The Hormone That Makes You Burn Fat (Just Add Water)

This is Dr. Helena Cristina de Lima Barbosa, and she’s a professor of functional biology, and her PhD is in pancreatic endocrinology and metabolism. She’s a Diabetes UK Fellow, and she’s an internationally-respected expert in glycemic homeostasis, molecular mechanisms involved in insulin secretion, and cell signaling.

So, what does she want us to know?

“The next Ozempic”, but we produce it in our bodies

The hormone that she’s been researching (known to its friends as FGF19) has been hailed by some as “the next Ozempic”, though it’s not a claim she makes personally at this stage (scientists being often more cautious in this regard than the popular press).

In her own words:

❝FGF19 had already been linked to a reduction in food intake. Our work broke new ground by showing that it also plays an important role by acting on the hypothalamus and stimulating an increase in energy expenditure in white and brown adipose tissue.

In other words, in addition to controlling appetite, it stimulates thermogenesis. So, in terms of therapy associated with obesity, it’d make a lot of sense❞

As to where it comes from, the hormone is produced in the small intestine and regulates bile acids, glucose production, and fat synthesis. Its brain effects are only recently being explored.

But there’s more:

❝The brain plays an extremely important role in controlling the body’s adiposity. At the same time as it receives information from peripheral tissues, it triggers commands.

These commands, apparently using the sympathetic nervous system (SNS), seem to be an interesting way of thinking about energy expenditure❞

Scientists such as Dr. Barbosa are the sort of people to follow the call of curiosity wherever it takes them (research grants permitting), and in this case, she and her team wondered whether the brain could be nudged into signalling more of this hormone to be produced, by triggering the sympathetic nervous system.

Now, there are various ways the sympathetic nervous system can be triggered, but a fairly accessible one that doesn’t rely on undue psychological stress, is cold water immersion.

Which offers a bonus, because of the hormone’s other role of stimulating thermogenesis (heat production), and, specifically, stimulating thermogenic adipocytes in order to do that.

Which, translating from sciencese, means: burning fat to keep you warm

Dr. Barbosa and her team found that FGF19 acts directly on the hypothalamus to drive thermogenesis, and that cold exposure increases FGF19 receptor expression in the hypothalamus. She suspects it has/had an evolutionary role in temperature control, but the upshot for us here and now today in the moment (and not on an evolutionary timescale) is that FGF19 increases energy expenditure, stimulates heat-producing adipocytes, and reduces inflammation, but only when the sympathetic nervous system is active.

How did they learn that? They (with the aid of computers and a small army of undergrads and doctoral students) analyzed the transcription of more than 50,000 single cells to identify hypothalamic cell types that express FGF19 receptors.

There was also a mouse study component, whereupon they confirmed that mice receiving FGF19 directly in the brain showed improved metabolic balance through increased sympathetic nervous system activity and thermogenesis.

You can read the paper itself in full, here: Central FGF19 signaling enhances energy homeostasis and adipose tissue thermogenesis through sympathetic activation

Do I have to take ice baths?

Not unless you want to, and as ever, do check with your doctor for safety reasons, especially if you have any heart condition.

See: Ice Baths: To Dip Or Not To Dip? ← our mythbusting main feature on this

A cold shower can offer the same SNS-activating (and thus, per Dr. Barbosa’s work, FGF19-activating) benefits with less discomfort and risk (of course nothing is risk-free; you could slip in the shower or something; please be careful).

You can read more about that, here: A Cold Shower A Day Keeps The Doctor Away?

But even that is not the only way. The important part is to create a short burst of controlled, safe, but stressful stimulation.

For more on that, see: The Stress Prescription (Against Aging!) ← our main feature leaning on the work of the incredible Dr. Elissa Epel, who for the past 20 years has specialized in the effect of stress* on aging. She’s led groundbreaking research on cortisol, telomeres, and telomerase, all in the context of aging, especially in women, as well as the relationship between stress and weight gain. She was elected member of the National Academy of Medicine for her work on stress pathways, and has been recognized as a key “Influencer in Aging” by the Alliance for Aging Research.

Indeed, she’s also been named in the top 0.1% of researchers globally, in terms of publication impact.

*Spoiler: chronic stress is very bad, whereas acute stress is very good in moderation

But that’s another (albeit closely related and overlapping) topic.

For now, we’re out of room for more today, so… Take care!