We all are born with brown adipose tissue and as we get older, we begin to lose this tissue. What is this? Simply called brown fat, it is an organ found around our collarbones. It really acts as our body's furnace burning calories, keeping us warm and getting our metabolic rate to keep moving. We know that not only does it decline as we age, but obese people have less of brown fat as well.

What regulates our brown fat and turns it on or off is a transmitter called serotonin. You may be familiar with serotonin as a neurochemical in the brain linked to depression.  

But did you know that as much as 95 per cent of our serotonin is circulating in our blood and not our brain.

Tryptophan which comes for our diet, is the building block for serotonin and the engine if you will, that converts tryptophan to serotonin is an enzyme called tryptophan hydroxylase. Too much serotonin turns off our brown fat and if we turn off the brown fat, down goes your metabolic rate increasing the risk for obesity.

There is a genetic variance in obese people where they have too much tryptophan hydroxylase driving the production of serotonin which in turn will turn off the brown fat. If you couple that with a high fat diet, you are really in trouble as a high fat diet also promotes expression of the enzyme driving more serotonin. A double whammy!

If we can inhibit the enzyme and slow down serotonin hormone, then the brown fat becomes more active and that could be very effective for reversing obesity and the related metabolic diseases including diabetes.

As the author Gregory Steinberg from McMaster says -too much of serotonin acts like a parking brake on your brown fat.

Our environment cues this activity as well. Our high fat western diet drives higher serotonin through the tryptophan hydroxylase enzyme activity. Too much serotonin means less brown fact activity which could mean obesity, fatty liver and diabetes.

What does this mean for the future. Well if a medication could block the enzyme activity not as much serotonin would be made and in mice when the enzyme was genetically removed or the enzyme was inhibited and then the mice were given a high fat diet, they were protected from obesity, fatty liver and prediabetes because the brown fat was able to burn more calories. What also was found was that when you inhibited serotonin in the blood stream it did not affect serotonin in the brain.