western diet comes from processed foods. MODULE 6 LESSON 2 V2.1 2019 PAGE 5 FUNDAMENTALS OF FUNCTIONAL NUTRITION COURSE Lesson 2 Table salt (refined salt) The most common salt used today is plain table salt. This salt is highly refined and usually has anti-caking agents added to it to stop it clumping together. Refined salt undergoes processes that include bleaching, kiln drying, heating, and/or altering with chemicals 1. Iodine is often added to table salt as a successful public health campaign against iodine deficiency which is still common in many parts of the world. Iodine deficiency is the leading cause of hypothyroidism, mental retardation, and other health problems 4,5.