The Complicated Science, History, and Psychology of Food Colorants

Spring is almost here and soon we’ll see pastel foods everywhere. Next up: St. Patrick’s Day. It’s a tradition to drink green beer on this day in America. And while this tradition may not be truly Irish, it’s definitely a fun way to celebrate! The green color makes it extra special. But, have you ever really thought about what makes your beer green? What about food colorants used in other products?

The language of color

You’ve probably heard different colors evoke different sets of emotions. Blue is calming, while orange is loud and adventurous. Purple is often associated with royalty and high quality. Black is elegant. White feels pure and clean. Red is a stimulant that can help you feel energized, while green is balanced and associated with nature. Yellow is playful and creative.

The psychology of color plays a role in many aspects of our lives. This also includes the branding, marketing, and development of food products. It is a critical aspect of the finished food. Sensory scientists may even conduct tests to determine which colors are best preferred by consumers.

What are food colorants?

According to the Food and Drug Administration, “A color additive, as defined by regulation, is any dye, pigment, or other substance that can impart color to a food, drug, or cosmetic or to the human body.”

Food colorants are often highly controversial and have a long history of use and abuse in the US and throughout the world. As consumers begin to avoid foods made with synthetic colorants, manufacturers have increasingly turned to natural alternatives.

Why use color additives in food?

You’ve heard it before: we eat with our eyes. Color additives are used to enhance natural colors in food and much more. Color plays an extremely important role in consumer acceptance. Think about it; would you purchase a steak that isn’t bright red or an orange that’s green? Often, color is not necessarily an indicator of quality or freshness, but it does have a huge impact on our senses. It’s our first impression of the food we’re about to eat.

In fact, you can prove the impact of food’s appearance with a simple experiment. Serve your friends samples of lemonade with added food coloring. Then, ask them to try each sample individually and tell you what flavor they taste. Often you will hear strawberry for red, raspberry for blue, and lime for green, even though they’re exactly the same lemonade! Color and appearance have a big impact on the sensory experience of eating food.

Food colorings bring emotion to food. They help celebrate a birthday with colorful sprinkles or St. Patrick’s Day with green shamrocks, for example. Pastel colors are used on Easter and during spring. Pink and red hearts are used on Valentine’s Day. Red and green signify Christmas. Black and orange mean Halloween. These colors are often rooted in tradition.

What flavor do you associate with each shape?

Color helps consumers identify flavor. We expect to taste apple when something is bright green or cherry when it’s red. When Pepsi launched Crystal Pepsi in the 1990s, it seemed sure to be a hit. But it turned out to be a huge flop because consumers expect cola to be brown, even though the brown color isn’t natural to the product.

Another example of failed color changes is Trix cereal. Due to consumer interest in clean label ingredients, General Mills introduced cereal using vegetable and fruit juices and turmeric extract to replace the synthetic dyes. Less than 2 years later, the company had to bring back the classic version with the beloved neon colors due to numerous complaints.

History of color in food

Humans have been coloring their food for centuries. Ancient cultures used vegetables and minerals to color many products, including food. Archaeologists agree that humans have probably colored foods since about 1500 BC. Saffron is mentioned in the Iliad as a food colorant and records indicate wine has been colored as far back as 300 BC. In medieval Europe, natural sources of food colorant were limited and expensive and thus reserved only for the wealthy. This led to the belief that brightly colored foods were of higher quality and more nutritious.

Food fraud

Some of the first encounters of food fraud occurred in bread in medieval times. Flour was expensive, and lime and chalk were often used to mimic the color of real flour. This led to many illnesses and the first laws regarding food adulteration. Further laws banned the coloring of butter and pastries to trick consumers into thinking they were getting the real thing.

Investigation into foods in 19th century England also found coffee and tea were artificially colored so that old product could be sold as new. However, it was difficult to enforce regulations at the time and the adulteration continued. Candies and jellies were colored with poisonous dyes to appeal to children. Copper was used to enhance green pickles. The list goes on.

Synthetic colors are discovered

In 1856, the first synthetic dye, mauve, was discovered in the US. This color had never been seen before and people found it very beautiful. Soon after, many more dyes were produced from byproducts of coal processing. Safety was not yet a concern at this point in history.

Butter and cheese were the first products to receive approval for artificial colors from the USDA to ensure consistent colors.

Did you know? When margarine was introduced in the 1870s, a great debate, known as the Margarine Wars, ensued over whether the naturally white fat should be colored yellow. At one point it was mandated margarine be tinted pink to distinguish it from butter. Once this ruling was overturned, margarine was sold with packets of yellow dye so the consumer could enjoy their margarine yellow by coloring it themselves. In 1950, margarine was finally allowed to be colored a (specific shade of) yellow. It wasn’t until 1967 that Wisconsin, the last state, finally gave in to allow colored margarine.

As time went on, more and more products were artificially colored. Unfortunately, sometimes colorants were used to cover low-quality products or defects, as they had been in the past. By 1900 it was found that these colors had ingredients such as lead, arsenic, and mercury. This lead to distrust by the public.

