N.C. State researchers find muscle-building substance in mustard greens, broccoli

CorrespondentJanuary 6, 2013 

  • All in the family Vegetables in the brassica family also are called cruciferous – “cross-bearing,” in Latin – because the four petals on the flowers of each often resemble a cross. They include kale, collard greens, broccoli, Brussels sprouts, mustard greens, turnip, rutabaga, cabbage, bok choy, Napa cabbage, kohlrabi cauliflower and canola/rapeseed. Staff reports

It turns out Mom was right – greens really are good for us.

But what Mom didn’t know is that vegetables such as kale, mustard greens and broccoli are more than just healthy foods – they may contain a substance that one day could strengthen the muscles of people suffering from debilitating disease and the effects of aging.

A team of N.C. State and Rutgers University researchers has discovered that natural steroids from plants such as mustard greens, collards and kale may hold the secret to stronger muscles, with none of the worrisome side effects of animal-derived steroids.

Debora Esposito, a postdoctoral associate at Rutgers University and N.C. State who is hosted at the NCSU Plants for Human Health Institute, and Slavko Komarnytsky, metabolic biologist and assistant professor at the N.C. State institute, together with a researcher at Rutgers, have evidence that the steroids produced by certain plants can increase lean body mass, the number of muscle fibers and the endurance of the muscles themselves.

Nature’s steroids

Mention “steroids” and “stronger muscles” and the first thing that probably comes to mind is athletes injecting themselves to gain an edge in performance. But Komarnytsky said there are countless people whose muscles have been made weak through the aging process, long hospitalization or such diseases as cancer and muscular dystrophy who could benefit from a muscle-building substance that comes without harmful side effects.

The NCSU-Rutgers team first exposed rat muscle cell cultures to synthetically created brassinosteroids, natural plant steroids found in mustard greens, cabbage, broccoli, kale and other members of the brassica family. Then they fed the plant steroids to rats. After 24 days, they tested both the brassinosteroid-fed animals and those that got regular food.

“The (brassinosteroid-fed) animals gained more lean body mass – more muscle tissue – than the control animals,” Komarnytsky said. Not only that, but rats that were fed plant steroids had larger muscle fibers and more of the type of muscle fibers that give endurance, he said.

The other surprise was that the plant steroids seem to be targeting a different part of the body than do traditional steroids, the type that once were derived from animals, such as testosterone.

Those steroids can come with dangerous side effects, such as an enlarged prostate, liver damage, and a surge in secondary sexual characteristics. The brassinosteroids the researchers tested don’t appear to pose the same problems, Komarnytsky said, though more study is needed.

“Classic animal steroids act through an … androgen receptor present everywhere in our body. The plant steroids don’t have high affinity for those receptors,” he said. “Our data suggests there is yet another unknown target in the cell… which is responsible for muscle increase and muscle strength and less responsible for androgenic effects.”

Next, the researchers will feed brassinosteroid extracts to horses, Esposito said. Like Komarnytsky, she began the plant steroid research at Rutgers and has continued it after a move to N.C. State. “One downside of the project so far is (the steroids) are present in plants in very low levels,” she said.

The team plans to look at varieties of broccoli and other vegetables to identify which have the highest amounts of the substance.

And though eating cabbage, greens and other brassicas is certainly a healthy choice, extrapolating from the dose the rats got, it might take more than 60 pounds of the vegetables to provide a human with the muscle-building qualities of the concentrated steroid, the researchers said.

“Our goal is for … a person who is aging, a person who is in the hospital and cannot exercise, a person who had surgery and cannot go to the gym” to get muscle help from a healthy substance they can take orally, Esposito said.

All in all, she said, the research “looks very promising.”

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