Andrew Gewirtz, university center professor at Georgia State University, said in a session at IFT 2015 that he previously didn’t believe the hype on metabolic syndrome and its relation to inflammation. However, after a recent study, by A. Gewirtz et al., he alleges emulsifiers may be harmful to human gut microbiota, causing inflammatory bowel disease, obesity and other sicknesses.
Another study, by K.R. Magnusson et al from Oregon State University, said people also must be careful with the levels of fat and sugar they ingest, as it may cause changes in the gut microbiota that lead to short and long-term memory loss.
Emulsifiers and the impact on obesity
Gewirtz said he believes emulsifiers, which have increased in use since the mid-20th century and are often used to help stabilized processed food, baked goods and confectionery, can cause an alteration of the gut microbiota (or bacteria) leading to inflammation. This may have assisted the rise of obesity and other similar disorders, such as diabetes, he suggests.
In testing this theory, Gewirtz led a study which fed emulsifiers, including polysorbate 80 and carboxymethylcellulsose, to one group of test mice emulsifiers. The researchers gave another group a normal diet, sans the emulsifiers. In the end, the emulsifier-treated mice had more problems with inflammation and obesity, whereas the mice that did not ingest the emulsifiers ad none of these issues.
Gewirtz said there may even be physiological factors increasing one’s need for consumption of emulsifier-based products. The general concept of food changing the nature of how the inside of the human body reacts doesn’t just apply to emulsifiers, Gewirtz said, but other additives may also cause this.
"We do not disagree with the commonly held assumption that over-eating is a central cause of obesity and metabolic syndrome," Gewirtz wrote in the study. "Rather, our findings reinforce the concept suggested by earlier work that low-grade inflammation resulting from an altered microbiota can be an underlying cause of excess eating."
High fat, sugar diets also alleged to be harmful
Oregon State University’s study found that both high-fat and high-sugar diets, when compared to normal diets, may cause gut microbiota to lose the power to adapt and adjust over time.
The study said a high-sugar diet at a young age impaired early learning. OSU said a both a child’s long-term and short-term memory may be harmed on this particular diet.
“It’s increasingly clear that our gut bacteria, or microbiota, can communicate with the human brain,” said Kathy Magnusson, a professor in the OSU College of Veterinary Medicine and principal investigator with the Linus Pauling Institute. “Bacteria can release compounds that act as neurotransmitters, stimulate sensory nerves or the immune system, and affect a wide range of biological functions,” she said. “We’re not sure just what messages are being sent, but we are tracking down the pathways and the effects.”
OSU’s study also looked at laboratory mice, this time putting them through a series of tests after giving them normal, high fat and high sugar diets. After the diets, the university monitoring changes in the mice’s mental and physical function.
In just four weeks on a high-fat or high-sugar diet, performance of the mice dropped compared to those who were on a normal diet. Researchers said the findings are consistent with other similar studies on the impact of fat and sugar.
The largest amount of damage may have been done to cognitive flexibility, the study found. Magnusson said it would be like driving home on a route that is very familiar, then one day that route is closed and you have to find a new way home. With a high level of cognitive flexibility, a person would be able to immediately adapt to the change and find the next best route. With impaired flexibility, it would be harder and more stressful to make way back home.
1) Source: Nature
Published in 2015: 2015; DOI: 10.1038/nature14232
“Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome”
Authors: A. Gewirtz, B. Chassaing, O. Koren, J. Goodrich, A. Poole, S. Srinivasan, R. Ley,
2) Source: Neuroscience
Published in 2015; 300: 128 DOI: 10.1016/j.neuroscience.2015.05.016
“Relationships between diet-related changes in the gut microbiome and cognitive flexibility“
Authors:K.R. Magnusson, L. Hauck, B.M. Jeffrey, V. Elias, A. Humphrey, R. Nath, A. Perrone, L.E. Bermudez