Brown fat curbing the blood sugar rollercoaster

It is not new news that incidence of type 2 diabetes is on the rise. There are many theories about as to why, which include environmental toxin exposure, shift in the microbiome, stress, and of course, a shift in diet to one more refined, processed and nutrient poor.

And most recently, it could be to do with the levels, activity and types of fat we store.

Specifically, a study released by the Garvan Institute of Medical Research in Sydney has identified that levels of brown fat in the body can impact blood glucose levels and fluctuations.

Brown fat is a type of adipose tissue in abundance in babies, but less so in adults. Found in the upper chest and neck, it is thought to be more akin to skeletal muscle, as it is packed full of mitochondria – our cellular energy creating engine rooms – which are what give this tissue its brown colour.

Brown fat’s function is to provide warmth, and has been found to utilise normal fat as energy when the body undergoes extended exposure to cold temperatures. When Dr Paul Lee and his team undertook research on healthy participants to monitor variations in brown adipose tissue activity, they found when in abundance and active, it also seemed to utilise glucose in the blood.

The blood glucose ride

Stabilising blood glucose is particularly important. Following consumption of certain foods, a roller coaster of high glucose, followed by high insulin (to move the glucose from out of the blood and into cells) and huge drop in blood glucose can occur. This initially causes an energy slump, and a craving for something sweet or stimulating can ensue.

So you eat or drink something for a quick energy hit, and therein begins a sugar and stimulant craving cycle.

The long term impact can result in insulin resistance, when the cells that have been barraged by insulin so heavily and so often to take more and more glucose, that flat out refuse to take any more. They are done. They ‘resist’ insulin. Blood glucose levels remain high, which can be inflammatory and damaging to blood vessels, and may result in a diagnosis of Type 2 Diabetes.

Different foods have different reactions times when it comes to blood glucose levels. Refined carbohydrates and sugars create a rapid surge.

When consuming carbohydrates in a whole food form that is packed with fibre, or combined with proteins and fats, the glucose release is slowed and therefore more stable. The sudden rise and significant reactionary crash in blood glucose levels is avoided, along with any major requirement for a pick-me-up.

But back to the brown fat

Lee and associates noticed the activity of the adipose tissue occurred in a circadian rhythm. Brown fat levels were seen to be highest in the morning. This could coincide with the rise of internal synthesis of cortisol, and then glucose, to get the body ready and raring to jump out of bed and take on the day, whilst generating heat to protect against the cooler mornings (when our hunter and gatherer forefathers would head out looking for food).

Pretty fascinating!

Where does that leave us?

It is still early stages of research, but this study indicates the important of adipose tissue in the body.

Brown fat appears to be converted from white fat when we eat until we have just satisfied hunger, or by consuming ursolic acid found in apple peel, prunes and herbs such as oregano and thyme.

Following Professor Lee’s study, brown fat tissue seems to like 1-hour bouts of moderate exercise, and exposure to temperatures between 14-16 degrees Celsius for 10-15 minutes. Achieving this in every day life could be difficult, and it is too early in the research process to prescribe as treatment for diabetes. As Professor Lee says: “A balanced diet and regular exercise are the cornerstones of healthy metabolism and should not be forgotten.”

In the meantime, perhaps to assist in the conversion of energy storing white fat into energy burning brown fat, why not head to your local beach for a wade followed by a swim. It could make a difference!

For more, please see the study here: http://www.cell.com/cell-metabolism/pdfExtended/S1550-4131(16)30056-0

References:

1. Kunkel, SD, Elmore, CJ, Bongers, KS, Ebert, SM, Fox, DK, Dyle, MC, Bullard, SA, & Adams, CM 2012, ‘Ursolic acid increases skeletal muscle and brown fat and decreases diet-induced obesity, glucose intolerance and fatty liver disease’,Plos One, vol. 7, no. 6, p. e39332.
2. Lee, P Bova, R Schofield, L Bryant, W Dieckmann, W Slattery, A Govendir, MA Emmett, L Greenfield, JR 2016, Brown Adipose Tissue Exhibits a Glucose- Responsive Thermogenic Biorhythm in Humans, Cell Metabolism, vol 23, pp 1-8.
3. Ruan, H Dietrich, M Liu, Z Zimmer, M Li, M, Singh, JP Zhang, K Yin, R Wu, J Horvath, T and Yang, X 2014, O-GlcNAc Transferase Enables AgRP Neurons to Suppress Browning of White Fat, Cell, vol. 159, no. 2, pp. 306-317.