Regardless of personal opinions, the sheer numbers of the trend are staggering: in recent years, anywhere from 20 to 30% of Americans say they are trying to avoid gluten, a naturally-occurring protein found in many grains. That's more than 60 million people--more than double the population of Texas.
So it behooves us to be certain the diet at least isn't harmful.
The devil is in what you replace the gluten-laden calories with--if you don't replace glutinous foods with red meat and full-fat dairy, you're going to be fine. That said, are any other negative consequences for those who have eaten gluten-free for decades?
There is a cohort out there; people with celiac disease. It is a genetic disorder whereby the body tags gluten, as an allergen, meaning it causes intense abdominal pain and intestinal damage. This damage reduces the body's ability to absorb nutrients, vitamins, and minerals, leading to further health complications. The cause of celiac disease and of non-celiac wheat sensitivity [or gluten sensitivity] is not known.
"Currently," says the Celiac Disease Foundation website, "the only treatment for celiac disease and non-celiac wheat sensitivity is lifelong adherence to a strict gluten-free diet."
People with celiac disease are often vitamin deficient and have a higher incidence (~15%) of having children with birth defects, most commonly neural tube defects (NTDs), which affect the growth of the brain, spinal cord, and spine.
Thankfully, these defects are relatively rare. The Centers for Disease Control and Prevention (CDC) reports roughly 3,000 affected pregnancies a year in the United States--that's less than 0.1%. But the CDC also says "Hispanic women have higher rates of neural tube defects than non-Hispanic women in the United States," about 40% higher than the average.
Why would Hispanic women and people with celiac disease both be affected this way? Is there a common factor? Well, it looks like there may be: a diet low in glutinous foods!
Corn flour, a staple in Hispanic cooking, does not contain gluten. A gluten-free diet, a requirement for people with celiac disease, obviously does not contain gluten either. However, it's not a lack of gluten that causes these birth defects, it's the absence of a different thing: folic acid. As we discussed in our previous post, grain products are fortified with folic acid as a public health strategy to prevent NTDs. But Hispanic women and people with Celiac disease eat less of these glutinous grains, and both demographics have a higher incidence of NTDs.
At the same time, is hard to completely blame gluten-free diets for this. Rates of NTDs were higher in Hispanic populations even before folic acid fortification, which might point to a genetic predisposition.
We don't have a smoking gun that a gluten-free diet increases the risk of NTDs, but it's a real possibility that people on gluten-free diets might be getting lesser amounts of important vitamins and minerals than people eating glutinous foodstuffs.
Joseph Smith, Press Officer for the CDC’s National Center on Birth Defects and Developmental Disabilities, says the CDC would know if something came up: “Although we are not examining the gluten-free trend on its own, we do regularly monitor blood folate concentrations in the U.S. population through the nationally representative sample from National Health and Nutrition Examination Survey. [...] If this survey indicates that blood folate concentrations are decreasing and/or neural tube defects are increasing, the [fortification] program can be revisited.”
Nevertheless, the Food and Drug Administration last year approved voluntary fortification of corn flour, a proactive first step to help the disproportionately affected Hispanic population. Sure, this nutritional deficit could be addressed with multivitamins, but perhaps it is time to fortify our efforts to supplement a wider array of staples to include people who may be falling through the fortification safety net right now.
Banner image courtesy of USDA.