Standing on a gently vibrating platform for 15 minutes a day can build bone mass and reduce fat in mice, according to a new study. The changes are due to a stem cell in bone marrow that can become muscle, bone or fat. Testing has begun in humans.
Biomedical engineer Clinton Rubin said he didn't start out intending to make lean mice.
"In my scientific heritage, I'm more of a bone head," Rubin said. "I study a bone disease called osteoporosis, or bone-wasting."
But fat and bone are cellular cousins — the same stem cell that's a precursor to bone cells is also a precursor to fat cells.
Rubin said scientists have known for a good long while that bones that get a lot of shaking tend to get larger. Tennis players are a perfect example.
For instance, "Roger Federer would have 35 percent more bone on his playing arm than his non-playing arm," Rubin said.
But even a small amount of vibrating will do.
The theory for why vibrations affect bone mass is that somehow the bone-marrow stem cell senses the motion and begins turning itself into bone to better tolerate the jiggling.
If that theory is true, Rubin thought, then it could have another implication: "If a precursor cell is deciding to become bone, maybe it isn't becoming fat."
So he and his colleagues at the State University of New York in Stony Brook set up an experiment in which they gave two groups of mice identical diets. But one group was put on a gently vibrating platform for 15 minutes a day.
When he measured the body fat of the group that got the daily jiggling, Rubin said, "Sure enough, they had 30 percent, 27 percent, less fat 15 weeks later."
And the mice also had stronger bones, as Rubin reported in the Proceedings of the National Academy of Sciences.
Scientists are about to launch a similar study in humans. Douglas Kiel works at the Institute for Aging Research at Hebrew Senior Life in Boston, where subjects will soon get 10 minutes of jiggling a day.
"People stand on a platform" that vibrates, Kiel said. "And since we're enrolling seniors, we also have a little bar to grab onto for safety."
Kiel's colleague Mary Bouxsein, of the Beth Israel Deaconess Medical Center in Boston, says the vibrations are quite mild.
"You do feel something," Bouxsein said. "But you're not being, you know, jolted around as if you need to hold on and you might falls off. It's really a quite minor stimulation."
Bouxsein said she and Kiel initially were only hoping the vibrations would improve bone growth. But now they're planning to see if there are any changes in body fat as well. Since she can't feed her subjects identical diets, she doesn't have high hopes for seeing a big difference.
And it's not as if she's opposed to people getting their vibrations by walking, running or something a little more aerobic.
"But if we had something that was, you know, very simple — you stand on this platform for 15 minutes a day and it may improve your musculoskeletal health, as well as cause you to weigh less or have less fat — that's pretty interesting or intriguing," Bouxsein said.
One important thing to note is that the vibrations do not remove fat cells. Rubin said that once fat cells form, they tend to stick around. And vibrating won't get rid of them.
"If you have a fat mouse, in order to get rid of the fat, you need to metabolize it, just as we've all learned," Rubin said. "You need to get those mice out running marathons or pumping iron, or whatever it is that mice do to reduce their fat mass."
Scientists are pretty clear that the techniques for reducing fat mass will work in humans, too.