Salt (sodium chloride) is a chemical agent used to cook or process food. Saltiness is regarded as one of 5 main tastes. (Scientists have not, as of 2018, identified a distinctive taste receptor for salt.) Sodium is an essential nutrient – there are illnesses associated with a deficiency. Consuming more sodium than the minimum has few health benefits. Excessive sodium is a health risk.
Public health campaigns in the 1980’s concentrated on avoiding sprinking salt on prepared food by the (with a salt shaker/salt grinder). Then public agencies set limits and compelled food processors to put salt on product labels. Disclosure of sodium in product labels for processed foods is required by law in North America and Europe. Campaigns moved on to changed limits, better labels, more information, labels on menus, etc. Michael Moss looked those campaigns, and resistance from industrial food manufacturers and processors in the Salt section of his book Salt, Sugar, Fat (2013). Marion Nestle has provided commentary on the Food Politics web site. (Search Salt in the search bar or search for posts tagged Salt). The food industry considers labelling and public health information represents the foot of government on the throat of free enterprise, and has resisted with scepticism about the science that says excess salt is bad. Scientific American published one article in July 2011 “It’s Time to End the War on Salt” discussing the inconclusiveness of clinical trials. A week later, Scientific American published an inteview with Marion Nestle who said:
But if you do a clinical trial where you try to put large amounts of people on a low-salt diet, you just don’t see much difference between the people who say they eat a lot of salt and the people who say they don’t eat a lot of salt. In clinical trials the relationship doesn’t show up. Two reasons: One that it’s impossible to put a population of people on a low-salt diet. Roughly 80 percent of the salt in the American food supply is in foods before people eat them—either in processed food or in restaurant food. Because so much salt is added to the food supply and because so many people eat out, it’s impossible to find a population of people who are eating a low-salt diet. They basically don’t exist.
… There’s a proportion of people in the population who are sensitive to salt—if you lower their intake of salt, then their blood pressure goes down. There’s another (probably larger) percentage of the population who doesn’t respond. They are people who can eat as much salt as they want and still their blood pressure is low. So you have this curious anomaly where whenever you do a clinical trial you get these complicated, difficult-to-interpret results that don’t show much of an effect. But everybody who works with patients who have hypertension think they do better [on a low-salt diet].
The upper limits for sodium intake, in milligrams, per day:
- US Department of Agriculture & Department of Health – Less that 2,300 for an adult in the general population; less than 1,500 milligram for a person with hypertension, or over 50:
- American Heart Association – less than 1,500;
- World Health Organization – less than 2,000 (or 5 grams of salt):
- Canada Department of Health Tolerable Upper Intake Level, 2,300.
These numbers are not stated in ranges for body type, or weight. The limits are stated as a single high number and a second lower number for persons diagnosed with hypertension, or defined by age or other statistical risks. Exceeding the upper limit is risky and harmful.
The salt crisis is rooted in history of food preservation. Mark Kurlansky’s excellent book Salt: a World History (2002) tells of the uses of salt to brine or pickle soybeans and vegetables in China (>700 BCE), to cure hams by the Celts (Gauls and Germans) and Romans (>100 BCE), the fermentation of fish to make Garum (Greek, Phoenician, Meditaranean, Roman fish sauce >900 BCE ) and oriental fish sauces ( China >2000 BCE ). The production of salt may have started about 8,000 years ago. Until the invention of canning and refrigeration, salt was used to preserve food. Some foods had to be soaked to make them palatable. Salt is used to control or kill bacteria or yeast to preserve food (salting, cure, brine or pickle) and to manage the activity of “good” yeast and bacteria. It is essential to cooking large quantities of food that will remain safe and palatable.
Food processing includes:
- harvesting & milling grain;
- packaging a product for transportation and sale;
- processing agricultural products to flour, powder and syrop;
- combining processed commodities to manufacture food product including products that can be served after adding water, or warming them with appliances;
- factory meals.
