Salt substitute proves elusive
Scientists are still learning how our bodies sense when something is salty. Salt enhancers may be the way to go.
If only science could find a substance that would taste salty without raising blood pressure -- the same way aspartame, saccharine and other sugar substitutes add sweetness without calories.
Researchers have been working for years on the problem -- but creating a salt substitute is a challenge, mostly because scientists don't understand exactly how our salt-sensing system works. The sweet sense is simple: Receptors on the tongue work like locks that send sweet messages to the brain when key-shaped sweet molecules snap into them. It's not hard to create substances that fit into the same sweet locks and trigger the same sweet messages.
Salt doesn't work that way. Instead, scientists think there are holes, or channels, in cell membranes that salt -- and only salt -- can pass through. When that happens, the brain gets a salty message.
Chemists have tested plenty of products over the years in their quest to trick the tongue into sensing salt, with limited success. There was lithium chloride, popular in the 1940s, which sneaked through salt channels and even tasted salty, but was eventually shown to be toxic (it was linked to loss of appetite, nausea, blurred vision, unconsciousness and even death). Most of today's "light" salts mix potassium chloride with sodium chloride (and sodium-free salts skip the sodium chloride altogether), but these products often have a bitter taste.
Other products, such as Benson's Gourmet Seasonings, Mrs. Dash Seasoning Blends and Trader Joe's no-salt spice mixes, contain herbs and spices that aim to distract the palate with extra flavor.
But none taste truly salty.
Some companies are looking to create salt enhancers -- flavorless, nontoxic compounds that would hold salt channels open wider or for longer periods of time after exposure to a little salt, making a small amount taste saltier. With molecules like these, manufacturers could use less sodium in their products but still achieve the same flavors.
The idea, says Gary Beauchamp, director of the Monell Chemical Senses Center in Philadelphia, was inspired by hypertension drugs that do the opposite: They close the channels so salt can't get through.
"There are all sorts of compounds in the patent literature and products that claim to be salt substitutes and enhancers," Beauchamp says. "Every flavor company has its own set of approaches to doing salt substitution."
But so far, there are no salt enhancers on the market, and challenges remain because salt does a lot more to food than make it taste salty. Besides adding flavor, salt affects the water content of sausages, the consistency of cheese and the crispness of pickles. It hinders the replication of harmful bacteria, influences the growth of yeast in bread dough and masks bitter flavors, which may be why vegetables taste so much better with a pinch of salt and why bread tastes horrible without it. Food scientists are working hard to get around these problems.
Emily Sohn is a freelance writer.
health@latimes.com
