Red Dye 40: Allergies, Sensitivity, and Safety


Red Dye 40 is an artificial substance that is commonly used to add red color to foods, drinks, and other products. The Food and Drug Administration (FDA) certifies Red Dye 40 as a safe food additive.

However, some products made with Red Dye 40 use two to three times the FDA’s accepted daily intake (ADI). The health effects of consuming higher amounts of Red 40 are not known.

Also Known As

  • Red 40
  • Red No. 40
  • Red #40
  • Red 40 Lake
  • Allura Red AC
  • FD&C Red No. 40
  • FD&C Red No. 40 Aluminum Lake

Some people have adverse reactions to food additives like Red Dye 40. They may experience side effects if they consume amounts usually considered safe. For example, about 4% of people with food allergies are allergic to food dye as well.

That said, there has not been a lot of research on the subject. Some studies have linked Red Dye 40 to migraines and worsening symptoms of attention-deficit/hyperactivity disorder (ADHD) in kids.

This article will go over what Red Dye 40 is and which products commonly use it. You will also learn about what research has said about the possible health risks of Red Dye 40 for children and adults.

What Is Red Dye 40?

Red Dye 40 is an artificially made food additive that comes from petroleum and oils. The substance is blended with foods to give them a red color. Red Dye 40 is one of the most common food additives in the U.S.

Artificial food colors are more stable than natural food coloring. They’re often used in foods that are intended to have a long shelf life.

Red Dye 40 keeps its color for a long time, but it can break down into its components when the food it’s in goes through changes in temperature or pH—either before or after you eat it.

Red Dye 40 dye and other food dyes may have effects on the body when consumed as well as when they break down into the separate chemicals they’re made of.

Common Foods With Red Dye 40

Red Dye 40 is often added to cereals, beverages, gelatins, candy, puddings, and dairy products. It is also found in over-the-counter (OTC) products like vitamins and pain relievers.

For example, Red Dye 40 can be added to ketchup, yogurt, dips, and other foods to give them a more vibrant color. It can also be mixed with other dyes to get a certain color.

The ingredients and additives, including Red Dye 40, are usually listed on the packages of the foods and other products that you buy. If not, searching for the manufacturer information online may help you find out what’s in a product.


While Red Dye 40 is also approved as an additive in Europe, product labels must state that the dye can be harmful to children.

Red Dye 40 Reactions and Allergies

Allergic reactions to a food can cause tingling and itchiness in the mouth, swelling of the lips, face, tongue, and throat, or hives. True allergic reactions (IgE-mediated reactions) to food coloring are rare.

Some research has suggested that Red Dye 40 might cause hypersensitivity reactions, but the symptoms are not well-defined or consistent.

With artificial food coloring, the chemicals that make up the dye can break down into very small molecules. Sometimes, the body sees these molecules as a threat, especially if they bind with proteins.

In response, the body may launch an attack that causes inflammation, autoimmunity, or even affect a person’s thoughts or actions (neurobehavioral symptoms).

Migraines and Red Dye 40

People who have migraines often have triggers. Food dyes, including Red Dye 40, have been linked to migraines and might be triggers for some people.

It is not known why food colorings would trigger headaches or migraines. Many people who get migraines report having a sensitivity or intolerance to foods that have red or yellow dyes in them.

Other symptoms of food intolerance include nausea, vomiting, diarrhea, or abdominal cramping.

Red Dye 40 and ADHD in Kids

While there isn’t a lot of research on Red Dye 40, most of it has been focused on how it could be linked to attention deficit hyperactivity disorder (ADHD).

Some research has shown that for kids with ADHD, restricting or eliminating Red Dye 40 from their diets can improve their symptoms.

One study suggested that 8% of children diagnosed with ADHD may have symptoms related to eating synthetic food colors, including Red Dye 40.

Research has also suggested that immune hypersensitivity to the chemical components of artificial food dyes could cause the behavioral symptoms that some children with ADHD experience when they consume the dyes.

Most people with ADHD do not notice changes in their symptoms related to food dye. However, a genetic predisposition to a food dye-associated immune reaction could be one reason why some people with ADHD do experience behavioral changes in response to food dyes.

Does Red Dye 40 Cause Cancer?

The long-term effects of Red Dye 40 consumption are still being researched. One question that scientists are trying to answer is whether food additives like Red Dye 40 could cause cancer or increase a person’s risk of getting cancer.

Like many other dyes, Red Dye 40 contains a human carcinogen called benzidine. Carcinogens are substances that have the ability to cause or promote cancer because of how they affect the body.

However, Red Dye 40 has not been linked to any specific type of cancer, and it is not clear how much exposure to the dye could potentially increase the risk of cancer.

Red Dye 40: FDA Safety

Red Dye 40 is one of nine certified color additives approved and regulated by the FDA. These additives are safe “when they are used in accordance with FDA regulations.”

How Can You Tell If You’re Reacting to Red Dye 40?

Reactions to food dyes can range from mild to severe. If you’re having a reaction to Red Dye 40 you might have symptoms like headaches, itchy skin, face swelling, or hives.

Signs of a Severe Reaction to Red Dye

Serious reactions to food dye can cause symptoms like difficulty breathing, dizziness, fainting, low blood pressure, and trouble breathing.

A severe, life-threatening reaction called anaphylaxis is an emergency that requires immediate medical attention.

Many foods and additives can cause symptoms in people who are predisposed to having a reaction.

People who have reactions often notice a pattern of symptoms linked to certain foods, drinks, or medications. However, it can be much harder to see a trend in your symptoms if you haven’t thought of food additives as a possible cause.

For example, a certain brand of cookies or candy can come in different colors. If a person only has a negative reaction to those cookies sometimes (when eating the red ones) they may not make the connection between the brand of cookies and their symptoms.

Is There a Test for Red Dye 40 Allergy?

There are no tests to diagnose a food dye allergy. If you think you might be reacting to Red Dye 40, changing your diet and tracking your symptoms can help you figure out if it’s the culprit behind your symptoms.

If you think you or your child might be having a reaction to food dyes, keeping a food diary and tracking your symptoms can help.

Even with this information in hand, don’t try to diagnose yourself. It’s important that you involve your healthcare provider, and you may need to see an allergist. They can figure out what is causing your symptoms and get the right treatment.

Other Red Food Dyes

While Red Dye 40 has been considered a possible risk factor for some health issues, it is not believed to pose a higher risk than other artificial food additives.

Many processed and packaged foods have red coloring. Other commonly used red dyes include:

  • Carmine (4-aminocarminic acid) is also known as natural red 4. This dye comes from the scale of dried insects. Carmine has been associated with some types of allergic reactions.
  • Citrus Red 2 is another artificial red dye that’s used to color the skin of oranges. It has been considered to be potentially toxic.

These food dyes are not limited to just food and medications. The dyes can also be found in:

  • Personal care products (soaps, lotion)
  • Cosmetics (eye shadow, blush, nail polish)
  • Household products (cleaning supplies, shampoo, Crayons)


If you think Red Dye 40 is causing symptoms or reactions, you’ll need to learn how to read labels on the things you eat and drink, as well as the products you use.

You’ll need to carefully check the ingredients on foods, medications, as well as personal, household, and cosmetic items to see if Red Dye 40 (or the other names it can go by) is listed.


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