In this episode of Tiny Show and Tell Us, we talk about why the FDA recently banned Red Dye No. 3 and how concerned people should be about its use in food. Then we cover icy winter roads and the fascinating science behind clearing them and taking a more sustainable approach that won鈥檛 hurt the environment.
Transcript of this Episode
Sam Jones: Welcome to Tiny Show and Tell Us, the bonus series where you write in with your favorite science news or factoid, we read your email aloud, and then dive deeper. I'm Sam Jones, and I'm here with my co-host Deboki Chakravarti.
Deboki Chakravarti: Hi Sam, I'm excited. Last time we talked about the Big Bang. We also talked about microchimeric cells. That's the thing we talked about.
Sam Jones: Yes.
Deboki Chakravarti: Just a reminder to all of you listeners, that if you want to be featured in one of these episodes, it's really easy. All you need to do is email tinymatters@acs.org or fill out the form linked in the episode description, and you can share with us your favorite little science tidbit that you've learned, and we'll talk about it and it'll be really fun for everyone.
Sam Jones: Yeah, please do. We have a lot of fun with this.
Deboki Chakravarti: Yeah, we do.
Sam Jones: All right, I will hop into it first. This is from listener Diana. Diana wrote saying, "FDA bans red number three artificial coloring, since evidence shows that it can cause cancer and lab animals." I saw this a lot in the news. Did you see this, like鈥�
Deboki Chakravarti: Yes, yeah.
Sam Jones:... when it came out. Okay. I felt like it was everywhere. I'm excited to talk about this because I think, well, I won't spoil anything.
Deboki Chakravarti: Yeah.
Sam Jones: I'll just talk about it. Okay. What is red number three? Also known as red dye number three. It was approved by the FDA for use in food, cosmetics, and pharmaceuticals way back in 1969. Like Diana mentioned, it's an artificial coloring. It's technically a synthetic red-pink food dye called erythrosine. Erythrosine is actually the name that it goes under in Europe, although it's really heavily restricted there and it's used in very few items. Like candied cherries is one of them, which are not the same as maraschino cherries, they're candied cherries. Then I think they're called glac茅 cherries, is how you would say it. Also some candied fruits. But other than that, it's outlawed. I don't know what the workaround was where they're like, we need these candied fruits and we need erythrosine in them.
Deboki Chakravarti: Yeah, yeah. We need them to be red. People will not believe that they're fruits.
Sam Jones: Yeah, exactly. But anyways, I typically think of it in foods like different candies. I'm talking about in the US, like fruit snacks, frosting on cupcakes, maraschino cherries of course, which as a child I was such a big fan of. I'd be like, "Can I please get a Shirley Temple but with 10 maraschino cherries?"
Deboki Chakravarti: That's so funny, because maraschino cherries are why I hated cherries for a long time. I think it was that and Robitussin. I just鈥�
Sam Jones: See, I kind of liked Robitussin. What's wrong with me? I don't know.
Deboki Chakravarti: That's so weird, I'm sorry. I hated them. Then it was not until grad school that I think cherries were on sale, and so my friends were buying them, just buying so many cherries. They're like, "You have to try one finally."听
Sam Jones: Like, a real cherry?
Deboki Chakravarti: Yeah, like an actual cherry. I was like, "Oh, these are good."
Sam Jones: I mean, now as an adult I'm like, "Okay, I'm not really a big fan of maraschino cherries." I still am not anti, but would I take a real cherry over a maraschino cherry? Yes, I would. But anyway, so red number three is used in maraschino cherries and tons of other foods. It's also used in drugs like acetaminophen and cough syrup, and it was used in cosmetics. Apparently also, I found that it's been used in dentistry to show where someone has plaque on their teeth, which I thought was interesting.
Deboki Chakravarti: Oh, interesting.
