The blogosphere was in a tizzy late this summer when General Mills announced that Cheerios were going gluten-free. People with celiac disease waxed nostalgic for a childhood staple that would soon be safe for them to consume again, and celebrated the imminent arrival of a low-sugar, respectably fiber-containing cereal option for their breakfast rotation. But since this announcement and roll-out, there's been controversy about how gluten-free the new Cheerios actually are. The ensuing debate has exposed the fault lines of the Food and Drug Administration's relatively new gluten-free labeling guidelines and exemplifies some of the dilemmas faced by gluten-free eaters in the modern supermarket.

By way of background: The FDA rule for gluten-free labeling states that foods can carry a gluten-free label if they don't contain gluten-containing grains such as wheat, barley or rye – or any ingredients derived from them. It does not, however, require manufacturers to test their final products to prove that they actually contain less than 20 parts per million of gluten – the threshold under which a product must fall to be considered gluten-free. In reality, this means it's unlikely anyone has ever tested a given product carrying a gluten-free label to verify it meets the gluten-free standard and is also free from cross-contamination.

Moreover, the FDA guidelines allow foods containing conventional oats to carry a gluten-free label because oats are a naturally gluten-free grain. This principle has been controversial, as it disregards the fact that oats are widely known to be cross-contaminated with gluten from contact with wheat and barley during growing (from crop rotation in the same fields) and processing (in the same plants on the same equipment). Although oat products carrying the gluten-free label are required to fall below the 20ppm standard, the fact remains that manufacturers aren't required to check, and the FDA is unlikely to do so either. While there are some companies who market certified gluten-free oats that have been grown in dedicated fields, processed in dedicated mills and then tested to verify their gluten-free status, supplies of this specialty crop are limited.

In this context, it's understandable how the new gluten-free Cheerios are poised to present a novel challenge for the young-ish FDA gluten-free labeling guidelines, calling into question how reliable and useful the label can actually be for people with celiac disease. Old Cheerios contained both wheat starch (derived from a gluten-containing grain) and conventional oats (likely contaminated with gluten during processing). New Cheerios no longer contain wheat starch, but they are still made with conventional oats due to supply constraints of certified gluten-free oats grown in dedicated fields. In this scenario, General Mills would be allowed to attach a gluten-free label to the product without any testing or any disclaimers alerting consumers to the possibility of cross-contamination. And in fact, multiple smaller manufacturers of oat-based products – granola and energy bars especially – do just that. (Consumers with celiac disease, beware!)

But this is General Mills – a large food company with deep pockets and a reputation to protect. And as such, the company has gone to great lengths in order to keep gluten out of its gluten-free Cheerios. According to the company's website, they have implemented a system to sift their conventional oats and remove stray grains of wheat or barley before milling them into flour. They also claim to conduct three separate rounds of testing for gluten content during the manufacturing process – testing the whole oats, the milled flour and the finished product, respectively – to ensure that the FDA standard is met at each point along the way. Indeed, three random boxes of Cheerios were tested by the independent and reputable Gluten Free Watchdog group in August, and were found to be in compliance of the FDA standard of less than 20ppm of gluten.

So what's the controversy? Well, as it turns out, the FDA has reportedly received complaints from 39 consumers who claim they've gotten sick after consuming the new gluten-free Cheerios. Moreover, the founder of Gluten Free Watchdog, registered dietitian Tricia Thompson, has raised objections to the testing protocols employed by General Mills, arguing that their method of pooling multiple boxes per lot of finished product for testing may obscure the presence of outlier boxes with high gluten content. This is because a single box with high gluten content could be combined with many low gluten boxes, and the lot's average gluten content would therefore meet the standard and pass inspection. As such, Thompson argues that gluten content of individual Cheerios boxes should also be reported to augment the lot testing process under certain circumstances. She further advises her subscribers with celiac disease to avoid gluten-free Cheerios as a precaution until testing methods are refined. The FDA is currently investigating consumer complaints and will be reviewing random samples of Cheerios boxes before rendering its verdict.

As a dietitian with celiac disease who also counsels others with celiac disease, it's somewhat of a tough call to make. On one hand, to date no one seems to have actually produced evidence of a single box of gluten-free Cheerios that was shown to be contaminated with gluten. We don't know whether any of the 39 complainants actually even had celiac disease; whether any of them had medical confirmation of exposure to gluten based on blood tests; and whether they saved the suspected boxes for testing. Furthermore, it is extremely common for patients in my practice to blame gluten for feeling ill when often it is something entirely different actually responsible for their symptoms. For example, it's possible that some celiacs may react to oats independently, even if they are gluten free.

On the other hand, General Mills' novel method of sorting oats hasn't been vetted to ensure efficacy – and lot testing of just a dozen or two boxes of Cheerios produced in a 24-hour period could easily allow outlier boxes to slip through.

What's an eater with celiac disease supposed to do?

The truth is that there's no way to eliminate the risk of exposure to gluten entirely if you're a person with celiac disease who eats anything that comes in a cardboard box or crinkly bag. No matter how much testing and review is done by manufacturers, and how carefully you read labels, there remains a small but inherent risk of cross-contamination. Even naturally gluten-free grains and flours carrying gluten-free labels have been shown to be cross contaminated with gluten; 10 percent of samples contained less than 20ppm of gluten in one Canadian study, and 5 percent of packed foods labeled gluten-free or certified gluten-free exceeded this threshold in excellent research conducted by Thompson herself. Our industrial food supply is massive and imperfect. There are all sorts of risks inherent to eating in America in 2015, and yet we all must do our best to eat our best.

I do not take lightly the importance of dietary vigilance for patients with celiac disease, and am certainly not one to encourage "cheating" under any circumstances. But I've seen patients with celiac disease literally give themselves an eating disorder due to fear of gluten cross-contamination – avoiding everything from plain coffee and rice to salad bars. And frankly, I think the detrimental physical and psychological consequences of this type of food paranoia are far worse than the potential ill effects of being exposed to gluten accidentally on an isolated occasion. In my clinical experience, the vast majority of patients who take reasonable precautions to avoid gluten in packaged foods by scrutinizing labels, choosing items labeled "gluten-free" when available and ordering carefully when dining out at restaurants are able to keep their celiac antibodies negative and maintain excellent symptom control without making themselves crazy or isolating themselves socially. Most of my gluten-free patients have hopped on the Cheerios bandwagon, and based on available information, I wouldn't discourage it any more than I'd discourage them from dining out at restaurants. I've even had a few bowls of gluten-free Cheerios myself.