The Salt of the Earth (Part 2)

Before you add some extra flavoring to your food, sample our show on the health effects of salt.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Neil deGrasse Tyson?

  Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:21Neil deGrasse Tyson?

  Welcome back to StarTalk Radio. I'm your host Neil deGrasse Tyson. I'm an astrophysicist with the American Museum of Natural History in New York City, where I also serve as the Director of the Hayden Planetarium. My co-host this week is the one, the only Eugene Mirman.

• 0:39Speaker 01

  Hello.

• 0:39Neil deGrasse Tyson?

  Hello, hello.

• 0:41Speaker 01

  Hello.

• 0:41Neil deGrasse Tyson?

  As you know, we're continuing our discussion on the science of salt begun in the previous hour.

• 0:46Speaker 01

  So lucky you found a salt comedian.

• 0:50Neil deGrasse Tyson?

  It was tough in the Yellow Pages, you know.

• 0:52Speaker 01

  I know a lot about salt.

• 0:55Neil deGrasse Tyson?

  Previously, in that previous hour, we discussed how salt has flavored human culture and human history.

• 1:02Speaker 01

  We did, yeah. We didn't phrase it that way luckily, but yeah.

• 1:06Neil deGrasse Tyson?

  And in this show, I want to focus differently on salt and find out what role it plays in our human biology, just in life in general, not so much culture, although that culture discussion was, I mean, I learned a lot.

• 1:19Speaker 01

  Yeah, I didn't know all that stuff.

• 1:20Neil deGrasse Tyson?

  Yeah, yeah, that's good.

• 1:22Speaker 01

  I mean, I figured, but now I know for sure.

• 1:24Neil deGrasse Tyson?

  And so we can ask the general question, you know, why do we love salt so much? You know, so many people just love salty snacks and they even prefer that over sweets. Actually, some they combine them, right? They have like the sweet-covered salty pretzel.

• 1:39Speaker 01

  Exactly. Salt is the original heroin.

• 1:44Neil deGrasse Tyson?

  Not heroin as the female hero, but...

• 1:46Speaker 01

  No heroin, the drug that makes you write great songs.

• 1:50Neil deGrasse Tyson?

  And so you wonder, is there some biological reason for preferring salty snacks? I mean, this is a, this is an important question. Just to remind everyone, salt, table salt, sodium and chloride, each of them rather deadly on their own.

• 2:02Speaker 01

  What about, isn't there salt that's iodine, iodinated?

• 2:06Neil deGrasse Tyson?

  Oh, oh, sorry. So what happens is iodine is a, is an important nutrient in the body. And, and back when we were trying to figure out how to keep the country healthy, most of that happened just before, but mostly after the Depression, people found ways to link certain nutrients to different foods that are common. Right, and so you can iodize salt and not would not have it affect the flavor in any fundamental way and still get iodine into the body. And vitamin D dissolves well in fat, so in in milk fat, so you add vitamin D to the milk. You don't put vitamin D in the salt, right?

• 2:41Speaker 01

  Right.

• 2:41Neil deGrasse Tyson?

  So you divide it all up and we have vitamins coming at us from every direction we turn.

• 2:45Speaker 01

  Hmm.

• 2:46Neil deGrasse Tyson?

  And but salt, you know, salt seems to be everywhere.

• 2:49Speaker 01

  Yeah.

• 2:50Neil deGrasse Tyson?

  So here's what happens, what you, once you eat salt, your body breaks it down into sodium and chloride ions.

• 2:55Speaker 01

  Mm-hmm.

• 2:55Neil deGrasse Tyson?

  And ions are like, it's where there's a net charge in the in the atom.

• 2:59Speaker 01

  Yeah.

• 2:59Neil deGrasse Tyson?

  And so that you can do interesting things when you have.

• 3:02Speaker 01

  You could turn it into like a party inside your body.

• 3:05Neil deGrasse Tyson?

  Well, it makes it a little more reactive. I mean, it's it's it's when when you have ions floating around floating around your body. And so sodium ions are are like really important for maintaining your blood pressure. And this is this issue with salt and your blood pressure that we always hear about. There's an intimate relation between the two. So for example, if your blood pressure goes down, just take this as an example, blood pressure goes down, then hormones in your body tell the kidneys to retain sodium. And when you retain sodium, that leads for you to retain water, which increases the volume and the pressure of your blood, bringing the blood pressure back up.

• 3:39Speaker 01

  Would you also be able to just eat a little salt? Would that have a similar effect or no?

• 3:42Neil deGrasse Tyson?

  Uh, well, well, that's that, so both of those work in the same way.

• 3:47Speaker 01

  Right.

• 3:47Neil deGrasse Tyson?

  Because now you have the extra, so so instead of it retaining the the the sodium and then forcing the increase in the water retention, you get the sodium for free, right?

• 3:56Speaker 01

  Right, so blood pressure is just all about having a perfect amount of salt.

• 3:59Neil deGrasse Tyson?

  Uh, in the end, yeah.

• 4:01Speaker 01

  And running and doing a lot of.

• 4:03Neil deGrasse Tyson?

  And eating healthy, right, right?

• 4:06Speaker 01

  Well, eating healthy, but in but with some salt.

• 4:09Neil deGrasse Tyson?

  And sodium ions play a role in muscle contraction and and the firing of your nerves. That's all, that's your electrical system. And in your electrical, I think it was the electrical system.

• 4:19Speaker 01

  Sure, of the body?

• 4:20Neil deGrasse Tyson?

  Of the body, right. You have your plumbing, that's your like your intestines.

• 4:23Speaker 01

  Okay.

• 4:24Neil deGrasse Tyson?

  You got your carpentry.

• 4:25Speaker 01

  And that's what, like your fingertips?

• 4:26Neil deGrasse Tyson?

  No, that's your bones.

• 4:28Speaker 01

  Okay. You, okay.

• 4:30Neil deGrasse Tyson?

