Episode 14: Are Food Dyes Safe to Eat?
In this episode we’re exploring the world of synthetic food dyes – from how they’re used to make food more appealing to the ongoing debates about their safety. Join us as we examine the regulations that govern their usage, navigate through the controversies, and answer the question “are the vibrant colors in our food just a feast for the eyes, or should we be concerned about what they’re doing to our bodies?”
M: I’m Professor Megan
S: and I’m Professor Susan, and we’re
Both: Your Nutrition Profs!
M: We are registered dietitians and college professors who have taught more than 10,000 students about health and nutrition. We have answered a LOT of questions about nutrition over the years –
S: Some we get asked every year and some are rarely asked but very interesting.
M: We’re here to share our answers to these common (and uncommon) nutrition questions with you.
S: So bring your curiosity and let’s get started.
Both: Welcome to our class!
Episode Introduction & Questions
M: Welcome everyone to today’s episode! Susan, what question are we answering today?
S: Today’s question is: Are food dyes safe? You know what? I really like this question but it does have a complicated answer.
M: It really, really does. So let’s start with some definitions.
S: Ok, that’s a good idea. When discussing food dyes the term “color” refers to all the colors including white, black, and gray. While a “color additive” is any chemical or substance that is added to something else that forms color. When color additives are used to enhance the color of food, they are also considered food additives. And this is what we’ll focus on primarily today.
M: Food dyes are used to enhance the natural color of a food or product to make them more appetizing, to add decoration, and to help us immediately identify things like candy flavors, medication dosages, and even left and right contact lenses.
S: One example of a color additive in food is the use of turmeric (which is a bright yellow spice). It is often added to mustard to enhance its color. Or we also use chlorophyll to make mint chocolate chip ice cream green. And coloring foods to make them more appealing- it’s not a modern idea.
Historical Use
M: Colors from plants, animals, and minerals have been used to color foods, drugs, and cosmetics since ancient times. Early Egyptians used several colors in cosmetics and hair dyes. For example kohl, made from the mineral galena mixed with soot, was used to create that signature black eyeliner that we often associate with ancient Egyptians.
S: Go Cleopatra. And in foods and beverages, it’s reported that wine was colored (with things like squid ink) as early as 400 BCE and substances like saffron, paprika, turmeric, beet extract, iron and lead oxides, copper sulfate, and various flower petals were used as food coloring for thousands of years.
M: Interestingly, controversy surrounding the use of food dyes is not a modern issue. In the early 14th century, King Edward I of Britain ordered that bakers who adulterated bread with lime to make it look whiter and to be should be “dragged down the street…. with the faulty loaf hanging around his neck”. And for repeat offenses the baker should be pilloried (or publicly ridiculed) for an hour, his oven destroyed, and be blackballed from ever baking in that city again.
S: Wow, that sounds a little harsh.
M: It does. It’s a little bit aggressive.
S: The French also took this pretty seriously. Adding color to butter was outlawed in the 1300s. So they would use things like saffron or marigold, and even carrot juice. But that got outlawed. By 1574 adding color to pastries to simulate that eggs were used was forbidden. But some of this may have been for good reason. At the time, copper compounds were used to make veggies appear greener… And apparently a poor young woman died after eating pickles that had been infused with copper.
M: Yikes.
S: Similarly, candies often contained vermillion from mercury and red lead to enhance red coloring, copper arsenate for blue, and white lead, all to increase the candy’s appeal to children.
M: In the U.S. ,in the late 1800s and early 1900s, pickles were bathed in copper sulfate, so we did not learn that lesson from the French. And lead chromate was added to milk, which caused a slight yellow tint, but it was added to hide that the milk was diluted with water. When the practice ended, some people actually refused to drink the white milk because they thought it was the one that had been adulterated!
Coal Tar Colors
S: Wow.. well in In 1856, an 18-year old scientist named William Henry Perkin discovered the first synthetic organic dye, it was a purplish color that he called mauve. He had been trying to synthesize an anti-malaria drug from coal tar. And that was the beginning of synthetic dyes as more “coal tar colors” were created.
M: Ok, so what is coal tar exactly?
