What Is Salt? How Much Salt Should I Eat?

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Main Category: Nutrition / Diet
Also Included In: Hypertension
Article Date: 20 Apr 2009 - 3:00 PDT

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The word salt is thought to come from the Latin sal, meaning salt. The English word "salary", which is similar in several European languages, is linked to the fact that salt was once a currency (legal tender) in many parts of the world.

Salt is a chemical compound called sodium chloride, with the formula NaCL (Na = sodium, CL = chlorine). Sodium chloride consists of 40% sodium and 60% chlorine. Salt is of low toxicity and is non-flammable. Seen under a microscope, table salt is made up of many cube-shaped crystals.

Salt exists naturally in seawater. When an area of seawater becomes enclosed it evaporates under the sun, a deposit is left. Over millions of years other sediments have been deposited over the salt, leaving beds of halite (rock salt) below the surface.

Salt used to be used just as a diet supplement and as a means of preserving food. Later, salt was used in such processes as tanning, dyeing and bleaching. Relatively more recently, salt has been used for glazing pottery, soap-making and the early manufacture of chlorine. Today salt is widely used in the chemical industry, and also for water softening.

The human body needs salt

Not only does salt help control your fluid balance, it also controls the way your muscles and nerves work. Our bodies automatically regulate how much salt, or sodium, there is present. If levels are too high we get thirsty and drink - this speeds up the elimination of salt through our kidneys.

How does salt affect my health?

Studies have indicated that too much salt consumption is linked to health problems, such as hypertension (high blood pressure) and osteoporosis. If you suffer from hypertension you would benefit from consuming less salt.

Very young children, very elderly people, as well as people with kidney disease cannot excrete sodium and regulate body fluid efficiently.

How much salt do I need?

According to the Food Standards Agency, United Kingdom, the human Guideline Daily Amount (GDA) should be:

• Age 11 years and over, 6g per day
• Age 7-10 years, 5g per day
• Age 4-6 years, 3g per day
• Age 1-3 years, 2g per day

Infants under 1 year should not be given salt because their kidneys are not matured.

How much is 6g of salt?

This is about one teaspoonful - not much. About three-quarters of the salt we eat is already in the food we buy.

It is impossible to work out exactly how much salt you eat in one day without knowing the precise salt content of each food and measuring the exact quantities you eat. However, knowing that a recommended daily maximum is 6g is useful, because you can then find out how much salt there is in some of the foods you normally eat. Most people are surprised at how much salt they eat when they sit down and work it out from the foods they are consuming.

What is the difference between sodium and salt?

Salt is sodium chloride (sodium plus chlorine). The sodium in the salt is what you have to look out for. 40% of salt is sodium. If sodium is listed on the label's nutritional information instead of salt you have to multiply the amount by 2.5 to get the equivalent salt content. For example, if a portion of food contains 1g of sodium per 100g, you will know it contains 2.5g of salt per 100g.

Food labeling - high and low salt foods

You should check the labels of foods to find out which ones are high and low in salt content. If the label has more than 1.5g of salt (or 0.6g of sodium) per 100g it is a high salt content food. If it has 0.3g of salt (0.1g of sodium) per 100g then it is a low salt content food. Anything in between is a medium salt content food.

• High salt content food = 1.5g of salt (or 0.6g of sodium) per 100g
• Medium salt content food = between the High and Low figures
• Low salt content food = 0.3g of salt (0.1g of sodium) per 100g

The amount you eat of a particular food decides how much salt you will get from it.

Doctors say we should try to avoid consuming foods that have a high salt content. It is a good idea to select, whenever possible, foods that say "no salt added".

UK traffic light labels

Some UK supermarkets and manufacturers have traffic light colors on the front of the pack. They are designed to help you glance at products and make quick decisions.

• High (red) = eat less amounts of these
• Medium (amber) = these are mostly OK
• Low (green) = these are definitely a healthier choice

How do I know how much salt a portion of food has?

Look at the label. If it says, for example, 1g of salt per 100g, and you consume 500g, you will get 5g. If the label specifies sodium, multiply the amount by 2.5.

The science behind recommendations on salt intake for humans

The Food Standards Agency, UK, aims to reduce the UK's adult population's consumption of salt to 6g per day by 2010. The Food Standards Agency (FSA) advice for salt consumption for adults and children is based on the recommendations of the SACN (Scientific Advisory Committee on Nutrition). SACN is an independent expert committee that advises the FSA and the DoH (Department of Health, UK).

In 1994 COMA (Committee on Medical Aspects of Food and Nutrition Policy) in its report - Nutritional Aspects of Cardiovascular Disease - recommended reducing the average salt consumption of the UK population to 6g per day. The recommendation was based on an association between high salt intake and hypertension (high blood pressure).

SACN reviewed the evidence since 1994. In 2003 SACN concluded that the evidence indicating a link between hypertension and high salt intake had, in fact, increased since 1994. The evidence indicated that current UK salt consumption increases the risk of developing hypertension. Hypertension raises the risk of stroke and premature death from cardiovascular disease. SACN confirmed that people would benefit from reducing their salt consumption to 6g per day maximum. Recommended daily consumption limits for babies and children were also lowered.

Alan Jackson, Chair of SACN, said "Meeting these targets would be of major benefit to public health. Even a small reduction in salt intake could help to reduce the burden of high blood pressure on our population." He added that the maximum salt consumption targets were achievable, and not ideal or optimum intake levels.

According to the FSA, the best way to reduce hypertension is to follow a diet that is low in salt, total fat and saturated fat, and high in vegetables, fruit and low-fat dairy products. People who maintain a healthy body-weight, do not consume too much alcohol, and are physically active are much less likely to suffer from hypertension, says the FSA. A study by Bibbins-Domingo and colleagues estimated that for the US population more than 800,000 life years could be saved for each reduction of 1 gram of salt (A Little Less Daily Salt Could Mean Fewer Deaths Among Americans).

Salt may be a natural anti-depressant

According to Kim Johnson, University of Iowa, rats that are deficient in salt shy away from activities they normally enjoy, like drinking a sugary substance or pressing a bar that stimulates a pleasant sensation in their brains. The researchers say that Evolution might have played an important part in the human hankering for salt. (Study Suggests Salt Might Be 'Nature's Antidepressant').

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Written by - Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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