  Right, you're plumbing, your carpentry, and you got your electrical.

• 4:33Speaker 01

  And you got your electrical.

• 4:34Neil deGrasse Tyson?

  Right, right.

• 4:35Speaker 01

  And then the roof.

• 4:38Neil deGrasse Tyson?

  So sodium ions, so they play a role there where it's important for controlling the pressure inside of your body's cells.

• 4:45Speaker 01

  Mm-hmm.

• 4:46Neil deGrasse Tyson?

  And what happens if the pressure gets too high or too low, the cell wall can just explode and that would be bad.

• 4:51Speaker 01

  Yes, it would be terrible if you had so little salt you exploded or so much salt you exploded. Either one sounds bad.

• 4:58Neil deGrasse Tyson?

  And the chloride ions, those are great. Those are used for digestion. You know, you know what the acid in your stomach is that digests with? It's hydrochloric acid.

• 5:06Speaker 01

  Is it really?

• 5:07Neil deGrasse Tyson?

  It's gotta get the chlorine from somewhere.

• 5:08Speaker 01

  So you can eat through a table?

• 5:09Neil deGrasse Tyson?

  It could at the right concentration, right. And it's been a mystery over all the years, why doesn't the hydrochloric acid dissolve your own stomach line?

• 5:16Speaker 01

  Yes. That's something I would like to ask you right now.

• 5:18Neil deGrasse Tyson?

  I don't have an answer for that.

• 5:20Speaker 01

  Oh, oh. We're all walking time bombs with melting stomachs.

• 5:24Neil deGrasse Tyson?

  So let's check out our clip. As we learned in the first hour, I had a long interview with Mark Kralinski, the author of Salt: A World History. Not only all the role that salt played in cultures and wars and love and deities, but also just the health of salt, the health considerations. And let's just pick up on that interview with Mark Kralinski, taken in my office at the Hayden Planetarium. Obviously, sweat is salty, tears are salty. So when you are low on salt, your body tends to crave salt.

• 5:58Speaker 02

  If you lack salt in your body, biologically, your body will have this need for salt, but you won't crave salt in the same way that if you didn't have enough water, you would be thirsty, or if you didn't have enough food, you would be hungry. I became aware of this by interviewing World War II veterans in the Pacific, who got very sick, very bad headaches, and just were feeling weak and on the verge of collapse. And they went to doctors and the doctors said, well, it's a lack of salt, and they gave them salt tablets, and then they were better. To a person, the people I talked to were absolutely amazed by this because they had experienced no desire to eat salt. So this is a Kralinski theory with no scientific backing whatsoever.

• 6:40Speaker 02

  But, you know, we really like salt, and almost anybody left to their own devices will eat much more salt than you need to survive. I think the reason for that is we have this built-in desire for salt because our system doesn't tell us, it doesn't warn us of a shortage, so it makes sure that we're just always getting enough.

• 7:01Neil deGrasse Tyson?

  That's the Kralinski theory.

• 7:02Speaker 02

  That's the Kralinski theory.

• 7:07Neil deGrasse Tyson?

  So do you know a full grown adult contains about 250 grams of salt, which would fill about three to four salt shakers, just in case you were wondering?

• 7:14Speaker 01

  I did not. I was both wondering and didn't know that offhand.

• 7:17Neil deGrasse Tyson?

  I know.

• 7:17Speaker 01

  But I now can't wait to go and tell people that myself.

• 7:20Neil deGrasse Tyson?

  You were burning to know this. And the only question about drinking seawater, you know why we can't drink seawater?

• 7:24Speaker 01

  Why not?

• 7:24Neil deGrasse Tyson?

  Because seawater is four times saltier than your blood. That's bad. And so if you were thirsty and you decided to drink seawater, your kidneys would use up the water trying to flush out the extra salt. So then it's actually just counterproductive. You'd actually die from thirst faster if you drank seawater. Crazy. We're done with this segment. But StarTalk returns, more about all the ways salt can season your health.

• 7:59Neil deGrasse Tyson?

  This is StarTalk Radio. I'm Neil deGrasse Tyson, here in studio with my co-host this week, Eugene Mirman. Eugene, thanks for joining me again.

• 8:07Speaker 01

  You're very welcome.

• 8:08Neil deGrasse Tyson?

  And you tweet at Eugene Mirman.

• 8:10Speaker 01

  I do.

• 8:11Neil deGrasse Tyson?

  M-I-R-M-A-N.

• 8:12Speaker 01

  Exactly.

• 8:13Neil deGrasse Tyson?

  And I follow you.

• 8:14Speaker 01

  Yes.

• 8:15Neil deGrasse Tyson?

  I don't know if you follow me too?

• 8:16Speaker 01

  Of course. That's what I know about science.

• 8:18Neil deGrasse Tyson?

  So, yeah, because you don't have to. It's not a prerequisite for being my co-host here, just so you know.

• 8:25Speaker 01

  Yes, no, I understand. I do it of my own free will.

• 8:28Neil deGrasse Tyson?

  I tweet at Neil Tyson if anybody's interested. They're just cosmic brain droppings, actually. So, topic for the show is salt and the flavor it adds to our lives, yes. And in a previous segment, we learned why salt is important for our health.

• 8:42Speaker 01

  Yeah.

• 8:42Neil deGrasse Tyson?

  In an interview that I had in my office with Mark Kralinski, author of Salt: A World History. But the real question that plagues us all is, how much salt is too much salt?

• 8:54Speaker 01

  Yeah.

• 8:55Neil deGrasse Tyson?

  This is what I don't know how much is.

• 8:58Speaker 01

  Well, definitely a glass of seawater is too much, because it has four times as we learned the salt. That's great to know. I always wondered why you can't drink it.

• 9:05Neil deGrasse Tyson?

  Somebody's paying good attention to what's going on here.

• 9:08Speaker 01

  Oh, yeah, I'm taking notes.

• 9:09Neil deGrasse Tyson?

