A claim you hear on longevity podcasts
The claim checked: Adults have some brown fat, and cold revs it up and makes more of it Hear it at 57:59
Six of ten studies found adults have brown fat or that cold raised its activity or volume, mostly in small groups of young men. Four were mixed; one saw no volume gain after one cold session.
Computed from 10 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
“adults also have some brown fat and they discovered this with with pet scanning and they found it mostly exists on your back in your shoulder blades and when you get cold it revs up you get more of this brown fat and this is a good thing because Brown fat is extremely healthy it revs up metabolism it burns white fat”
controlled trial · 2013 · landmark
“Daily 2-hour cold exposure at 17°C for 6 weeks resulted in a parallel increase in BAT activity and CIT and a concomitant decrease in body fat mass.”
Recruited brown adipose tissue as an antiobesity agent in humans. J Clin Invest
Who: Healthy young Japanese men (mean age 24.4, BMI 22.0); cold-training arm limited to men with low or undetectable BAT activity
PMID 23867622
other primary study · 2013 · landmark
“Here, we show that a 10-day cold acclimation protocol in humans increases BAT activity in parallel with an increase in nonshivering thermogenesis (NST).”
Cold acclimation recruits human brown fat and increases nonshivering thermogenesis. J Clin Invest
Who: 17 healthy young adults (age 23 +/- 3.2 years), male and female
PMID 23867626
other primary study · 2014 · landmark
“Human BAT is inducible and suppressible by controlled mild cold and warm exposure, respectively, independent of seasonal fluctuations.”
Temperature-acclimated brown adipose tissue modulates insulin sensitivity in humans. Diabetes
Who: Five healthy young men (21 ± 2 years, BMI 22) living in a clinical research unit
PMID 24954193
trial or observed group · 2014 · landmark
“Based on the PET tracers 18 FDG and [ 11 C]acetate, this study demonstrates for the first time that daily cold exposure not only increases the volume of metabolically active BAT by 45% but also doubles its cold-induced oxidative capacity in adult humans.”
Increased brown adipose tissue oxidative capacity in cold-acclimated humans. J Clin Endocrinol Metab
Who: Six healthy lean men aged 23 ± 1 years, BMI 24.5
PMID 24423363
trial or observed group · 2026
“Cooling increases the volume and intensity of active BAT both in Danish and Greenlandic adults.”
Brown Adipose Tissue and Metabolic Markers Differ Between Greenlanders and Danes With Cold Activation. J Clin Endocrinol Metab
Who: healthy adults aged 18-50 living in Denmark, 13 Greenlanders and 11 Danes matched for age, sex and BMI (mean age ~35, BMI ~26)
PMID 41243523
other primary study · 2009 · landmark
“Defined regions of functionally active brown adipose tissue are present in adult humans, are more frequent in women than in men, and may be quantified noninvasively with the use of 18F-FDG PET–CT.”
Identification and importance of brown adipose tissue in adult humans. N Engl J Med
Who: Adult patients undergoing clinical 18F-FDG PET-CT scans at Beth Israel Deaconess, Boston (2003-2006), plus neck-surgery biopsy specimens
PMID 19357406
controlled trial · 2020
“As was expected, we did not find an increase in the estimated BAT volume after acute cold exposure and mirabegron treatment.”
The effect of mirabegron on energy expenditure and brown adipose tissue in healthy lean South Asian and Europid men. Diabetes Obes Metab
Who: Healthy young (18-30 y) lean Dutch South Asian and Europid men with MRI-detectable supraclavicular BAT
PMID 32558052
other primary study · 2014
“In summary, we here show that the ‘Iceman’, who has a lifestyle with frequent exposure to extreme cold, does not have a greater heat production and BAT activity during mild cold conditions compared to his non-acclimatized monozygotic twin brother.”
Frequent extreme cold exposure and brown fat and cold-induced thermogenesis: a study in a monozygotic twin. PLoS One
Who: One pair of 52-year-old male monozygotic twins: one habitually exposed to extreme cold ('Iceman'), one not
PMID 25014028
controlled trial · 2016
“Our PET imaging results revealed that the metabolic rate of oxygen (MRO 2 ) in BAT during cold stimulus was significantly higher when compared to RT (0.7 ± 0.3 versus 1.2 ± 0.3 mL/100 g/min, p = 0.01, RT vs. cold, respectively).”
Human brown adipose tissue [(15)O]O2 PET imaging in the presence and absence of cold stimulus. Eur J Nucl Med Mol Imaging
Who: Healthy adults (5 men, 2 women), age 36 +/- 11, BMI 25.5
PMID 26993316
other primary study · 2021
“Nevertheless, winter swimmers had substantially higher cold-induced thermogenesis than controls.”
Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. Cell Rep Med
Who: 16 young healthy lean Danish men (8 experienced winter swimmers, 8 matched controls; 1 BAT-negative swimmer excluded)
PMID 34755128
None.
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