In recent weeks, Health and Human Services Secretary Robert F. Kennedy Jr. has said that “very, very strong studies” link food dyes to cancer and ADHD. Experts are concerned about the impacts of unhealthy diets and obesity in the U.S., but some say Kennedy overstates the role of food dyes in chronic disease.

The dyes haven’t been shown to cause cancer in humans. Studies show a possible link to symptoms of attention-deficit/hyperactivity disorder in children.

Recently, Kennedy has taken his “Make America Healthy Again” campaign on the road, appearing in some states that have passed legislation to limit food dyes and other additives. So far, governors in California, Arizona, Utah, Virginia and West Virginia have signed laws disallowing certain food dyes from school meals, some beginning as soon as later this year, and West Virginia also enacted a law that will ban seven synthetic food dyes outright from sale in the state beginning in 2028. Lawmakers in two dozen additional states have introduced or passed bills that would restrict synthetic food dyes, which are present in a variety of foods, from soft drinks to cereal.