This page contains a Flash digital edition of a book.
edited by katie barnes. email: katiebarnes@leisuremedia.com research round-up


Scientists have discovered a new type of ‘beige fat’ cell, present in most adults, that they believe has the ability to burn fat


fi ghting fat W


e all know that too much fat is a bad thing. However, studies into different types of fat


– specifically those that burn energy rather than store it – suggest there might be new ways to tackle obesity. White ‘bad’ fat is the type of fat that


stores calories, and excess amounts of it cause people to put on weight. It’s found in abundance in obese people. Brown fat is a type of fat that


generates heat but that also burns calories, and it has been linked to helping control weight. Brown fat dwindles with age – indeed, it was believed to be present only in children until researchers in 2009 found that it’s also active in up to 7.5 per cent of adults. But in July 2012, a study in the journal


Cell* reported the discovery of beige fat – another type of fat present in “most or all human beings” which has the ability to both store and burn calories.


beige – the new brown The existence of beige fat cells was first suggested in 2008 by Dr Bruce Spiegelman, a cell biologist at Harvard Medical School. But it wasn’t until this recent study, conducted by Dr Spiegelman and scientists at Harvard’s Dana-Farber Cancer Institute, that it’s been possible to isolate the cells and determine their genetic profile. Beige fat cells, the scientists say, can


be found in humans in small deposits around the collarbone and spine. In this study, they cloned beige fat cells in mice to look at them more closely. The scientists discovered that beige


fat is similar to brown fat in some ways. Both contain iron, which gives them their distinct colour, and both have an


Irisin, a hormone produced by exercising muscles, may stimulate beige fat cells


abundance of mitochondria – a part of the cell which can produce heat and burn calories. But there were also some significant


differences. Brown fat cells give off high levels of UCP1 – a protein that mitochondria need to produce heat and burn calories. In comparison, beige fat cells usually express low levels of UCP1. However, beige fat can be stimulated to produce a lot of UCPI when exposed to irisin, a hormone released by muscles during exercise or when muscles shiver due to exposure to cold temperatures. It was also found that the cells differ


from each other genetically. Brown fat cells originate from muscle stem cells. In comparison, beige fat cells emerge from white fat cells – making it possible for them to store fat when levels of UCP1 are low, but burn it when muscles release irisin through exercise.


fighting obesity The study reports: “The therapeutic potential of both kinds of brown fat cells is clear, as genetic manipulations in mice that create more brown or beige fat have strong anti-obesity and anti- diabetic actions.” It’s hoped these discoveries may lead


to new treatments for obesity. Indeed, Spiegelman has already set up a biotech company, Ember Therapeutics, in an attempt to develop irisin in drug form to stimulate brown and beige fat cells to increase weight loss. However, this is still a very new fi eld.


While more brown and beige fat cells are found in fi t compared to sedentary people, for example, more research is needed to prove the two are directly linked. It’s believed that the effects of irisin may only be temporary, but scientists don’t know this for sure yet.


*Spiegelman, Bruce et al. Beige Adipocytes Are a Distinct Type of Thermogenic Fat Cell in Mouse and Human. Cell, p366-376, July 2012 38 Read Health Club Management online at healthclubmanagement.co.uk/digital september 2012 © cybertrek 2012


KZENON / SHUTTERSTOCK.COM


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134