RFK plans to phase out synthetic food dyes by 2027. Here's what they do to your brain and body, according to science.

• The US is calling on food companies to remove all synthetic food dyes by 2027.
• Announcing the move, Robert F. Kennedy Jr. said food companies are open to the change.
• Here's the evidence on synthetic dyes and health issues like cancer and ADHD.

US Health Secretary Robert F. Kennedy Jr. said Tuesday that he has ordered food companies to remove eight petroleum-based dyes from their products.

Speaking alongside the FDA and food activists, Kennedy said brands will have until 2027 to voluntarily reformulate their food and drinks using natural dyes like carmine, turmeric, and beets — or add warning labels to their products.

The move comes three months after the US Food and Drug Administration (FDA) banned Red 3, shortly before the Trump administration took office.

The eight dyes under scrutiny today include Citrus Red No 2 and Orange B, which are not widely produced. Those two should be dropped with immediate effect, FDA Commissioner Dr. Martin Makary said.

Others are more commonly used. Red 40 is used in Gatorade, Doritos, and Skittles. Yellow 5 is used in Vigo's saffron rice, Fruit Loops, and some mustards. Blue 1 is used in Mountain Dew Baja Blast. Green 3 is used in Nyquil.

The benefit of using these petroleum-based dyes is economic — they're cheaper, stable year-round, and less prone to fading than fruits, vegetables, and spices. Hydrocarbons, extracted during petroleum refinement, are fused with salts to create a vibrant color.

However, consumer advocates and researchers have raised concerns about health risks.

Kennedy, who made synthetic food dyes a central concern in his presidential campaign of 2024, thanked "warrior moms who power the MAHA movement" for galvanizing political appetite for this change.

During the press conference, Makary said "kids have been living in a toxic soup of synthetic chemicals." He cited studies that found links between synthetic food dyes and health issues like ADHD and cancer.

Here's what we know about the link between synthetic food dyes and health problems:

The science of food dyes and ADHD

Kennedy has repeatedly said that he believes artificial food dyes cause ADHD in children.

Over a decade ago, US and European regulators reviewed the same evidence linking synthetic food dyes to ADHD in kids — but they drew different conclusions.

The EU concluded that the evidence was persuasive. Since then, many European brands have started using natural dyes instead. Products that contain synthetic dyes must display an ADHD warning for consumers.

The FDA, however, said more research was needed to warrant a change. (To date, no federal studies have been conducted.)

A decade later, in 2021, researchers in the California EPA reviewed the available evidence on seven artificial food dyes. They concluded that synthetic dyes can affect behavior in some kids. California Gov. Gavin Newsom responded, ordering food companies to remove dyes from snacks in public schools by 2027.

The big question is: why would dyes impact kids' behavior?

Scientists don't know for sure, since there are no large-scale, randomized control trials. One study found it might have something to do with how food dyes interact with histamine. Another study found that red dye probably doesn't have a huge influence on kids' brains, but it seems to fuel hyperactivity in the short term.

There may be a genetic factor at play. UK researchers found evidence that some children appear to be more susceptible to the effects of food dye than others, based on their genes.

Some dyes in the food system have been linked to cancer

In the late 1980s, scientists found male lab rats exposed to high levels of Red 3 developed thyroid tumors.

Based on that study, the FDA declared Red 3 a carcinogen in 1990, and announced a ban on the dye in cosmetics.

However, it took 30 years to see a ban on Red 3 in food. The dye remained in food and drink, in part due to lobbying from the maraschino cherry industry, which holds sway in many cherry-producing states.

Earlier this year, driven by public demand, the Biden administration's FDA delivered a ban on Red 3 in food and drinks, giving food companies until 2027 to phase out the dye.

"The FDA cannot authorize a food additive or color additive if it has been found to cause cancer in humans or animals," Jim Jones, then the FDA's deputy director for human foods, said in a statement when he announced the ban in January.

Consumer advocates have pushed for bans on other dyes, voicing concerns about cancer risk.

A review published in 2012 linked red 40 to multiple cancers. FDA tests conducted in the early 1990s concluded that some batches of Yellow 5 and Yellow 6 have been contaminated with carcinogens such as benzidine. The agency said the risk is too low to warrant concern.

Less evidence for other health issues

Beyond ADHD and cancer, Makary said petroleum-based food dyes are linked to allergic reactions in kids. That's based on a few studies that found dyes like Red 40 and Yellow 5 can cause hives in some people.

Makary also said synthetic dyes may be linked to insulin, genomic disruption, and GI issues. Evidence is limited to tests in petri dishes and animals, and more research is needed in humans. Here's what we know so far:

• A 2013 study found Red 40 disrupted glucose metabolism in rats.
• A 2012 study found Yellow 5 caused DNA disruptions in human blood cells.
• A 2022 study found Red 40 caused colitis in mice.

In an emailed statement, the National Confectioners Association, which represents US candy companies, pushed back against the proposal to nix synthetic dyes.

"FDA and regulatory bodies around the world have deemed our products and ingredients safe," the NCA said, adding that they want to work with the Trump administration to "eliminate consumer confusion and rebuild trust in our national food safety system."

But Makary was bullish in the press conference. Holding up a bottle of juice, he said: "To the companies currently using these dyes, try watermelon juice."