Summary: Researchers found that wheat gluten induces brain inflammation in mice, a finding that could have implications for human health.
The study revealed that when mice consumed gluten, inflammation occurred in the hypothalamic region of the brain, which plays a vital role in regulating metabolism. While past research demonstrated gluten’s effects on weight gain and inflammation in the digestive system, this is the first study highlighting its impact on the brain.
The findings raise questions about potential long-term effects on humans, such as weight gain, blood sugar regulation issues, and impaired memory.
The research indicated that gluten, when added to the diet of mice, caused inflammation in the hypothalamic region of the brain.
Mice models are deemed valuable for studying human physiology due to similarities in various systems, suggesting potential implications for humans.
While the exact reason for the inflammation is still unknown, one theory suggests that indigestible components of gluten may trigger an immune response similar to that seen in celiac patients.
Source: University of Otago
In what is believed to be a world first discovery, University of Otago researchers have found that wheat gluten causes brain inflammation in mice.
The research, led by Associate Professor Alex Tups, and published in the Journal of Neuroendocrinology, may be of importance for human physiology.
“Mice are an excellent model to study human physiology. They have a very similar circulatory, reproductive, digestive, hormonal and nervous system. “So, it is quite possible that the same inflammation we found in mice could happen in humans.”
The study investigated whether a standard diet, referred to as low fat diet (LFD), enriched with 4.5% gluten (matching human average daily consumption), or a high fat diet (HFD), enriched with 4.5% gluten, alters body weight, metabolic markers or central inflammation in male mice.
“Gluten, which is found in cereals such as wheat, rye and barley, makes up a major dietary component in most western nations.
“While previous studies have shown gluten promotes body mass gain and inflammation in mice in the enteric nervous system and gastrointestinal tract, we investigated the impact of gluten on the brain.”
While somewhat expectedly, the study confirmed a “moderate obesogenic effect of gluten when fed to mice exposed to a high fat diet, for the first time we can report gluten-induced hypothalamic (brain) inflammation,” Associate Professor Tups says.
“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 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.”
The hypothalamic region of the brain is vital for coordinating basic metabolic functions like body weight regulation and blood sugar regulation.
“If gluten led to hypothalamic inflammation in humans and therefore brain damage, it can be bad in the long run, such as 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.
Why this is happening is not known, he says.
“This is entirely new and so we don’t know yet why it is the case.
“It could be that digestion resistant components of wheat of gluten can lead to an immune response as seen in celiac patients that then manifests in the brain. These are early days and we need future studies to confirm whether this has implications for celiac or gluten sensitive people.”
However, Associate Professor Tups says the finding does not mean people should suddenly stop eating gluten.
“We are not saying that gluten is bad for everyone. For gluten tolerant people to go entirely gluten free may have health implications that may outweigh potential benefits. Often people don’t consume wholefoods and highly processed gluten free products are often low in fiber and high in sugar.
“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.”
Dietary wheat gluten induces astro‐ and microgliosis in the hypothalamus of male mice
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.