Government intervention

In 1906, the Food and Drug Act was introduced to prohibit the use of poisonous and deleterious ingredients in foods. Unfortunately, this act did not do enough to protect consumers. In 1938, the Federal Food, Drug, and Cosmetic Act was introduced and required manufacturers to certify all colors using a representative sample from every batch.

In 1950, the approved color FD&C Orange No. 1 was found to cause illness in children that had eaten Halloween candy with the additive. The FDA then reevaluated all colors and passed the Color Additive Amendment of 1960. This amendment divided colors into “certified” and “exempt from certification” colors. It also defined how the FDA must consider safety for the color additives, as well as conditions for safe use.

Each color additive was assessed for safety, and today less than a quarter of the original colors remain. Currently, the FDA is in charge of overseeing color additives in food and lists approved colorant regulations in the Code of Federal Regulations (CFR). Color additives are highly regulated and continue to undergo safety evaluations.

What are the different types of food colorants?

Colors are generally divided into two categories: synthetic colors created in a lab and natural colors derived from nature. Each type of colorant has its advantages and disadvantages.


Synthetic colorants are those produced by man (or woman) in a lab from purified petrochemicals. There are currently seven colors approved for general use in human food in the United States and two more approved for use in specific applications.

  • FD&C Blue No. 1- Sky Blue
  • FD&C Blue No. 2- Royal Blue
  • FD&C Green No. 3- Teal Green
  • FD&C Red No. 3- Hot Pink
  • FD&C Red No. 40 – Orange-red
  • FD&C Yellow No. 5 – Lemon-yellow
  • FD&C Yellow No. 6 – Orange
  • Orange B: Only approved for use in hot dog and sausage casings
  • Citrus Red No. 2: Only approved for use to color orange peels

There are four classes of synthetic dyes: azo, xanthene, triphenylmethane, and indigoid. Each class has different properties for use in foods and can help determine which color might be best in specific applications based on how the product will be processed, how it will be stored, and intrinsic properties of the food, itself.

Synthetic colors are available in the form of dyes or lakes. Dyes are simply straight colors that dissolve in water and absorb light to cleanly transmit a certain wavelength of light in the form of color. Lakes are insoluble and disperse in food. This dispersion causes light to scatter and the color to appear opaque. Lakes are dyes that have been reacted with aluminum hydroxide to create a powder.

The advantages of using synthetic colorings include heat stability, light and oxygen stability, and vibrant colors. They have a long shelf life. Creating colors in a lab ensures consistency. When using natural foods for coloring, there is a large amount of variation from season to season and batch to batch. Supply chain sourcing of product can also become a concern when weather disrupts harvests and yield.

Below is an example of the structure of FD&C Yellow No. 6. The bright color is due to the presence of conjugated double bonds (double lines) in the molecule. Compare its structure to the natural color pigments below.

File:FD&C Yellow 6.svg
FD&C Yellow No. 6 – Orange color

Synthetic colorants get a bad rap for a number of reasons, including the infamous Southampton study that claimed these additives were responsible for ADHD in children. While this study has largely been disproven, the concern lives on.

As consumers become more interested in food ingredients, many have begun to actively avoid synthetic colors. In fact, 3 in 5 consumers in the US do not purchase foods with synthetic colors. However, the technical challenges of using natural colors are more complicated than you might expect.


Natural colorants are derived from fruits, vegetables, flowers, insects, or minerals. Examples include turmeric for yellow and paprika for red. Other sources include anthocyanins from berries, beta-carotene from carrots, and lycopene from tomatoes.

Colors are extracted from their source similar to the concentration process of fruit and vegetable juices. They may be in liquid or powder form.

The structure of a common anthocyanin pigment from grape skins is shown below. You can see this molecule also has many conjugated double bonds, as compared to synthetic FD&C Yellow No. 6.

Malvidin, an anthocyanin pigment in grape skin

Here are some common approved natural colors exempt from certification:

  • Betalain: red-purple from beets
  • Saffron: yellow-orange spice
  • Cochineal: red from insects
  • Annato: orange-yellow carotenoid from tropical seeds
  • Caramel: brown/tan from heated sugar
  • Titanium: bright white from ore
  • Spriulina: blue-green from phycocyanins in algae

For the full list, check out this FDA resource

Carmine and cochineal extract are red colorants that recently came under fire in the media. These natural colorants are made from Dactylopius coccus insects that feed on cacti in Peru, Mexico, and the canary islands. They have been used for hundreds of years as natural colorants. However, in 2012 Starbucks infamously removed carmine from their products in response to consumer outcry. They replaced this color with lycopene from tomatoes.

Using natural colorants in food

Natural color sources come with many technical challenges. These pigments are often unstable in the presence of heat during processing and light during storage. They are often also unstable at different pH levels. For example, anthocyanins are natural pigments that range from red to purple to blue depending on how acidic the product is. However, as the pH increases the stability of the molecule decreases.

