More cutting edge research on ways to deflate that spare tire and destroy that muffin top! Some great info on the supplement CLA, the fat vs fit debate, and other cool stuff. Running a little behind since technically it is October now, but all of these were published in August 2008.
On to the data
Beneficial effects of conjugated linoleic acid and exercise on bone of middle-aged female mice.
Banu J, Bhattacharya A, Rahman M, Fernandes G. Department of Medicine, Division of Clinical Immunology and Rheumatology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
Conjugated linoleic acids (CLA) are a group of polyunsaturated fatty acids that has recently been shown to have several beneficial effects on different diseases, including prevention of bone loss. The important feature of CLA is to reduce fat mass, thereby reducing body weight significantly.
Although loss of body weight is known to increase bone loss, there is increasing evidence that CLA maybe beneficial to bone. Another factor that can reduce body weight is exercise (EX). It is well established that moderate EX stimulates bone formation. In this study, we analyzed the changes in bone using pQCT densitometry in middle-aged C57Bl/6 mice fed CLA (0.5%) and/or exercised. Twelve-month-old mice were divided into the following groups: group 1, corn oil, sedentary (CO SED); group 2, corn oil, exercise (CO EX); group 3, CLA, sedentary (CLA SED); and group 4, CLA, exercise (CLA EX). Mice were maintained in the respective experimental regimens for 10 weeks, after which mice were scanned using DEXA and killed. The lumbar vertebrae, femur, and tibia were analyzed using pQCT densitometry. CLA, when given alone or in combination with EX, significantly reduced body weight and increased lean mass. CLA treatment also significantly increased bone mass. Further, additional increase in bone mass was observed in mice treated with a combination of CLA and EX in almost all the bone sites analyzed.
Conclusion: We conclude that CLA, when consumed as a dietary supplement along with moderate treadmill exercise, significantly increases bone mass in middle-aged female mice.
My Notes: I believe this is one of the first studies to look at CLA and bone! The HUGE downside is that the effects of CLA for fat loss appear to be VERY specific to species. It is awesome stuff IF you are a mouse or rat! The human studies for fat loss as not nearly as good. My guess is that the same thing probably applies here too. CLA appears to be "safe" so I wish more researchers would study it in humans, although I know first hand that is much higher on the "pain in the butt" factor for those conducting the research.
Whole-body skeletal muscle mass is not related to glucose tolerance or insulin sensitivity in overweight and obese men and women.
Kuk JL, Kilpatrick K, Davidson LE, Hudson R, Ross R. School of Kinesiology and Health Studies, Queen's University, Kingston, ON K7L3N6, Canada.
The relationship between skeletal muscle mass, visceral adipose tissue, insulin sensitivity, and glucose tolerance was examined in 214 overweight or obese, but otherwise healthy, men (n = 98) and women (n = 116) who participated in various exercise and (or) weight-loss intervention studies. Subjects had a 75 g oral glucose tolerance test and (or) insulin sensitivity measures by a 3 h hyperinsulinemic-euglycemic clamp technique. Whole-body skeletal muscle mass and visceral adipose tissue were measured using a multi-slice magnetic resonance imaging protocol.
Total body skeletal muscle mass was not associated with any measure of glucose metabolism in men or women (p > 0.10). These observations remained independent of age and total adiposity. Conversely, visceral adipose tissue was a significant predictor of various measures of glucose metabolism in both men and women with or without control for age and (or) total body fat (p < style="font-weight: bold;">
Conclusion: Although skeletal muscle is a primary site for glucose uptake and deposition, these findings suggest that unlike visceral adipose tissue, whole-body skeletal muscle mass per se is not associated with either glucose tolerance or insulin sensitivity in overweight and obese men and women.
My Notes: Rather surprising results, as I would have expect muscle mass to correlate well with insulin sensitivity. Visceral adipose (that spare tire area) was a predictor though! So time to drop some abdominal fat if you want better insulin sensitivity (which is a good thing). See this post on Fit or Fat
and Metabolic Flexibility for a literature review
Exercise but not diet-induced weight loss decreases skeletal muscle inflammatory gene expression in frail obese elderly persons.
Lambert CP, Wright NR, Finck BN, Villareal DT. Department of Internal Medicine, Washington University School of Medicine, Campus Box 8303, St. Louis, MO 63110, USA.
Many obese elderly persons have impaired physical function associated with an increased chronic inflammatory response. We evaluated 12 wk of exercise (aerobic and resistance) or 12 wk of weight loss (approximately 7% reduction) on skeletal muscle mRNAs for toll-like receptor-4 (TLR-4), mechanogrowth factor (MGF), TNF-alpha, and IL-6 in 16 obese (body mass index 38+/-2 kg/m2) older (69+/-1 yr) physically frail individuals. Vastus lateralis muscle biopsies were obtained at 0 and 12 wk and analyzed by real-time RT-PCR. Body composition was assessed by dual-energy x-ray absorptiometry. Body weight decreased (-7.5+/-1.2 kg, P=0.001) in the weight loss group but not in the exercise group (-0.3+/-0.8 kg, P=0.74). Fat-free mass (FFM) decreased (-2.9+/-0.6 kg, P=0.010) in the weight loss group and increased (1.6+/-0.6 kg, P=0.03) in the exercise group.
Exercise resulted in a 37% decrease in TLR-4 mRNA (P<0.05) style="font-weight: bold;">
Conclusion: In conclusion, exercise but not weight loss had a beneficial effect on markers of muscle inflammation and anabolism in frail obese elderly individuals.
Obesity and obstructive sleep apnea: Or is it OSA and obesity?
Carter R 3rd, Watenpaugh DE. Centre de Recherche du Service de Santé des Armées, La Tronche, France; United States Army Research Institute of Environmental Medicine, Natick, MA, USA.
Obstructive sleep apnea (OSA) consists of repetitive choking spells due to sleep-induced reduction of upper airway muscle tone. Millions of adults and children live unaware of this condition, which can have a profound affect on their health and quality of life. Obesity, gender, genetic, and hormonal factors mediate risk for OSA and interact in a multifaceted manner in the pathogenesis of this disease. Obesity is the most established and primary risk factor given that body mass index, visceral fat, and neck circumference are major predictors in the clinical expression of OSA. Many studies have shown weight loss or gain significantly impacts OSA severity. More recently, accumulating evidence indicates OSA promotes weight gain, obesity, and type II diabetes in a variety of ways, such that obesity and OSA form multiple interleaved vicious cycles. Thus, creative strategies to increase physical activity, improve diet, and otherwise facilitate weight management become particularly vital given the epidemics of obesity and OSA in the United States. In this regard, the American College of Sports Medicine recently launched the "Exercise is Medicine" (initiative exerciseismedicine.org). In the future, medications may emerge to treat obesity, OSA, and their sequelae with minimal side effects.
Conclusion: However, there are effective ways to approach these problems now without waiting for "the magic pill".
My Notes: Knowledge is key, but agreed that there is no "magic pill"