Sam Jones: I don't know if it still is. That I'm not entirely sure of, but I thought that was still kind of an interesting tidbit. Okay, so red number three has been banned in cosmetics since 1990. It was banned based on data showing that it could cause cancer in rats. Apparently just a couple years later, in 1992, the FDA announced that it would revoke the use of red number three in food and ingested drugs. That'd be something like acetaminophen or what I just mentioned, cough syrup.
Deboki Chakravarti: Yeah.
Sam Jones: That they would revoke it for the same reason: cancer observed in rats. But according to a page on the FDA's website, "The agency decided not to take action at that time given the resources required to move this authorization." That's very vague, but essentially they didn't follow through, for whatever reason. It's important to note that, at that point, there was no data showing that there was concern for red number three in humans. Let's fast forward to 2025, about 33 years later. On January 15th of this year, the FDA did take action by issuing an order to revoke authorizations for the use of red number three in food and ingested drugs. Essentially what they were talking about in 1992, now they're doing in 2025.
Deboki Chakravarti: I see.
Sam Jones: Even though they've put forth this order to revoke authorizations, these things do take time. Manufacturers of food, they will have until January 15, 2027, and manufacturers of drugs will have until January 18, 2028 to reformulate their products. Of course, that means that you may still see red number three as an ingredient in a food or drug product past those dates because it just needs to be manufactured before then. Let's think about how long some candies last. What's the shelf life? I feel like you could still see products, food and ingested drug products on shelves that have red number three until 2030 or whatever, but it's a phase out.
I thought this was interesting. This action is based on something called the Delaney Clause of the Federal Food Drug and Cosmetics Act, which was enacted in 1960 as part of something called the Color Additives Amendment to the Federal Food Drug and Cosmetics Act. So many words. What it does is, "Prohibit FDA authorization of a food additive or color additive if it has been found to induce cancer in humans or animals."
Like I mentioned, for decades at this point, there has been evidence that red number three causes cancer in male rats who have been exposed to high levels of the dye. It has to do with, they think, some hormonal changes. But again, these are very high levels.
Deboki Chakravarti: Yep.
Sam Jones: First, we're not rats.
Deboki Chakravarti: Speak for yourself, Sam.
Sam Jones: Yeah, right. Also, this dye is used in very, very small quantities in the things we're consuming. There is no evidence in humans that red number three causes cancer. There's still no evidence in humans, so I want to be clear about that.
Deboki Chakravarti: Yeah.
Sam Jones: When this news was coming out, on social media, I was coming across a lot of scientists who are saying essentially this is overblown. Tien, who did the research for this episode, I asked her to look into it a little bit, and she found a couple great articles that I'm going to link to that were more nuanced than, "This is bad. This is a bad idea to ban this," or, "this is a good idea to ban this," and really trying to put this ruling into context. I think some of the FDA history stuff we just talked about is some good context.
But also, she came across a PBS article where a scientist named Loren Hoffseth at the University of South Carolina summarized some other animal studies on red number three that found some harmful effects. I'm just going to quote him in the article that he wrote. "Several studies exposing rats and pigs to red number three observed enlarged tumorous thyroid glands and abnormalities in hormone regulation. Red three can have toxic effects on the brain in multiple ways. Rat studies have found that this synthetic dye increases oxidative stress, which damages tissues and reduces the antioxidants that control oxidative stress, impairing communication between neurons."
Red number three, is it good for us? I think scientists would confidently say, no, it's probably not good for us. But, does it have what you'd call carcinogenic potential, the potential to cause cancer? This researcher at the University of South Carolina, Loren would say so. But again, there's still this question of, in what amounts?
Deboki Chakravarti: Right.
Sam Jones: This is my opinion based on what I was reading, and I think Tien felt similarly. But essentially, the best approach here is not to jump to super scary conclusions based off of lab animal data. I think that is a blanket statement across the board.
Deboki Chakravarti: Totally.
