NEW YORK (Reuters) - As schools begin reopening their doors to children nationwide, the U.S. government has told a federal judge that states have no power to sue over new rules they say make school meals less healthy.

FILE PHOTO: Newark Prep Charter School students eat lunch inside of the schools cafeteria in Newark, New Jersey April 16, 2013. REUTERS/Lucas Jackson

In a Monday night court filing, the government said New York, five other states and Washington, D.C., could not sue based on speculation that changes to the federally funded National School Lunch Program could cause health problems for children and require more spending on treatment.

The government also said the states lacked power to sue under a doctrine known as “parens patriae,” Latin for “parent of the nation,” because it allegedly would not protect children from harm.

“This rule recognizes that a state has no legal interest in protecting its citizens from the federal government, and that only the United States, not the states, may represent its citizens and ensure their protection under federal law in federal matters,” U.S. Attorney Geoffrey Berman in Manhattan said in a filing in the federal court there.

The office of New York Attorney General Letitia James, who led the state coalition, did not immediately respond on Tuesday to requests for comment.

New York, California, Illinois, Minnesota, New Mexico, Vermont and the District of Columbia sued Agriculture Secretary Sonny Perdue on April 3 over changes in the school lunch program, which feeds more than 30 million, mostly lower-income children.

The states accused Perdue of acting arbitrarily and capriciously by ignoring dietary guidelines and scientific research when he allowed fewer whole grains and more sodium in meals, easing rules championed by former first lady Michelle Obama.

Among the changes were halving the required amounts of whole grains to be served, giving schools more flexibility to serve foods with refined grains such as noodles and tortillas, and delaying or shelving targets for sodium intake.

Schools were also permitted to serve low-fat chocolate milk, rather than fat-free milk.

Berman called the new rules only “minimum requirements,” and said states remained free to enact stricter requirements.

He also said the states offered no proof that children at 4,100 schools exempted from earlier whole grain rules suffered adverse health consequences.

Excessive sodium intake has been linked to heart disease, high blood pressure and stroke. Relatively higher refined grain consumption has been linked to type 2 diabetes, heart disease and obesity.

The case is New York et al v. U.S. Department of Agriculture et al, U.S. District Court, Southern District of New York, No. 19-02956.