The Health Dangers of Food Dye Blue No. 2

The U.S. Food and Drug Administration (FDA) regulates food additives. There are currently seven certified color additives approved for use in foods, according to the FDA. These artificial food colorings are called “FD&C” color additives because they are approved for use in food, drugs, and cosmetics.
Artificial food colorings have been linked to behavior changes in children, as well as other pediatric health concerns, including a predisposition to cancer, allergies, gastrointestinal and respiratory problems, and more, according to a study. These findings have sparked public concern, as the dyes are widely used in foods such as cereals and candies that are marketed to children.
Background

Food manufacturers use synthetic dyes mainly for product and formula development.
BananaStock/BananaStock/Getty ImagesFood manufacturers use synthetic dyes mainly for product or formula development reasons, according to the FDA. The dyes protect against color loss, even out natural variations in food color, and make “fun foods” colorful and more visually appealing. Food dyes also help products match our expectations. For instance, manufacturers dye strawberry ice cream pink and mint ice cream green.
In April 2025, the FDA announced a plan to phase out petroleum-based synthetic dyes from the country’s food supply. Food dye Blue No. 2 is among six dyes that will be eliminated by the end of the year.
Blue No. 2

FD&C Blue No. 2 is also called indigo blue or indigotine. It is a synthetic version of indigo, a dye naturally produced from plants. Indigotine is distinguished by a rich royal-blue color, and it is currently used for coloring foods and drugs, says the International Association of Color Manufacturers.
Hyperactivity in Children
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Hyperactivity in children.
Darrin Klimek/Digital Vision/Getty ImagesA review indicated that limited literature exists regarding a possible role of artificial blue food colorings in causing symptoms of ADHD in children. It was stated that more research is needed to fully determine the neurotoxicity of artificial blue dyes in humans.
That said, a study demonstrated that color additives including FD&C Blue No. 2 are linked to a number of health problems that disproportionately affect children. These include behavioral changes in children both with and without diagnosed disorders. The pediatric populations analyzed in the study included children diagnosed with autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), as well as children without behavioral disorders.
It is important to note that the limitations of studies regarding the effects of synthetic dyes can be varied and comprehensive. One limitation is the lack of comprehensive and specific research on the long-term effects of these dyes in different populations, especially in children and individuals with food sensitivities.
Also, the diversity of synthetic dyes used in the food industry hampers the generalization of results. The lack of standardization in the methods used to assess the effects can also compromise the validity and comparability of studies. Another common limitation is the difficulty of isolating the effects of synthetic dyes from other food components, making the attribution of causes and effects complex.
What’s more, the influence of individual factors, such as diet and lifestyle, is often not fully controlled in studies, which can affect the interpretation of results. These limitations highlight the need for a more comprehensive and rigorous approach when investigating the effects of synthetic dyes on human health.
- Advances in Nutrition: The Effects of Natural and Synthetic Blue Dyes on Human Health: A Review of Current Knowledge and Therapeutic Perspectives
- Cureus: A Review of the Association of Blue Food Coloring With Attention Deficit Hyperactivity Disorder Symptoms in Children
- International Association of Color Manufacturers: Indigotine.
- International Journal of Environmental Research and Public Health: Synthetic Colors in Food: A Warning for Children’s Health
- U.S. Food and Drug Administration: Color Additives in Foods
- U.S. Food and Drug Administration: HHS, FDA to Phase Out Petroleum-Based Synthetic Dyes in Nation’s Food Supply

Sylvia E. Klinger, DBA, MS, RD, CPT
Medical Reviewer
Sylvia Klinger, DBA, MS, RD, CPT, is an internationally recognized nutrition expert who is relentlessly passionate about helping people fall in love with creating and enjoying delicious, safe, and nutritious foods.
As a food and nutrition communications professional, Dr. Klinger is a global nutrition professor, award-winning author, and the founder of Hispanic Food Communications.
She is on the board at Global Rise to build a formal community nutrition program as part of an ambitious initiative to create a regenerative food system in Uganda in partnership with tribal and community leaders. This program included an extensive training session on food safety and sanitation that displayed cultural sensitivity and various communication strategies and incentives to spread these important food safety and sanitation messages into the communities.
Her Hispanic background fuels her passion for nutrition, leading her to empower and encourage those in her community through the foods they enjoy in their kitchens. At the same time, she understands everyone’s needs are different and seeks to individualize nutrition and exercise to best fit each person and their journey to a happy, safe, and healthy life.
Her latest book, The Little Book of Simple Eating, was published in 2018 in both Spanish and English.
In her spare time, Klinger explores food and culture all over the world with her family, realizing the power a healthy lifestyle has to keep people together.

Ramona French
Author
Ramona French owned a massage school and taught massage for 28 years. In that time she wrote textbooks on Swedish, acupressure, deep tissue and lymph drainage massage. She is the author of "Introduction to Lymph Drainage Massage" and "Milady's Guide to Lymph Drainage Massage." Her book, "The Complete Guide to Lymph Drainage Massage," published by Milady, was released in October 2011.