Wheat gluten causes brain inflammation, finds new study

“Mice are an excellent model to study human physiology. They have a very similar circulatory, reproductive, digestive, hormonal, and nervous system,” said Alex Tups, lead author of the study, in a press release. “So, it is quite possible that the same inflammation we found in mice could happen in humans.”

Experiments in a mice model

The team fed male mice with a low-fat diet (LFD) enriched with 4.5 percent gluten and a high-fat diet (HFD) enriched with 4.5 percent gluten. They wanted to see how this alters body mass, metabolic markers and systemic as well as central inflammation in mice relative to mice fed LFD, which naturally does not contain gluten.

The researchers found HFD when gluten is added, increases body mass but has no effect on caloric intake or energy expenditure or when added to LFD. 

C-reactive protein, a ring-shaped protein found in blood plasma, which rises in response to inflammation was increased in mice fed gluten-enriched LFD. 

“The brain has two types of immune cells similar to macrophages in the blood. These are called astrocytes and microglia. We found that gluten as well as HFD increases the number of those immune cells. The effect of gluten added to a normal diet increased the cell number to the same extent as if mice were fed an HFD. When gluten was added to the HFD, the cell number went up even further,” added Tups.

“If gluten led to hypothalamic (the region of the brain vital for coordinating basic metabolic functions) inflammation in humans and therefore brain damage, it can be bad in the long run, such as an increase in body weight and impaired blood sugar regulation. If these effects became persistent they might exacerbate the risk of e.g. impaired memory function which is linked to disturbed blood sugar regulation,” said Tups.

People shouldn't stop consuming gluten

The team said they don’t know why this happens but also cautioned that the conclusions drawn by the study don’t mean that people stop consuming gluten.

“We are saying that future studies need to reveal whether our findings in mice are translatable to humans and whether gluten-induced astro- and microgliosis may also develop in gluten-sensitive individuals,” said Tups.

The study was published in the Journal of Neuroendocrinology.

Study abstract:

Gluten, which is found in cereals such as wheat, rye and barley, makes up a major dietary component in most western nations, and has been shown to promote body mass gain and peripheral inflammation in mice. In the current study, we investigated the impact of gluten on central inflammation that is typically associated with diet-induced obesity. While we found no effect of gluten when added to a low-fat diet (LFD), male mice fed high fat diet (HFD) enriched with gluten increased body mass and adiposity compared with mice fed HFD without gluten. We furthermore found that gluten, when added to the LFD, increases circulating C-reactive protein levels. Gluten regardless of whether it was added to LFD or HFD led to a profound increase in the number of microglia and astrocytes in the arcuate nucleus of the hypothalamus, as detected by immunohistochemistry for ionised calcium binding adaptor molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP), respectively. In mice fed LFD, gluten mimicked the immunogenic effects of HFD exposure and when added to HFD led to a further increase in the number of immunoreactive cells. Taken together, our results confirm a moderate obesogenic effect of gluten when fed to mice exposed to HFD and for the first-time report gluten-induced astro- and microgliosis suggesting the development of hypothalamic injury in rodents.