Space-grown lettuce could help astronauts avoid bone loss

NASA is preparing to send humans to Mars sometime in the 2030s. The 3-year mission will expose astronauts to a long period of microgravity, which will cause them to lose bone mass. But now, scientists report transgenic lettuce that produces a bone-stimulating hormone.

Someday, astronauts could grow the lettuce in space and help guard against bone loss – simply by eating a big bowl of salad. In addition, the lettuce might help stave off osteoporosis in resource-limited areas here on Earth, the researchers say.

The 3-year mission could leave astronauts vulnerable to osteopenia, and later, osteoporosis. A medication containing a peptide fragment of human parathyroid hormone (PTH) stimulates bone formation and could help restore bone mass in microgravity, but it requires daily injections. Transporting large quantities of the medication and syringes and administering it during space missions is impractical.

So Yates; Somen Nandi, Ph.D.; Karen McDonald, Ph.D.; and their colleagues wanted to find a way for astronauts to produce it themselves – while also enjoying some tasty greens, which are severely lacking in astronauts' mostly canned and freeze-dried diets.

"Astronauts can carry transgenic seeds, which are very tiny – you can have a few thousand seeds in a vial about the size of your thumb – and grow them just like regular lettuce," Nandi says. "They could use the plants to synthesize pharmaceuticals, such as PTH, on an as-required basis and then eat the plants."