  So, let's check on a clip with Mark Kralinski, find out how much salt is too much salt. That's been a raging debate among nutritionists and doctors and the people who just love their salty snacks. Let's check out, find out what he has to say.

• 9:23Speaker 02

  At that basic cellular level, your body would not function without sodium and chloride.

• 9:28Neil deGrasse Tyson?

  So how much salt do we actually need?

• 9:31Speaker 02

  Can I talk to a doctor on this one? I don't remember the exact amount, but we're talking about a very small amount. As I said, if you eat red meat, you get all the salt you need.

• 9:40Neil deGrasse Tyson?

  But I eat red meat and pretzels and popcorn and all these other salty things, so I'm totally...

• 9:44Speaker 02

  You're way over. You could just eat the pretzels and popcorn. You don't need the meat. The more difficult question is how much salt is too much? Here's where you get into big debates because it's not the same answer for everybody. Our kidneys are designed to deal with excesses of sodium and chloride. And if everything is working the way it should be, you should be able to eat enormous excesses of salt without any consequence. And many people can, but some people can't.

• 10:15Neil deGrasse Tyson?

  So your point is, we should not think of too much salt as a general health problem. It's only a health problem for which it's too much salt.

• 10:24Speaker 02

  Yeah, you know, the health community gets very angry with me about this because, you know, the problem with health officialdom is that they want there to be sweeping rules so that they can catch everybody. And they don't like it when people like me say that some people can eat excesses of salt with impunity because then, you know, everybody will say, "Oh, I'm one of those people." But some people can and some people can't. You get these comparisons. For example, when I get into this debate with health people, they start making comparisons to smoking. It's not the same thing as smoking. Any amount of smoking is bad for you. Any amount of salt isn't bad for you. A certain amount is bad for you.

• 11:10Speaker 02

  And how much that amount is depends on the individual.

• 11:15Neil deGrasse Tyson?

  Limits here. So the the US, the Food and Drug Administration suggest an upper limit for salt intake of five, between five and six grams per day.

• 11:24Speaker 01

  Mm hmm. And how much, what's that the equivalent of?

• 11:27Neil deGrasse Tyson?

  Well, what's and and they want you to take in less if you're known to have high blood pressure or some other health issue. So a gram is one thousandth of a kilogram?

• 11:37Speaker 01

  Yes, no, that so far, but meaning like vaguely like when you see it on a table.

• 11:41Neil deGrasse Tyson?

  So we do it. So watch. So a kilogram is a little over two pounds, 2.2 pounds. Just call it two pounds.

• 11:46Speaker 01

  Sure.

• 11:46Neil deGrasse Tyson?

  So a thousandth of two pounds is a 500th of a pound and an ounce is a 16th of a pound. So 600, this is a 30th of, one gram is a 30th of an ounce.

• 11:56Speaker 01

  Okay.

• 11:56Neil deGrasse Tyson?

  Approximately, just doing that off the top of my head. So a 30th of an ounce.

• 12:00Speaker 01

  The same amount a teenager needs to get high to enjoy a concert.

• 12:03Neil deGrasse Tyson?

  I guess I don't know.

• 12:05Speaker 01

  I'm just guessing.

• 12:06Neil deGrasse Tyson?

  And so, but the, but actual data from people's real food consumption tells us that the average American man consumes more than 10 grams of salt per day, almost twice as much as.

• 12:19Speaker 01

  And that's in their coffee alone.

• 12:21Neil deGrasse Tyson?

  That's right. Well, so, so here's the problem. So of course, increased salt gives you, puts you at risk of high blood pressure and heart disease and stroke and, and some people are more salt sensitive than others and for reasons that aren't always well known, just the genetic spread of what people are in this world.

• 12:40Speaker 01

  Is there a test to find out if you're one of the people who can eat unlimited salt without having no harm done to you?

• 12:46Neil deGrasse Tyson?

  That.

• 12:46Speaker 01

  Is that a test anyone gives somebody?

• 12:49Neil deGrasse Tyson?

  What's funny is some tests, you know that they don't work for you because you died from it.

• 12:53Speaker 01

  Yes, yes, I guess I'll eat a pound of salt later this evening and if I live, I know that I'm finding salt.

• 13:00Neil deGrasse Tyson?

  You are cool eating, eating salt. Now here's an interesting study. So last year in the New England Journal of Medicine, which you read every night before you go to sleep.

• 13:07Speaker 01

  Yeah, I can't fall asleep without reading some, some horrifying medical information.

• 13:11Neil deGrasse Tyson?

  They reported that if people removed a half a teaspoon of salt from their diet. Okay. So that would be like about three grams for, per day, that it would prevent nearly 100,000 heart attacks each year.

• 13:26Neil deGrasse Tyson?

  And that's, you know, if what's weird is people freak out. Do you remember the alar scare with apples? There was like, might have been cancer from the alar on apples and people stopped eating apples.

• 13:36Speaker 01

  Yeah.

• 13:36Neil deGrasse Tyson?

  And, and the, the risk that you would have experienced from that was really low, but that it was any risk at all, people reacted. And so here we have, we can prevent a hundred thousand heart attacks just by reducing it.

• 13:47Speaker 01

  Right. Well, I think if apples were as fun as salt, then it wouldn't have been treated like that.

• 13:52Neil deGrasse Tyson?

  But here's the problem. It's hard to reduce that much salt from our diet because eighty percent of the salt we consume is already in the food when we buy it.

• 14:01Speaker 01

  Right.

• 14:02Neil deGrasse Tyson?

  And the food that, put up the list, you know, who doesn't like potato chips? I love potato chips.

• 14:07Speaker 01

  Yeah. Who doesn't like soups and cheeseburgers? I'm reading from your same list.

• 14:12Neil deGrasse Tyson?

  And no, the thing is with potato chips, I've tried the low salt potato chips. It's like, why am I wasting my time? I can't go.