Sam Jones: But, is there harm in banning run number three? I don't think so. I mean, the harm is, in my opinion, overblowing the research, freaking people out, and then having that translate to fear of any artificial dye or process. Should red number three dye be banned? I'm not against it, but I also think that people need to, if they can find that nuance, we do not have evidence that this will cause cancer in people.
Deboki Chakravarti: Right.
Sam Jones: Especially because it's in such tiny amounts compared to what it's been used in lab research.
Deboki Chakravarti: Definitely. It reminds me of the California, you know how there's so many things, I forget the name of the law or whatever, but the-
Sam Jones: There's a sticker on so many things you buy.
Deboki Chakravarti: Yeah, and it makes it seem like there's so many things that can cause cancer in California and nowhere else, but it's really just California has these really low thresholds for what they'll put warnings on for potential cancer causing things. There's value to that, but there's also the risk then that you see that warning everywhere, and then you're just like, oh, but then it's meaningless almost. At what point am I supposed to take it seriously?
Sam Jones: Right.
Deboki Chakravarti: Which isn't to say, again, that here we should be keeping red three, but it's just like, how do we approach talking about compounds like this that have some risk, but maybe are not as terrifying as they might seem based on how they're being talked about?
Sam Jones: Yeah, absolutely. This is a scicomm issue.
Deboki Chakravarti: Yeah, for sure.
Sam Jones: This is an effective use of science communication issue for sure.
Deboki Chakravarti: Yep, totally. Well, thank you, Sam. I'm here with something from listener Rose. Yes, this is going to be fun because we're going to be talking about winter, which hopefully is wrapping up here in the United States.
Sam Jones: Oh my gosh.
Deboki Chakravarti: We can't be sure until we make it through June without snow.
Sam Jones: I know. Yeah, I'm like, by the time this episode comes out, I will be very disappointed if it feels like winter.
Deboki Chakravarti: For sure. Rose says, "I work in winter maintenance/deicer space as a chemical engineer, and there's so much interesting research going on in this space. Before working in the winter road maintenance world, I thought winter maintenance was simply storm comes, plows go out, salt goes down. But, it's so much more. From software that can optimize your plowing routes, to making decisions on when and how to apply deicers and how to get the best data to make these decisions, there's a lot of bodies doing these studies like the Transportation Research Board or Clear Roads Research."
Then Rose shared some of her favorite ongoing research. There's one on how to apply deicers and how to minimize their use. There's also more on using real time data on road friction, using floating car data in Sweden to get real time data. We'll talk about that a little bit more as I get into this. First off, I want to say that I was really in a weird head space when I first started reading this. Deicer, it's just spelled the way that you think. It's D-E-I-C-E-R. But, my brain read it as dicer, and I was like-
Sam Jones: Me too, or dee-cer, and I was like, "What's a dee-cer?" Then I looked it up, I should have highlighted it and been like, "Deboki, this is deicer," but I thought that I was just losing my mind.
Deboki Chakravarti: I am so relieved because when I finally, it took me an embarrassingly long time to realize that it was deicer, and I was just like, "I have never heard this word before. This is so cool." But it is still really cool, even when you know what the word is.
I too, like Rose, thought winter maintenance was just like there are plows and there is salt, and you just do it.
Sam Jones: Dump it, yeah.
Deboki Chakravarti: Yeah. I think this is my favorite category of thing that's things that you take for granted in the world around you. Where you're just like, that just works and hopefully things just keep working and you just take it for granted.
Sam Jones: Yeah.
Deboki Chakravarti: Anyways, getting into the actual science. Deicers are things that lower the freezing point of water. Basically it melts ice or prevents it from forming. I was really curious about how often that word deicer comes up in research, so I very unscientifically looked it up on EurekAlert, which is a handy resource for anyone who likes to see press releases on the latest scientific discoveries. I only found eight press releases with the word deicer, but they did sound really cool. I think one of the core things that they're all about is trying to make deicers that are better for the environment.
