|
|
|
UCP-3’s Role In Enhancing Fat Oxidation |
|
|
|
|
Written by Robbie Durand
|
|
Thursday, 12 February 2009 |
|
Page 1 of 5
 Over the last few years, it has been increasingly evident that low-carb
diets are more effective for weight loss than low-fat diets.1, 9, 10,
11 In addition to added weight loss, low-carb diets also seem to
improve lipid profiles. One study reported that an Atkins-style diet
approach, which included a vitamin and nutritional supplements, caused
more weight loss than a low-fat diet. Along with losing an average of
26 pounds, dieters assigned to the low-carbohydrate plan lost more body
fat and lowered their triglyceride levels and raised their HDL, or good
cholesterol, more than the low-fat dieters. The low-fat dieters lost an
average of 14 pounds.2 Many nutritionists once thought that
high-fat/high-protein diets were more effective for weight loss than
low-fat diets simply due to reduced caloric intake; however,
low-carbohydrate diets do more than just curve the appetite— they turn
on fat-burning genes.
High-Protein/High-Fat Diets Turn On Fat-Burning Genes
Several animal and human studies indicate that dietary fats increase the expression of genes regulating fat metabolism in skeletal muscle.6, 7 Plasma fatty acids are increased after a short-term high-fat diet and also increase the expression of several key genes associated with fatty acid metabolism.3 For example, one study investigated low- and high-fat diets and changes in enzymes that control fat metabolism in endurance-trained men. Irrespective of training, beta-hydroxyacyl-CoA-dehydrogenase activity in the thigh muscle was significantly increased by an average of 25 percent after adaptation to a fat-rich diet and was unchanged after adaptation to a carbohydrate-rich diet.4 Another study reported that in as little as five days, athletes on a high-fat, high-protein diet— during a 20-minute exercise bout— increased fat oxidation almost twofold over those on a high-carbohydrate diet; in conjunction, there were significant increases in the fat-oxidation enzymes in skeletal muscle after the high-fat diet.7
Catecholamines Increase Brown Adipose Tissue
Adipose tissue is divided into two types: white and brown adipose tissue (BAT). Extensive work over the last 30 years, principally on rodents, has demonstrated the thermogenic function of BAT. BAT therefore contrasts with white adipose tissue, which stores energy. BAT contributes to an increased metabolism by the generation of heat, which contributes to increased basal metabolism. Brown adipose tissue is rich with sympathetic nerves and mitochondria, and is responsible for a major portion of the thermogenesis. In the resting state, about 90 percent of the oxygen consumption takes place in the mitochondria.29 Therefore, stimulating mitochondrial activity can increase thermogenesis. As promising as increasing brown adipose activity sounds, many researchers have given up on activating brown adipose tissue through the use of pharmacological drugs due to rapid loss of brown adipose tissue after birth in humans. Beta 3-adrenoceptor agonists are effective thermogenic anti-obesity agents in rodents. Their main sites of action are white and brown adipose tissue and muscle. Beta 3-adrenoceptor mRNA levels are lower in human than in rodent adipose tissue, and adult humans have little brown adipose tissue. A new study challenges the notion that that brown adipose tissue is lost in adulthood. The researchers speculated we contain more brown fat than we previously thought however more research needs to be conducted.12 Brown fat can be increased by chronic cold exposure, but also beta-agonists, which stimulate sympathetic activity. Brown adipose tissue is activated by increasing catecholamine levels; it has been shown that adults with pheochromocytomas (tumors of the adrenal gland which produce excess adrenaline) have more brown adipose tissue than normal people.15 Could long-term use of supplements or drugs that increase thermogenesis increase brown adipose tissue? No one knows for sure, but it may be possible. Activated BAT rapidly releases fatty acids and produces heat. This is achieved by the numerous mitochondria in brown adipocytes and a specific protein in the mitochondria called UCP (uncoupling protein), which activates respiration and diverts the free energy of oxidation to thermogenesis.
DNP: That’s Not Chicken I Smell Being Cooked…That’s Me!
Dan Duchaine introduced dinitrophenol (DNP)— a powerful stimulator of UCP— several years ago as a weight-loss drug, but you would have to be crazy to take it. DNP, a benzene-based chemical, is nothing new and came to the attention of public health officials during World War I. DNP was used mainly in the manufacture of dynamite. Something unusual happened…the workers began building up considerable quantities of DNP in their bodies, both through skin contact and by inhaling the compound's vapors. At first, the workers' symptoms were mild: sweating, light fever, increased appetite, heart palpitations and insomnia. Then, as the days passed, the DNP levels in their bodies steadily increased, along with more serious side effects such as excess increases in body temperature and some people died as a result. One of the more specific side effects of inhaling the compound was weight loss. After the war, physicians lost no time in prescribing it to dieters. In humans, it speeds up the metabolic rate until eventually the body burns itself up. Amazingly, DNP had the ability to stimulate metabolism by as much as 50 percent.35 The comparisons to the current drugs for increasing thermogenesis are a mere shadow of DNP, at least in terms of thermogenesis. While the ephedrine/caffeine/aspirin stack has been shown to provide safe weight loss, it has only been shown to have an approximately a 3 percent increase in metabolic rate. Unfortunately DNP’s therapeutic index was razor-thin and it was not until thousands of people suffered irreversible harm (high dosages can cause blindness) that mainstream physicians realized that DNP’s risks outweighed its benefits and abandoned its use. Doctors reported that some patients (upon autopsy) who used high dosages of DNP were literally “cooked to death.” Researchers are still researching safe and effective ways of increasing UCP. There are several types of UCPs that can be increased safely by diet and thermogenics.
|
|
Research and Review 