S: Yeah it sounds kind of nasty, right? Well coal tar is the substance that is leftover when coal is turned into coke… not cocaine, not Coca-Cola. But coke is a solid fuel that contains mostly carbon, and some coal gas. Coal tar is used to produce refined chemicals like creosote and coal tar pitch and) that’s used in roofing, paving, and as a base for coatings and paint, and dyes. It contains many, many chemical compounds including known carcinogens like benzene.
M: So that’s what they use to make synthetic food dyes? That’s scary…
S: It is kind of scary, right? And in the 1880s Congress figured they needed to step in to provide a little bit of oversight for use of these dyes. The USDA Bureau of Chemistry began to research the use of colors in foods… and butter and cheese were the first foods authorized to have added color. By 1900 (so about 20 years later) foods, drugs and cosmetics were artificially colored. Not without harm though. Some were blatantly poisonous (and contained lead, arsenic, and mercury). And some were used to hide inferior or defective foods.
M: It just gets worse and worse...
S: Doesn’t it?
M: We definitely need more regulation! So in 1906 Congress passed the Pure Food and Drug Act. It prohibited the use of poisonous or harmful substances like lead and arsenic or mercury in candies or using colors to conceal damaged or inferior foods. And the USDA was made responsible for enforcing this.
S: A year later the USDA posted a list of seven colors they called “straight colors” and these were approved for use in food. A straight color is something that has not been mixed or chemically reacted with another substance. A voluntary certification program was created for manufacturers of these color additives. And new colors were added to the original seven as they became approved. When the FDA was created in 1927 it took over color regulation from the USDA.
M: By 1931 fifteen straight colors had been approved, most made from coal tar. Six of these colors are still available today.
S: The Food, Drug, and Cosmetic Act (or the FD&C Act) was passed in 1938 to improve upon and replace the previous one because it was not stringent enough to protect the general public from snake oil salesmen that sold dangerous health products. The FD&C Act increased government oversight and introduced stricter requirements for food, drugs, cosmetics, and medical devices.
M: In terms of food colors, the FDA created a naming system, labeling and recordkeeping guidelines, and an approved list for the coal tar color additives that they considered “harmless and suitable” to be used in foods.
S: You still see FD&C today referring to the act on the approved list. The list also contained color additive “lakes” which were a combination of straight colors and substrates that act like a special base material and that holds and strengthens the color.
M: In 1950, several children developed abdominal pain and diarrhea after eating Halloween candy containing large amounts of FD&C Orange #1, one of the original 7 colors approved in 1907.
S: OOPS!
M: Following this the FDA reevaluated its “approved” list.
S: Yes they finally did! They found several dyes on the list, many made from coal tar, which were associated with some serious adverse effects. FDA removed these from the list. And now most approved colors are made from petroleum instead of coal tar, which contains fewer known harmful chemicals. But, still sounds a little crazy.
M: Definitely! The FD&C was amended in 1960 to provide guidelines the FDA must use to evaluate color additives. New rule: A color additive couldn’t be permanently listed unless there was scientific data establishing safety.
S: I mean, that sounds like a good rule to me! Doesn’t it?
M: Definitely!
S: Crazy, right? Prior to this they didn’t have to prove they were safe? Whoa.
M: I know, right? 200 color additives were provisionally listed until they could be evaluated. As of 2021, the FDA has approved 36 food dyes including both synthetic or artificial dyes and natural food dyes derived from plants, minerals, or animals.
Current Regulation
S: So how are these dyes regulated today?
M: Excellent question. The FDA regulates safety, defines adequate intake amounts and labeling guidelines, and approves acceptable uses.
S: So here’s how it works. Each individual batch of artificial dyes must be certified by, get this… the Color Certification Branch of FDA.
M: That sounds like fun!
S: I know, I had no idea that even existed until I did this research. Manufacturers must provide information to these color certifiers about production, storage, and how each batch will be used. Samples are tested for purity, moisture content, and harmful minerals or impurities and that testing takes about 5 days. And that batch cannot be used until it is certified and it MUST be stored separately from other batches.
M: Batches of natural food dyes do not have to be certified, but still need FDA approval before adding them to foods. Most of these are straight colors, not lakes, and they must also comply with purity and use specifications. Make sure to check out our website, YourNutritionProfs.com where we have a blog post all about those natural food dyes because in this episode we’re focusing more on these artificial dyes.
