Eating too much salt is a significant risk factor in developing high blood pressure, which can lead to heart disease and stroke, notes the FSA. Studies show that reducing salt in the diet can lower blood pressure within four weeks. Approximately 75% of salt consumed is from processed foods, 10-15% is added by consumers and 10-15% is naturally present in food.

Salt Content Varies Widely

The UK survey looked at the salt content in the canned, fresh/chilled and dried soup categories and results showed wide variation within each category and flavor of soup. The dried soup category ranged from 1.2g to 2.9g of salt per serving, while two brands of canned mushroom soup contained twice the amount of salt of another canned mushroom brand. No brand was consistently high or low in salt.

The recommended maximum daily intake for salt is 6g, according to FSA, and adults typically exceed that level by 3.5g. The Agency launched a public health campaign in September 2004 to highlight the risk of eating too much salt and the increased risk of high blood pressure, heart disease and stroke.

"The results show a considerable variation in the level of salt in soups," says Gill Fine, Director of Consumer Choice and Dietary Health, Food Standards Agency. "We welcome the commitment that some manufacturers and retailers have made to reduce salt content in soups, but the fact that such a popular and convenient food can provide more than a third of the daily salt limit shows that continued effort in this area is still needed."

Americans, Canadians Also Eat Too Much Salt

In a report earlier this year, the U.S. Institute of Medicine (IOM) of the National Academies set the tolerable upper intake level (UL) of salt -- the maximum amount that people should not exceed -- at 5.8 grams of salt (2.3 grams of sodium) per day.

Older individuals, African Americans, and people with chronic diseases including hypertension, diabetes, and kidney disease are especially sensitive to the blood pressure-raising effects of salt and should consume less than the UL, the report says.

More than 95 percent of American men and 90 percent of Canadian men ages 31 to 50, and 75 percent of American women and 50 percent of Canadian women in this age range regularly consume salt in excess of the UL.

Potassium Blunts Effects of Salt

To lower blood pressure, blunt the effects of salt, and reduce the risk of kidney stones and bone loss, adults should consume 4.7 grams of potassium per day, receommends the IOM. However, most American women 31 to 50 years old consume no more than half of the recommended amount of potassium, and men's intake is only moderately higher.

Canadians typically eat more potassium than their American counterparts. African Americans in the United States generally get less potassium than non-Hispanic whites, and because they have a higher prevalence of elevated blood pressure, increased potassium intake may have particularly significant benefits for them.

The typical Western diet is high in salt and low in potassium -- the opposite of what evidence shows is optimal for good health and reducing the risks of chronic disease, the IOM report says.

Key: Less Sodium, More Potassium

"Research is needed to find ways to help people select better food choices to reduce their salt intake and boost their potassium consumption," Lawrence Appel, chair of the panel that wrote the report and professor of medicine, epidemiology, and international health, Johns Hopkins University, Baltimore.

In addition, because Americans and Canadians get the majority of their salt -- 77 percent, according to one study -- from prepared and processed foods, research should be done to help food processors develop alternative technologies that can reduce the amount of salt added during processing without impairing taste, shelf-life, or product qualities at an affordable cost.

Soup Survey Results

The UK Soup survey results are available at the Food Standards Agency website.

Advice on how to reduce salt intakes can be found on the FSA's dedicated website.