Red 40 is a common artificial food dye made from petroleum. Manufacturers typically add red 40 to foods and beverages to enhance natural color, add extra color, or help identify certain flavors.

There are currently no restrictions on using red 40, and the food dye has Food and Drug Administration (FDA) approval. However, some research suggests that there may be some negative health effects of consuming this food dye.

In this article, we will look further into the safety of consuming red dye 40, any associated allergies, possible behavioral changes, related health conditions, and how a person can identify red 40 in foods and drinks.

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According to the FDATrusted Source, approved color additives, including red dye 40, are safe to consume as long as a manufacturer follows FDA guidelines when adding them to foods and drinks.

The World Health Organization (WHO) suggests that average exposure to red 40 through food and drink consumption does not pose a health concern.

A more recent 2023 study in mice suggests that consuming red dye 40 may cause DNA damage and colonic inflammation, which may lead to colorectal cancer. However, the results of animal studies do not necessarily apply to humans, and the authors state that more studies in humans are necessary.

A 2021 review of both animal and human studies also suggests that consuming red dye 40 may result in changes in the brain, such as changes in brain activity, memory, behavior, and brain structure.

Red dye 40 may contain benzene. According to the American Cancer SocietyTrusted Source, benzene exposure can increase the risk of developing cancer.

According to an older 2017 review, there is evidence to suggest that consuming artificial food dyes, such as red dye 40, can cause an allergic reaction. However, allergic reactions to color additives are rareTrusted Source.

It can also be difficult to identify the exact cause of an allergic reaction to food unless a person keeps a detailed food journal.

If a person experiences an allergic reaction to red dye 40, it will most likely affect the skin, causing symptoms such as hives and swelling. In very rare cases, a person may experience anaphylaxis.

Anaphylaxis: Symptoms and what to do

Anaphylaxis is a severe allergic reaction that can be life threatening. The symptoms develop suddenly and include:

  • hives
  • swelling of the face or mouth
  • wheezing
  • fast, shallow breathing
  • a fast heart rate
  • clammy skin
  • anxiety or confusion
  • dizziness
  • vomiting
  • blue or white lips
  • fainting or loss of consciousness

If someone has these symptoms:

  1. Check whether they are carrying an epinephrine pen. If they are, follow the instructions on the side of the pen to use it.
  2. Dial 911 or the number of the nearest emergency department.
  3. Assist the person in moving from a sitting position to lying down. If they have vomited, turn them onto their side.
  4. Stay with them until the emergency services arrive.

Some people may need more than one epinephrine injection. If the symptoms do not improve in 5 to 15 minutes, or they come back, use a second pen if the person has one.

In a 2022 review of 25 studies on red dye 40 and behavioral changes, the authors noted that 64% of those studies (16 out of 25) found some evidence of an association between the two. There are further animal studies that also show a positive association between red dye 40 and behavioral changes.

A 2021 review suggests that there is a link between red 40 and neurobehavioral changes, such as worsening symptoms of attention deficit hyperactivity disorder (ADHD). However, the research also suggests that some people may be more sensitive to the effects of red dye 40 than others.

A 2020 reviewTrusted Source suggests that red 40 can trigger behavioral changes in children, including changes associated with ADHD and autism spectrum disorder (ASD). Although there is no direct evidence to link red dye 40 to ASD, the research suggests that families of children with ASD typically avoid foods containing red 40 to help avoid behavioral challenges.

Overall, the research suggests that there is some connection between red dye 40 and behavioral changes, particularly in people with ADHD or ASD. However, experts agree there is a need for more research in this area.

A 2023 study in mice suggests that red dye 40 can damage DNA, leading to low level inflammation in the colon and rectum. This type of inflammation may develop into colorectal cancer. However, animal studies do not necessarily indicate that the same effect will occur in humans.

Some research from 2022 suggests that red 40 is a risk factor for the development of colitis (inflammation in the large intestine). Colitis can cause abdominal pain, diarrhea, and blood in the stool.

Research also suggests that red dye 40 can change the gut microbiome, which helps keep the body healthy. Changes in the gut microbiome can affect the immune system, hormones, and central nervous system. These effects may contribute to depression, mood changes, and behaviors associated with ASD.

Red 40 can appear in a wide range of processed foods and drinks, including:

  • sodas and other drinks that require color
  • candies
  • icings
  • seasonings and spices
  • cooking sauces and dressings
  • table sauces
  • products containing gelatin
  • cookies and cakes
  • ice cream and ice pops

The FDA requiresTrusted Source manufacturers to clearly list all ingredients of a product on the label, including food dyes such as red dye 40.

There are several other ingredient names for red dye 40 that manufacturers may list on product labels, including:

  • Allura red
  • Allura red ac
  • C.I. 16035
  • C.I. food red 17
  • D&C red no. 40
  • food red 17
  • food red no. 40
  • curry red
  • R-40

Red dye 40 is a type of artificial food dye that manufacturers use to add color or enhance natural color in foods and beverages. It typically appears in processed foods and drinks such as candies, sodas, icing, cookies, cakes, and spices.

Research suggests there is likely to be a link between red 40 consumption and behavioral changes as well as certain health conditions, such as colitis. However, experts agree there is a need for more research in this area.

A person can identify red dye 40 in foods and drinks by checking the labeling of a product. Manufacturers may list it under as several other names, including Allura red and food red 17.