ONTARIO, Canada, Tuesday December 23, 2014 – A team of Canadian scientists have discovered how to turn up the jets on the body’s metabolism and burn more fat.
The researchers at McMaster University in Hamilton, Ontario, found a key hormone that is elevated in overweight people and contributes to obesity and diabetes by inhibiting the activity of brown adipose tissue, commonly known as “brown fat.”
Brown fat acts as the body’s furnace to burn calories, as well as to keep the body warm.
Obese people have less brown fat, but until now it was not understood why.
The key was found to lie in one of the body’s two types of serotonin.
The more familiar type of serotonin in the brain or central nervous system affects mood and appetite, but this makes up only five percent of the body’s serotonin.
The lesser-known peripheral serotonin circulates in the blood and makes up the other 95 percent of the body’s serotonin.
The scientists discovered that this peripheral serotonin reduces brown fat activity and turns down the body’s metabolic furnace.
The findings of the study, published earlier this month in Nature Medicine after five years of research, is the first to show that blocking the production of peripheral serotonin makes the brown fat more active.
According to Gregory Steinberg, the paper’s co-author: “Our results are quite striking and indicate that inhibiting the production of this hormone may be very effective for reversing obesity and related metabolic diseases including diabetes.”
“Too much of this serotonin acts like the parking brake on your brown fat,” he said. “You can step on the gas of the brown fat, but it doesn’t go anywhere.”
The researchers may also have identified the culprit responsible for elevated levels of peripheral serotonin.
“There is an environmental cue that could be causing higher serotonin levels in our body and that is the high-fat western diet,” co-author of the paper Waliul Khan indicated.
“Too much serotonin is not good. We need a balance. If there is too much, it leads to diabetes, fatty liver and obesity.”
The scientists found that when they genetically removed or inhibited tryptophan hydroxylase (Tph1), the enzyme that produces the majority of serotonin, mice fed a high-fat diet were protected from obesity, fatty liver disease and pre-diabetes due to an enhanced ability of the brown fat to burn more calories.
Steinberg was quick to point out that inhibiting the peripheral serotonin does not affect the serotonin in the brain or central nervous system functioning.
This marks a complete departure from earlier weight loss drugs, which worked to suppress appetite by affecting levels of brain serotonin, but were associated with hazards including cardiac complications and increased risk of depression and suicide.
“Moving forward, we think it’s a much safer method to work with increasing energy expenditure instead of decreasing the appetite, which involves more risks,” Steinberg concluded.