• 14:17Speaker 01

  Well, then you have to add other spices to cover for them being those.

• 14:20Neil deGrasse Tyson?

  Well, is that what that is with the barbecue flavor?

• 14:22Speaker 01

  Maybe, I mean barbecue, I'm sure is very salty.

• 14:24Neil deGrasse Tyson?

  But just the vinegar flavor?

• 14:25Speaker 01

  Maybe. I mean, probably any chips. Maybe chips is not the thing that you could use.

• 14:29Neil deGrasse Tyson?

  I'm just saying, I can't, you know, when I eat potato chips, I can't think of, you know, this needs vinegar. You know, it's just not a thought I ever have. I, I think there's nothing I've ever eaten where I said, this needs vinegar.

• 14:38Speaker 01

  I don't know. Vinegar makes the soup dumplings delicious.

• 14:42Neil deGrasse Tyson?

  But, you know, pasta and there's a lot of, there's a lot of salt and cheese and of course soups.

• 14:48Speaker 01

  Yeah.

• 14:48Neil deGrasse Tyson?

  Pizza.

• 14:49Speaker 01

  Yeah.

• 14:49Neil deGrasse Tyson?

  You know, and.

• 14:51Speaker 01

  So what you're saying is if you, if you make food for yourself, you'll be fine. And if you eat at a deli where you buy like pizza and chips.

• 14:59Neil deGrasse Tyson?

  I think so, the deli.

• 15:00Speaker 01

  Left to live.

• 15:00Neil deGrasse Tyson?

  Yeah. Deli, it's, you know, deli should have like warning salts or, you know, it's salt.

• 15:06Speaker 01

  I think that was a thing, wasn't it? I think that, that there was talk of there being like a salt warning or limits on salt.

• 15:12Neil deGrasse Tyson?

  Well, actually.

• 15:13Speaker 01

  By the FDA, I believe.

• 15:14Neil deGrasse Tyson?

  In a way, given the previous hour that we discussed salt, delis are like the holdout from another era. Where you preserve the meats with salt and smoke and all these other ways. And so the deli is kinda, and we, we, especially particularly in the, in the, in the, in the big cities, New York and LA.

• 15:32Speaker 01

  Yeah.

• 15:32Neil deGrasse Tyson?

  There's this, you know, you walk by a deli, you gotta, you gotta slow down and maybe step in there. Right, you know.

• 15:37Speaker 01

  And get some salted cold cuts.

• 15:38Neil deGrasse Tyson?

  And then the deli goes in.

• 15:40Speaker 01

  And try and see if you can't kill yourself with them.

• 15:41Neil deGrasse Tyson?

  And they go in for the kill with those huge sweet desserts.

• 15:44Speaker 01

  Right.

• 15:45Neil deGrasse Tyson?

  Because if the salt wasn't good enough to kill you, the dessert will get you. You know, in other cultures, there's not a habit of adding salt.

• 15:51Speaker 01

  Though they have food in other cultures. America's the last country left that still has food. And we make it all salty to try to destroy ourselves.

• 15:59Neil deGrasse Tyson?

  But think of in China and other Asian cultures, that you know, there's soy sauce. It's in the sauces. It's not, there's no salt shaker on the table typically in a Chinese restaurant. And.

• 16:08Speaker 01

  That's big, yeah, but Chinese food's problem is not lack of salt.

• 16:13Speaker 01

  Deliciously salty.

• 16:14Neil deGrasse Tyson?

  And you know, it's fun, I was fun, I was great to learn that in a, in a, in a jar, not jar, a bottle of Worcestershire sauce.

• 16:21Speaker 01

  Mm hmm.

• 16:21Neil deGrasse Tyson?

  You know, the active ingredient in the flavor is an anchovy.

• 16:23Speaker 01

  Oh, really?

• 16:24Neil deGrasse Tyson?

  It's a dissolved anchovy.

• 16:25Speaker 01

  It sounds delicious.

• 16:26Neil deGrasse Tyson?

  Well, they.

• 16:26Speaker 01

  No wonder I like it.

• 16:29Neil deGrasse Tyson?

  And so, you know, it's, it's, one of why you don't like it or.

• 16:32Speaker 01

  No, I love it.

• 16:33Neil deGrasse Tyson?

  Yeah, yeah, it's great, it's great, and I.

• 16:34Speaker 01

  And I love anchovies, they're so salty. Are they naturally salty? It's probably a little salt added, huh?

• 16:39Neil deGrasse Tyson?

  Well, I think they are from salt water, so you get some salt for free.

• 16:42Speaker 01

  Oh, good.

• 16:43Neil deGrasse Tyson?

  But, but, right, and, and, and, so, so it's a, when, when, when you're taking the salt separately. So what you can do is you can say, since so much salt is coming from my diet, I will remove salt shakers from my table.

• 16:55Speaker 01

  Yeah.

• 16:55Neil deGrasse Tyson?

  That would be a very good way to do, to have some force on what, on what you're, what, on avoiding the heart attack that the studies show.

• 17:04Speaker 01

  Right, right, just don't have a salt shaker, who, but who adds like salt to their pizza? Like, who does that?

• 17:10Neil deGrasse Tyson?

  Right, yeah, this pepperoni is not salty enough. You gotta, you know, you gotta, you gotta do this. And, by the way, so, of course, modern salt, we mentioned earlier, has some additives.

• 17:18Speaker 01

  Yeah.

• 17:18Neil deGrasse Tyson?

  Uh, there's the, the, the pouring, uh, I don't know what they use for that. It's, it's an ingredient that they put in so the salt will continue to pour. Because salt loves water and it loves caking, and so.

• 17:30Speaker 01

  That's why some salt shakers are full of rice also.

• 17:32Neil deGrasse Tyson?

  Yes, exactly, the rice absorbs that, and that was the Morton salt, uh, uh, motto, when it rains, it pours. Is that clever?

• 17:40Speaker 01

  Yes. Now I understand.

