Do you know what’s in your cereal? 

Eva Mendes thinks it’s about time you find out. 

The American actress took to Instagram to call for the removal of artificial food dyes in Kellogg's cereal, and it sparked heated comments.

"I grew up on cereal. I still love it but I won’t eat @kelloggsus anymore after I found out that so many of the ingredients they use here in the US are BANNED in other countries. Why? Because they’re harmful for children," Mendes posted on Instagram Oct. 8. On Tuesday, she encouraged her followers to join in on a "peaceful march to Kelloggs HQ to ask them to REMOVE artificial food dyes."

The reactions were swift: “YES Eva!!!! Thank you for speaking out about this and advocating for safer products for our kids!” wrote @barenaturals. Follower @angelise_rivera disagreed: “You guys will believe there's some big conspiracy theory here instead of accepting the FACT that artificial dyes are tested for safety." Kellogg's most recent Instagram post from Sept. 25 has been flooded with over 2,000 comments demanding better ingredients.

"Our products – and the ingredients we use to make them – are compliant with all applicable relevant laws and regulations," Kellogg's said in a statement to USA TODAY. "We remain committed to transparently labeling our ingredients so consumers can easily make choices about the food they purchase."

Who’s right when it comes to the issue of food dyes? Depends who you ask. 

Some states are starting to outlaw these dyes, and Mendes wants a bigger push. Dozens of protesters rallied outside of the Michigan headquarters of WK Kellogg Co. on Tuesday, delivering petitions with more than 400,000 signatures, according to the Associated Press.

What artificial dyes are in Kellogg's cereal?

Kellogg's Froot Loops uses Red Dye No. 40, Yellow Dye No. 5, Yellow Dye No. 6, Blue Dye No. 1 and butylated hydroxytolune (BHT), which according to WebMD, is a lab-made chemical added to foods as a preservative. BHT can also be used to treat genital herpes, AIDS and cold sores. However, research on BHT as a carcinogen has mixed results depending on the animal and parameters tested.

Meanwhile, in Canada, the company uses concentrated carrot juice, watermelon juice, huito juice and blueberry juice to color Froot Loops.

According to Kellogg's, more than 85 percent of their cereal sales contain no colors from artificial sources.

"We continuously innovate new cereals that do not contain colors from artificial sources across our biggest brands, offering a broad choice of nourishing foods for our consumers," the company said.

Some artificial dyes could be banned from California schools

Do food dyes cause ADHD, cancer?

A 2021 report from California's Environmental Protection Agency linked artificial dyes to "hyperactivity and other neurobehavioral problems" in some children, and similar research previously prompted the European Union to restrict food coloring.

"There's a strong suggestion that there is a relationship between intake of these materials and changes in behavior… particularly in children that are susceptible, that already have ADHD, or related behaviors," Asa Bradman, a professor and chair of University of California Merced's public health department who worked on the California review, previously told USA TODAY. "Exposure to the dyes seems to exacerbate the symptom."

Scientists can't say for sure that there is a proven link, but food dye opponents often point to concurrent rises in artificial coloring consumption and rising ADHD diagnostic rates among children.

"The reality is these have no nutritional or other benefits. They're totally aesthetic," Bradman said.

Red 3 has also been linked to cancer in animal studies. In 1990, the FDA prohibited its use in cosmetic products due to these concerns, yet it is still permitted in food items.California recently banned six dyes from use in public schools. Other state lawmakers are making similar pushes.

"I'm constantly flipping labels over. It takes me four hours to grocery shop. It shouldn't have to," Pennsylvania State Rep. Natalie Mihalek previously told USA TODAY. The FDA completed its last exposure assessment of the six chemicals banned in the recent California bill in 2016, the agency told USA TODAY in late September. The FDA will host a public meeting to take "a fresh look at the process" of assessing chemicals in food products after they hit the market.

Do food dyes make ADHD worse?Why some studies' findings spur food coloring bans

Contributing: Cybele Mayes-Osterman and Eduardo Cuevas