Sunday, June 10, 2012

Cold Thermogenesis - A Safe Ephedra Alternative? 70kcal Increase in 24h Energy Expenditure is Negligible, 50% Lower Than Ephedrine, Not Likely to Occur Obese or Older People

Image 1 (odditycentral): Jin Songhao, one of China’s most seasoned icemen and not exactly as lean as you may expect based on what you currently read around the blogosphere, managed to beat the previous world record for the longest ice bath - 120min! Congrats, Jin!
Ephedrine for years the go-to OTC fat burner for physique athletes and average Joe's and Jane's alike is no longer (officially) available: No matter how bold the label claims about X mg of "ephedra extract" may be - NONE(!) of the currently available "ephedra based" over-the-counter (OTC) fat-burners contains significant amounts of the active alkaloids, which made the old Mua huang based herbal ephedra products so effective. Against that background, dieters are constantly on the look-out for novel "gimmicks" to help them finally get rid of those annoying love-handles. One of those gimmicks, which has caught quite some attention as of late, is called "cold thermogenesis" and revolves around the idea that our bodies should consume more energy to keep a normal body temperature in a cold, compared to a normal temperature environment.

How is that different from a "thermogenic fat burner"

The most obvious difference between cold thermogenesis and "thermogenic fat burners" is actually so straight forward that I hardly dare stating that the former is induced by exposing yourself to low(er than normal) temperatures, while the promise of the latter is that the various ingredients of currently or formerly available OTC "fat burners" will induce a thermogenic response, irrespective of the current ambient temperature.

Figure 1: Antropomorphic data of the study participants (Cypess. 2012)
The results of a recently published study from the the Boston Harvard Medical School does yet provide somewhat more sophisticated insights into the differences between cold exposure and a sympathomimetic (i.e. an activator of the sympathetic nervous system), such as ephedrine. On three separate, independent study visits that took place in random order the ten healthy volunteers (age 27.1 years) who participated in the study (see figure 1 for DEXA based anthropometric data) and had been fasting since 12am the day before were exposed to one of the following "stimuli":
  • ephedrine - a single intramuscular dose of 1mg/kg ephedrine
  • saline control - an equal volume of saline
  • cold exposure - in a surgeon’s cooling vest (Polar Products) w/ water temperature 14 °C
60min after the injection of ephedrine, saline, or the initiation of cold exposure, the change in metabolic rate was measured and blood was drawn to determine several metabolic and endocrine markers. Another 60min later, PET-CT scanner images (cf. figure 2, right) to quantify BAT mass and activity were taken. Since the participants obviously had to get rid of their cooling vests for this procedure, the total cold exposure time was limited to 120min, so that it is questionable how valid the 24h energy expenditure calculation (cf. figure 3) actually is. After all, it is not very likely that the norepinephrine levels would constantly stay at 200% over baseline (cf. figure 2).
Figure 2: Metabolic and endocrine effects (expressed relative to saline) of ephedrine injection and cold exposure (main image); CT scans with green arrows in the combined scans indicating  the principal cervical, supraclavicular,
and thoracic depots of BAT (Cypess. 2012)
As far as the acute phase is concerned, it is yet quite obvious that both cold exposure and ephedrine elicited statistically significant effects on various metabolic and endocrine parameters. The exact nature and the purported mechanism that is responsible for these metabolic and endocrine effects are however very different for both treatments:
  • while ephedrine lead to an increase in blood glucose (probably subsequent to increased glyconeogenesis), cold exposure did not 
  • while ephedrine lead to significant increases in lactic acid levels (corresponding to increases in glucose + glucose oxidation), cold exposure did not
  • while ephedrine lead to profound increases in β-hydroxybutyrate (increased ketone productions from fat), cold exposure did not
  • while ephedrine increased serum non-esterified fatty acid (NEFA) concentrations (due to increased lipolysis), cold exposure did not
  • while ephedrine elevated insulin production (probably due to stress induced insulin resistance), cold exposure did not (p = 0.29)
  • while ephedrine lead to highly significant (p < 0.001) increases in C-reactive peptide, cold exposure elicited "only" significant elevations (p = 0.005)
  • while ephedrine produced already highly significant increases in noripenephrine levels, those were even more pronounced upon cold exposure
  • while ephedrine lead to statistical significant increases in thyroid hormone Total T3 (+14%, p = 0.026) and Free T4 (+19%, p = 0.014), cold exposure did not
  • while ephedrine lead to a profound (-22%) and statistical significant (p = 0.007) drop in ghrelin ("hunger hormone" and metabolic regulator), cold exposure did not
In conjunction with the combined CT scans from figure 2 these differences clearly indicate that contrary to ephedrine, which is a mere sympathomimetic (put simply a potent "stim" ;-) without depot-specific (here brown adipose tissue) thermogenic effects, mild cold exposure (remember: those were no ice-baths!) has the ability to stimulate brown adipose tissue (BAT) energy expenditure without significant systemic effects on heart rate or thyroid hormone metabolism.

What does that mean? Is GNC soon going to carry cooling vests instead of fat burner pills?

