Should You Be Concerned About Food Dyes?

The controversy around food dyes is confusing. Are they safe or dangerous? Do they cause hyperactivity? Does the U.S. have more of them than other countries (and if so, why)? 

Case in point: Recently, a particular food dye, Red No. 3, was restricted for use in the U.S. A number of people bemoaned to me the loss of the Swedish Fish color they had grown up with and loved. But actually, Swedish Fish do not have Red No. 3. Instead, they contain Red No. 40, which has not been restricted. Except in California, where Red No. 40 will not be allowed in food served at school, starting in 2028. Oh, except for food that is sold at schools as part of a fundraising effort.

Like I said, it’s confusing, and there is a lot of misinformation. “Europe doesn’t allow any food dyes” is a common refrain from people who think they should all be banned in the U.S. But in fact, it does. Most of the food dyes used in the U.S. — nearly all — are also approved for use in Europe. (Here’s an example list from the U.K.) To be clear: the fact that Europeans use food dyes doesn’t automatically indicate that there are no concerns, but I bring this up just to underscore that this particular claim is false.

There are many questions, so let’s get into specifics — beginning with why we use food dyes at all and then answering some of the concerns I hear all the time. 

Why do foods have dyes, anyway?

Foods are dyed colors because it makes them more enjoyable to eat. In research terms, drawing on this summary paper: “Colour is the single most important product-intrinsic sensory cue when it comes to setting people’s expectations regarding the likely taste and flavour of food and drink.”

We evolved to like brightly colored foods, often because they indicated readily available calories (as in fruit). When foods are processed, they lose their color, and food dyes are used to add that color back. Put differently: if strawberry icing on your Pop-Tarts was beige, you wouldn’t like them as much. 

Foods can be dyed with either natural or synthetic dyes. Natural dyes would be, for example, derived from beets (natural dyes are distinct from natural flavorings, but both are produced from plants). Synthetic dyes are made chemically, and tend to be brighter (and cheaper to produce). The FDA has a full list of approved dyes. Food coloring is a food dye, and can also be natural or synthetic, but directly added food coloring at home is only a tiny part of your total consumption of food dyes. 

In talking about food dyes, one common response is: we should eat only natural, whole foods. Food dyes are generally a part of ultra-processed foods, which have their own detractors. But as I have written about before, there is more nuance to the ultra-processed food debate than is often represented in public discussion. It is fairly unrealistic to avoid all ultra-processed foods, and it is not fun. 

Sometimes, food is about enjoyment and joy. Dyes tend to make food more enjoyable, which is good for consumers, but they also enhance demand, which is good for food companies.

It is absolutely true that foods do not need dyes, though, which is why there is a high regulatory bar for including them in food and other products like cosmetics. 

So that’s the “why” on food dyes. Now to the questions and concerns, in no particular order.

What is the deal with Red No. 3?

Red No. 3 (also called erythrosine) is a synthetic food dye — basically, it’s a manufactured chemical that can be used to dye foods or other items a pinkish-red. It was discovered in 1876 and has been used since. 

At this point, a relatively small number of foods use Red No. 3. These include particular brands of candy corn, some (but not all) icing, and some types of cocktail cherries. 

Many safety studies of dyes are performed in animal models — a lot of rats. In male rats, studies have shown that higher doses of Red No. 3 in the food resulted in thyroid issues. It is not clear that this is translatable to humans. The doses are much higher than would be true for humans. In addition, male rats have hormone sensitivities that make it unlikely that the mechanisms there would translate to people. There is no direct evidence of any concerns in humans. 

However, due to the rat data and the high level of caution around dyes, Red No. 3 has been slowly banned from cosmetics over the past several decades. In Europe, the dye is banned from use in foods other than cocktail cherries (it is very hard to get the right cocktail cherry color without this dye). It is allowed for other uses, like pharmaceuticals.

In the U.S., although the dye was not banned as a food additive until this year, many foods have moved away from using it. California banned the use of Red No. 3 several years ago, and that forced many U.S. manufacturers to adjust their formulations. Over the next few years, this dye will be phased out.

Do food dyes cause hyperactivity? 

There are a number of food dyes that have been linked to hyperactivity in kids. Most notable is Red No. 40 (this is the one in Swedish Fish, by the way), but there are blue and yellow dyes that raise the same concerns.

