Science Friday - Are Food Dyes Really Bad For You?

Episode Date: August 25, 2025

What do Flamin’ Hot Cheetos, lime Jell-O, and Kraft Creamy French Salad dressing have in common? They've all gotten a glow-up from artificial food dyes. Petroleum-based food dyes have become a target of RFK Jr.’s “Make America Healthy Again” agenda—but what does science say about their effects on health? Joining Host Flora Lichtman to discuss is Asa Bradman, an expert in the health effects of food dyes and other things we’re exposed to in our environment.Guest:Dr. Asa Bradman is a professor of public health at the University of California Merced based in Merced, California.Transcripts for each segment will be available after the show airs on sciencefriday.com.Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Hi, I'm Flora Lickman, and you're listening to Science Friday. Today on the show, how worried should we be about artificial food dyes? There's been kind of a growing recognition that there's some legitimate science about these concerns. What do flaming hot Cheetos, lime jello, and craft creamy French salad dressing have in common? Well, for one thing, they have gotten a glow up from artificial food dyes. Think red 40, blue one, yellow six. You have seen them in the small print in the ingredients list. These petroleum-based dyes have become a target of Robert F. Kennedy's FDA.

Food dye is just a no-brainer. Nobody wants to eat petroleum. Everybody knows there's enough science out there that we know it's terrible for you. Do we know that? What do we know? Let's find out. Joining me now is Dr. Asa Bradman, who has studied the toxicity of artificial dyes. He's a professor of public health at the University of California, Merced. Asa, welcome to Science Friday. Thank you. It's an honor to be here.

Let's start with the basics. What are these artificial food dyes made of? So the artificial food dyes are derivative of petroleum products. And they were developed in the early part of the last century and recognized as an ingredient for food as a way to, you know, make them more enticing, to make them fun, and to, you know, attract people to food products. And if any of you have children out there, you know often how fun it is to have, you know, a great range of colors, especially with candies. It can make food very attractive. When did we start expecting that our food was going to be, you know, sometimes neon colored? Well, there's actually a long history of the use of mostly natural food dyes.

So, I mean, turmeric and other ingredients were used to color foods. I mean, of course, a lot of foods are naturally colorful, meat, fruits, and vegetables. Of course, color is part of our natural environment and our food. But early on, there was some kind of slow development of artificial food colors. And in fact, some of the early colors used even things like arsenic. There are some surprising history with some of these. And then when there was an explosion in chemistry, science, and technical capacity, people recognize that we have these really bright colors that we can derive from petroleum products,

and they started to be using in foods. And then they were ultimately reviewed and approved for use in food products. But there was then a backlash to them, right, in the 70s? Yeah. So in the 1970s, there was some. early concerns that came out of some studies that there might be impacts on the health of children, particularly changes in behavior. And over time, there's been a number of studies that have examined that. And as the quality of those studies have improved, and as more of them have been

conducted, there have been kind of a growing recognition that there's some legitimate science about these concerns. Okay, so tell us, what are the impacts of the artificial food dyes we all every day. I was involved with a project in the state of California that was initially funded by the legislature who asked the Office of Environmental Health Hazard Assessment to conduct a risk assessment and review of the literature on artificial food colorings to better understand what the impacts may be. And before I go into that, too, I want to really kind of give a shout out to the state office and Dr. Mark Miller who led many of these efforts. I'm really speaking for a larger group of people who worked really hard on this report. So the concerns have been that there are changes in behavior and

children that are related to exposure that look a lot like what we call ADHD or attention deficit hyperactivity disorder. And so these can be behaviors like difficulty settling down, concentrating or other kind of behaviors that can make it hard to learn or function in some places. And of course, this is a big concern across our society right now because there has been an increase in children with ADHD. And these kinds of things are often, you know, difficult to assess. But when we looked at the literature, there is enough evidence to really support an association between consumption of artificial food dives. and changes in behavior in children.

