Tuesday, August 25, 2009

Hormones and Belly Fat?

A colleague of mine forwarded an interesting study to me the other day (Obesity, Aug 20, 2009 – Janssen et al.). The study, from researchers at Rush University in Chicago, had been covered in some of the national news media and it suggested that testosterone levels were associated with belly fat in postmenopausal women. This recent finding confused my colleague because there are hundreds of other research trials (in men, premenopausal, and postmenopausal women) suggesting just the OPPOSITE effect (that higher testosterone levels are generally associated with a reduction in belly fat levels).
The main difference between this recent study (and several others like it) is that it is a study of “statistical correlations” (indicating that levels of one thing are related in some way to levels of another thing) – rather than a study of a specific “intervention” (such as actually altering testosterone levels and measuring a change in belly fat levels). Such statistical correlations (i.e. X is related to Y) often have no relationship to “causality” – meaning that one thing does not necessarily cause or lead to the other (think about a rooster crowing when the sun comes up in the morning – the two events of crowing and sunrise are correlated, but the rooster does not cause the sun to rise). Such correlation studies are still valuable to scientists because they provide guidance for future intervention studies – but you actually need to DO those interventions to prove out the theories generated by the statistical correlations.
Consider another recent study published in the journal Metabolism (June 2008) – researchers from Columbia University found a correlation between belly fat and testosterone levels in postmenopausal women. However, if you looked at the actual characteristics of the women in the study, you see that the women with the lowest testosterone levels in fact had the highest levels of belly fat. In fact, a 30% reduction in levels of either total testosterone or free testosterone (the bioavailable type) was associated with almost TRIPLE the belly fat compared to women with higher testosterone levels (292% higher belly fat levels in women with a 28%-30% reduction on testosterone levels). The women with the lowest testosterone levels also had the most belly fat, the most total body fat, the highest body weight, and the largest waist circumference.
Obviously, overall metabolic balance in the human body is a much more complex picture than simply drawing a straight line from one hormone to one effect in the body – and it is the maintenance of balance that seems to be the most important consideration for improving or maintaining health and well-being. In addition to the studies that my own group has conducted and presented at some of the leading scientific conferences (American College of Sports Medicine, American College of Nutrition, International Society for Sports Nutrition, The Obesity Society, American Society for Nutritional Sciences), when we are able to naturally maintain metabolic balance (i.e. ratio between cortisol and testosterone) we are also able to measure significant improvements in mood state, body fat, and levels of fatigue and depression (see slides and abstracts from these peer-reviewed scientific conferences at www.WisdomOfBalance.com).
Thanks for reading – until next time…
Shawn M. Talbott, PhD LDN FACSM

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