A unique, first-of-its kind study  looked at brown fat in women with PCOS.
Before we delve into the study, note that there are two main types of fat: brown, and white. Brown fat is considered to be metabolically active, as it behaves more like muscle than white fat. In fact, when it’s activated, brown fat actually burns white fat for energy.
Brown fat cells have many more mitochondria than white fat calls, and contribute to the body’s energy via heat production and dissipation. This is because brown fat cell mitochondria have Uncoupling Protein 1 (UCP-1), which facilitates heat production via uncoupling aerobic respiration. 
This brown adipose tissue’s ability to burn energy is regulated by several factors. These include environmental temperature, the sympathetic nervous system, inflammation, thyroid hormones, age, nutritional status, and activity.
Recent studies in rat models suggest significant reduction in brown adipose activity when compared to normal fats. They also show that transplanting brown adipose tissue from healthy animals could reverse many of the reproductive and metabolic issues in PCOS. 
This is an incredibly important area to study, and it’s exciting to see how this new research sheds light on how these fat differences may affect PCOS.
Details of the Study
The study focused on 44 women with PCOS, and 11 women who didn’t have the condition.
Researchers measured the skin temperature above the women’s collarbones: this area in particular has been validated to be a measurement of brown adipose activity. [18-21]
They used wireless monitors to compare the temperature above the collarbone to the upper arm skin, which reflects white fat. They measured this over the course of four days, with readings taken every 15-30 minutes.
What they found was intriguing:
The temperature above the collarbone was higher than the arm temperature in both groups. This makes sense, since brown fat generates heat. Also, the temperature in this area was higher during sleep in both groups, suggesting a circadian rhythm of fat burning.
Overall, women with PCOS had lower temperatures above their collarbones, suggesting they had less brown adipose tissue function. This was the case during both waking hours, and while they were at rest.
The arm temperature was similar between the two groups, suggesting the white adipose tissue functioned similarly. They also found that the women who had lower brown fat activity had higher testosterone levels.
Since metabolic issues are so prevalent in PCOS, improving brown fat function is likely beneficial. This is particularly important for those who suffer with insulin resistance, abdominal fat gain, and weight loss resistance.
What Can Be Done to Help Improve Brown Fat?
Here are a few key tips:
- Keep the temperature low. Exposing your body to cool (and even cold) temperatures may help recruit more brown fat cells. Some research has suggested that just two hours of exposure to temperatures around 66˚F (19˚C) each day may be enough to turn recruitable fat to brown. Cold showers or cold pools can also help, if you’re a trooper! Cold thermogenesis has also been shown to improve insulin sensitivity.
- Exercise. Irisin is a hormone produced by muscles, and this helps transform white fat to brown. Women with PCOS have been found to have low irisin levels. Include weight training and HIIT for the biggest PCOS benefits.
- Polyphenols with antioxidant functions like quercetin, grapeseed, green tea, and pine bark have been found to improve brown fat function.
- Time-restricted feeding—eating in a 12- or 10-hour window—can improve insulin sensitivity. Insulin resistance reduces brown fat cell activity.
1. Yilmaz B, Vellanki P, Ata B, Yildiz BO. Metabolic syndrome, hypertension, and hyperlipidemia
in mothers, fathers, sisters, and brothers of women with polycystic ovary syndrome: a systematic review and meta-analysis. Fertility and sterility. 2018;109(2):356-364.e332.
9. Cypess AM, Kahn CR. The role and importance of brown adipose tissue in energy homeostasis. Current opinion in pediatrics. 2010;22(4):478-484.
14. Yuan X, Hu T, Zhao H, et al. Brown adipose tissue transplantation ameliorates polycystic ovary syndrome. Proc Natl Acad Sci U S A. 2016;113(10):2708-2713.
18-21. van der Lans AA, Vosselman MJ, Hanssen MJ, Brans B, van Marken Lichtenbelt WD. Supraclavicular skin temperature and BAT activity in lean healthy adults. The journal of physiological sciences : JPS. 2016;66(1):77-83.
Boon MR, Bakker LE, van der Linden RA, et al. Supraclavicular skin temperature as a measure of 18F-FDG uptake by BAT in human subjects. PLoS ONE. 2014;9(6):e98822.
Smith AD, Crabtree DR, Bilzon JL, Walsh NP. The validity of wireless iButtons and thermistors for human skin temperature measurement. Physiological measurement. 2010;31(1):95-114.
van Marken Lichtenbelt WD, Daanen HA, Wouters L, et al. Evaluation of wireless determination of skin temperature using iButtons. Physiology & behavior. 2006;88(4-5):489- 497.
2. Teede HJ, Misso ML, Deeks AA, et al. Assessment and management of polycystic ovary syndrome: summary of an evidence-based guideline. The Medical journal of Australia. 2011;195(6):S65-112.
Teede H, Deeks A, Moran L. Polycystic ovary syndrome: a complex condition with
psychological, reproductive and metabolic manifestations that impacts on health across the lifespan. BMC medicine. 2010;8:41.