Red Dye 40 is one of the most widely used food dyes, as well as one of the most controversial.

The dye is thought to be linked to allergies, migraine, and mental disorders in children.

This article explains everything you need to know about Red Dye 40, including what it is, its potential side effects, and which foods and beverages contain it.

Red Dye 40 is a synthetic color additive or food dye made from petroleum (1).

It’s one of the nine certified color additives approved by the Food and Drug Administration (FDA) for use in foods and beverages (2).

It’s also approved as a food dye for use within the European Union (3).

Certified color additives must undergo FDA certification every time a new batch is produced to ensure they contain what they’re legally supposed to.

Conversely, exempt color additives do not require batch certification, but the FDA must still approve them before they can be used in foods or beverages.

Exempt color additives come from natural sources, such as fruits, vegetables, herbs, minerals, and insects (4).

Manufacturers use color additives in foods and beverages to enhance naturally occurring colors, add color for visual appeal, and offset color loss that may occur due to storage conditions.

Compared with their natural alternatives, synthetically produced color additives provide a more uniform color, blend easier, are cheaper, and do not add undesirable flavors (2).

For this reason, synthetic color additives are used more widely than natural color additives.

summary

Red Dye 40 is a synthetic food colorant or dye produced from petroleum. Every batch of Red Dye 40 must undergo an FDA certification process.

Based on current evidence, the Environmental Protection Agency (EPA) has determined Red Dye 40 to be of low concern (5).

Furthermore, the Food and Agriculture Organization and World Health Organization agree that the estimated dietary exposure to Red Dye 40 for people of all ages does not present a health concern (6).

Red Dye 40 has an acceptable daily intake (ADI) of 3.2 mg per pound (7 mg per kg) of body weight. This translates to 476 mg for a 150-pound (68-kg) person (3).

The ADI is an estimate of the amount of a substance in food that can be consumed daily over a lifetime without adverse health effects.

The European Food Safety Authority (EFSA) estimated that the average exposure of red dye from foods and beverages is below the ADI for people of any age (3).

One study showed that Americans ages 2 years and older consumed an average of 0.002 mg of Red Dye 40 per pound (0.004 mg per kg) of body weight per day (7).

The study also noted that children ages 2–5 years had the highest average daily intake of Red Dye 40 at 0.0045 mg per pound (0.01 mg per kg) of body weight, whereas adults ages 19 years and older had the lowest at 0.0014 mg per pound (0.003 mg per kg) of body weight.

Another study observed that American’s intake of Red Dye 40 may be higher, with those ages 2 years and older consuming a daily average of 0.045 mg per pound (0.1 mg per kg) of body weight (8).

That same study also showed that American children ages 2–5 years consumed a daily average of 0.09 mg of Red Dye 40 per pound (0.2 mg per kg) of body weight.

Compared with the ADI, these results suggest there’s a comfortable margin of safety in regards to Red Dye 40 consumption.

Summary

Health authorities have deemed Red Dye 40 safe for people of all ages. The ADI for Red Dye 40 is 3.2 mg per pound (7 mg per kg) of body weight.

Consumer advocacy groups like the Center for Science in the Public Interest have questioned the safety of Red Dye 40, as its consumption is thought to cause allergies and migraine (9).

Allergies are your body’s immune response to a substance that does not cause a response in most people.

These substances — called allergens — may be pollen, dust mites, mold, latex, food, or components of food.

Allergens can cause symptoms, such as sneezing, facial swelling, watery eyes, and skin irritation when eaten, breathed, or touched.

Allergies have also been linked to migraine, a type of headache characterized by intense, throbbing pain (10, 11, 12).

The symptoms of an allergy may occur within minutes to hours of contact with the allergen and last several hours to days (13).

Allergic reactions have been reported in children and adults for both synthetic and natural food colors, but they tend to be rare, mild, and mainly involve the skin (14, 15, 16, 17).

