The news must’ve sent product developers diving below their benchtops in shock. On June 13, 2006, the American Medical Association (AMA), Chicago, issued a statement taking the food industry to task for, in the words of AMA board member J. James Rohack, “their current practice of adding unhealthy amounts of sodium to their products.” The group then outlined a list of remedies, including halving the sodium in foodservice and processed foods over the next decade, stepping up education efforts to inform consumers about the benefits of moderate sodium reduction, and clarifying labeling vis-à-vis sodium, with warnings added to the most egregiously saline offenders.
But with all the focus on trans fats and high-fructose corn syrup, we could be forgiven for paying selective attention to what the gadflies at the Washington, DC-based Center for Science in the Public Interest (CSPI) call the “forgotten killer.” Even if salt isn’t the unsung assassin CSPI accuses it of being, the brewing battle over sodium’s health effects—and the need for its reduction in prepared foods—has been simmering on the backburner for years. Now, however, it may be fixing to boil over.
The boiling point
Why cut back on salt? The average American consumes somewhere in the neighborhood of 6 to 10 grams per day, according to the American Heart Association (AHA), Dallas. With salt approximately 40% sodium by weight, that works out roughly to the equivalent of 2,900 to 4,300 mg of sodium.Those sodium totals matter because, according to the National Heart, Lung, and Blood Institute (NHLBI), Bethesda, MD, “There is a clear causal link between habitual sodium intake and blood pressure. The evidence taken as a whole is sufficiently strong to warrant a specific recommendation about reducing dietary salt intake.”
Other factors such as heredity, race, insufficient consumption of calcium, magnesium and potassium, and overall health also influence blood pressure. Nevertheless, the NHLBI cites results from its own INTERSALT trial, along with those of large-scale population studies, showing that “lowering sodium intake by 100 mmol (about 2,300 mg) a day—from 170 mmol (about 3,800 mg) to 70 mmol (about 1,500 mg)—is associated with a 3 to 6 mm Hg reduction in systolic blood pressure.” Among the general population, that would lead to 11% fewer strokes, 7% fewer coronary events and 5% fewer deaths.
With 65 million American adults—almost one-third of us— suffering from hypertension, and with hypertension tied to America’s number-one killer, cardiovascular disease, as well as stroke and other conditions, the healthcare costs alone warrant taking the issue seriously. Thus, the NHLBI, AHA and the 2005 U.S. Dietary Guidelines for Americans all recommend healthy people consume no more than 2,300 mg of salt (about 1 teaspoon) per day. Groups at risk, such as African Americans, the middle-aged and elderly, and those with high blood pressure should pare back to fewer than 1,500 mg per day.
All in good taste
There’s one reason why so many of us max out our daily sodium limits by the time we’ve had our first coffee break: It just tastes so good. And taste is the operative word: Like sweet, sour, bitter and umami, salty is a fundamental taste whose appeal is virtually hardwired into our DNA. “I’ve never met anybody who doesn’t like the taste of salt,” says Naomi Novotny, vice president and cofounder, SaltWorks, Woodinville, WA. “We’re so programmed to like that taste, and I think part of that is because it is so essential to our well-being that it’s just one of those things that we crave.”She’s not kidding, according to Ray Salemme, Ph.D., CEO, Redpoint Bio, Cranbury, NJ. “When you taste salt, it’s a pleasurable experience and it tremendously enhances the taste of many other foods. There’s absolutely no doubt about that,” he says. “The reason that this response has evolved, and the reason that people and, actually, animals have connected it to a pleasurable response is that salt is something that you need as a living organism to maintain all kinds of ionic balances within the body.”
The evolutionary reasoning goes like this: Early humans who took a liking to salt were more inclined to consume essential sodium, along with associated nutrients. More nutrients led to better health, better health led to preferential survival, preferential survival led to increased reproductive success and, eons later, our salt-seeking genes remain an artifact of that natural selection process. “You have sensors for sugar or carbohydrates, which are appetitive, because those are things you need for energy,” Salemme explains. “You have sensors for savory, which are amino acids or nucleic acids, because that’s the protein that you need to get. And you also have an appetitive taste for salt because, as a free-moving animal, you’re constantly excreting salt and taking salt in, in order to maintain your ionic balance.”
One of a kind
That raises the question of how, physiologically speaking, we taste salt in the first place. As it turns out, the mechanics of salt perception are actually quite simple. Sodium ions enter the taste cells on our tongues through embedded ion channels. Once inside, they trigger a signal that sensory neurons transmit to the brain for recognition as salty. Because this ion channel is unique to sodium, “that makes it almost, I’d say, impossible to replicate completely,” says Markus Eckert, technical vice president, flavors, Mastertaste, Teterboro, NJ.
