Calorie-dense diets, such as those in Western societies, are generally regarded as "palatable" – while comprising highly processed food items that contain lots of saturated fat and refined sugar. These include – but are not limited to – conventionally grown red meat, processed meats, vegetable oils, ice cream, sweetened yogurts, cakes, cereal, biscuits and soft drinks. Such a diet will invariably result in adverse effects: According to a discrete study by researchers from Macquarie University in Australia, high-fat diets override the brain's ability to stop eating after feeling full, which can lead to added weight and, in some cases, obesity. Researchers also found that people who ate a calorie-dense Western diet performed poorly on memory-related tasks – including remembering what they ate – and reported reduced feelings of fullness.
Understanding how gut microbes and diet work together
The current study, one of the few to focus on microbes in the upper gastrointestinal tract (GIT), looked at the relationship between the type of diet and gut microbes by studying the role of diet-induced microbes on the digestion and fat uptake using murine tests. Two types of mice were used in the study: The first type were mice bred in isolated chambers to prevent any intestinal bacteria growth, while the other type were healthy mice that have non-disease-causing microbes.
When both groups were fed a high-fat diet, the germ-free mice didn't absorb the fatty foods and discharged them in their stool. Those who had microbes in their gut, however, gained weight. Upon further examination, the team found an increased level of microbes from the Clostridiaceae and Peptostreptococcaceae families. In particular, Clostridiaceae microbes were linked to increased fat absorption. When these microbes were introduced in germ-free mice, they gained the ability to absorb lipids and gained fat. Conversely, the diet reduced the populations of Bifidobacteriacaea and Bacteriodacaea, which were commonly associated with leanness. (Related: Obesity is a social thing: Study finds health habits are “contagious” and highly influenced by social groups.)
This builds on evidence which stated that certain types of microbes release bioactive compounds after being exposed to dietary fat that has been broken down during digestion. According to researchers, this can lead to overnutrition and obesity over time – even impact extra-intestinal organs such as the pancreas.
"These bacteria are part of an orchestrated series of events that make lipid absorption more efficient," explained Dr. Eugene Chang, the study's senior author and a director at the University of Chicago Medicine. "Few people have focused on the microbiome of the small intestine, but this is where most vitamins and other micronutrients are digested and absorbed."
Applying what we've learned
While the study is still in its preliminary stage, the team is optimistic that this could be used in developing pre- or probiotics to increase nutrient uptake for people with conditions such as Chron's disease, which reduces the GIT's ability to absorb nutrients. They also added that the results presented by the study could have real-world applications such as procedures to treat obesity and cardiovascular disease. "This work has important implications in developing approaches to combat obesity," they concluded.
A Western diet is chock-full of refined sugars – and these include artificial sweeteners. Learn more about how these can negatively impact your health by following Sweeteners.news today.
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