Given that manufacturers use Red Dye 40 along with several other food additives, it’s difficult to identify which ingredient — if any at all — is causing symptoms of an allergic reaction.

While no test is perfect for confirming or disproving a food dye allergy, a double-blind, placebo-controlled oral food challenge is considered the gold standard (18, 19, 20, 21).

During this food challenge, your healthcare provider will provide you with foods in capsules, some of which are suspected to be the allergen, but neither you nor the physician will know which ones.

After you swallow one of the capsules, the physician observes for any symptoms of an allergic reaction to determine or rule out an allergy. You repeat this process until all the pills are swallowed.

Summary

Both synthetic and natural food colors have been reported to cause mild allergic skin reactions like hives.

Red Dye 40 has been linked to aggression and mental disorders like attention deficit hyperactive disorder (ADHD) in children.

Children with ADHD are often easily distracted, have trouble holding their attention on tasks, are forgetful in daily activities, fidget, and have outbursts of anger at inappropriate times (22).

The FDA acknowledges that, while the current research indicates that most children don’t experience adverse behavioral effects when consuming foods that contain Red Dye 40, some evidence suggests that certain children may be sensitive to it (2).

Indeed, a review of 34 studies estimated that 8% of children with ADHD living in the United States, United Kingdom, Australia, and Canada may have behavioral symptoms related to synthetic food colors (23).

Synthetic food colors are thought to cause behavioral symptoms in children because they may cause chemical changes in the brain, inflammation from an allergic response, and the depletion of minerals, such as zinc, that are involved in growth and development (24).

Studies in children with ADHD have demonstrated that restricting synthetic food dyes from the diet led to significant improvements in symptoms (23, 25, 26, 27).

However, these improvements were found mainly in children with general food sensitivities or intolerances (28).

While the restriction of synthetic food dyes — including Red Dye 40 — may be an effective treatment option for reducing behavioral symptoms in children with ADHD, more research is necessary to confirm this (29).

Summary

There’s increasing evidence to suggest that synthetic food dyes may worsen behaviors in children with ADHD.

As one of the most widely used color additives, Red Dye 40 is found in a variety of foods and beverages, including (2):

  • Dairy products: flavored milk, yogurt, puddings, ice cream, and popsicles
  • Sweets and baked goods: cakes, pastries, candy, and chewing gum
  • Snacks and other items: breakfast cereals and bars, jello, fruit snacks, chips
  • Beverages: soda, sports drinks, energy drinks, and powdered drink mixes, including some protein powders

According to studies, breakfast cereals, juice drinks, soft drinks, baked goods, and frozen dairy desserts are the greatest contributors of synthetic food dyes in the diet (3, 8, 30, 31).

Like other color additives, Red Dye 40 is also used in the production of cosmetics and pharmaceuticals (4).

You can identify Red Dye 40 by reading the ingredient list. It’s also known as:

  • Red 40
  • Red 40 Lake
  • FD&C Red No. 40
  • FD&C Red No. 40 Aluminum Lake
  • Allura Red AC
  • CI Food Red 17
  • INS No. 129
  • E129

While manufacturers are not required to list the amount of an ingredient used, they must list ingredients in descending order by weight.

This means that the first ingredient listed contributes the most by weight while the last ingredient listed contributes the least.

Note that choosing to exclude or limit your or your child’s consumption of foods or beverages with Red Dye 40 will pose no harm, as it’s non-essential to the diet.

In fact, doing so may benefit health in other ways, considering the foods and beverages that contain the dye are often also rich in added sugars, saturated fats, and sodium.

Summary

Red Dye 40 goes by several names. The largest dietary contributors of the dye are breakfast cereals, juice drinks, soft drinks, baked goods, and frozen dairy desserts.

Red Dye 40 is a synthetic food dye made from petroleum.

While the census from health organizations is that Red Dye 40 poses little health risk, the dye has been implicated in allergies and worsened behavior in children with ADHD.

The dye goes by several names and is commonly found in dairy products, sweets, snacks, baked goods, and beverages.