Researchers from The Scripps Research Institute have pinpointed a specific hormone in the brain that appears to be responsible for triggering fat burn in the gut.
Serotonin has been established before as a driving factor for fat loss. However, it wasn't clear how exactly the neurotransmitter was able to influence fat reduction. To find out, Supriya Srinivasan and colleagues carried out experiments on Caenorhabditis elegans.
Commonly used as a model organism in biological applications, the roundworm has a simpler metabolic system than people but features a brain capable of producing a lot of the same signaling molecules that a human brain does. As such, many researchers believe that results involving C. elegans may have potential relevance to humans.
For a study published in the journal Nature Communications, the researchers erased certain genes in C. elegans to determine if it was possible to disrupt the path between serotonin in the brain and fat burning. Testing genes one after the other, they were able to zero in on a gene that codes for FLP-7, a neuropeptide hormone.
FLP-7 And Fat Metabolism
According to the researchers, FLP-7 was actually identified as a muscle contraction-triggering peptide when applied to pig intestines. Back then, it was believed that the hormone connected the brain to the gut but it was not specifically linked to fat metabolism.
After identifying FLP-7 as a fat-burning trigger, the researchers moved on to determining if it has a direct connection to levels of serotonin in the brain. Lavinia Palamiuc, the study's first author, led this part of the study by tagging FLP-7 using fluorescent red protein, allowing for the peptide to be viewed within C. elegans.
Based on their observation, the researchers saw that FLP-7 was released by brain neurons responding to elevated levels of serotonin. The neuropeptide hormone then entered the circulatory system and started the fat-burning process within the gut.
"That was a big moment for us," said Srinivasan. And understandably so, as this is the first time that researchers discovered a brain hormone that selectively and particularly spurs the fat-burning process without affecting food intake.
Manipulating FLP-7
While increasing levels of serotonin have a massive effect on food intake, reproductive behavior, and movement, increasing levels of FLP-7 did not have any obvious side effects, noted the researchers. Based on observations, the researchers simply continued functioning as usual while burning more fat.
According to Srinivasan, this finding may encourage studies in the future to focus on how levels of FLP-7 can be regulated without resulting in side effects typically experienced when levels of serotonin are manipulated.
Supported by grants from the NIH's Office of Research Infrastructure Programs and National Institute of Diabetes and Digestive and Kidney Diseases, the current study also included work from Tallie Noble, Megan Vaughan, Emily Witham, and Harkaranveer Ratanpal.
Burning Off Fat Effectively
For those interested in losing body fat, another study offers another tip: what time you eat your dinner may have a hand in how you burn off fat. According to the study, consuming meals within a smaller time frame in a day may boost weight loss abilities by increasing the body's capacity to consume proteins and burn fat.
