Too much Salt?

Why do we need salt? How much should we be eating? What happens if we eat too much salt – or not enough?

Why do we need salt?

Over the centuries, salt has been a highly valued commodity, traded and fought over for its unique place in flavouring and preserving our food. Our bodies need the sodium in salt to work properly. For example: 

  • For our muscles and nerves to work properly
  • To maintain blood volume and blood pressure
  • To help absorb nutrients in the gut 

How much should we be eating?

Individual salt intake should be no more than 6g per day (approximately 1 teaspoon. That’s according to the NHS. Some health experts had recommended reducing this further by 2025. However, a large study published in The Lancet in 2106, suggested that too little salt increases the risk of heart attack and stroke. This suggests what is known as a U-curve effect i.e too much or too little is bad for our health. While research continues 6g per day seems a reasonable target.

Salt consumption has fallen in recent years, as a result of changes such as less salt in bread. However, according to research published by Public Health England in 2016, most of us still consume around 8 g per day i.e more than is recommended. This is mainly due to our consumption of 'hidden' salt in processed foods. Each gram of salt contains 0.4 grams of sodium. 

What happens if we eat too much salt?

High levels of sodium consumption are associated with hypertension and increased risk of Cardiovascular Disease (CVD) and stroke. CVD is a leading cause of death worldwide, according to the World Health Organisation. 

An independent scientific review published in the prestigious New England Journal of Medicine in March 2013 and in a meta analysis published in April 2013 agree that reduced sodium intake results in lower blood pressure and consequently reduced risk of CVD and stroke. 

In addition, a high sodium diet flushes calcium from the bones. This heightens the risk of osteoporosis, renal stones, loss of muscle mass and age-related renal failure.

Salt is also a “probable cause of stomach cancer” according to The World Cancer Research Fund. Recent research even suggests that too much salt can hasten cognitive decline as we get older.  

However, some reports have queried the research into salt’s effect on blood pressure on the grounds of insufficient sampling techniques, so further trials are recommended to establish parameters for sodium in the diet.  

What happens if we eat too little salt?

Sodium deficiency is rare in our diet, because so much of the food we eat contains salt. However, it can occur, particularly in the elderly, for example where salt is being lost through severe diarrhoea and vomiting. The symptoms are not usually very specific and can include headache, vomiting, fainting and fatigue. In the most severe, rare cases it can lead to more serious consequences such as coma and brain damage.

As reported above, a 2016 study published in The Lancet suggests that too little salt can increase the risk of heart attack and stroke. 

Where does most of the salt we eat come from?

Up to 80% of our salt consumption in the UK comes from processed food.  This includes most ‘fast foods,’ snacks and bottled sauces and most processed meats (like sausages and luncheon meat) – and even less obvious sources, like bread and breakfast cereals. Click here for more information on how to reduce your salt intake.

Conclusions

  • We all need some salt to stay healthy– but only around 6g (around a teaspoon) a day, less than most of us currently consume.
  • So we should eat less processed food, as this is usually the main source of salt in our diet.
  • This will reduce the risk of a range of illnesses, from heart disease and stroke to osteoporosis and kidney failure - without reducing our salt levels so drastically that this leads to possible health risks. 

Rachel Laughton-Scott  September 2013, Reviewed and updated by Devika K K Jethwa  December 2016, Next review date December 2019

How much salt?

Salt reduction tips

Reduce your salt intake