Making Fat Beautiful
Want to control weight? Avoid diabetes? Appear more youthful? You might want to change your white fat to brown. Fortunately the color shift—and the function of fat—is under your control.
Greek Gods, Bears, and Your Waistline
New research from Harvard, led by cell biologist Bruce Spiegelman and published in Nature has discovered something important - exercise can convert white fat to brown.
The process goes something like this: exercise induces production of a complex molecule called PGC1-alpha. The researchers found that particular molecule eventually led to the increase of a protein named Fndc5.
And that protein blew up.
Like many biological molecules which simultaneously perform multiple roles, Fndc5 split into five pieces including one which appears to be a new hormone. The researchers named it irisin.
Iris is a genus of plants which includes the beautiful flowers which grace a household terrace. It's derived from the Greek word for rainbow.
Iris was also the goddess of the rainbow - and personal messenger for Hera, Zeus' often betrayed and ingenious, jealous wife. The ancient Greeks (and perhaps some present day economically stressed Greeks) believed that rainbows exchanged matter between ocean and sky - replenishing the water of clouds from the water of seas. Rainbows gave us the rain that waters the earth. Iris was both godly messenger and cosmic transformer.
What does irisin do? Flow through blood from muscle to fat, where it converts visceral white fat into brown fat. Brown fat burns calories much more quickly - and Spiegelman thinks the brown fat he sees may even be a special form of brown fat - unlike the common rodent variety derived from muscle cells.
The Color of Fat
Fat used to be stable, really boring stuff - what physiologists liked to call "storage droplets." You eat your sandwich, digest the protein, sugar, and fat, and watch the fat molecules and a good part of the sugar turned into white storage fat that pops up unevenly throughout your body. Most people thought of white fat in the context of cellulite and oversized backsides.
Then physiologists discovered white fat was an endocrine gland. When white fat migrated to your abdominal organs, it become a rather unsavory endocrine gland, popping out all kinds of hormones - resistin, adiponectin, TNF alpha - that can make you more prone to diabetes, heart attack and stroke.
Brown fat is a very different type of cell. Its color is the result of numerous mitochondria - the energy workhorses of our lives.
Brown fat "burns" energy much faster than white fat. It's what keeps hibernating bears alive.
Humans infants have lots of brown fat. Until quite recently we were thought to lose all of it well before adulthood.
Then just a few years ago researchers started find little deposits of brown fat in chest and neck.
What the new research means is that you can voluntarily make your own - by changing white fat into brown fat.
Give irisin to mice and they don't gain weight - even on a high fat diet. Their glucose levels remain stable.
Irisin may be one of the mechanisms why physical activity is so regenerative in humans - and provide another mechanism for weight control.
Metabolism and Fast Burning Fat
Not far from Dr. Spiegelman's lab Harvard's Professor Gerzstein has researched the extraordinary ability of human exercise to burn fat calories - after you've stopped exercising. . In some people following intense exercise, the fat burning is extensive and goes on all day.
Is some of this due to irisin and brown fat production?
Years ago Professor Colin Shapiro of the University of Toronto exercised older people in bright light and without. They lost the same amount of weight, but those who exercised in light gained muscle mass.
Was that partially due to exercise turning white fat to brown? Light has many physiologic effects- and inducing changes in brown fat might be one.
Of course brown fat may do far more than energetically burn off fat stored energy - with endocrine effects of its own.
Drug Effects and Human Effects
Soon there will be moves afoot to convert these recent discoveries into drugs. Injecting irisin or proteins similar to it will be tried as a way to control weight and glucose metabolism. Why not replace the effects of exercise with a drug anyone can take?
Because exercise will do more than any drug.
Some estimates are that physical activity can increase human lifespans six or seven years. Yet the effects go beyond life extension.
Exercise changes mood; heart disease risk; cancer risk; your appearance. It also creates some of the great human pleasures, particularly in the form of sports.
Yet one major lesson from recent research is the transformative power of the individual in controlling their own biological destiny.
Exercise constitutes any use of voluntary muscle. In this way standing is a form of exercise, as is fidgeting.
And now it appears that exercise can help change white fat - especially the sometimes nasty stuff in our abdomen - into brown.
That's a much bigger trick than shifting brown eyes to blue eyes. Through activity under your control you can change one tissue into another - another example of the body's enormous regenerative capacity.
That's power you can use.