• 17:42Neil deGrasse Tyson?

  Yeah, you didn't understand that your whole life.

• 17:44Speaker 01

  Yeah, exactly. Because I didn't grow up figuring out why salt was messed up in the 50s.

• 17:49Neil deGrasse Tyson?

  And so there's those additives, and of course, they add iodine to, um, it also prevents goiter.

• 17:55Speaker 01

  Uh huh. Oh, good. Wait, uh, I think we have to wrap up last.

• 17:59Neil deGrasse Tyson?

  Yeah, we'll wrap up now, but we have another segment coming, more about salt, more of my interview with Mark Kralansky, author of Salt: A World History, and we'll be back in the StarTalk Studios. Willie Brass Tyson here with Eugene Mirman.

• 18:17Neil deGrasse Tyson?

  Welcome back to StarTalk Radio. This is Willie Brass Tyson, your astrophysicist host. With me this week is Eugene Mirman. Eugene.

• 18:27Speaker 01

  Hello, Neil.

• 18:29Neil deGrasse Tyson?

  And our tasty topic this week is on salt.

• 18:33Speaker 01

  Yes.

• 18:33Neil deGrasse Tyson?

  And the science behind it. Now, now, you're an expert on salt because you're one of the voices in Bob's Burgers.

• 18:39Speaker 01

  Yes, which is a salt-based cartoon. Yeah.

• 18:43Neil deGrasse Tyson?

  Animated feature on Fox?

• 18:46Speaker 01

  Yes.

• 18:46Neil deGrasse Tyson?

  And, and, and it's some, it's before or after The Simpsons and Family Guy? How do I find it?

• 18:51Speaker 01

  It's, it's after The Simpsons and before Family Guy. They luckily don't air three shows at once and space them out.

• 18:56Neil deGrasse Tyson?

  Simultaneously?

• 18:57Speaker 01

  Yeah, so it's, it's 8:30, 8:30 on Fox.

• 19:01Neil deGrasse Tyson?

  Uh, Eastern Pacific, right?

• 19:03Speaker 01

  Yeah, yeah.

• 19:04Neil deGrasse Tyson?

  The Central.

• 19:04Speaker 01

  And Central's 7:30.

• 19:06Neil deGrasse Tyson?

  Exactly. No one cares about Mountain Time, right?

• 19:07Speaker 01

  No, but they, they know. But when they hear me say this, they're like, ugh, he's skipping Mountain Time.

• 19:12Neil deGrasse Tyson?

  It's, you know, more people live in the metropolitan area of New York than in the entire Mountain Time Zone.

• 19:18Speaker 01

  See?

• 19:18Neil deGrasse Tyson?

  Yeah, that's why.

• 19:19Speaker 01

  That's why I don't even bring it up. Unless my hand is forced.

• 19:24Neil deGrasse Tyson?

  So Bob's Burgers, that makes you an expert on salt.

• 19:26Speaker 01

  Yes.

• 19:28Neil deGrasse Tyson?

  I cannot rely entirely on that. I have my interview clips from Mark Kralansky, who wrote Salt: A World History.

• 19:34Speaker 01

  It's a wise choice to spread out the experts.

• 19:38Neil deGrasse Tyson?

  So, you know, as we know, we have a basic need for salt.

• 19:41Speaker 01

  Yeah.

• 19:41Neil deGrasse Tyson?

  Interesting study, our researchers found that the biological hardwiring in our brain for salt follows the same pathways and nerve cells as some addictive drugs.

• 19:54Speaker 01

  Yes.

• 19:55Neil deGrasse Tyson?

  So...

• 19:56Speaker 01

  It really is the original heroin.

• 19:57Neil deGrasse Tyson?

  That's right.

• 19:58Speaker 01

  I think it actually, or MSG follows the same pathway.

• 20:01Neil deGrasse Tyson?

  Something where you gotta come back and have it and need more of it and even more, and you reach a new plateau of it and then you gotta put more on it, right? I mean...

• 20:09Speaker 01

  Oh, just like an actual drug.

• 20:10Neil deGrasse Tyson?

  That's what I'm saying.

• 20:11Speaker 01

  Where you're like, this is not working anymore. I need a whole bottle of salt and a bottle of whiskey.

• 20:16Neil deGrasse Tyson?

  And it's interesting, we complain, we complain about salt consumption today, but it used to be much higher.

• 20:23Speaker 01

  Right, but that's because they had no other way. Yeah, but people died at 41.

• 20:26Neil deGrasse Tyson?

  I know, I know. Well, so I asked...

• 20:28Speaker 01

  Because they were so salty.

• 20:28Neil deGrasse Tyson?

  I asked Mark Kowalski about this, just to get some insights.

• 20:32Speaker 01

  Good.

• 20:32Neil deGrasse Tyson?

  Into the decrease in our salt consumption. Let's see what he tells us.

• 20:38Neil deGrasse Tyson?

  Data shows that salt consumption is down 50% per capita from a couple of hundred years ago. Is that entirely because we're not eating preserved foods in the way we once did?

• 20:49Speaker 02

  We eat much less salt than we used to because we don't live on a diet of salted food. For instance, you know, in northern countries in the wintertime, almost everything you ate was salted, and also salted, much more salted than it is now. So, in prior centuries, people ate enormous, enormous quantities of salt. And I'd love to know, there doesn't seem to be any way of researching this, what the comparison is on blood pressure, whether people in earlier times had higher blood pressure.

• 21:19Neil deGrasse Tyson?

  I don't know. And with higher blood pressure, there would have been more strokes.

• 21:23Speaker 02

  Yes.

• 21:24Neil deGrasse Tyson?

  And strokes would have been more severe, and so...

• 21:26Speaker 02

  And heart problems.

• 21:27Neil deGrasse Tyson?

  And you go to an old cemetery, half the cemetery, people died, you know, between 50 and 60 or earlier, so it makes you wonder.

