Are Food Dyes Really Bad For You?

FLORA LICHTMAN: This is Science Friday. I’m Flora Lichtman. What do Flamin’ Hot Cheetos, lime Jell-O, and Kraft 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 1, Yellow 6. 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.

ROBERT F. KENNEDY JR.: 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.

FLORA LICHTMAN: 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.

ASA BRADMAN: Thank you. It’s an honor to be here.

FLORA LICHTMAN: Let’s start with the basics. What are these artificial food dyes made of?

ASA BRADMAN: 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 make them more enticing, to make them fun, and to attract people to food products. And if any of you have children out there often, you know often how fun it is to have a great range of colors, especially with candies. It can make food very attractive.

FLORA LICHTMAN: When did we start expecting that our food was going to be sometimes neon colored?

ASA BRADMAN: 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. We eat 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 is some surprising history with some of these. And then when there was an explosion in chemistry, science, and technical capacity, people recognized 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.

FLORA LICHTMAN: But there was then a backlash to them in the ’70s?

ASA BRADMAN: 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 a growing recognition that there’s some legitimate science about these concerns.

FLORA LICHTMAN: So tell us, what are the impacts of the artificial food dyes we all eat every day?

ASA BRADMAN: I was involved with a project in the State of California that was initially funded by the legislature to ask 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 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 in 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 difficult to assess. But when we looked at the literature, there is enough evidence to really support an association between consumption of artificial food dyes and changes in behavior in children. And now, I want to be clear here that these studies are not showing that there’s long-term induction of, say, ADHD. It may be more of a transient effect.

FLORA LICHTMAN: Well, how long did the behaviors last?

ASA BRADMAN: Well, these studies were often over days or weeks. And so we would think when we look at the metabolism of these chemicals, they get out of your body relatively quickly. We think of alcohol. If you drink some alcohol, you’re tipsy for a bit. It may be something like that where there’s a transient effect.

So I would not expect the impacts to last for 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 are neurotoxic, like lead or maybe some pesticides– if there’s a insult to the neurodevelopmental process early in life, in particular, we can shift that development towards a less optimal outcome.

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.

FLORA LICHTMAN: And do the studies separate out the dye from this 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 foods?

ASA BRADMAN: 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.

We’re talking about ultra-processed 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.

FLORA LICHTMAN: Do we have any idea about the mechanism by which these artificial dyes would cause these neurological effects in kids? Why are they doing that?

ASA BRADMAN: 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 rodents, but provides a model for what may be happening in children.

FLORA LICHTMAN: What about cancer? Is there an association between any of these dyes that people are using now and cancer?

ASA BRADMAN: Well, a lot of the cancer concerns have focused on a dye called Red No. 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 15, FDA revoked the authorization for the use of Red No. 3 based on something called the Delaney clause.

The Delaney clause is a rule that basically states that we can’t add products to a food or use an additive in food that causes cancer. And there was evidence that Red No. 3, 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 the particular cancer that was 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 No. 3 is more likely, for example, to cause cancer in a rodent and less likely in a human.

When we look at some of the other food dyes, it’s less clear about whether they’re associated with cancer. There’s some evidence, if we look, say, for example, at Red No. 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 a few more steps there compared to Red No. 3. But there could be concerns about some of the current food dyes. And again, that’s something that has to be evaluated in future studies.

FLORA LICHTMAN: I know you study lots of exposures, pesticides, flame retardants, metals, VOCs, air quality. I mean, I think the big question that I have around this is, how does this risk or food dye risk compare to the risks of other exposures we face every day?

ASA BRADMAN: 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. It would be unethical to 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 we’re in a unique situation where we have material that’s approved for human consumption.

FLORA LICHTMAN: The experiment’s happening every day in all of us.

ASA BRADMAN: Exactly. So these kinds of structured studies where kids were exposed to a food dye 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 Makary 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 lower risks.

FLORA LICHTMAN: I think the thing that a lot of parents will want to know in particular is 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?

ASA BRADMAN: 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, 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, I’m less concerned about that as an occasional and festive and fun event versus having a product where they might be drinking a beverage or eating candy every day and getting exposed every day, perhaps for breakfast in cereals or lunch and a beverage.

So it’s important to think about chronic exposure versus episodic exposure. And I tend to be more concerned about the chronic exposures. When my kids were little, I wouldn’t say, don’t eat this. Don’t eat that. 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.

FLORA LICHTMAN: 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. And so the burden of risk is not going to fall equitably across people in this country or people in the world.

ASA BRADMAN: Exactly. And I think that’s very important. I mean, the foods that contain artificial food coloring, almost by definition are what we call ultra-processed foods. And 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.

FLORA LICHTMAN: 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?

ASA BRADMAN: 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 carrots.

And many of these products come from plants and nature that we have been eating for generations and 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.

FLORA LICHTMAN: What about consumers? Do you think that consumers can learn to love Earth-toned foods?

ASA BRADMAN: Yes. But 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, I think over time, there can be a response to hear that products that people will continue to love and enjoy.

But I think too colors, they do make food fun. They’re not essential at least in the food environment. So I think over time, we will see the opportunity to have bright colors and the fun associated with that will continue.

FLORA LICHTMAN: Well, thank you for sharing this with us, Asa.

ASA BRADMAN: Thank you so much. It’s really been a pleasure to talk with you.

FLORA LICHTMAN: Dr. Asa Bradman, professor of public health at the University of California, Merced, based in Merced, California.

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