Report details salt reduction rationale

27 July 2007

MedWire News: A report by the American Medical Association (AMA) describing the cardiovascular health benefits of limiting sodium consumption has been published in the Archives of Internal Medicine.

The report represents the basis for the AMA’s earlier recommendation, issued in June 2006, that sodium levels should be reduced in processed and restaurant foods. The Archives editor notes that the current article includes developments made both internally by the AMA and in the course of peer review.

Barry Dickinson and Stephen Havas of the AMA, based in Chicago, Illinois, explain that observational studies and randomized controlled trials document a consistent effect of sodium consumption on blood pressure (BP).

They note that even small reductions in population BP distribution yield substantial public health benefits, with a 1.3-g per day lower lifetime sodium intake linked to an approximately 5-mmHg smaller rise in systolic BP as people advance from 25 to 55 years of age.

“This corresponds to a 20% lower prevalence of hypertension and a reduction in mortality rates of 9% for coronary heart disease, 14% for stroke, and 7% for death from all causes and would save 150,000 lives annually,” the authors write.

Furthermore, they note that “the virtual absence of either hypertension or a progressive rise in BP with advancing age in populations with an average sodium ingestion less than 1400 mg per day supports the concept of a threshold above which the risk of harmful cardiovascular disease consequences begins to increase.”

According to the report, most of the world’s population consumes between 2300 and 4600 mg of sodium daily, while the average adult intake in the USA is estimated at 4000 mg per day per 2000 kcal. And around 80% of daily sodium intake now comes from processed foods in most of the western world, with a disturbing 55% increase in sodium intake charted from the early 1970s to 2000 in the USA.

As even motivated individuals find it difficult to moderately reduce sodium intake - because most sodium consumption comes from salt added during food processing and by restaurants - the AMA asserts that a meaningful initiative to reduce the nation’s salt intake will rely on food manufacturers and preparers to act.

Dickinson and Havas say that governmental agencies in England, Ireland, Australia, New Zealand, France, and Finland have been far ahead of the USA regarding salt reduction.

“In Finland, the population-wide decrease in the ratio of dietary sodium to potassium since 1972 is associated with an average population decrease in DBP of approximately 10 mmHg, while deaths from both stroke and ischemic heart disease among 30- to 59-year-old men and women decreased 60%,” they point out.

Arch Intern Med 2007; 167: 1460-1468