• 21:34Speaker 02

  Yeah, yes, but that's also a reflection on our improved ability to treat diseases, not necessarily that we're healthier.

• 21:44Neil deGrasse Tyson?

  But you could ask the question, if we upped salt consumption today, given what we know about excess salt, to the levels of 200 years ago, that would be a fascinating experiment to at least do on paper, what consequences, how many people would die, more people would die each year? That's gotta be a doable thought experiment.

• 22:03Speaker 02

  Yeah, if you upped people's salt, but then you had better treatment for high blood pressure and heart attacks and strokes, would it all level out? The fact that we're even discussing this, I should tell you, means that we have brought on the fury of the American Medical Association, which doesn't seem to think that people should be guinea pigs. I don't know. That's their hangup.

• 22:28Speaker 01

  I do really like the idea of a salt town where 1,000 people's intake of salt goes sky high, and we see if they die or not over a period of decades.

• 22:40Neil deGrasse Tyson?

  It's funny that the guinea pig as a metaphor, it doesn't think people should be guinea pigs, right? Because they're people.

• 22:45Speaker 01

  Right. We should maybe first give salt to guinea pigs.

• 22:48Neil deGrasse Tyson?

  Exactly.

• 22:49Speaker 01

  See how their blood pressure is, and then try it on kids. On human children.

• 22:56Neil deGrasse Tyson?

  So, I don't know if you knew that the United States is the largest producer and consumer of salt in the world. We produce 40 million tons each year.

• 23:05Speaker 01

  I have a feeling that we are the largest producer and consumer of a lot of things.

• 23:09Neil deGrasse Tyson?

  It's true.

• 23:10Speaker 01

  Even probably turmeric.

• 23:11Neil deGrasse Tyson?

  And that's a billion dot billion dollars' worth of salt. And guess what? Only 8% of that is used for food.

• 23:18Speaker 01

  What's the rest of it used for?

• 23:21Neil deGrasse Tyson?

  Well, half of it is used for de-icing roads.

• 23:24Speaker 01

  Right.

• 23:25Neil deGrasse Tyson?

  How do you like that? You've driven by these big salt repositories in municipal centers where they just back up the dump trucks and load up.

• 23:32Speaker 01

  Get a lot of salt.

• 23:33Neil deGrasse Tyson?

  Load up the salt. And, of course, it's had a bad environmental impact. The plants along the side of the road are sort of susceptible to salt.

• 23:41Speaker 01

  Salty. Are too salty.

• 23:43Neil deGrasse Tyson?

  The industry claims 14,000 uses of salt.

• 23:46Speaker 01

  Name 2,000. I mean, I believe you, but just name just 2,000 of them.

• 23:53Neil deGrasse Tyson?

  So, some people still put salt in the water to raise the boiling temperature so you can cook foods a little faster. That's a good one. Also, I do this. I put in a dash of salt while you're boiling vegetables, and it keeps the color of your broccoli bright and green.

• 24:05Speaker 01

  I did not know that.

• 24:06Neil deGrasse Tyson?

  Rather than that faded green you get in canned broccoli. Yeah, yeah. And you also use it, I would do this, it helps make ice cream freeze.

• 24:12Speaker 01

  Yes.

• 24:13Neil deGrasse Tyson?

  The salt is not in the ice cream, but in the surrounding bath.

• 24:14Speaker 01

  Yeah.

• 24:15Neil deGrasse Tyson?

  And here's something you might not have known. You use the salt because it melts the ice at the temperature of the ice. And liquid at that temperature absorbs heat faster than solid chunks do in contact with the ice cream canister. What do you think of that?

• 24:30Speaker 01

  I think you're lying. No, I think that's neat.

• 24:34Neil deGrasse Tyson?

  More when StarTalk continues, I'll tell you how I make my ice cream. On a StarTalk show devoted entirely to salts. We'll see you in a moment.

• 24:50Neil deGrasse Tyson?

  Welcome back to StarTalk. I'm Elyse Grant Tyson here in studio with my host this week, Eugene Mirman.

• 24:58Speaker 01

  Hello.

• 24:58Neil deGrasse Tyson?

  And we are talking about salt and the way it flavors our lives. I was going through a list of the salt industry's claim of 14,000 uses of salt. And you asked me to name 2,000 and I'm prepared to do that now.

• 25:10Speaker 01

  Great.

• 25:12Speaker 01

  Other than, of course, removing rust and making soap go.

• 25:15Neil deGrasse Tyson?

  Well, okay. But I wanted to continue. The ice cream thing is important because there's important thermodynamics that goes on in ice cream.

• 25:21Speaker 01

  Yeah.

• 25:21Neil deGrasse Tyson?

  If you have the ice cream batter, I mean, the mixture in the canister and you start churning it. If it's just simply ice that's around the canister, edges of the ice touch the canister and the heat isn't pulled out of the mixture very, very efficiently. You can plunge your hand into a pile of ice. It's cold, but you're not, you're okay with it.

• 25:43Speaker 01

  But salty ice.

• 25:44Neil deGrasse Tyson?

  If you melt the ice with salt, you are not raising the temperature of the ice. The ice becomes liquid at the same temperature it used to be as ice.

• 25:55Speaker 01

  At 32 degrees?

• 25:56Neil deGrasse Tyson?

  Well, no, even colder. It's just colder ice. It'll melt the ice at 25 degrees. You melt it, now you have water at 25 degrees and water will suck that heat out like it's nobody's business.

• 26:06Speaker 01

  Oh, wow.

• 26:06Neil deGrasse Tyson?

  That's why you'll freeze much faster in water than in any other bath you could put yourself in.

• 26:12Speaker 01

  That's why it's terrible to fall into the ocean off a boat.

• 26:14Neil deGrasse Tyson?

  Off of the Titanic, yes.

• 26:16Speaker 01

  That's just one boat, but I bet any boat, even a small boat, it would be terrible.