Instant foods used chemical additives – for instance as a binding agents – e.g. to make starch and water into a pudding. The food industry wants to identify whatever it produces and sells as safe, nutrition, and authentic or wholesome. In Salt, Sugar, Fat (2013), investigative journalist Michael Moss looked at the three dominant additives used in food processing, and aspects of the food industry
- financial and market constraints; investor and corporate governance
- sell more,
- lower production cost,
- consumer expectations: convenience, flavour, texture;
- product development
- the business strategy of putting new products into the market
- the quasi-science of flavour,
- product line extensions,
- marketing, social and financial engineering;
- the politics of getting the food industry to describe its food.
Salt is used to enhance the flavour and texture of food. Michael Moss reported on his interviews with personnel at Cargill, a major supplier of salt to the food processing industry in his 2010 New York Times article “The Hard Sell on Salt” and Salt, Sugar, Fat. Without salt:
- The Cheez-It was not palatable. The colour faded. The crackers became sticky when chewed, and the mash packed onto the teeth. The taste was medicinal;
- Corn Flakes tasted metallic;
- Eggo waffles evoked stale straw;
- The butter flavor in the Keebler Light Buttery Crackers, which have no butter, disappeared;
- Many products, including meat products, develop what food industry people called Warmed Over Flavour, described as cardboard or damp dog hair.
Other sodium compounds added to processed food: sodium bicarbonate, sodium citrate, sodium phosphates, sodium pyrophosphate, monosodium glutamate.
Food products high in sodium:
- Sandwich spreads, condiments and salad dressings;
- Processed meat, cold cuts, charcuterie;
- pickles, olives,.
- Processed (flaked/puffed or shaped and toasted) breakfast cereal;
- Tomato juice, vegetable juice and tomato-clam (some very high);
- Processed spaghetti sauces and tomato sauces (very high);
- Pizza – bread topped with tomato sauce, cheese, and whatever else (most very high);
- Canned soups (monstrously high);
- Soy sauce, hoisin sauce and fish sauce (monstrously high);
The food industry has created some products that are made without adding salt and other sodium compounds. It’s a niche – another diet option. “Healthy” (whole grain, high fiber, low-fat, and organic) products often are as salty as anything else, or more (e.g. low-fat mayonnaise in a product line may have 150-200% the sodium of the regular mayonnaise). Reduced” or “low” sodium statements by manufacturers are generally mere puffery. “No added sodium” generally means no sodium, but not always.
The idea of a low sodium diet is to consume less salt. There are many sources of information, and the quality of information varies. Sources may promote a fad or a personal theory. Buyer beware.
The Low Sodium Program and other resources at Please Don’t Pass the Salt are as clear as anything I have read. There are other sources on the Internet. For instance What Can I Eat at Hacking Salt. The authors of Hacking Salt released The Easy Low-Sodium Diet Plan and Cookbook in 2017. (It is available inexpensively as an ebook for Kindle devices and apps). The Amercian Heart Association Low-Salt Cookbook (4th ed., 2011) is good.
Living without salt means learning to taste differently. It does not mean that everything is going to be bland. People get habituated to the amount of salt they normally consume. Bertino, Beauchamp & Engelman reported in The American Journal of Clinical Nutrition, Volume 36, Issue 6, 1 December 1982, Pages 1134–1144:
A group of young adult subjects was placed on self-maintained, low sodium diets for 5 months. Taste responses to salt in solutions, soups, and crackers were determined both during the 2 months preceding diet initiation and during a 5-month period when subjects lowered their sodium intake. Taste responses were also determined in a control group with ad libitum salt consumption throughout the same period. Perceived intensity of salt in crackers increased. The salt concentrations of maximum pleasantness in soup and crackers fell in the experimental subjects but not in the control subjects. These results demonstrate that the preferred level of salt in food is dependent on the level of salt consumed and that this preferred level can be lowered after a reduction in sodium intake. The implications of these findings for the maintenance of low sodium diets are discussed.
Also “Effect of dietary sodium restriction on taste responses to sodium chloride: a longitudinal study”, The American Journal of Clinical Nutrition, Volume 44, Issue 2, 1 August 1986, Pages 232–243