Dietary Salt and Sodium
Sodium in the diet primarily comes from eating salt. While some of it comes from directly adding it to food, most of the salt we eat is already present in processed foods.
How much salt should we eat?
Our bodies need a small amount of salt for a variety of functions, such as the working of nerves and muscles. However, there is enough sodium present in all foods that a lack of sodium does not generally cause any problems in these areas. It is rarely necessary to add extra salt to food.
Salt levels are often included in the nutritional information on food packets. Salt is also called sodium chloride, and the figures given may be for salt or for sodium.
The recommended maximum daily intake of sodium for a healthy adult is 2.4 g, which is equivalent to 6 g of salt. This is about a level teaspoonful. Many food labels also use a traffic light system, in which high levels of salt may be indicated by a red label.
Because of increased awareness of the problems of eating too much salt, average salt intake in the UK has fallen by 15% since 2001.
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Why is too much salt a bad thing?
Many people are asked to follow a low-sodium diet because eating too much sodium can make high blood pressure worse. High blood pressure is a leading cause of strokes and is a major risk factor for coronary heart disease.
When we eat salt, it draws water into the bloodstream, increasing the blood volume. This is the mechanism by which it increases blood pressure.
Too much salt can also increase the risk of:
It has also been shown to worsen symptoms of asthma.
Which foods contain high levels of sodium?
Many of the foods that are high in sodium are easy to spot because they taste salty. These include:
- Bacon and other cured meats.
- Hard cheese.
- Yeast extract.
- Stock cubes.
- Salted nuts and crisps.
However, the salt content in bread, breakfast cereals, biscuits (even sweet ones such as digestives) and sauces (such as mayonnaise and ketchup) may also be quite high. The salt levels in different brands may vary, so if you are trying to cut down on sodium then check the packaging label.
Once you have got into the habit of choosing lower-salt products, you will become familiar with which brands are a better choice for you.
Since consumers and manufacturers have become aware of the dangers of eating too much salt, many food products are now 20-40% lower in salt than they were ten years ago. Public Health England publishes targets for salt reduction in processed foods, which are updated regularly as the food industry gradually reduces the salt content in foods.
Some medications also contain salt, particularly some indigestion remedies and medications which are taken as fizzy drinks (effervescent formulations). The packet should provide you with information on what level of salt the medication contains. If you are concerned about this, ask your doctor if there is an alternative you can take.
Using less salt
If you regularly add salt to the cooking water for pasta or vegetables, try cooking them without. It may take you a little while to get used to the different taste but it can make a big difference to your salt intake.
If there are foods which you enjoy which have a high salt content then eat them in smaller quantities or less often. We all need some salt in our diets but most of us consume more than we need.
Food without added salt can be made tastier by adding pepper, herbs or spices. It is also possible to buy a low-sodium form of salt which can be added to food. This contains more potassium as an alternative to the sodium in regular salt, which is a healthier choice for most people. However, it is probably a better option to get used to food tasting less salty.
Using more salt
There are some people for whom trying to eat less salt may not be a good idea.
Some people may feel dizzy because of low blood pressure and they may be advised by their doctor to eat a bit more salt to keep their blood pressure up. They should also drink plenty of fluids to keep the blood volume up. It is rarely necessary to make much effort to eat more salt.
Those who are exercising heavily, particularly in hot weather, may lose a lot of salt through sweating. It is important for them to keep up their salt levels as well as their fluids. Oral rehydration sachets are sometimes used by people who have diarrhoea and sickness (vomiting). These contain salt to replace the salt which is lost in the course of the illness.
As mentioned above, some medications can lower the sodium level in the blood. There are quite a lot of different reasons why sodium in the blood may be low. Your doctor may want to do some further tests. However, if they conclude that your sodium level is low because of medication, they may suggest that you eat more salt. They may also give you a course of sodium tablets to raise your sodium level to the normal range.
Further reading and references
Salt; British Heart Foundation
Data on salt consumption; Public Health England
Salt reduction: targets for 2017; Public Health England