If you read the scientists' rave conclusion that "[i]n contrast to ephedrine [...] mild cold exposure stimulates a specific response by the SNS [sympathetic nervous system] to activate BAT and increase energy expenditure with few other metabolic effects" and their subsequent reference to the "obesity and diabetes pandemics" and the demand for "safe and novel treatments" of the latter, it is quite understandable that people who are referred by their gurus to "scientific evidence" like this are willing to believe that "cold thermogenesis" would help them to finally get rid of their beer-, burger- and burrito-bellies.
Figure 3: Increase in 24h energy expenditure (kcal/day, left) and detectable BAT volume (right; Cypess. 2012)
If you do yet take a look at the actual metabolic effects (cf. figure 3) the 2x more pronounced effect of ephedrine on 24h energy expenditure (+140kcal/day vs. 70kcal) confirms what my previous overview of the metabolic and endocrine effects of ephedrine and cold exposure already suggested: Ephedrine does not simply have more "side effects" it is also more effective.
Figure 4: Activity of BAT activity in relation to body fat levels (van Marken Lichtenbelt. 2009)
Important:  One thing the scientists wink at in both the abstract as well as the conclusion are the profound inter-individual differences in terms of detectable BAT volume and activity. While the median volume of detectable brown adipose tissue in men and women was 22mL and 20mL, respectively, there was one female subject with a BAT mass of 190mL (85x over median!), one with 7ml and one woman without any detectable brown adipose tissue. Similarly, the BAT mass in the men ranged from 46mL to 12mL. Both the existence of individuals without any significant amounts of metabolically active body fat, as well as the observation of high inter-personal variability in the study at hand stand in line with previous results of Saito et al. who found a ratio of 15/32 (45%) non-responders in young (23-35y) and 22/24 (92%!) in older (38-65y) subjects (Saito. 2009). And as if that alone would not render the practical value of cold exposure as a means to battle the "obesity and diabetes pandemic" questionably enough, van Marken Lichtenbelt et al. report that exactly those people for whom ephedrine and other sympathomimetics such as sibutramine would actually pose a non-negligible health risk, i.e. obese and metabolically deranged people, don't just have 40% less brown adipose tissue, but also a -76% reduced BAT activity (van Marken Lichtenbelt. 2009; cf. figure 4). The implications of these findings should be obvious: It is a) by no means certain that sitting in a non-heated room, let alone an ice-bath, is not just going to give you a cold, but even if it works it is b) probably not going to make a difference for those people who need it most - I mean, let's do the math: "70kcal/day minus 76% of the former equals 16.8kcal per day"!
That being said, even the profoundly greater total increase in energy expenditure in the ephedrine group is of a "magnitude" (I would write "minitude" if such a word existed) that would be completely negligible if it were not for the bad and "dangerous" sympathostimulating side effects (Andraws. 2005), which will allow you to train longer, to diet harder (Astrup et al. ascribe 75% of the weight loss effect due to the ingestion of the infamous ECA stack to anorexia, i.e. loss of appetite; cf. Astrup. 1992) than any ice-filled bathtub in the world will ever do.

Skip on ice-baths, stop winning about the ephedra ban. Get your diet & workouts in check!

Image 2: I don't think Francine Sablan, IFBB Figure Pro and like Adelfo one of Myotropics' sponsored athletes, uses the air-conditioning, let alone a funky cooling vest or ice-baths to propel her fat loss. And why would she? She loves working out and she has her diet in check ;-)
I know this is not going to be a popular conclusion, but believe me, the additional +70kcal/day you could expend in the cold, if you are one of the lucky non-obese "responders" (see red box above), won't make you lose a single pound. Even the "good old" ECA stack (remember: the Cypess study used intravenously administered ephedrine; hence, the effect sizes are directly comparable with pertinent studies from the late 1980s and 1990s using orally administered herbals) worked its fat burning magic only, when it was combined with a comprehensive diet and exercise protocol - and in those scenarios it was mostly the influence of its sympathostimulating activity on your ability to adhere to your diet and to endure the hardships of strenuous workouts and not its often-touted and largely overestimated "thermogenic" effects (cf. Astrup. 1985; Astrup. 1992) that were mostly responsible for the larger-than-life results, people are still raving about.

  1. Andraws R, Chawla P, Brown DL. Cardiovascular effects of ephedra alkaloids: a comprehensive review. Prog Cardiovasc Dis. 2005 Jan-Feb;47(4):217-25. 
  2. Astrup A, Bülow J, Madsen J, Christensen NJ. Contribution of BAT and skeletal muscle to thermogenesis induced by ephedrine in man. Am J Physiol. 1985 May;248(5 Pt 1):E507-15.
  3. Astrup A, Toubro S, Christensen NJ, Quaade F. Pharmacology of thermogenic drugs. Am J Clin Nutr. 1992 Jan;55(1 Suppl):246S-248S.
  4. Cypess AM, Chen YC, Sze C, Wang K, English J, Chan O, Holman AR, Tal I, Palmer MR, Kolodny GM, Kahn CR. Cold but not sympathomimetics activates human brown adipose tissue in vivo. Proc Natl Acad Sci U S A. 2012 Jun 4. 
  5. van Marken Lichtenbelt WD, Vanhommerig JW, Smulders NM, Drossaerts JM, Kemerink GJ, Bouvy ND, Schrauwen P, Teule GJ. Cold-activated brown adipose tissue in healthy men. N Engl J Med. 2009 Apr 9;360(15):1500-8. Erratum in: N Engl J Med. 2009 Apr 30;360(18):1917.
  6. Saito M, Okamatsu-Ogura Y, Matsushita M, Watanabe K, Yoneshiro T, Nio-Kobayashi J, Iwanaga T, Miyagawa M, Kameya T, Nakada K, Kawai Y, Tsujisaki M. High incidence of metabolically active brown adipose tissue in healthy adult humans: effects of cold exposure and adiposity. Diabetes. 2009 Jul;58(7):1526-31. Epub 2009 Apr 28.