If people in the UK cut the amount of salt they consumed to the recommended daily maximum, it could prevent one in seven cases of stomach cancer, said the World Cancer Research Fund (WCRF) on Tuesday, after examining the latest figures for diet and cancer incidence.

The recommended daily maximum intake of dietary salt is 6.0 g, about the same as in a level teaspoon.

But people in the UK on average eat 43% more than this: 8.6 g of salt a day.

WCRF say that although there has been a significant downward trend in levels of salt consumed in the UK, from 9.5 g a day in 2000/01, to 8.6g in 2008, the latest year for which up to date figures are available, it is still too much.

The charity bases its estimates on the latest Food Standard Agency statistics on salt intake, and on cancer incidence data from the latest Office of National Statistics (ONS), Public Health Wales Cancer Incidence, ISD Scotland Cancer Statistics and the Northern Ireland Cancer Registry.

WCRF want to see one standardized “traffic light” system on the front of food and drink packaging, to help bring down salt, fat and sugar consumption in the UK.

About three quarters of the salt consumed in the UK comes from eating processed food.

A 2011 survey said one fifth of the salt consumed in the UK comes from bought bread, which contains too much salt. There is a similar pattern in the US, where a federal report shows bread and rolls contribute more salt to the American diet than salty snacks.

WCRF say the UK needs a standard system with traffic light labelling on the front of packaging showing clearly the amount of salt, sugar, fat and saturated fat.

Kate Mendoza, their Head of Health Information, told the press:

“Standardised labelling among retailers and manufacturers – rather than the different voluntary systems currently in place – would help consumers make better informed and healthy choices.”

Cancer Research UK also wants to see standardized labelling as a way to help people control their salt intake:

“Improved labelling – such as traffic light labelling – could be a useful step to help consumers cut down,” Lucy Boyd, an epidemiologist with Cancer Research UK, told the BBC.

She said the WCRF figures confirm a report they published recently: too much salt contributes significantly to the number of stomach cancer cases in the UK.

One area that is confusing with different labels using different standards, is the difference between salt and sodium content.

Sometimes UK food labels don’t show list salt, they list sodium content, as they do in the US. Salt is sodium chloride, and the sodium accounts for 40% of the weight.

So to work out how much salt is in the food whose label lists the sodium content, simply multiply the sodium content by 2.5: thus 0.4 g of sodium x 2.5 = 1 g of salt.

According to the latest figures, there are 7,500 new cases of stomach in the UK a year, with nearly 5,000 deaths due to the disease.

Cutting salt intake to 6.0 g a day would prevent 1 in 7, or 1,000 cases a year, say the WCRF.

It would also lead to other benefits, because salt is linked to high blood pressure, which is a risk factor for stroke and heart disease, and is also tied to osteoporosis and kidney disease.

Mendoza explained that stomach cancer is difficult to treat because most cases are not diagnosed until the cancer is well-established.

Because it is so advanced by the time it is caught, only about 15% of patients live more than 5 years after diagnosis, making stomach cancer the 7th leading cause of cancer death in the UK.

This places even greater emphasis on making lifestyle choices to prevent the disease occurring in the first place – such as cutting down on salt intake and eating more fruit and vegetables,” said Mendoza.

THe WCRF and the Association for International Cancer Research (AICR) maintain the Continuous Update Project (CUP), an ongoing review of cancer prevention research that offers up to date evidence on how a healthy diet and physical activity reduces cancer risk.

A team of scientists led by Dr Teresa Norat at Imperial College London carries out the ongoing systematic literature reviews.

The CUP, which builds on the WCRF/AICR’s 2007 Second Expert Report, is considered the world’s biggest database of evidence on how lifestyle factors, such as food, diet, exercise and weight control affect cancer risk.

Currently, the cancers being updated include breast, colorectal, pancreatic, and prostate cancer. Endometrial, ovarian, bladder and kidney cancers are shortly to be added, and other cancers are also expected to join the database in the next year or two.

Written by Catharine Paddock PhD