Investors, regulatory review geeks, policy wonks, foodies, statistics nerds and just plain citizens are getting courtside seats in the back and forth between Golden Valley-based General Mills (NYSE:GIS) and the Food and Drug Administration over a provocative question: Is Cheerios a drug or a breakfast cereal?

As connections between diet and health increasingly become a part of the public debate across the supermarket aisles, breakfast tables and food company executive suites, the Cheerios controversy offers a window into the decision-making process at the FDA, the limits of health claims in marketing statements and the increasing transparency of the debate.

But greater transparency may not necessarily translate into greater clarity for consumers as the controversy goes on. (See related stories here and here.)

Cheerios brand has been a significant revenue and profit contributor for General Mills as the company has sought to capitalize on linking the popular breakfast cereal to proven health benefits of a fiber-rich diet in lowering LDL, or “bad,” cholesterol.

Since the controversy erupted into public view last May, both sides have continued in dialogue with meetings and at least one exchange of letters. Intense public interest in the case spawned multiple Freedom of Information Act (FOIA) requests, opening a rare window into the ongoing conversation. As the two parties negotiate through the Cheerios dispute, General Mills has had to react quickly and publicly.

This past May, the FDA publicly issued a warning letter to the Minnesota-based company asserting that labeling on Cheerios boxes and website claims violated the Food and Drug Act. Cereal box labels claimed a specific cholesterol-lowering benefit of 4 percent from a daily diet of the cereal. While not disputing the validity of the claim, the FDA said that quantifying the benefit ”caused it [Cheerios] to be a drug ... because the product is intended for use in the prevention, mitigation, and treatment of disease” [high-cholesterol], according to the FDA warning letter. The agency also said that the website claims had not mentioned the benefit of low-fat, low-cholesterol diets as required.

General Mills responded that the science behind the disputed claim was “not in question.” While removing the challenged labeling, the company said: “Cheerios’ soluble fiber heart health claim has been FDA-approved for 12 years, and Cheerios’ ‘lower your cholesterol 4% in 6 weeks’ message has been featured on the box for more than two years ... The FDA is interested in how the Cheerios cholesterol-lowering information is presented on the Cheerios package and website. We are in dialog with FDA, and we look forward to reaching a resolution."

The FDA issues literally hundreds of warning letters a year, and they are all made public.

Nothing new so far, other than the headline-grabbing nature of the controversy surrounding the favorite finger food of toddlers everywhere. And that’s where the public dispute stood last May.

Then, in early October, the FDA posted a letter sent to the cereal giant, taking issue with General Mill’s statistical interpretation of the results and use of four of five research studies used to back the health claims the company was making. The letter to General Mills was the subject of more than three FOIA requests and under FOIA guidelines was posted on the agency’s website. (The Star Tribune reported that it was one of the FOIA requestors.)

The “FDA would need to consider the totality of the publicly available scientific evidence to support such a statement (on health benefits) and also how to convey information in a way that is not misleading,” the letter said. It did acknowledge that one study “appears to provide data that soluble fiber from whole oats can lower LDL cholesterol by an average of 4% in six weeks.”

General Mills, for its part, responded with a press release and letter to the agency posted on its website, highlighting the fact that the FDA acknowledged the validity of the one study on which the 4% reduction claim was made. “We agree that this study supports the factual claim on our Cheerios package,” the company statement said. General Mills also had cited several studies that “reinforce that the Cheerios studies are consistent with the body of scientific literature relied upon by FDA when it approved the soluble fiber from oats [coronary heart disease] health claim.”

And that’s where the public side of the debate stands.

While follow-on inspection reports are often made public under FOIA, “it is relatively unusual for interim correspondence to be the focus of repeated FOI requests,” according to FDA spokesperson Siobhan DeLancey. “I would guess that this case attracted more requests because both the product and the company are so well known.”

And we may be in for more public back and forth into FDA regulatory oversight, not just with General Mills. Health and Human Services Secretary Kathleen Sebelius, in announcing a Transparency Task Force last June, pledged to “give the American people a seat at the table and make the FDA more open and accountable.”

In a separate development, an industry-led consortium of food and beverage companies, including General Mills, which had been developing a ‘Smart Choice’ simple nutritional label for packaging, suspended operations last month. That followed an announcement by the FDA that the agency intends to develop standardized criteria on which future front-of-package nutrition or shelf labeling will be based.