What the science says about artificial food dyes

Washington Post

23-04-2025

The Department of Health and Human Services said Tuesday that it plans to phase out petroleum-based food dyes from the nation's food supply. Robert F. Kennedy Jr., the health secretary, has called the dyes 'poison' and long blamed artificial additives for chronic disease and illness in the United States.
Companies add dyes to food, such as candy, cereals, drinks and snacks, for brighter, attractive colors. The dyes are either natural, such as red beet juice, or synthetic.
'The ingredients used in America's food supply have been rigorously studied following an objective science and risk-based evaluation process and have been demonstrated to be safe,' Melissa Hockstad, the chief executive of Consumer Brands Association, a food industry trade group, said in a statement. 'Removing these safe ingredients does not change the consumer packaged goods industry's commitment to providing safe, affordable and convenient product choices to consumers.'
But consumer advocacy groups said there is sufficient evidence that the dyes may cause some harm to some children. They argue that artificial dyes are not worth the potential risk given their lack of nutritional value.
'From the vantage point of consumers, it boils down to why do we want to take a chance on these things when it comes to the health of our children?' said Brian Ronholm, director of food policy at Consumer Reports. 'Even if it doesn't technically point to causing cancer, there is risk involved in terms of how it impacts neurobehavior in children.'
The Washington Post spoke with food scientists and nutrition experts to answer questions about the synthetic dyes in food.
In January, under the Biden administration, the FDA banned red dye No. 3 in food. The dye, which gives food a cherry-red color, has been linked to cancer in animals.
In 1990, the agency banned the use of the red dye in cosmetics because preliminary animal research suggested a link to thyroid cancer. The FDA has said there's no evidence that ingesting the coloring causes cancer in humans. The agency said its decision was based on a federal law prohibiting additives found to cause cancer in humans or animals at any dose.
In some studies, synthetic food dyes used in the U.S. have been associated with hyperactivity and behavioral effects in children.
In 2021, the Office of Environmental Health Hazard Assessment in California published a review of seven food dyes such as red dye No. 3, red dye No. 40 and yellow dye No. 5. The review concluded that the consumption of food with added dyes is associated with hyperactivity, restlessness and other neurobehavioral problems in some children, though sensitivity can vary.
'They're not needed,' said Alyson Mitchell, a professor and food chemist at the University of California at Davis and a co-author of the California review. 'They don't present the consumer with any benefit. Only a potential risk.'
But some researchers disagreed on whether the existing evidence is conclusive and said it's hard to isolate the effect of one ingredient or additive because we eat a combination of various foods every day.
Research hasn't found a plausible mechanism for how synthetic dyes could affect the behavior of children, and the findings tend to be based on parents' observations 'rather than some strict criteria that wouldn't be subject to bias,' said Ronald Kleinman, physician-in-chief emeritus at Mass General Hospital for Children.
'This is an example where we really don't have any evidence that the natural food colorings are really any better than the synthetic food colorings,' Kleinman said. 'There are so many other things for us to consider in the general health of children that food colorings are way down on the list.'
The FDA has previously said it would examine potential effects of color additives on children's behavior. The 'totality of scientific evidence' indicates that most children do not suffer adverse effects when consuming food colored with the dyes, but some evidence suggests that certain children may be sensitive to them, it said.
The evidence is 'complicated' and 'mixed,' said Marion Nestle, an emeritus professor of nutrition, food studies and public health at New York University. But, she said, 'these dyes are unnecessary.'
'If there's any question at all about whether they might be harmful,' Nestle said, 'let's get rid of them.'
California decided to ban certain artificial dyes in food served in public schools. And in West Virginia, Gov. Patrick Morrisey (R) signed legislation last month banning foods containing seven synthetic dyes in schools from Aug. 1 and foods with the dyes in the state starting in 2028.
Artificial and natural dyes are listed on the ingredients label.
Checking the label is a 'reasonable step' for someone who's concerned about attention-deficit/hyperactivity disorder-like symptoms, or their irritability and mood, said Joel Nigg, a professor of psychiatry at Oregon Health & Science University. A person who reduces their consumption of foods with artificial dyes 'should notice the benefit within a few days,' if it is a factor, he said.
'Food dyes are not a major contributor to ADHD,' Nigg said. 'But they do play a small role in worsening attention and behavior in children.'
For home cooking and baking, natural dyes — extracts from fruits and vegetables — can add color.
The extracts for natural dyes have thousands of compounds and often different flavor profiles, which makes them problematic, Mitchell said. Natural dyes are more challenging for manufacturers to use, and it's not as simple as replacing artificial with natural alternatives.
'Natural does not imply safety,' Mitchell said. 'I have some concerns that we might be replacing one problem with another problem.'
'I think we need to recalibrate our expectation of color in food,' she said.
Marlene Cimons contributed to this report.