Canadian scientists have been involved in thermogenic research for a number of years. The mechanism underlying cold adaptation would, of course, be of interest to dwellers in this northern country. Writing from the University of Alberta in Edmonton, Paul Trayhurn explains:
“In the past decade, views on the function of Brown Adipose Tissue (BAT) have undergone a fundamental revision. This has been accompanied by a major change in our perspective on energy balance and its regulation. BAT is the only tissue in mammals in which heat is the primary product of metabolism. The tissue has traditionally been considered to be important in the generation of heat by non-shivering mechanisms in the newborn or a number of mammalian species, and to play a key role in the arousal of hibernating animals. Within the past decade, it has also been shown to be the main site of non-shivering thermogenesis in adult rodents adapted to the cold. From this, the concept has developed that BAT plays a major role in energetics.”
(Int’l Jour. of Obesity, 4(Suppl. 1), 17-29, 1990).
While scientists were trying to understand and explain the concept of thermogenesis, it occurred to them that continued BAT activation in people might lead to a reduction in white fat. For years, however, it was an accepted fact that adult humans did not have enough BAT to burn enough calories to make a difference. Then the uncoupling protein (UCP) was found. What makes the BAT cells different from all the other cells in the body is the presence of a small protein molecule that “uncouples” the train of biochemical events that normally turn calories into the kind of energy cells needed to carry out metabolic processes. As a result, the energy generated in BAT is simply wasted; it is radiated away from
BAT into the blood and into neighboring tissues as heat. The discovery of the uncoupling protein unlocked the mysteries of thermogenesis. It was quickly discovered, for instance, that cold adaptation occurs because the cold generates an increase in the amount of uncoupling protein present in BAT. The more UCP the greater the capacity for thermogenesis.
Next it was found that the frequent activation of thermogenesis resulted in an increase in the amount of BAT in the body. More BAT, more UCP, more capacity for thermogenesis. Maybe adult humans DID have enough BAT to make a difference; or, if not, they could acquire it. M.J. Stock, of the University of London, wrote the following regarding this discovery:
“Due to the high thermogenic capacity, BAT, even in very small quantities, such as those found in an adult male, can significantly influence heat production. As little as 50g of BAT could make a contribution of 10-15% additional energy turnover in humans. This would be more than sufficient to cause large differences in fat deposition between individuals with active or inactive dietary induced thermogenesis.”
(Infusionstherapie 16(6), 282-4, 1989).
Meanwhile, scientists were postulating that some deficiency in the body’s ability to burn calories in thermogenesis might have something to do with obesity. Genetic, environmental and dietary factors were investigated. It was determined that the body unable to burn calories as heat stores them in white fat. For example, Arene Astrup of the University of Copenhagen in Denmark, one of the pioneering researchers in thermogenesis, wrote:
“In a number of obesity syndromes in rodents, the sympathetic mediation (of thermogenesis) is defective, and this leads to extreme sensitivity to cold and to obesity… Likewise, the hypothesis has been advanced that a diminished thermogenesis in BAT may be the cause of some human obesity.”
(Acta Endocrinology, Suppl. 278, 1-32, 1986).
The Harvard Studies
Astrup’s hypothesis led to a flurry of research on this topic, especially those medical institutions associated with Harvard University. Of major impact to countless humans are findings that genetic defects in thermogenic capacity can sometimes be totally reversed by ingesting the correct substances. Thin & Slim Naturally is a reflection of those findings. The Harvard Group reported:
“These findings demonstrate that in the fa/fa rat (a genetically obese rat) a mixture of (substances that activate thermogenesis) reduces food intake but also minimizes the fall in metabolic rate that usually accompanies such an energy deficit, effects that led to a reversal of their gross obesity.”
(Journal of Nutrition 117(2), 383-9, 1987).
Also this:
“These studies indicate that, unlike food restriction, the (thermogenic) mixture prevents or arrests the development of obesity in the fa/fa mutant by normalizing their energetic efficiency to that of the lean.”
(American Journal of Physiology 252(3 Pt 2), R507-13, 1987).