This concern came to the top of many people’s minds in 2022 when the California Office of Environmental Health Hazard Assessment put out a report that suggested that these links might be causal. This report was important in leading to a ban on the use of the dyes in school food in California.

I have written extensively about this particular issue and that report. The evidence in the report is mixed, and I am skeptical about strong conclusions. About half of the studies on this topic find an impact of food dyes on hyperactivity, but half do not. Among those that do, the results are most pronounced when the authors consider parent reports of behavior. In some cases, objective behavior metrics show no impact, even when parents report that children behave worse.

My overall read of this literature — which aligns with what the FDA has said in the past — is that it’s unlikely that these food dyes have any meaningful effect on behavior. Others obviously disagree here, but having looked carefully at the data, it does not seem compelling to me. 

Does Europe ban most food dyes? 

No, it does not. Here is a full list of food dyes allowed in the U.K. This 2017 paper summarizes food dyes that are allowed in the U.S. and in Europe. As the paper notes, there are 39 allowed food colors in the EU and 36 in the U.S. There are several synthetic colors that are allowed in the U.S. and not the EU (Green No. 3, Citrus Red No. 2, and Orange B). There are also 16 additives that are authorized in the EU and not in the U.S., including aluminum, silver, and gold, and nine synthetic-origin colors (things like Patent Blue V and Green S).

The three synthetic dyes that are authorized in the U.S. and not the EU are not commonly used. Orange B hasn’t been used since 1975, Citrus Red No. 2 is used only for marking orange skins, and Green No. 3 is the least used food dye in the U.S. (because you can make green by mixing blue and yellow). 

So the idea that the U.S. is a haven of food dyes while the EU has none is deeply misleading. There are, however, a few differences that do deserve discussion.

The first is Red No. 3, discussed above. It has been disallowed for use in food in the EU for many years and is only now restricted in the U.S. It is allowed in other EU products and in cocktail cherries, but not in any other food.

A second difference is in how Red No. 40 and several other dyes (including blues and yellows) are regulated. In the EU, foods and drinks containing these dyes must be labeled with indications that the dyes could cause hyperactivity. As I noted above, I do not think the data really supports this warning, but it is required in the EU and not the U.S. One result of this requirement is that fewer foods contain these dyes than might otherwise. Manufacturers are more likely to choose plant-based coloring, which is less vibrant but does not require labeling. 

Finally, as of recently, the EU (but not the U.K.) has eliminated the use of titanium dioxide nanoparticles in foods. This is a whitening agent used in, among other things, Skittles. There are concerns, based on studies of cell behavior and some evidence in rats, that these chemicals could be genotoxic, meaning they can damage cells, which could lead to cancer. There is evidence of danger in humans, but the FDA has concluded that the dye is safe, although it restricts the amount that can be used.  

Overall: The claim that Europe does not use food dyes is not correct. There are some additional restrictions in Europe, but also some synthetic food dyes that are allowed in Europe and not the U.S. The additional restrictions rest, in large part, on how much one wants to extrapolate from studies in animals and petri dishes. 

How can you tell which food dyes are in things? 

My read of the evidence above is that, for the most part, one should not overly obsess about avoiding food dyes. 

However, if you decide you want to avoid them, how do you do so? This answer is easy: the ingredient list. Food dyes are listed there (usually at the end), and if you are trying to avoid them, that’s where to look. Often they are explicit, although “artificial colors” may also be listed if the amounts are very small. 

The bottom line

• Foods are dyed colors because it makes them more enjoyable to eat. This also enhances demand, which is good for food companies.
• Concerns about Red No. 3 dye are based on rat studies that are probably not applicable to humans. But also, very few foods in the U.S. and Europe contain this dye anymore. Over the next few years, it will be phased out.
• There are a number of food dyes (Red No. 40 and some blue and yellow dyes) that have been linked to hyperactivity in kids. Based on the data, though, it’s unlikely these food dyes have any meaningful effect on behavior.
• The claim that Europe does not use food dyes is not correct. 
• For the most part, you should not overly obsess about avoiding food dyes. If, however, you decide you want to avoid them, they are included on the ingredient list.

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