Introduction

There is a lot of confusion around the ideal amount of sodium and salt we should consume. Are sodium and salt the same? Do we need sodium? Is salt bad for you? It is important to understand these questions (and their answers) so that you can make informed decisions about your diet and managing your health. The NHS recommends that the daily intake of salt for adults should be a maximum of 6g, which is approximately one level teaspoon. However, it has been found that the average adult consumes much more salt than this. Also, unknown to many people,  most of the salt we consume is found in processed foods that we buy at the supermarket rather than that we add to food ourselves. Carry on reading so you can find out more about sodium, where it can be found, and its importance and potential risks for our health. 

Sodium and salt

Sodium is an important mineral that is involved in many bodily functions, including maintaining the balance of fluids and the sending and receiving of electrical signals within the nervous system. Salt and sodium are terms that are often used interchangeably. However, there is, in fact, a slight difference between them. Usually, the sodium we consume comes in the form of salt, which is actually sodium chloride. In other words, salts added to food (such as table salt) contain sodium. Salt is used to flavour and preserve food (as bacteria can’t live if there is a lot of salt). Other foods naturally contain sodium. Later on, I will discuss foods that contain sodium.

Importance of sodium in the body 

Sodium is an essential mineral in the human body and is involved in many of its systems. This includes the renal (kidneys), endocrine (hormonal), immune (the body’s defence system) and nervous (brain and nerves) systems. 

Wherever sodium goes in the body, water follows. Therefore, sodium helps to keep the body’s fluids in balance. In the nervous and muscular systems, sodium is involved in creating signals in the nerve cells to trigger muscle contraction and movement. Sodium and potassium are pumped into and out of cells. This is known as the sodium-potassium pump. This system helps electrical signals to be passed along nerves to the muscle cells. It has been estimated that 500mg of sodium is needed a day for these functions in the adult body.

Health considerations

Although sodium is essential for the body, it needs to be tightly regulated because too much is associated with many health conditions, especially high blood pressure.

Blood pressure and heart disease

In the body, the kidneys get rid of any excess sodium. However, if there is a lot of sodium, the kidneys may have difficulty keeping up. In this case, sodium stays in the body. As mentioned before, water follows sodium. Therefore, if there is more sodium in the body (specifically, the blood),, the volume of water in the blood will also increase. The resulting increase in blood volume puts more pressure on the blood vessels, which hold and transport blood around the body. Over time, this increased pressure may damage the blood vessels, leading to other problems such as cardiovascular disease and stroke. Indeed, many studies have found an association between a higher sodium intake and high blood pressure, such as the recent UK-Biobank study.¹ Bear in mind that individuals may react differently to increased sodium levels as there may be genetic variations between people.

Osteoporosis 

Calcium is a mineral that binds to bones and makes them strong. Calcium leaves the body in urine and the amount that leaves increases with the amount of sodium that is present in the blood. When the blood contains excessive amounts of sodium, too much calcium might be lost - and calcium may be taken away from bones to make up for this deficit. In turn, this causes the bones to become thinner, which is known as osteoporosis.² 

Recommended daily intake

As mentioned before, in the UK, adults are recommended to have no more than 6g of salt each day -  equivalent to approximately 1 teaspoon. The recommendations are slightly less for children and very little salt for babies. This includes salt that is added to food and salt that is already in foods that we may buy or cook with. In fact, most of the sodium that we consume is found in processed foods  that we buy, rather than the salt added to foods that we cook.^3,4,5  

It has been found that the average adult in England consumes 40% above the recommended amount of sodium per day. That is a lot higher than you might be expecting. On top of that, the UK’s recommendation is actually higher than the WHO’s recommendation of 5g per day. 

Foods high in salt

Up to 85% of the salt we eat comes from food that we buy at the supermarket. This includes salty foods such as crisps and other snacks, but there is also lots of salt in other foods, such as bread and cereal. 

Bear in mind that low-salt foods generally contain approximately 0.3g or less of salt per 100g. These are labelled as green on food packages. If there is only information regarding sodium, then you can multiply that number by 2.5 to work out the salt content. 

The main sources of sodium in the diet have been found to be meat items (27%), grains and cereals (26%), dairy products (14%) and ready meals (13%).⁶

Processed meats 

Sausages, ham, meat pies, sausage rolls, bacon and other processed meat products contain lots of added salt. For example, two rashers of bacon can contain as much as 2.84g of salt, which is nearly half of the recommended daily adult intake. You can try alternatives, such as tuna or mushrooms, to offset this. 

Bread

A lot of us eat bread often, every day and sometimes multiple times a day. So, although there is not much salt in bread compared to other foods, it adds up. Action On Salt found that two thick slices of bread may contain up to 2.03g of salt. That being said, there is a lot of variation of the salt content in different breads, so be sure to check the labels. 

Pasta, rice and pizza dishes

Pasta and rice themselves usually don’t contain much salt. It is everything else in these dishes that are salty - such as the sauce, meat, cheese and other toppings. Try to limit these items when making these dishes. 

Condiments and sauces

Most condiments and sauces, such as tomato ketchup, mustard, pesto or brown sauce, contain lots of salt. Even though you might think these items are acceptable since you only use a little on the side of a dish, they can actually add a lot of salt. One tablespoon of tomato ketchup contains 0.3g of salt and, perhaps even more surprisingly, 4.1g of sugar. In one tablespoon of soy sauce, there is around 2.75g of salt. To reduce the salt in your diet, switch these out for reduced-salt versions or try making your own sauces at home. 

Dairy products

Cheddar is the most popular cheese in the UK and has been found to contain 0.52g of salt per 30g portion. Cheese is high in salt, cholesterol and fat; however, it does contain some healthy minerals such as calcium. Therefore, instead of cutting it out completely, try to eat it in moderation or choose low-salt options. Other types of cheese, such as mozzarella and emmental, may contain less salt than cheddar. 

Fast food and restaurants 

Food from restaurants and fast food chains usually contain very high levels of salt in order to make the food tastier. However, it can be hard to tell if there is a lot of salt in the food. Salt may not just be added to foods that are obviously less healthy, such as burgers or pizza, but also to sandwiches and soups. You can visit The Department for Environmental, Food and Rural Affairs (DEFRA) website to learn more about this.

Natural sources

Vegetables do contain a small amount of sodium however, they also contain many other vitamins and minerals. An example is beetroot, which does contain sodium but is also a great source of potassium and folate. 

Conclusion

Sodium is a vital mineral and plays diverse roles in our bodies - especially within the nervous system and controlling the fluid balance in the body. However, too much sodium can cause high blood pressure and be damaging to the heart and blood vessels. The daily recommended amount of salt intake is 6g, but it is important to recognise that many adults exceed this limit, and often unknowingly. This high level of salt intake is mostly through processed foods rather than directly adding salt to foods. As such, it is essential to be mindful when purchasing foods and always look at the nutritional label. It also helps limit foods high in salt and swap them for low-salt alternatives. For more tips and information, you can visit the NHS or DEFRA websites.