• 26:20Neil deGrasse Tyson?

  Yeah. Even small boats.

• 26:23Speaker 01

  Yeah.

• 26:24Neil deGrasse Tyson?

  Well, in my interview with Mark Kralansky, who wrote Salt, A World History, he actually has recipes for food in his book. I had to ask him about it. I said, where's he going with this? Let's find out.

• 26:36Speaker 02

  I think that recipes are great archival material. And it kind of gets misunderstood, you know, this isn't a cookbook. I'm not saying that if you cook this recipe, you'll have a great dish. Many of the recipes I don't even try. I'm interested in the ingredients they use, often the way things are talked about. You can find a lot of interesting things in old recipes. When I did my cod book, I almost put a disclaimer there, you know, don't try this at home, folks. And when the book came out in Icelandic, I went to Reykjavik and they did this big dinner in my honor. And to my absolute horror, they prepared all these dishes that were recipes from my cod book.

• 27:20Speaker 02

  What a horrendous meal that was. Serves me right, I guess.

• 27:25Neil deGrasse Tyson?

  Is there any recipe from your salt book that you have tested and you would recommend for the listener?

• 27:31Speaker 02

  Oh, yeah. Some of the Chinese recipes, which I got from Chinese chefs in Sichuan province, are really good. And there is a medieval Italian recipe for sardines with salt and oranges, which I make all the time. It's great.

• 27:49Neil deGrasse Tyson?

  I noticed that in Chinese restaurant, there's no salt shaker on the table. So there's salt that's apparently infused into the condiments, I guess.

• 27:56Speaker 02

  Well, for the Chinese way of thinking, and it's not a bad way of thinking, actually, the chef decides what the food should taste like.

• 28:04Neil deGrasse Tyson?

  What a concept.

• 28:05Speaker 02

  Yeah. Of course, then you get to the issue of what is the importance of individual choice, which historically has not been prized thing in China.

• 28:14Neil deGrasse Tyson?

  So, you know, early in Earth's history, it's very likely that the oceans were much saltier than they are today because they hadn't had the chance to have these long sustained and long earned salt deposits that then get land underneath the Earth and it locks them away. And all that salt used to be in the ocean. Oceans that then spread into the lakes and the valleys and when those dry up, the salt stays there, gets buried under however many layers of...

• 28:44Speaker 01

  So the sea, so the ocean was much, much saltier.

• 28:47Neil deGrasse Tyson?

  Much saltier, very, it's likely that it was much saltier than it is now, perhaps twice as salty.

• 28:52Speaker 01

  Could you have walked on it? Could you walk across the salty, salty ocean?

• 28:57Neil deGrasse Tyson?

  And so, so essentially because all the salt would have been in the ocean, you can do that experiment, take the salinity of the Dead Sea and you said you could sit in the water.

• 29:07Speaker 01

  You could sit in it, yeah.

• 29:08Neil deGrasse Tyson?

  Yeah, so double, yeah, so double it.

• 29:11Neil deGrasse Tyson?

  Double the salt, we'll see what, what, what comes of it.

• 29:13Speaker 01

  Right.

• 29:14Neil deGrasse Tyson?

  So, so think about it, that, back then, that's when life formed. So, life back then would have been quite salt-loving.

• 29:21Speaker 01

  Yeah.

• 29:21Neil deGrasse Tyson?

  In its day. And what we wonder is whether the Jupiter's moon Europa has, it has a liquid ocean beneath a frozen icy top that has been liquid for billions of years. We're wondering if that's a salt, a salty, a salty lake.

• 29:37Speaker 01

  With some of the same kind of life that existed here billions of years ago.

• 29:40Neil deGrasse Tyson?

  Possibly. And so, one day, I want to go ice fishing on Europa and find out what's...

• 29:44Speaker 01

  I'll take you. I will fold all the stars and we will fly there.

• 29:50Neil deGrasse Tyson?

  Find out if anything comes up and licks the camera lens, because this is exactly what the conditions are that we've got, that spawned life here on Earth. When we come back in our final segment, there's more on what role salt has played in our lives and what salt might be in our future. See you in a moment.

• 30:20Neil deGrasse Tyson?

  Welcome back to StarTalk Radio. I'm your host, Neil deGrasse Tyson. And I'm here with my co-host, Eugene Mirman. And we've been trying to discuss and figure out and...

• 30:29Speaker 01

  Salt?

• 30:30Neil deGrasse Tyson?

  Probe, probe how salt has flavored human history.

• 30:34Speaker 01

  Yes.

• 30:36Speaker 01

  I like that that's every, every back...

• 30:39Neil deGrasse Tyson?

  I'm trying to just, you know, just try to pun it out there. So, you know, have you been to like Whole Foods lately? You can go to like the salt section and you get salt in like 10 different colors. Have you, have you done this?

• 30:49Speaker 01

  Uh, no, but I'm aware of that. I'm aware of lots of different kinds of salt and colors and flavors and like, you know, like smoked salt and stuff like that, truffle salt.

• 30:59Neil deGrasse Tyson?

  Salted salt.

• 30:59Speaker 01

  Salted salt.

• 31:00Neil deGrasse Tyson?

  Truffle salt.

• 31:01Speaker 01

  That's a thing. That's a thing. I think I have it.

• 31:03Neil deGrasse Tyson?

  You got to preserve the salt somehow, so...

• 31:06Speaker 01

  I think it's that flavor not to keep salt salty.

• 31:09Neil deGrasse Tyson?

  So of course, not all of them are white. Some are black, blue, red, green, yellow. And in fact, some dyes actually come from salt.

• 31:18Speaker 01

  Mm hmm.

• 31:18Neil deGrasse Tyson?

  And when I spoke with Mark Kralansky, he wrote, of course, Salt, A World History, and we've been using clips of my interview with him for both of these hours. I asked him about the colored salts, because I see it in grocery stores. And I wonder, you know, they make these sort of backhanded claims like the colored salt is healthier than the regular salt, because you find all these colored salts in the healthy parts of healthy stores, right?

