Irisin: Produced During Exercise, It’s a Protein With Promise

Did you know that one of the most important health supplements doesn’t come in a capsule or tablet? And better yet, it doesn’t cost a dime! Most of us know regular exercise is beneficial, but too many of us push it to the bottom of our to-do list. Why? Too much effort, not enough time and it’s no fun are common reasons.

For those looking for additional excuses, there’s plenty of erroneous fodder out there from various sources. Some say it’s wasted energy with few, if any, proven health benefits, while others claim it can actually be dangerous. However, the evidence contradicting this anti-exercise rhetoric is almost overwhelming.

In fact, research has shown a regular exercise program, tailored to your age and physical condition can be essential to maintaining and improving your health.

Looking for additional information on how exercise actually benefits humans? This article takes a closer look at recent studies, demonstrating the mechanisms involved at the cellular level. Study this compelling evidence and soon your remaining exercise excuses will be extinguished.

Feel the Burn

Not only is physical exercise important to overall body health, it’s also key to maintaining a healthy weight. We need to incorporate exercise into our daily routine, particularly as we grow older. Because as our metabolism slows, we burn fewer calories and, consequently, store more fat.

Exercise has the opposite effect. First, it sparks the machinery that burns the calories (fat) to produce the energy our bodies use. Second (and here’s the fascinating part), we continue to burn fat even after we’ve stopped exercising.

Protein Power

Exercise, like caloric restriction and certain small-plant nutrients, activates a gene in cells, including muscle cells, known as PGC1-alpha. This gene assists other genes involved in energy production, like those that produce proteins to increase the output of our cellular dynamos, the mitochondria.

But there’s more to the story, according to a recent study by a research team from Harvard Medical School, University of California San Francisco, Italy’s Universita` Politecnica delle Marche and Denmark’s Odense University. (See “Research Update” below) The scientists discovered the exercise-stimulated production of PGC1-alpha, in turn, initiates a series of events that produce messenger protein, irisin.

Released from the exercised muscle to enter the blood stream, irisin is transported to a specific type of fat, the white fat cell. Once bound to the white fat cell membrane, it sends signals (hence its name from Iris, the Greek messenger goddess), to the fat cell, instructing it to convert from white to brown fat.

Why is this significant? Brown fat tissue is comprised of cells with machinery designed to convert the fat stored to heat, rather than chemical energy (ATP) as occurs in white fat. This is how hibernating animals, like bears, stay warm during the cold winter months. It also explains how we continue to burn fat/lose weight even after we’ve stopped exercising. (Not to mention why we keep sweating for some time after a workout.)

Mouse to Man

The research team made their initial discovery in experiments with mice. Their subsequent study with human subjects showed we, too, produce the protein. In fact, it increases two-fold in our blood after a session of aerobic exercise.

When the group compared the irisin protein from mouse and human blood samples, they were somewhat astonished. It was identical. In fact, all species of mammals, analyzed to date, manufacture identical irisin proteins. This conservation of identity across all mammals may indicate an important evolutionary role for irisin, as an agent vital to life and survival/propagation of the species. But the question is, does it function the same way across species today?

More Irisin, Less Obesity

If it does, irisin will be a very important discovery for human health. Reducing white fat would have a profound effect on glucose homeostasis, potentially preventing type II diabetes, as well as several other health concerns associated with metabolic syndrome. Research is needed to determine exactly how human fat tissue responds. Do we develop healthier brown adipose tissue while we lose unhealthy white fat in response to exercise?

A “yes” answer could eventually lead to therapeutics either containing irisin or developed with agents that can “tweak” muscle cells to make more of this healthy protein. Caloric restriction, as well as certain plant nutrients (Resveratrol, berberine, green tea), would stimulate PGC1-alpha synthesis. This, in turn, could support and amplify irisin production during exercise.

More Exercise, Cleaner Cells

As if leaner cells weren’t enough of a potential exercise benefit, how about cleaner cells? Another recent report describes the activation of a cell house-cleaning apparatus, autophagy, in exercised muscle cells.

Briefly, a research team at Texas Southwestern Medical Center studied the cellular machinery of mice. They found that the process of removing old worn-out components (mitochondria, proteins, etc.) and replacing them with new was more active in those mice on a regular exercise program.

The methodology is complicated, but they linked this increase in exercise-induced autophagy to improvements in metabolism. For example, this cleaning out of old cells helps convert old muscle cells with poor glucose metabolism (diabetic-like) to younger-acting cells with a healthy, metabolic balance. Organs, including the pancreas and liver, also exhibited improved metabolism of glucose following exercise.

Their Findings, Your Health

These studies support the value of a regular exercise program for maintaining and improving your health. Of course, it’s important to consult with your health professional regarding what’s appropriate for your age, health and physical condition. He/she can also help you devise a healthy diet and determine the plant-derived nutrients that are best for you.

Research Update

A research team, from Harvard Medical School, University of California San Francisco, Italy’s Universita` Politecnica delle Marche and Denmark’s Odense University, examined the relationship between skeletal muscle, exercise and age-associated obesity and diabetes. An article published in the weekly scientific journal Nature, summarizes their promising findings.

Previous work identified the activation of a transcriptional factor, PGC1-alpha, in muscle as a prominent effect of exercise. The researchers were also aware of studies showing that mice, genetically modified with an over-expressing gene coding for PGC1-alpha, were resistant to age-associated obesity.

The team hypothesized that muscle cells, during exercise, might be producing a substance that is secreted into the blood stream. They speculated this substance acts on other tissues, such as adipose tissue, to reduce fat cell content.

To test their theory, the researchers used a mouse model in which the PGC1-alpha gene was inactivated in one group of animals (gene knock-out or KO mice). These mice, in contrast to another group with a normal gene composition, did not show the anticipated health benefits when exercised, like decreased fat content and improved blood-glucose levels.

Comparing blood samples from the two groups led to the discovery of a new substance, a protein, produced by the animals with the active PGC1-alpha gene. The investigators named the new protein irisin (after Iris, the Greek messenger goddess). To deliver its “message,” irisin followed a path from secretion by the mouse muscle cell through its blood stream to white fat cells throughout the mouse body.

The irisin bound to the white fat cells, which responded to the “messenger” by reprogramming their genetic material, converting them to brown fat cells. Rather than storing fat, brown fat cells are engineered to burn it for heat production.

The team also observed an increase in the amount of energy used by the mice when the blood levels of irisin were mildly artificially increased. Even with no changes in movement or food intake, these mice lost weight and their blood sugar levels became more balanced.

The researchers discovered irisin is produced with exercise in other animals, including humans. They noted a remarkable conservation between species. In fact, the irisin from mouse and man is identical.

The group believes humans will benefit from therapeutics that either contain irisin or an agent that stimulates irisin production. They predict it could help improve the obesity epidemic in the western world as well as age-associated health concerns like metabolic syndrome and diabetes.

This Research Update highlights articles related to recent scientific inquiry into the process of human aging. It is not intended to promote any specific ingredient, regimen, or use and should not be construed as evidence of the safety, effectiveness, or intended uses of the Juvenon product. The Juvenon label should be consulted for intended uses and appropriate directions for use of the product.