Bread baskets are so passé.

Going gluten-free is incredibly popular these days. Talk to your friends and family. Check a menu or glance in your pantry. Chances are, someone you know or a restaurant you visit has jumped on the anti-gluten bandwagon.

For some, it's a serious medical choice. About one in every 133 Americans suffers from celiac disease, according to the Center for Celiac Research at MassGeneral Hospital for Children. If people with this inherited autoimmune disease eat foods that contain gluten (a protein found in some grains, especially wheat, barley and rye) it causes damage to the small intestine, making it harder for their body to absorb nutrients. It results in symptoms ranging from abdominal pain and constipation to fatigue and headache.

Others avoid cereals, pastas and bread because they have a wheat allergy; they have a true allergic reaction to the proteins found in wheat, reports the Mayo Clinic. Symptoms can include swelling, hives, itching and gastrointestinal distress.

When it isn't celiac disease or a wheat allergy

There are others who avoid gluten because they feel better without it. They haven't been diagnosed with celiac disease or a wheat allergy, but they can definitely tell the difference when they avoid products made from those grains. There are likely two explanations for why they feel better without gluten.

One simple explanation is that they're more aware of what they're eating, so there's a good chance they're eating healthier and possibly losing weight.

"There's nothing magical about eliminating gluten that results in weight loss," Heather Mangieri, a nutrition consultant and spokesperson for the Academy of Nutrition and Dietetics, tells Scientific American. "Any of us that eliminates or removes cookies and candies from our diets, and replaces them with fruits and vegetables is going to feel better."

But there are others who don't test positive for celiac disease but they still don't feel well when they eat foods with gluten. They often have what's known as non-celiac gluten sensitivity and they might experience some of the same symptoms, like bloating, constipation, headache and fatigue. However, there's no medical test to see if you have gluten sensitivity.

"These patients absolutely do exist," Stefano Guandalini, M.D., director of the University of Chicago Celiac Disease Center, tells WebMD. "They do have real symptoms."

As many as 18 million Americans have some non-celiac sensitivity to gluten, says Beyond Celiac, a nonprofit that promotes widespread understanding of celiac disease.

But non-celiac gluten sensitivity isn't as well understood as celiac disease. Until recently, some doctors weren't convinced it was real, and even now there's not a lot of clarity over how to diagnose it or what causes it.

What if it's not the gluten protein?

Foods high in vitamin D: Milk For some people, it's not the gluten protein, but it could be lactose in dairy products causing symptoms. (Photo: Sea Wave/Shutterstock)

There are likely some people who are not tolerant to the actual gluten proteins. But new research suggests that for many people, it may not be the gluten protein causing symptoms in these cases. A group of carbohydrates called FODMAPs (fermentable oligo-di-mono-saccharides and polyols), which can be poorly absorbed by some people, may be to blame. Wheat, barley and rye — gluten-containing grains — are all high in FODMAPs.

Interestingly, it's not just the grains that are worrisome if FODMAPs are the cause of your problems, NPR points out. These FODMAP carbs can include:

  • fructan found in wheat, as well as garlic and artichokes
  • lactose found in some dairy products
  • galactans found in some legumes

Researchers at Monash University in Australia developed a low-FODMAP diet for people with irritable bowel syndrome and other chronic gut disorders. The diet may help people with non-celiac sensitivity to gluten if FODMAPs are the true culprit.

Because there's no test for gluten sensitivity, doctors diagnose the condition by ruling out celiac disease and wheat allergies and then typically suggesting a gluten-elimination diet. If the patient feels better without gluten, a diagnosis is often made.

Gluten-free isn't always better

According to recent data from the National Health and Nutrition Examination Surveys, in the past five years, the number of people who were diagnosed with celiac disease didn't budge over .77 percent, yet during that same time period, people without the disease who decided to go gluten-free more than tripled.

Cutting out gluten just for the heck of it isn't always the healthiest route, caution nutritionists. Whole grains, which have gluten, are a good source of fiber, vitamins and minerals, Katherine Tallmadge, a dietitian and author of "Diet Simple," tells Scientific American. On the other hand, gluten-free products are often made with refined grains, which are lower in nutrients.

Studies show gluten-free diets can be lacking in nutrients including fiber, iron, folate, niacin, thiamine, calcium, vitamin B12, phosphorus and zinc, she says.

"You can eat a healthy diet without gluten, but you have to be very knowledgeable, and most people aren't," Tallmadge says.

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.