Cutting salt intake most important - Healthy diet does not offset increased salt intake

The recommended upper limit of adult salt intake in the UK is 6g a day - around one teaspoon.Previously, experts believed that eating high amounts of fruit and vegetables might help counteract the effect of high salt on blood pressure.The scientists at number of institutions, including Imperial College London and Northwestern University conducted a study to analyse the diets of over 4,000 people and have found out that healthy diet may not offset the harmful effect of sodium on blood pressure. The study has been published in the American Heart Association's.

It's thought that vitamins and minerals in fruit and vegetables might in some way affect blood vessels, enabling them to lower blood pressure.However, while these foods do tend to lower blood pressure, the new research suggests they do not counteract the adverse influence of salt intake.The researchers found a correlation between high blood pressure and higher salt intake, even in people who were eating a high amount of potassium and other nutrients. The researchers estimated salt intake by analysing sodium in the urine, as well as analysing dietary data.

In the study the researchers reviewed data on sodium intake and intake of 80 nutrients, such as proteins, fats, vitamins, minerals and amino acids, that may relate to blood pressure in 4,680 women and men (ages 40-59) in Japan, People's Republic of China, the United Kingdom and the United States participating in the INTERMAP study. The data included sodium and potassium excretion levels in urine collections. Researchers concluded that other dietary nutrients may not reduce the detrimental effects of sodium.

"Regularly consuming excessive amounts of sodium, derived mainly from commercially processed food products, is an important factor in the development of the elevated blood pressure patterns," wrote co-lead author Jeremiah Stamler, M.D. "To prevent and control the ongoing epidemic of prehypertension and hypertension, the salt content in the food supply must be reduced significantly."

About 3/4 of the sodium Americans eat comes from processed, prepackaged and restaurant foods - not from the salt shaker when cooking or at the table. The American Heart Association recommends adults consume no more than one teaspoon of salt (2,300 mg sodium) total per day through all the foods they eat."We're learning more about the role other nutrients play in influencing the blood pressure-raising effects of sodium, and that the focus on sodium remains important," said Cheryl Anderson, Ph.D., vice-chair of the American Heart Association's Nutrition Committee. "Restaurant and prepackaged food companies must be part of the solution because Americans desire the ability to choose foods that allow them to meet their sodium reduction goals."

The American Heart Association convenes food industry leaders and influencers to identify ways to improve the food supply and has developed a sodium reduction campaign to help.The scientists behind the research are now advising people to monitor their salt intake - and for food manufacturers to lower the salt content in their products.

Dr Queenie Chan, joint lead author of the research from the School of Public Health at Imperial, said the research shows the importance of cutting salt intake.

"We currently have a global epidemic of high salt intake - and high blood pressure. This research shows there are no cheats when it comes to reducing blood pressure. Having a low salt diet is key - even if your diet is otherwise healthy and balanced."

She added: "As a large amount of the salt in our diet comes from processed food, we are urging food manufacturers to take steps to reduce salt in their products."

The team acknowledges that because the data was collected over four days, it provides information from a snapshot of time. They now hope to focus on longer-term studies, with a greater number of people.