And now, I want to be clear here that these studies are not showing that there's a, you know, a long-term induction of, say, ADHD. It may be more of a transient effect. Well, yeah, how long did the behaviors last? Well, these studies were often over, you know, days or weeks. And so we would think when we look at the metabolism of these chemicals, they get out of your body, you know, relatively quickly. we think of alcohol. If you, you know, drink some alcohol, you're tipsy for a bit. It may be something

like that where there's a transient effect. So, you know, I would not expect the impacts to last forever in a child's life. But importantly, children, especially very young children, are developing very rapidly and changing very rapidly. So when we look at other kinds of chemicals that we know are neurotoxic, like lead or maybe some pesticides, if there's a insult to the neurodevelopmental process early in life in particular, we can kind of shift that development towards a less optimal outcome. Right. So it may be that exposures to some of these food dyes, we know that they seem to be having an impact on children's brains and neurobehavioral system. So it's possible, especially for very young children, that there could be a long-term effect.

But that's something that hasn't been studied, but I think is important to consider. And do the studies sort of separate out the dye from the ultra-processed foods that you would find the dye in? So that you know that it's actually from the dye itself, not from the ultra-processed food? Yes. But again, there's a range of studies. And they vary in quality. But you raise a good point there. When we look at foods in general in our food system, foods that have artificial food coloring

are also things that have high concentrations of refined carbohydrates, other food additives. You know, we're talking about ultra-process foods that have a range of products that aren't really food, but are designed to make it more attractive or taste a certain way. or stay on the shelf for a long time. I mean, you're right that when we look at the ecosystem, so to speak, of foods with artificial food coloring, they tend to be things that are not healthy. Do we have any idea about the mechanism by which these artificial dyes would cause these neurological effects in kids? Like, why are they doing that?

Well, in looking at the animal studies, there do seem to be impacts on. activity and memory and learning in rodents. And there do seem to be an impact on their ability to remember and learn and solve problems. And then there's also changes in some of the neurotransmitters, which carry signals from one nerve to the next. And there also seem to be microscopic changes in brain structure. So those would be the mechanisms that could underlie changes in behavior, both in, you know, rodents, but provides a model for what may be happening children. Right.

What about cancer? Is there an association between any of these dyes that people are using now and cancer? Well, a lot of the cancer concerns have focused on a dye called Red Number 3. And this particular dye has an interesting history because it was banned by the FDA in, I believe it was 1990, from cosmetics because of concerns about cancer. But just in January 15th, FDA revoked the authorization for the use of red number three based on something called the Delaney Clause. The Delaney Clause is a rule that basically states that we can't use products, add products to a food or use an additive in food that causes cancer. And there was evidence that red number three in particular may be associated with cancer in rodents. And again, it was taken out of cosmetics in 1990, but it was only just in January of 2025 a few months ago that it was taken out of food.

And I don't really understand why there was such a long delay there. I think part of the issue here was that this particular cancer that was identified, identified in rodents, the mechanism of the induction of that cancer may not be the same biological process in humans. So it's possible that this red dye number three is more likely, for example, to cause cancer in a rodent and less likely in the human. When we look at some of the other food dyes, you know, it's less clear about whether they're associated with cancer. there's some evidence, if we look, say, for example, at red number 40, which is a really common dye, that it may be associated with inflammation. And inflammation in the body in the long term

has been associated with cancer risk. So there's kind of a few more steps there compared to red number three. But there could be concerns about some of the current food dyes. And, you know, again, that's something that has to be evaluated in future studies. After the break, how do the risks around food dyes compare to all the other stuff we're exposed to? If your child goes to a birthday party on the weekend and has some cupcakes that are bright pink or something like that, I'm less concerned about that versus having a product where they might be drinking a beverage or eating candy every day. You know, I know you study lots of exposures, pesticides, flame retardants, metals, VOC, air quality.

I mean, I think the big question that I have around this is, how does this risk, the sort of food die risk, compare to the risks of other exposures we face every day? Given that we're observing changes of concern in children based on what are essentially clinical studies, I think that actually raises a particular concern. Another point here to understand, and for most chemical, exposures or toxicological exposures, you can't do essentially a clinical trial with children. You know, it would be unethical to give children, some children, some lead and another children no lead, and then see what the impact is and see if you can identify a safe dose. But, you know, we're in kind of a unique situation where we have material that's approved for human consumption.