S: Definitely. So once a batch of artificial dyes meets FDA requirements it’s assigned a unique lot number so it would be something like FD&C Yellow #5 lot #1 and these batches are subjected to FDA inspection for continued certification.
M: So then batch owners sell these dyes to food manufacturers and processors for use in their products.
S: To use a new color or to use an existing color in a new way, you have to petition the FDA and provide safety data and use information. The FDA evaluates all of the info, asks for public comment, and, if it’s approved, it puts it on the list.
M: And to use any color additive in food, drugs, etc, the manufacturer MUST comply with the listing regulations issued by the FDA.
S: If they use anything that’s not on the list, the product is considered “adulterated”. If the manufacturer doesn’t invoke a voluntary recall the FDA can take action such as issuing warning letters to the manufacturer or the user.
M: Warning letters are not uncommon and are often sent for simple labeling mistakes. The FDA keeps a list of these on their website. So for example, someone might get a warning letter for the undeclared use of colors in dehydrated papaya or in bakery products like Lemon Poppy and Strawberry muffins.
S: I’ve actually seen on the news, sometimes they’ll post recalls and they’ll say we’re recalling this particular product because something on the label wasn’t right.
M: Yeah.
S: If warning letters don’t work or if the problems are really egregious, the FDA can impose alerts or seize the products.
M: Wow, that's good.
S: It’s kind of brutal but I’m glad they can.
Dye Choice
M: So what makes a dye a good choice for use in food?
S: Well apparently, a good food dye is water-soluble so that it’s going to mix evenly with the food, and after dissolving the color remains.
M: Most consumers think that the color of food products should match taste because “we eat with our eyes”. So for example, orange foods should taste like oranges (except for things like Cheetos, of course),
S: We do not want that to taste like oranges!
M: Red drinks should taste like cherry, strawberry, or raspberry, and purple things should taste like grapes.
S: And I agree with that! I wouldn’t want to eat pink butter, blue chicken, or purple ketchup.
M: I remember purple ketchup.
S: I do too.
M: I remember when that came out. I don’t think it lasted very long.
S: No, because consumers don’t want purple ketchup!
M: Alright, so we process foods, and we add coloring to make them more appealing. If we didn’t use food coloring to liven up the look of some of our foods, things like hot dogs would be gray. And that doesn’t sound appetizing either!
S: No it does not. And as we mentioned previously, natural food colorings are also available and they are used widely. The most common are carotenoids, chlorophyll, and turmeric that we already mentioned, and anthocyanin, and one is derived from an insect – cochineal extract, and that extract’s color lake, carmine.
M: So if there are so many natural food colorings available, why do we NEED artificial ones?
S: Well I’m not sure “need” is the right word… but the main reason artificial dyes are used over natural dyes are they’re cheaper, they extend shelf life, and you can get a wider variety of hues and colors.
M: Oh that makes sense. It’s hard to get the same the bright colors of candy or cereal with natural ones compared to artificial. Synthetic food dyes are especially prevalent in products marketed to children. Studies have found that more than 80% of candies and fruit flavored snacks contain artificial colors.
S: And our food is colored by thousands of different substances, but only 7 synthetic food colorings are FDA approved for widespread use in food. Some sources we found list 9 but 2 of them, Orange B and Citrus Red #2 aren’t used in foods any longer. So the remaining 7 are Blue #1 and #2, Green #3, Red #3 and #40, and Yellow #5 and #6. The last three, Red #40, and Yellow #5 and #6 reportedly account for 90% of all dyes used in foods. They are also the three most commonly linked to potential side effects! Which makes sense if they’re used that much, right?
M: Yes. So all of these color additives are created from crude oil except for Blue #2 which is a synthetic version of the plant-based indigo dye.
S: So you might be thinking - dyes are made from crude oil? Why would we do that? Why would we want that in our food? But if you consume any processed foods, a lot of food additives in addition to dyes are made from petrochemicals. Things like TBHQ (or tert-butylhydroquinone) is found in many foods from frozen chicken nuggets and pizza to rice crackers and cookies. Benzoic acid and sodium benzoate, made from petrochemicals, are used for food preservation and pickling. And BHA and BHT are used as flavoring agents.
