Life
It is a truth universally acknowledged that relationships often have one partner who loves salty olives, and another who hates them. But why do some people like salty food over, you know, dessert? The answer, according to science, is more complicated than you might think: it has to with everything from your personality, to your genetics, to a kind of protein found in your spit, according to one study.
Salt may have been crucial to the development of human evolution. It's thought that human hunting patterns may have been influenced by salt licks; as tasty animals gravitated towards salty areas to get their dose of NaCl, humans followed, and consumed salt in their meat. It's a myth that the word salary comes from Roman soldiers receiving their pay in salt (they were paid in money, like any sensible army), but salt has been a huge part of human culture since the ancient world, forming the basis of trade alliances and building up huge empires, even if these days it's seen as little more than a table condiment and a sometime health hazard. Humans require table salt for health and detect its taste on their tastebuds with great accuracy (often far more intensely than sugar). But if you've got a serious salt tooth, there can be other factors involved beyond a craving for tortilla chips.
If You Love Salt, Your Saliva Could Be Partially To Blame
New science has revealed that if you have a tendency to over-salt your food, or seem to have a much higher tolerance for it than others (these pretzels, to paraphrase Seinfeld, are not making you thirsty), part of the issue might be your saliva proteins. The scientists behind the study classified people into sensitive and less sensitive salt-taster groups based on how salty they thought a test substance was, then tested the saliva of both groups. The people in the less sensitive group had lower amounts of endopeptidases, enzymes that break down proteins and are also found in the intestines, in their saliva. It seems that endopeptidases may be a key part of the tongue's ability to taste and detect salt, but it's not clear how people's enzyme saliva levels change or why.
But Saltiness Could Also Be Genetic
Your preference for salty foods could also be influenced by your genes. In 2016, scientists discovered in a study of 1580 Korean people that folks who have a particular variation in the TAS2R38 taste receptor gene are much more sensitive to bitter-tasting foods than those who lack the variation — but, oddly, it didn't make them into sweet-seekers. Instead, the people with the variation sought out far more salt and avoided dark green leafy vegetables (no kale for them), possibly to mask seriously bitter tastes or make food more palatable.
However, the gene's variation appears to have a different effect on children. A 2006 study on the tie between genetics and taste in parents and children found that these genes were closely tied to how much kids liked sucrose and sugary breakfast cereals, but that they didn't seem to have much effect on adult preferences for sweet things. We're not entirely sure why this is, but tastes are also subject to a lot of other elements beyond genetics, including environment and cultural factors.
The More Salt You Eat, The More You Love It
What your parents say is true: The more you have of something, the more you learn to like it, at least when it comes to sweet and salty tastes. We've known about this for a while; a study in 1986 found that people who had their salt intake increased developed higher tolerance for salty soup, while studies throughout the '80s and '90s found that people who'd been on low sodium diets preferred less salt in general. And this influence appears to start young: in a hilarious and kind of disgusting study in 2015 with preschoolers, "infants eating starchy table foods at six months old were more likely to lick salt from the surface of foods at preschool age and tended to be more likely to eat plain salt" than those who'd been given less salty fare. So... that's cool.
It May Also Be Related To Your Personality
An extremely odd study published in Appetite in 2007 reported that there appears to be a link between the kinds of personality traits you have and the kinds of food you like. "For example, participants high in novelty seeking showed strong preference for salty tastes, whereas participants high in reward dependence showed strong preference for sweet tastes," the scientists wrote. And a 1990 study of sweetness and saltiness in adults showed that "the more outgoing individuals liked sweeter lemonade than the more reserved subjects, and subjects who felt they had self-control over their health liked lower levels of salt in broth, while those who felt that chance or others controlled their health liked higher levels." But whether this effect is universally applicable, and what it actually means — whether these things are just correlated, or if one of them causes the other — remains unknown.