The experiment's happening every day in all of us. Exactly. So these kinds of structured studies where kids were exposed to a food die or not under a structured scientific protocol, we can actually do those kinds of studies. So the fact that we're actually seeing changes in behavior in some children does raise concerns for me. And I want to emphasize here that it appears when you look at the literature that some children may be more vulnerable than others. And that's where we have to think about, one, what's going on in terms of vulnerability. But two, given when we look at the weight of evidence in the scientific literature, there's an argument here to look for alternatives. And that's exactly what RFK and Commissioner McHry from the FDA have concluded that there's enough evidence to move these materials out of the food manufacturing.

ecosystem and try to look for alternatives that are likely to have, you know, lower risks. Right. You know, I think the thing that that a lot of parents will want to know in particular is, like, how concerned should they be about this particular risk? And I guess that's what I'm asking. Can you put this risk in context of all the things that parents have to worry about their kids getting exposed to? I think it's something to consider and that it's also an easy one to deal with. I mean, Whole Foods is a good example. There are other natural food stores that will not sell products with artificial food coloring. So it's clear that there's choices out there. To put it in context, though, of larger issues, given the evidence, you know, I think, again, you can make a strong argument

for avoiding these materials. But also we have to think about frequency of exposure and a little bit about age. If your child goes to a birthday party on the weekend and has some cupcakes that are bright pink or something like that, you know, I'm less concerned about that as kind of an occasional and, you know, festive and fun event versus having a product where they might be drinking a beverage or eating candy every day and getting exposed, you know, every day, perhaps for breakfast and cereals or lunch at a beverage. So it's important to think about, you know, chronic exposure versus episodic exposure. And, you know, I tend to be more concerned about the chronic exposures.

You know, when my kids were little, I wouldn't say, you know, don't eat this, don't eat that. You know, if you go to a birthday party, have fun. At the same time, though, I think that there is reason for the food industry to take seriously what the Food and Drug Administration is saying and take this as a challenge to improve products in many of the foods that are marketed in this country. I mean, I think this also gets to the equity piece of this, which is that many of the foods that contain these dyes are cheaper, right? And so the burden of risk is not going to fall equitably across people in this country

or people in the world. Exactly, and I think that's very important. I mean, you know, the foods that contain artificial food coloring, almost by definition, are what we call ultra-processed foods. And, you know, we have things like highly refined carbohydrates, lots of preservatives and other additives, often high in salt. So, it's part of a larger system that's delivering calories and ingredients that we really know are not healthy. The FDA has approved these four new natural-based dyes. Do we know that they're safer? Are they safer just because they're natural? That's a great question. And I think that's something we need to look at going forward. But many of the products that they're approving or that are used as alternatives

to these colors are in foods that we normally eat. And I think we can be confident they're safe, for example, beets and, you know, carrots. And many of these products come from plants and nature that we have been eating for generations and, you know, probably through our whole evolution and development as human beings. But, of course, they should be evaluated seriously, both during the approval process and then over time to make sure that they're safe. What about consumers? Do you think that consumers can learn to love earth-toned foods?

Yes. But, you know, you also have to think about that by earth-tone, you're kind of implying that the natural colors are less bright or vibrant than some of the artificial colors. And I think that's probably true. But having some experience in the food industry and food processing industry, you know, I think over time, there can be a response to here that products that people will continue to love and enjoy. But I think, too, colors, you know, they do make food fun. They're not essential, at least in the food environment. So I think over time we will see,

you know, the opportunity to, you know, have bright colors and the fun associated with that will continue. Well, thank you for sharing this with us, Asa. Thank you so much. It's really been a pleasure to talk with you. Dr. Asa Bradman, Professor of Public Health at the University of California, Merced, based in Merced, California. Thanks for listening. Don't forget to rate and review us wherever you listen. It really does help us get the word out and get the show in front of new listeners. Today's episode was produced by Kathleen Davis.

I'm Flora Lichtman. Thanks for listening.