23 October 2007—It’s the diet that we dare not even dream of—eat like a medieval lord, then simply command the body not to produce fat—but new research by engineers and scientists in New York and Maine gives reason to dream. According to a report to be published this week in the online edition of Proceedings of the National Academy of Sciences, imperceptible vibrations transmitted through the whole body could help prevent weight gain in mice by inhibiting the production of fat cells in their bone marrow. Staying slim may be as simple as standing still�oh, and exercising too.
In a study led by Clinton Rubin, chair of the department of biomedical engineering at Stony Brook University, in New York, mice that stood on a vibrating platform for 15 minutes daily produced fewer fat cells than normal. The findings complicate a traditional understanding of weight loss that focuses mainly on metabolism.
Researchers have known for quite a while that mechanical signals can determine the fate of stem cells—undifferentiated cells that divide and become many different types of tissue—in bone marrow. Rubin, who calls himself a ”bonehead,” led the pack in understanding how bones develop long before he turned his attention to fat. ”Mechanical signals are important for stem cells to decide what to be when they grow up,” he says.
Bones need mechanical input in order to grow and stay strong. Studies at NASA have shown that astronauts lose 2.5 percent of their bone density each month they stay in space. On the other hand, athletes, like archers or baseball players, who selectively work one arm or leg, will grow thicker bones on that side of the body.
To solve the problem of bone loss in space, Rubin started experimenting with vibrations. At the Johnson Space Center, in Houston, volunteer test subjects endured 90 days of fully horizontal bed rest, which roughly simulates what the body goes through during zero gravity. Without having to carry the weight of the body, the skeleton loses much of its mass. So Rubin designed a vibrating platform that would recreate some of the strain of weight. For 10 minutes a day, the device gets cranked up to 30 hertz, an imperceptible level of oscillation. The vibrations run up the body through the feet, sending mechanical signals to stem cells in the bone marrow. The signals reach these cells in their adolescence, before they differentiate, and encourage them to become bone cells as opposed to blood or something else.
At some point, Rubin asked the question that led him to study fat. ”We saw that we could grow bones with these signals,” he says. But ”if we’re growing bone, what aren’t we growing?” As he showed in research published this week, the answer is fat cells.
Rubin used the same device as the one in the NASA study to see if vibrations would have any effect on the weight of mice. Every day, for 15 minutes, the mice were placed on the platform, this time vibrating at 90 Hz. After 12 weeks, the mice had 27.4 percent less fat in their torsos than a control group.
Rubin is cofounder of Juvent Medical, which is marketing his vibrating platform for osteoporosis, but he’s wary of its benefit to dieters. According to him, the study shows only that there is a developmental basis to obesity and that mechanical prevention could someday be an option.
But other companies exploited the concept of shaking the pounds off long ago, and today you can buy several takes on the idea such as a machine called the Power Plate. This kind of thing will do nothing for people who are already obese, says Rubin. But more important, marketed vibration platforms oscillate at dangerous levels, sometimes exceeding 10 times the force of gravity, he says. He can quickly rattle off a list of associated disorders—lower back pain, white finger disease (a numbness experienced by lumberjacks and other operators of vibrating machinery), pugilista dementia (a cognitive impairment that boxers suffer from). ”Vibration is a very nasty pathogen,” he says.
Until Rubin designs a less powerful Power Plate, it’s probably best to stick with solid ground and solid science.
To Probe Further
Afferent Corp., in Providence, R.I., is developing another therapeutic use of imperceptible vibrations.
See ”Balancing Act,” IEEE Spectrum, April 2005.