Depression and Gluten Sensitivity

Yes, Gluten May Make You Depressed If You're Gluten Sensitive

A study shows gluten causes depression in those with non-celiac gluten sensitivity. Getty Images/Jacqueline Veissid

June 3, 2014 — Gluten may cause depression in people who have non-celiac gluten sensitivity, a new study shows.

The study, reported in the medical journal Alimentary Pharmacology and Therapeutics, could explain why people without celiac disease who follow a gluten-free diet feel better when gluten-free, even when they continue to suffer from digestive symptoms such as diarrhea and bloating, the study's authors said.

"We have hypothesized that the reason why patients might feel better on the gluten-free diet is that gluten is having a detrimental effect on their mental state and the cessation of gluten improves their well-being rather than the gastrointestinal symptoms per se," the study said. "Indeed, short-term exposure to gluten appeared to specifically induce current feelings of depression."

In fact, the study showed that gluten — in a purified form — had no effect on digestive symptoms; the study participants did not report additional gastrointestinal symptoms when they eliminated gluten-containing grains from their diets and then consumed the purified gluten. However, the researchers did not rule out the possibility of some other component of those grains causing gastrointestinal symptoms.

Study Included Self-Diagnosed Gluten Sensitives

The researchers, who hail from Monash University in Melbourne, Australia, looked at 37 people diagnosed irritable bowel syndrome who didn't have celiac disease but who reported feeling better on a gluten-free diet.

The researchers removed gluten from their diets and placed them on a diet low in the type of carbohydrates known as FODMAPs — fermentable, oligo-, di-, monosaccharides and polyols. They then challenged the people with nearly pure gluten in varying doses (none of the participants knew when they were receiving gluten or a placebo).

The low-FODMAP diet seemed to quell participants' gastrointestinal symptoms, and the gluten challenge didn't aggravate those digestive problems, the study said. However, those consuming gluten (again, without knowing whether they actually were getting gluten or a placebo) reported more depression.

In fact, "the observed change in current feelings of depression is appreciable," the researchers wrote. The participants went from largely being "neutral depressive," or even-keeled, to "mild depressive" during their three-day gluten challenges.

4 Possible Reasons For Gluten's Depressive Effects

The study detailed four possible ways gluten could make people depressed:

  1. Gluten could increase the levels of cortisol, a hormone associated with depression and anxiety. However, the researchers tracked cortisol and found no difference in levels between those consuming gluten and those consuming a placebo.
  2. Gluten could lower levels of the neurotransmitter serotonin -- lower levels of serotonin have been linked with depression.
  3. Small fragments of gluten that mimic opioid compounds could cross the blood brain barrier and affect mood, emotion and memory.
  4. Gluten could alter gut microbia. A recent study linked changes in gut microbia to changes in emotion and sensation in adult women.

    The research didn't provide enough information to determine which of these mechanisms — if any — might be responsible for the feelings of depression in the study group consuming gluten, the authors said.

    In addition, the participants only consumed gluten for three days, which may not have been long enough for the maximum possible change in psychological state, the authors said.

    Depression Commonly Reported in Celiac, Gluten Sensitivity

    This was the first study to look closely at depression in those with non-celiac gluten sensitivity, but depression is a common complaint both for people with gluten sensitivity and people with celiac disease.

    It's not clear why this occurs, although there's speculation that in celiacs, poor absorption of nutrients can lead to deficiencies in certain B vitamins that help to regulate and improve mood. However, this explanation wouldn't carry over to people with gluten sensitivity, who don't have the same intestinal damage.

    Other researchers in the field have speculated about the possibility of gluten having some sort of direct depressive effect on the brain, and this current study — while not determining the mechanism for a depressive effect — offers some evidence for that.

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