One of the most recent ones was from Osaka Metropolitan University that's trying to find a better one for the environment. There's also one from 2018 that's looking at beet juice deicers that are supposed to be better. But, it turned out that actually mayflies that were exposed to the deicer didn't do so great. They were retaining more fluid and they had more salt in their blood. They even had salt coming out of their gills apparently, so yeah.
There's also a press release from 2020 about work looking at how frogs that have grown up in ponds that are higher in salt thanks to deicers have worse infections. These are some of the consequences environmentally of deicers that people, I think, are trying to navigate and is why people are looking at finding deicers that are better for the environment. Even if, unfortunately, the beet juice one wasn't great. We were really intrigued by what Rose said about floating car data. I had never heard that term before.
But basically, floating car data is the data that comes from the bajillions of drivers that are out on the road every day. The data is anonymized and it's sent super fast, so it's really helpful for when you want real-time measurements of things like traffic. It can also be used for other purposes, to figure out how to best deploy winter road maintenance. Then Rose also mentioned in what she sent in this idea of residual salt. That's basically salt that's left over. My basic understanding is that what we want to do is see how much salt is left on the road from the last time it got salted, because then ideally you don't have to apply as much salt the next time around. Knowing that residual salt is a way to actually reduce the amount of salt you're having to use overall.
Sam Jones: That's so interesting. I mean, I don't think about it, I guess as much on main roads, but I think about it sometimes on sidewalks where I'm like, "Who did this? This is absurd." The amount of salt is just absurd.
Deboki Chakravarti: Yeah.
Sam Jones: Yeah.
Deboki Chakravarti: That's funny, because I feel like I think of Boston and walking on sidewalks there where you can see which landlords care about not getting in trouble鈥�
Sam Jones: That's true.
Deboki Chakravarti:... and which ones don't. I fully have eaten it on sidewalks in front of a lot of people just because it's so covered in ice. There are researchers working on figuring out residual salt. There are scientists in Sweden who are developing models to predict how much residual salt is left on the road. There are also researchers in Japan who have made a salinity sensor to measure the residual salt. My favorite is that there are scientists at Washington State University who have designed a smart plow. Apparently snowplows have a sensor to look at pavement temperature already, but the smart snowplows look at temperature and also the salt left over from previous saltings so that you can potentially give less salt. Yeah, there's a lot of really cool, interesting technology and science going on in the world of winter roads.
Sam Jones: That is so fascinating. I wonder how slowly you have to be driving for the plow to be able to pick up on salt concentration, because I feel like temperature is pretty easy, but I'm like, salt would be hard.
Deboki Chakravarti: Yeah, and how much distance are you averaging or taking that measurement over? Yeah, that's a great question.
Sam Jones: Right, yeah. No. Oh, that's so cool. I love that though.
Deboki Chakravarti: Yeah.
Sam Jones: That's really fun. We need salted roads so we're not all getting in accidents or wiping out. But also, yeah, sometimes it can be really excessive, and that's obviously not good for the environment or my dog's paws, I want to just say.
Deboki Chakravarti: Oh, do they really suffer?
Sam Jones: Oh, yeah, it hurts a lot. When I bring them inside, we go in through the basement so I can put them in the tub and hose down their feet.
Deboki Chakravarti: That's really cute though.
Sam Jones: Yeah, I know. It's sad and cute. But yeah, it'd be nice to avoid that.
Deboki Chakravarti: Yeah. Well, thanks to Diana and Rose for submitting to Tiny Show and Tell Us, a bonus episode from Tiny Matters created by the American Chemical 中国365bet中文官网 and produced by Multitude. A big thank you to science journalist Tien Nguyen who did the research for this episode.
Sam Jones: You can send us an email to be featured in a future Tiny Show and Tell Us episode at tinymatters@acs.org. Or you can of course fill out the form that is linked in this episode's description. We'll see you next time.
References:
- 听
- 听
- 听听
- 听
- 听
;void(0);){kind=link}