Anthocyanin pigments from blueberries in solutions of increasing pH

Even if the pigment is able to survive processing, the color may be less vibrant than consumers are used to. Colors may also fade during storage. As more products turn to clean label, natural alternatives, consumers must learn to accept their food will look different.

In addition to their clean label designation, natural food colorants may also provide health benefits. Beta-carotene, for example, is an important precursor for Vitamin A. This vitamin is critical for vision and immune system development. Anthocyanins may have antioxidant properties. There is a lot of research being done today on improving the stability of natural colorants in food and their potential benefits to human health.

Current Regulations

The Nutrition Labeling and Education Act of 1990 mandates that food colorants must be listed on the ingredient label for all foods. Certified (synthetic) colors must be listed by name, e.g. FD&C Blue No. 1. Colors exempt from certification (natural colors) do not have to be listed by name and may be listed as “artificial colors,” “artificial color added,” or “color added,” to inform the consumer that color has been added to the product. The exception here is cochineal/carmine. This natural color must be listed by name due to allergenic concerns.

The term “natural” may not be used even for natural colorants unless the color is natural to the product, itself. For example, the use of strawberry juice to color strawberry ice cream.

Certification of each batch of synthetic colors is required by the FDA prior to use. Drug and cosmetic companies must also comply with these laws. Natural colors, on the other hand, are exempt from certification. However, they must be approved by the FDA as a food colorant prior to use.

Are food colorants safe?

The FDA is responsible for ensuring food ingredients such as colorants are safe in the United States. To determine if a color additive is safe, they assess the effects of consumption, the chemical composition of the ingredient, levels of exposure, and the availability of methods to test for purity and amount in foods.

Yes, color additives are safe when they are used in accordance with FDA regulations. When the FDA approves the use of a color additive in food, our regulations specify: the types of foods in which it can be used,
any maximum amounts allowed to be used, and how the color additive should be identified on the food label.

US Food and Drug Administration

The FDA has reviewed scientific data and concluded that food colorants are safe for children and adults when used in accordance with regulations. However, they do recognize some children may be sensitive to synthetic colorants, specifically Yellow No. 5, and research is ongoing. This additive may cause itching or hives. However, the majority of people do not see this issue.

In Europe, manufacturers have largely moved away from synthetic colorants. Some of those approved for use in the US, such as Green No. 3, are prohibited in the EU. Azo dyes (Yellow No, 5, Yellow No. 6, and Red No. 40) as well as Blue No.1, must carry a warning label.

Despite these regulations, a 2016 review by the European Food Safety Authority did not find evidence to substantiate a causal link between food dyes and cancer or ADHD in children based on current acceptable daily intake (ADI) levels. Studies are ongoing.

So, what makes my beer green on St. Patrick’s Day?

green beer-food color-st. patricks day
Photo by Patrick Fore on Unsplash

One answer is spinach! The chlorophyll pigment, just like the pigments found in leaves of trees, is used to provide a beautiful green shade. Vegetable juice is an approved colorant.

C-3 position Chlorophyll a.svg
Chlorophyll molecule

Spirulina is another natural option. This is a natural blue-green colorant made from the pigment phycocyanin found in cyanobacteria algae. This is a relatively new colorant approved for use in certain applications.

Traditional food coloring using Blue No. 1 (Brilliant Blue) or Green No. 3 (Fast Green FCF) is most common in bars in the US today. You can even make your own green beer at home. Simply put a drop of food coloring in the bottom of your glass and pour a light colored beer, such as a pilsner or blonde ale, to achieve a green shade.

Bottom line

Color is an important characteristic for the quality and enjoyment of food and plays a large role in flavor identification. Companies are moving away from synthetic colors in response to consumer demand and evolving science. The FDA has strict regulations on all colors used in food, drugs, and cosmetics. Currently, evidence shows synthetic colors are safe when used as directed. However, synthetic colors are less expensive than those from natural sources and are more reliable, too. As more research is completed on expanding functionality of natural colors, their scope is likely to increase.

If you are trying to avoid consuming artificial colors, be sure to check the label. You can cast your vote on the issue by using your dollars at the grocery store.

Still curious? Check out the resources below or send me a question!


Burrows, J.D., A. (2009), Palette of Our Palates: A Brief History of Food Coloring and Its Regulation. Comprehensive Reviews in Food Science and Food Safety, 8: 394-408. doi:10.1111/j.1541-4337.2009.00089.x

DDW. Manufacturing Methods for Natural Colors.

European Food Safety Authority. Food Colours.

Food and Drug Administration. 2018. Color Additives Questions and Answers for Consumers.

Food and Drug Administration. 2003. Color Additives: FDA’s Regulatory Process and Historical Perspectives. Food Safety Magazine. (Reprinted)

Institute of Food Technologists. What Makes Your Beer Green for St. Patrick’s Day?

McAvoy, SA. 2014. Global Regulations of Food Color. The Manufacturing Confectioner. (PDF)

Wrolstad, RE. 2007 Colorants. In: Food Chemistry: Principles and applications. 2nd Edition. STS Press.

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