Salt, or sodium chloride, is essential for life. In fact, no mineral is more essential to human survival than sodium, because it allows nerves to send and receive electrical impulses, helps your muscles stay strong and keeps your cells and brain functioning. However, salt is a nutrient that the body cannot produce and therefore it must be consumed.
While the need for salt is unquestioned, we often hear that we consume too much. Food producers in many countries find themselves under increasing pressure to reduce the amount of sodium in their products to reduce population-wide salt consumption. In the US, the federal government is pushing food manufacturers to change their recipes in an effort to reduce their sodium content.
This will change the taste and texture of many foods made in the US. Government officials recently indicated a voluntary sodium reduction scheme; however, this was met with widespread opposition. The public comments on the Federal Register website were overwhelmingly against sodium reduction.
Salt and health
The government’s plan has also become contentious, with some medical researchers presenting evidence that population-wide sodium reduction is unnecessary and/or potentially harmful.
The government points to the US Department of Agriculture’s dietary guidelines as the basis for pushing sodium reduction, which recommend between 3.75 and 6g of salt a day. However, critics of the government guidelines say that the USDA has been wrong in the past. Most recently, it changed its view on eggs, finding they were part of a healthy diet after 40 years of saying that they were bad.
For decades, Americans have also been told that they need to drastically reduce their salt intake. However, the latest research, including a report from the Journal of the American Medical Association, indicates that low-salt diets can lead to insulin resistance, congestive heart failure, cardiovascular events, iodine deficiency, loss of cognition, low birth weights, and higher rates of death. Studies show dangerous side effects from lowering salt intake below 7.5g a day.
More recent research that looks at total health outcomes suggests that the healthy range for salt consumption is far higher than the maximum recommended. A 2014 study, published in the New England Journal of Medicine, tested sodium consumption in more than 100,000 people in 18 countries. The study found that the healthy range for salt consumption was between 7.5 and 12.5g per day. The amount of salt Americans eat every day is on the low end of this range.
Dr Michael Alderman and Dr Hillel Cohen of the Albert Einstein College of Medicine reviewed 23 observational studies covering some 360,000 individuals and published their comprehensive results in the July 2012 edition of the American Journal of Hypertension. They also found that both the very low and very high levels of salt consumption negatively affected health, but in between those extremes, a very broad safe range of salt consumption resulted in optimum health.
One recent example is a review of available research on salt and health by the US Institute for Medicine (IOM) at the National Academy of Sciences. The consensus of the experts on this panel was that blood pressure is only one of many factors that should be considered in evaluating dietary changes. The 2013 IOM report concluded that there was not sufficient evidence to support populationwide sodium reduction schemes.
As a result of the IOM report and other research on salt and health, Hypertension Canada has actually raised its recommendation on the minimum level of sodium consumption, the first national organisation to do this. The available evidence shows that significant cuts in salt consumption can result in small reductions in blood pressure for some people, while causing the risk of a cascade of several other negative health impacts (insulin resistance, diabetes, increases in cholesterol and triglycerides, cardiovascular events) for everyone.
Low-salt diets can be especially harmful for the elderly. In older people, mild hyponatremia (low sodium concentration) is the most common form of electrolyte imbalance in the blood. Indeed, several recent medical papers found a direct relationship between hyponatremia and unsteadiness, falls, bone fractures and attention deficits. Elderly people on low-salt diets can experience lack of thirst, which leads to dehydration and loss of appetite that leads to a host of health problems.
How much salt do we eat?
Much of the reporting on salt also leads people to believe that we are eating more salt than ever before, but this is a myth. Before the advent of modern medicine, the nutritional need for salt was not widely understood. Instead, people relied heavily on, and valued, salt as a food preservative.
Military records from the early 1800s to the Second World War show that the average soldier was consuming between 15 and 17g of salt a day. This is far above the average salt consumption we see today and is a number that has remained consistent since 1945.
Even with the advent of refrigeration, salt is still used in many products as a preservative and indispensable in others. Bread, cheese, processed meats – none of these can be made without salt. Drastically lowering the salt content of processed meats significantly increases the likelihood of bacterial growth and places the public in greater danger. Regardless, government agencies and health organisations around the world recommend a maximum salt intake of between 3.8 and 6g of salt per day. There is almost no population on Earth that consumes this little salt.
We are routinely told that most of our salt intake comes from processed foods and eating out, thus the effort to get restaurants and food manufacturers to adjust their recipes. In fact, every single population throughout the world, regardless of state of development, culture and cuisine, all ingest a similar amount of salt when compared with the US average.
Salt for healthy eating
In a separate salt reduction effort, the US Department of Agriculture has proposed a complete overhaul of school lunches subsidised by the federal government. These changes, to be implemented over a period of years, aim to limit calories, reduce sodium and increase the consumption of vegetables and whole grains.
This effort has been opposed by the School Nutrition Association because of concerns over food waste. In fact, studies show that kids are more likely to eat their vegetables if they have adequate salt. Darkgreen vegetables like spinach and broccoli are among the most nutritious foods, but contain bitter phytochemicals.
A research paper from the University of Pennsylvania examined the response of tasters to varying amounts of salt in a range of foods that were naturally bitter, including vegetables and other foods deemed to be healthy. Reducing the salt intake made these foods less appealing and adversely affected the tasters’ nutrient intake. In another study conducted at Ohio State University, cooked broccoli was fed to individuals from three different age groups: children, adults and senior citizens. The broccoli florets were prepared with different levels of salt and the results showed that salt significantly increased the palatability of broccoli.
A University of Vermont study to measure food consumption in schools before and after the salt reduction mandate confirmed what school lunch officials feared: they witnessed most students putting fruits and vegetables into the trash. Though students were required to place more fruits and vegetables on their trays, they ate less of each.
Salt regulation
Like all other essential nutrients, our bodies regulate the proper amount we need to stay healthy. If you eat too much salt, the body simply eliminates it along with all other waste materials. Likewise, any activity resulting in excessive loss of these nutrients, such as exercise, has to be counterbalanced by an increased consumption of salt to make up for this additional loss.
If you don’t get enough salt, the body reacts by going into overdrive. The hormonal system, called the renninangiotensin- aldosterone system switches on to counter the effects of insufficient salt consumption. If low salt levels persist, then the consequences for our overall health can be very severe.