• 31:42Speaker 01

  What do they claim it like it's like, like a magic? Like, what do they claim that it does? Like, healthy how? Like, less?

• 31:49Neil deGrasse Tyson?

  I don't know. I'm just-

• 31:50Speaker 01

  Does Mark know?

• 31:51Neil deGrasse Tyson?

  Saying.

• 31:52Speaker 01

  I hope Mark knows.

• 31:52Neil deGrasse Tyson?

  Let's find out what Mark Kralansky says about other stuff that you find in salt, some of which changes its color.

• 32:01Speaker 02

  A sea salt holding tank is just a piece of seabed that's dammed off, and whatever is in the bottom of that bed, sand, dirt, minerals, can get into the salt. And then there's a process. You can wash salt, because salt has lots of amazing properties. And one of them is that it will only hold water to a certain point. And so if you have enough of a density of salt, the water can go through it without washing it away. So you can wash salt. And it used to be, until modern times, a goal of salt producers to try to get all that stuff out and try to get it as white as possible. The gray salt of Guerin in Brittany, which is now very fashionable, and health people

• 32:46Speaker 02

  keep telling you, eat this, because the gray is so good for you. It was considered a huge problem, and the French government tried to work with them to clean it up, because the Spanish were outselling them, because they were able to get their salt whiter.

• 32:58Neil deGrasse Tyson?

  But I go now to Whole Foods, and there's a wall of salt, and it's a spectrum of salt colors: pink, blue, gray.

• 33:06Speaker 02

  Yeah, all of these colored salt is history reversing itself. The red sea salt from Hawaii, the Polynesians never ate it. And if you read James Cook's diaries-

• 33:18Neil deGrasse Tyson?

  The explorer, James Cook.

• 33:19Speaker 02

  The British explorer, traveling in the Pacific, found that Polynesians had this red sea salt. He tried to eat it, and he wrote, "This stuff tastes terrible." But what he didn't understand is they weren't eating it. They were using it in rituals.

• 33:31Neil deGrasse Tyson?

  And do you know what made that one red?

• 33:32Speaker 02

  Clay. There used to be all kinds of different salts and all kinds of different colors. Every color is an impurity. Sodium chloride is white. And then they figured out, largely the Morton Company, how to make salt consistent both in crystallization and in color, and make all salt the same. And we had that for a half a century. And then, I guess, everybody decided this was boring. And now people, they want to have salt that's different colors. And, you know, a lot of this stuff was the rejects of early industry.

• 34:05Neil deGrasse Tyson?

  So when in doubt, just sell it at a Whole Foods nature place and people just buy it up?

• 34:09Speaker 02

  Yeah, absolutely. And, you know, it's fine. It's not bad for you. But I find the claim that it's better for you to be a little bogus.

• 34:16Neil deGrasse Tyson?

  So all the colors are just like dirt and sediment left over in the salt?

• 34:21Speaker 01

  I didn't know that there was a world of people trying to make salt more fun. I didn't know that that was like a thing you could choose to do with your life.

• 34:28Neil deGrasse Tyson?

  Well, other things, did you know that because our body has very high salinity, salt water is a very good conductor of electricity, which makes you an awesome target for lightning?

• 34:41Speaker 01

  That's why lightning loves people so much.

• 34:42Neil deGrasse Tyson?

  That's why.

• 34:43Speaker 01

  And hates cats because they're just not as salty.

• 34:45Neil deGrasse Tyson?

  Lightning would much rather go through you than through the air. And if you had the option to reach the ground and you provide six foot of nice, conductive, salty, lick body fluid, it'll go sideways into you to get to the ground rather than go from the ground to the cloud as it, you know, lightning strikes backwards.

• 35:04Speaker 01

  Yeah, it starts at the ground and then it flies up.

• 35:06Neil deGrasse Tyson?

  Exactly.

• 35:07Speaker 01

  Out of my hands. So in a way, you can shoot lightning as a person. You just do it once and then you probably burn.

• 35:12Neil deGrasse Tyson?

  And plus, you know, there's all these sort of wet, wet invertebrates that don't like salt, like slugs. Have you ever put salt on a slug?

• 35:21Speaker 01

  I have not. Would, I haven't. And I also don't know what it does. But when we were talking.

• 35:26Neil deGrasse Tyson?

  I don't see how that's possible.

• 35:28Speaker 01

  Well, I don't see how.

• 35:28Neil deGrasse Tyson?

  You're a comedian. How could you have never done this?

• 35:31Speaker 01

  Well, I think it's funny is the amount that you think it would be more reasonable than I had put salt on a slug. Because I don't know, I mean, I don't know where you get a slug. Like, it's not like I grew up like in a sluggy, I didn't grow up in a forest raised by wolves and slugs. What happens when you put salt on a slug?

• 35:49Neil deGrasse Tyson?

  It doesn't like it. Yeah, you kill the slug.

• 35:51Speaker 01

  You kill it? Because what happens?

• 35:52Neil deGrasse Tyson?

  Well, it shrivels up. It sucks out all the water from the slug.

• 35:55Speaker 01

  You know, if you light it on fire, same thing.

• 36:00Neil deGrasse Tyson?

  I'm gonna stop there. I need a tweet of the week. We're running, that's the end of our hour here. How about, I got one, right? How about oceans, lake beds, mines, grocery stores, blood, sweat and tears, exploding stars, sources of sodium and chloride when you need it. That is my StarTalk Tweet of the Week. You've been listening to StarTalk Radio, brought to you in part by the National Science Foundation. Find us on the web at StarTalkRadio.net. I tweet at Neil Tyson. Eugene Mirman tweets at Eugene Mirman.

• 36:33Speaker 01

  Yes.

• 36:34Neil deGrasse Tyson?

  Thanks Eugene for another episode of StarTalk Radio. As always, keep looking up.