In a new study, scientists have used a mouse model to show that the consumption of wheat gluten is linked to brain inflammation. This could have major implications for human health and physiology, the researchers suggested. The findings have been reported in the Journal of Neuroendocrinology.
Study leader Alex Tups, an Associate Professor at the University of Otago, noted that mice are an excellent research model that have circulatory, digestive, hormonal, nervous, and reproductive systems that are very similar to humans; and that, "it is quite possible that the same inflammation we found in mice could happen in humans."
In this work, the researchers exposed different groups of mice to various diets: either a standard, low fat diet (LFD) that had been spiked with 4.5 percent gluten, which aligns with the average daily consumption by a human; or a high fat diet (HFD) that was also boosted with 4.5 percent gluten. The investigators assessed whether these diets altered body weight or biomakers of metabolism and inflammation in the (male) mice.
Gluten can be found in foods that contain wheat, rye, barley, like bread, cereal, or pasta, and it is a primary component of the average person's diet in many western nations. Tups noted that previous research has indicated that gluten consumption promotes weight gain and inflammation in the gastrointestinal tracts and enteric nervous systems of mouse models. But this study was assessing the impact of gluten on the brain.
The research showed that mice that ate HFDs had moderate obesity, as well as inflammation in a region of the brain known as the hypothalamus. The hypothalamus is crucial to the regulation of food intake and body weight. There are immune cells in the brain known as astrocytes and microglia. Gluten and HFD were found to increase the levels of both of these 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," said Tups.
"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 this effect persists over time, the risks could become worse, and may affect memory function, which has been associated with impaired regulation of blood sugar.
"This is entirely new and so we don't know yet why it is the case," said Tups. It could be that in celiac disease patients, the parts of wheat gluten that are tough to digest might be leading to an immune reaction that eventually manifests in the brain. Additional work will be needed to determine whether these results are important for people who are gluten sensitive, intolerant, or celiac.
These results do not suggest, however, that wheat tolerant people should immediately stop eating gluten, said Tups.
"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 whole foods 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."