M: And that’s not all… Some chewing gum contains petroleum wax, and the active ingredient in pain relievers like Tylenol and Advil and some synthetic vitamins are also made from petroleum.
S: So we consume, already more petroleum products than we think.
M: Absolutely.
Safety
S: So back to our original question, are artificial food dyes safe to consume? This is pretty controversial.
M: For sure! There have been several studies linking some artificial dyes to allergic reactions, cancer in animals, and attention deficit hyperactivity disorder (or ADHD) in children, but these findings have been mixed and inconsistent.
S: And not all of these studies are generalizable to humans. Many studies test on rats and several have very small sample sizes and so they may not be particularly applicable.
M: In my research, I saw that some studies testing food dyes on rats lasted up to two years and comparatively speaking, two years of artificial dye exposure to a rodent is the equivalent of approximately 65 human years, so that’s something to keep in mind.
S: Yeah, definitely. And perhaps dose makes the poison. According to the FDA the Acceptable Daily Intake of total synthetic dyes is 7.0 mg/kg/day, but each dye also has its own acceptable daily limit... to make things even more complicated
M: BUT it’s almost impossible to know exactly how much of each dye is in a product. Food dyes, like all food additives, must be listed in the food’s ingredient list. But the exact amounts of each are not and these dyes have several different names…. So tracking your intake in a typical American diet would be quite difficult.
The Colors
S: Yeah, it would. So let’s talk a bit more about these approved artificial dyes.
M: Blue #1 and #2 are primarily used in beverages and candy. Think blue sports drinks or blue icing on cupcakes. Are they safe? Probably. There have been a few small studies that indicate this dye is actually not well absorbed by the GI system. And if you remember back to our #2 episode, eating foods with blue dye often affect the hue of your poo.
S: You know, I kind of have a story about that.
M: Oh! Tell me.
S: On my mother’s 80th birthday cake, we had bright blue frosting.
M: Ok.
S: And the next day I knew we had bright blue frosting.
M: Oh my gosh.
S: Very common.
M: Yes.
S: Green #3 is rarely used in candy or beverages. And, so because it's so rare, the risk of consuming this color seems to be negligible.
M: Red #3 provides a pink color to foods. In the mid 1980s, the FDA recommended that this dye be banned because of convincing evidence that it could cause thyroid tumors in rats and it WAS actually banned from use in cosmetics and lakes.
S: But it’s still on the food dye list?
M: Yes. Congress did not comply and this is really thought to be due to pressure from the cherry industry and the USDA. At that time Red #3 was used to color maraschino cherries.
S: So just one industry stopped it! Well, I think that happens more often than we think.
M: Unfortunately.
S: Do you like maraschino cherries, Megan?
M: I do but typically only in a cocktail.
S: Oh me too. I’ll have them in cocktails maybe, or a malt. There's a place I get shakes.
M: Why don’t I know about this place?
S: You want me to tell you where it is?
M: Yes, I want a shake!
S: EZ’s!
M: You know, I’ve only eaten there like twice. Well let's do that after this episode.
S: Oh well they have really good shakes We’re not sponsored but we’re open to it
M: Oh my gosh, EZs reach out! Contact us!
S: But…. back to Red #3
M: But now the point about Red #3 and cherries seems to be moot. They use Red #40 instead to get that bright red color. Red #3 is now only used in a few foods – like some cake icing, fruit roll-ups, Skittles, and chewing gums. But it’s still VERY controversial and hopefully Congress will revisit this ban soon.
S: That would be nice. Speaking of Red #40, that Megan just mentioned...it’s the most widely used food dye in the United States! It’s found in so many different foods from sodas to slushies, and juices, candy, breakfast cereals, dairy products, like strawberry milk, Jell-O, puddings, pet food and sausage.
M: I see it listed on all sorts of foods, but it’s also found in over-the-counter medications, dietary supplements, and cosmetics. The Environmental Protection Agency, the Food and Agriculture Organization and the World health Organization all report having a “low concern” associated with Red #40.
S: However, an FDA review committee did acknowledge that there are ‘problems’ with the dye, but evidence of harm was not consistent or substantial. It does contain a chemical called benzidine which is a known human and animal carcinogen that is permitted in low, presumably safe levels in dyes.
