If you want to enjoy the winter more but can’t stand the cold, physiologists at Hôpital Montfort in Canada have an interesting suggestion for you. Take supplements containing EGCG and caffeine. They boost your body’s heat production and drive out the cold.
Can you lose weight by being cold? Rats and mice do, but humans don’t, scientists thought until recently. Rodents have brown fat tissue, which produces more heat the lower the ambient temperature is, and adult humans don’t have this. But in 2009 some studies were published in which it emerged that young adults have active brown fat tissue [N Engl J Med. 2009 Apr 9; 360(15): 1500-8.] and now scientists have changed their tune.
This discovery opens up new perspectives, according to the Canadian physiologists. Could you lose weight by making the brown fat tissue work harder? The first thing you think of is exposure to the cold. But might it be possible to jack up the heat production of brown fat tissue by ingesting certain substances?
That might just be possible. In 1990 researchers showed that subjects burned more calories if they took 5 mg caffeine per kg bodyweight at a temperature of 5 degrees Celsius. [J Appl Physiol. 1990 May; 68(5): 1889-95.]
The Canadians suspected that combining the caffeine with EGCG, a flavonoid in green tea, might enhance the effect. So they did an experiment with 8 male students, who took 600 mg caffeine and 1600 mg EGCG and were exposed to a temperature of 15 degrees Celsius for a period of three hours. The researchers repeated the experiment again, but gave the subjects a placebo.
The researchers then calculated the amount of energy the men used up to produce warmth, and how much energy they used up for shivering. The curves with the black circles represent the measurements taken after the men had taken caffeine and EGCG. As you can see, the combination increased warmth production, and reduced energy expended on shivering.
The supplementation boosted heat production by ten percent, and reduced shivering intensity by 25 percent.
“Although some inter-individual differences were observed, EGCG and caffeine seem to stimulate non-shivering thermogenesis either by a notable increase in energy expenditure or a decrease in shivering intensity”, the Canadians write.
“The present study provides an experimental approach for human investigations into the potential role of diet and bioactive food ingredients in modulating non-shivering thermogenesis during cold exposure. Stimulating non-shivering thermogenesis pathways in such a manner may not only prove to be important for improving fine motor performance and survival in cold exposed human subjects, but may also provide important targets in the search of targets for the management of obesity and diabetes.”
Effects of green tea extracts on non-shivering thermogenesis during mild cold exposure in young men.
Gosselin C, Haman F.
Unité de Recherche sur la Nutrition et le Métabolisme, Hôpital Montfort, 713, Chemin Montréal, Ottawa, ON, Canada K1K 0T2.
The effects of epigallocatechin-3-gallate (EGCG) and caffeine on non-shivering thermogenesis (NST) during cold exposure is unknown. The purpose of the present study was to quantify the effects of co-ingesting EGCG and caffeine on the thermogenic responses of a 3 h cold exposure. A total of eight healthy males were exposed to mild cold, using a liquid-conditioned suit perfused with 15°C water, on two occasions and consumed a placebo or an extract of 1600 mg of EGCG and 600 mg of caffeine (Green tea). Thermic, metabolic and electromyographic measurements were monitored at baseline and during the cold exposure. Results showed that the AUC of shivering intensity over the cold exposure period was reduced by approximately 20 % in the Green tea (266 (sem 6) % maximal voluntary contraction (MVC) × min) compared with the Placebo (332 (sem 69) %MVC × min) (P = 0·01) treatments. In contrast, the total AUC for energy expenditure (EE) was approximately 10 % higher in the Green tea (23·5 (sem 1·4) kJ/kg × 180 min) compared with the Placebo (327 (sem 74) kJ/kg 180 min) (P = 0·007) treatments. The decrease in shivering activity combined with an increase in EE, following the ingestion of EGCG and caffeine during the cold exposure, indicates that NST pathways can be significantly stimulated in adult human subjects. The present study provides an experimental approach for human investigations into the potential role of diet and bioactive food ingredients in modulating NST during cold exposure. Stimulating NST pathways in such a manner may also provide important targets in the search of targets for the management of obesity and diabetes.
PMID: 23237788 [PubMed – as supplied by publisher]