The battle over food health claims took an interesting turn last week in San Francisco when City Attorney Dennis Herrera sent a letter to Kellogg Company on Tuesday taking issue with their claim that Cocoa Krispies “now helps support your child’s immunity.”

Herrera, evidently, is dubious. 

“At a time when parents are increasingly worried about the spread of the H1N1 virus (‘swine flu’),” he wrote in a letter to Kellogg President A.D. David MacKay, “it is vitally important that parents receive accurate information about what they can do to protect their children’s health.”

Herrera requested a laundry list of information including consumer research, marketing studies, scientific research, and any additional “sources, studies, research or other documents” upon which the cereal giant has based it claims.  

Kellogg’s immunity claims are “a potential violation” of California’s Unfair Competition Law, Herrera wrote, and may “undermine critical public health efforts to prevent the spread of [H1N1 virus] that the President has declared to be [a] national emergency”.

Kellogg has 30 days to respond to Herrera’s requests for information, or he will seek to put a stop to, or alter, the company’s advertising pitch. Kellogg, however, is standing by its claims.

“The claim we’re making is based on peer-reviewed and published research as well as authoritative statements from the Institute of Medicine,” said company spokeswoman Ashley Currie, “which state that the antioxidants and nutrients in Kellogg’s Rice Krispies cereals have been shown to support the body’s immune response.”

Kellogg has “added more positive nutrition” to its Rice Krispies cereals in response to data from the U.S. Department of Agriculture (USDA) which show that Americans don’t get enough of vitamins A, C, and E, Currie said. “These nutrients have been identified by the Institute of Medicine and other studies as playing an important role in the body’s immune system.”

In addition to a wide range of nutrients and vitamins, the web site Fooducate describes the cereal as “an excellent source of Vitamin B1,” but notes too that it’s high in sugar. Sugar and high fructose corn syrup comprise the second and third ingredients after rice, and three-quarters of a cup – a single serving according to Kellogg – has 160 calories.