M: Right. It’s been linked with allergic reactions, and may increase hyperactivity, and possible irritability in some children. But reportedly only a small number of people are affected and those diagnosed with ADHD may be particularly sensitive. But according to the FDA, ingestion of free benzidine raises cancer risk to just under the ‘concern’ threshold, or one cancer in 1 million people.
S: Hmmm, 1 in a million. That’s interesting how they figure that out.
M: The second most used dye is Yellow #5, which provides a bright lemon yellow color. It’s found in gelatin desserts, candy, cereals, pet foods, juices, and baked goods. It’s also found in cosmetics, shampoos, mouthwash, and paint.
S: And this one is also controversial. There is some evidence that it causes an allergy-like reaction, things like hives, itching, coughing, or vomiting in 0.1% of people, especially those who are aspirin sensitive.
M: Yeah, I was reading that this is the one most linked with allergic reactions. And like Red #40, it too contains benzidine. And if YOU want to limit your intake of yellow #5, be prepared to carry a list of ingredient names with you as there are about 20 different ones for this dye. But most of the names have “yellow” in them so that should help.
S: The last controversial dye is Yellow #6 and it comes in third for most widely used synthetic dye. Some studies indicate it could be a carcinogen in animals but these results are pretty inconsistent. And here in the US, the FDA has concluded that there is no significant risk to humans.
M: But it also contains benzidine, so is it safe?
S: You know, like a lot of things we discuss on this podcast, it’s complicated.
Research & Ongoing Controversy
M: In the 1970s, a pediatric allergist, Dr. Feingold, proposed a link between artificial food colorings and additives to inattention and hyperactivity in children, particularly those with ADHD. His “Feingold Diet” suggested that removing these additives from a child's diet could alleviate behavioral issues.
S: But the diet had very strict rules and it was difficult to follow. Additionally, these early research findings faced skepticism due to research method limitations and lack of conclusive evidence.
M: More recent studies have explored the impact of diet on ADHD, with many showing some link between artificial dyes and children’s behavior but overall, the connection remains complex and is not universally accepted within the scientific community.
S: So this not universal acceptance is clearly demonstrated by differences seen in food dye regulation and use in the US compared to other parts of the world. In the EU, warnings are required on most foods dyed with synthetic color. And the British government has issued public advisories that eliminating certain food dyes might benefit children with hyperactivity or ADHD.
M: The good news is that most companies eliminated artificial dyes from their products sold in Europe so they wouldn’t have to have a warning label. YEA! BUT…they continued to sell the same foods in the U.S. with artificial food dyes in them. As we stated previously, they’re cheaper, more shelf-stable, and provide a brighter color.
S: There has been a little bit of movement on artificial dyes in the U.S. As we mentioned previously, FDA did recommend banning of Red #3 although it remains on the approved list. And in 2011, the FDA conducted a review of food dyes following a Citizen Petition filed by the Center for Science in the Public Interest.
M: Following the review the FDA acknowledged that “For certain susceptible children with Attention Deficit/Hyperactivity Disorder and other problem behaviors, the data suggest that their condition may be exacerbated by exposure to a number of substances in food, including but not limited to, synthetic color additives.” But took no action on requiring additional safety testing of dyes or requiring any type of warning label.
S: But there has been public pressure put on food companies and this has prompted several to pledge to stop using artificial food dyes in at least some of their products. In 2013, Kraft took Yellow #5 and #6 out of its Mac and Cheese and replaced it with paprika, annatto, and turmeric. Yea! And guess what? It’s still a big seller!
M: And in 2015 General Mills reported that they HOPED 90% of its cereals would be free of artificial ingredients by the end of 2016. Kellogg’s even made a similar promise but their goal date was 2019.
S: But none of these companies made their deadlines. General Mills initially took artificial dyes out of cereals like Trix and Lucky Charms, but based on consumer complaints and declining sales, went back to using artificial dyes. However, more than 85% of their cereals now do use natural colors and flavors. Kellogg’s did meet their 90% goal, but were a few years late.
M: Mars has removed artificial colors from dinnertime foods, but not their candies. Mars candies pledged to do it for their products including Skittles, Starburst, and M&M’s. Interestingly, Mars has removed these artificial dyes from their European versions. They said “consumer expectations regarding colors in food differ”.
