Salt has a key place at the table of a debate about whether federal dietary guidelines go too far in limiting its consumption.
U.S. Dietary Guidelines set the limit for sodium consumption far lower than what most people consume. Outlining the new guidelines, released every five years and most recently out in 2011, the Los Angeles Times called salt the "latest enemy highlighted in the nation's battle against obesity and poor eating habits." Among government concerns about salt consumption levels, the Centers for Disease Control and Prevention reported that "high sodium intake can increase blood pressure and the risk for heart disease and stroke."
But critics say U.S. Dietary Guidelines on sodium consumption have set the limits too low, posing their own set of health problems. And they note that without the flavor enhancement provided by salt, some senior citizens don't eat adequately, among other challenges.
The salt debate is an oft-heated discussion that has raged for years, notes Britain's Daily Mail: "But some experts are now saying that too little salt might be just as dangerous as too much, and that continuing to drive levels down could actually lead to an increase in deaths from heart disease. A paper published in the American Journal of Hypertension warns that once average daily consumption dips to below 6.35 g, the risk of heart attacks and strokes starts to increase once more."
Why there may be risks with lower levels of salt consumption is not well understood, although some experts say that restricting salt intake may slightly increase the levels of cholesterol and triglycerides. Those are fats linked to heart disease.
The Salt Institute, an industry marketing organization, is one of the most vocal groups questioning what it sees as the demonizing of salt. This week, it issued a news release that says the guidelines hurt the elderly, citing a study last year in the Journal of Hypertension, written by researchers at the Albert Einstein College of Medicine, that found the recommended salt level "is too low and can have dire health consequences including increased morbidity and mortality." It also cited a study by University of Washington researchers published in the American Journal of Preventative Medicine that it said "makes it clear that it is also virtually impossible to have a nutritionally adequate diet when limited to such a low level of daily sodium."
The institute bolstered its case with a study by Harvard researchers published in Metabolism showing that low-sodium diets are linked to more insulin resistance, important to diabetes.
For every study cited, there's a counter viewpoint and criticism of study design, on either side of the discussion.
The federal government took public response to its recommendations during the last quarter of 2011. It drew not only comments from individuals, but a strong response from manufacturers who rely on sodium for flavor or as a preservative in their food products, among others.
Dr. Michael Alderman, a former president of the American Society of Hypertension, is one of the biggest critics of the government efforts to drastically cut salt from the American diet. A professor at the Albert Einstein College of Medicine, he has said his own research indicates that too little salt also increases the risk of heart attacks and strokes, based on examination of 23 studies that look at how salt affects the human body.
But his connection to the Salt Institute has led some to question whether he's biased. He acknowledges that he was paid $750 nearly 20 years ago to attend a meeting on the institute's behalf and he was an unpaid member of its diet advisory board for more than a decade. He notes both of those facts publicly and said he has no conflicts of interest in the salt discussion, just some expertise.
As the debate about salt rages, both sides agree on one thing: Salt is important to the human body and its function. It includes sodium chloride, a compound that helps control how much water circulates in the body, and is crucial to nerve signal transmission, muscle contraction and maintaining the body's chemistry. Its chloride component is needed for digestion and to get carbon dioxide to the lungs, so it can be expelled.
Foods contain trace amounts. But most of the salt in the American diet comes from restaurants and processed foods, as well as the salt shaker on nearly every table in America.
The article in the Mail said that once Britain started an anti-salt campaign, it "is now said to have the lowest salt intake of any developed country in the world." Its experts "say that more lives could be saved if we consumed even less salt. But from time to time, studies have cast doubt on the benefits of salt restriction."
A number of scientists are calling for more studies to look at whether cutting back on salt increases health risk or benefits.