Original Cheerios, a popular breakfast cereal produced by General Mills Inc. (NYSE:GIS), will be free of genetically modified organisms, the company said on Thursday, making it the first major U.S. food brand to relent to pressure from consumers and advocacy groups who oppose the use of GMO in food products.

The Minneapolis-based company said that the change affects only the "Original" brand of Cheerios, which now will come with the label "Not Made With Genetically Modified Ingredients," and not involve other varieties such as Apple Cinnamon Cheerios or Honey Nut Cheerios. General Mills said that it had been working for more than a year to eliminate GMO content from Original Cheerios. The company, in a statement, said that it could bring about changes to the breakfast cereal because “the main ingredient in original Cheerios is whole grain oats – and there are no GMO oats.

“We use just a small amount of corn starch in cooking, and just one gram of sugar per serving for taste.  So we were able to change how we source and handle ingredients to ensure that the corn starch for original Cheerios comes only from non-GMO corn, and our sugar is only non-GMO pure cane sugar.”

However, the company warned that the product could still have some traces of genetically modified ingredients, due to contamination from other sources during manufacturing or shipping. The company said it changed the sourcing for the original Cheerios and made fresh investments to separate the production of GMO-free Cheerios from other varieties.

“We made investments in new systems at our production facilities to separate the ingredients we use to make original Cheerios from our other products.  For example, we store only non-GMO corn starch where we store our corn starch and only cane sugar where we store our sugar,” the company said, but did not disclose how much the company had invested in its new facilities. 

The company said it faced challenges in sourcing GMO-free products as use of GM seeds are widespread in the U.S., which prevented the company from shunning GM-content in other products.

“For our other cereals, the widespread use of GM seed in crops such as corn, soy, or beet sugar would make reliably moving to non-GM ingredients difficult, if not impossible,” the statement said, noting that in Europe, which has a national standard for labeling non-GM content, the company is able to give its consumers the option of choosing between GM and non-GM products.

“Almost half of the cropland in the U.S. is used to grow genetically modified crops, and 70 to 80 percent of the foods in the average grocery store likely contain GMOs,” the company said, adding that it believes GM content is safe for consumption, but that it is offering the new product to meet consumer demand.

Last year, Green America, an advocacy group, had launched GMO-Inside, a campaign asking General Mills to go GMO-free, which garnered huge positive response from consumers.

The group, in a statement posted on its website, had noted that “thousands of concerned consumers have flooded Cheerios’ Facebook page,” in response to a call to protest General Mills' contribution of more than $1.1 million to “No on 37” in California, a group which campaigned against a ballot initiative in California that required labeling of GM ingredients.

“Removing GMOs from original Cheerios is an important victory in getting GMOs out of our food supply and an important first step for General Mills,” Todd Larsen, Corporate Responsibility Director at Green America, said in a statement.

General Mills did not specify when the non-GM Cheerios would hit store shelves, but stressed that the Original Cheerios would taste the same as always.