S: So that’s why they’re still in the U.S.? We like our food- candy brighter?
M: We like our candy brighter!
S: So that’s actually really interesting. So they think American parents aren’t as concerned?
M: No…I mean, I hope not. It’s more likely because the EU actually requires warning labels and the U.S. doesn’t, so they’re not incentivized to make these changes. Some countries like Norway, Finland, and France have actually banned foods that contain dyes like Red #40 so you won’t find any dyed maraschino cherries there!
S: No shakes! You know, it’s really not easy to make these coloring changes. Natural colors don’t perform the same as their artificial counterparts. I mean, General Mills tried to make the change and sales dropped so….. natural colors are not as vibrant or stimulating.
M: Recently a 2021 Health Risk Assessment by the California Environmental Protection Agency reviewed all published studies about dyes and children– especially what they called “challenge studies”. In a challenge study, the children were placed on a dye-free diet for several weeks. Then dyed foods were introduced, sometimes a mixture of dyes, sometimes just Yellow #5, and their behaviors were measured using various standardized methods.
S: They then compared the behaviors before and after the introduction of the dyes. A little over half of the studies reviewed reported evidence of an association between dyes and adverse behavior. But just under half did not report any behavior changes. So you can see why it’s still so controversial and complicated.
M: But overall, they concluded synthetic food dyes are associated with inattentiveness, hyperactivity, and restlessness in some but not all children, and found associations in children both with and without preexisting behavioral disorders.
S: Another thing they looked at was the average total dye exposure for children. And they found that children between ages 5 and 18 – their exposure was 0.22 mg/kg body weight/day – which is well below the 7.0 recommendation from the FDA. And, not surprisingly, Red #40, Yellow #5 and Yellow #6 were the most consumed.
M: The health assessment also concluded that more research needs to be done. We need more research in humans to determine things like
S: And we have mentioned that the EU has warnings in place for dyes…. Well ,the California Legislature this year (2023) took up a bill, AB 418, a proposed ban on the sale of foods containing 5 food additives including Red #3, although this is the only color-related additive. This is the first law of its kind in the U.S. and, if it passes, would take effect January 1, 2025.
M: The EU has already banned these five ingredients. If passed, Californians could no longer buy Skittles, Sour Patch Kids, Hot Tamales, or Campbell’s Chunky Soup unless the formulas were changed. But there is some controversy, of course –
S: Of course...
M: Can a state ban the sales of food containing specific food additives that have been approved by the FDA? I’m sure it’s going to go to the courts.
S: Yeah and at the time of this recording the bill hasn’t passed yet. It’ll be interesting to see how it all plays out….it could be history in the making….
Bottom Line
M: Absolutely… So, bottom line, are artificial food dyes safe?
S: Ok, well…
M: Warning labels may be warranted – especially for Red #3 and #40 and Yellow #5 and #6 – as these are more likely to affect children’s behavior and/or induce allergic reactions in some people.
S: It’s really hard to know how much dye is in your food, even if you look at the ingredients list because there are several different names for each dye.
M: Thanks for joining us today. This was an interesting topic to research - we really hope you enjoyed it!
S: If you did, make sure to rate and review and tell your friends all about it. It helps us so much!
M: If you didn’t like it - don’t tell anyone…
S: And be sure to follow us anywhere you get your podcasts so that you don’t miss an episode!
M: Join us next time for a snack-i-sode all about kefir, a fermented dairy drink with probiotic health benefits.
Both: Class dismissed!
S: We hope you enjoyed this episode. You can find the show notes and a list of sources on our website, yournutritionprofs.com.
M: Your homework is to follow us at your nutrition profs on Instagram and to listen to our next episode. You can listen on Amazon Prime, Apple Podcasts, Spotify, or anywhere podcasts are found. We’d appreciate it if you’d “like” us, write a review, subscribe, and invite your family and friends to join us too.
S: If you have a nutrition or health question you’d like answered, let us know! We may do a show about it! Send an email to yournutritionprofs@gmail.com or click on the “Contact Us” page on our website: yournutritionprofs.com
M: Thanks to Brian Pittman for creating our artwork. You can find him on instagram @BrianPittman77
Both: See you next time!