A research team led by Hiroshi Ohno at the RIKEN Center for Integrative Medical Sciences (IMS) in Japan has uncovered a promising approach to combat obesity. Their study, published in Cell Metabolism, shows that supplementing the gut with acetate significantly reduces fat and liver mass in both normal and obese mice—provided Bacteroides bacteria are present in the gut.
Acetate and Gut Bacteria: A Powerful Combination
The researchers discovered that acetate alone isn’t enough. When Bacteroides bacteria coexist in the gut, they help eliminate more sugars from the intestine and shift the host’s metabolism toward burning fat for energy. This dual mechanism results in effective weight loss and reduced fat accumulation in the liver.
Obesity and Fiber: The Link Through Acetate
Obesity affects hundreds of millions globally and increases the risk of heart disease, type-2 diabetes, and cancer. While excessive intake of sugars and starches is a major contributor, dietary fiber appears to offer protection. Interestingly, although fiber is indigestible by mammals, it becomes beneficial when fermented by gut bacteria in the large intestine.
One of the key byproducts of this fermentation is acetate, a short-chain fatty acid known to support healthy metabolism. However, the amount of acetate produced varies from person to person, limiting the benefits of fiber alone.
AceCel: Delivering Acetate Where It Matters
To overcome this limitation, Ohno’s team developed AceCel, a supplement made by combining acetate with cellulose. This formulation ensures acetate reaches the distal large intestine—where it can have the greatest impact.
In their recent study, the researchers administered AceCel to both normal and obese mice. Remarkably, the mice lost weight without losing muscle mass. Other short-chain fatty acids did not yield the same results, highlighting acetate’s unique role.
AceCel Shifts Metabolism Toward Fat Burning
Further investigations revealed how AceCel alters metabolism. Compared to control mice, those given AceCel burned more liver fat and fewer carbohydrates while at rest. This metabolic pattern mimics that of fasting or ketogenic diets, which are known to promote weight loss.
Bacteroides: The Key Microbial Partner
Curious about the microbial changes, the team analyzed the gut microbiota. They found a noticeable increase in Bacteroides species in the AceCel-fed mice. To confirm the bacteria’s role, they tested AceCel on germ-free mice and on mice colonized with specific Bacteroides species.
As reported by medicalxpress, the results were clear: AceCel did not affect body, liver, or fat mass in germ-free mice. However, when Bacteroides species were present, the mice experienced significant fat loss. This confirmed that both acetate and these bacteria are necessary for the metabolic benefits.
How the Combination Works
The team discovered that the acetate–Bacteroides combination increases fermentation of carbohydrates in the gut. This process reduces sugar absorption, forcing the body to rely more on fat for energy. Additionally, it minimizes sugar storage as glycogen in the liver, further contributing to weight reduction.
A Potential Solution to the Obesity Crisis
“Developing a treatment or prevention strategy for obesity is an urgent issue,” says Hiroshi Ohno. “We found that acetylated cellulose can prevent obesity by modulating the gut microbiome’s function.”
Looking ahead, the team plans to test the safety and effectiveness of AceCel in humans. If successful, AceCel could become a key ingredient in functional foods designed to prevent obesity and improve metabolic health.