Osteoporosis: Enhanced lettuce could strengthen astronauts’ bones

Eating lettuce containing a hormone that boosts bone formation might help astronauts from losing bone mass in space – and might even help treat osteoporosis on Earth too

By Alex Wilkins

Lettuce genetically-modified to produce a bone-forming hormone could be eaten by astronauts to keep them healthier on long missions.

Bone loss, or osteoporosis, is a common problem when people spend a long time in the microgravity of space. Astronauts on the International Space Station need to exercise for at least 2 hours each day and take a bone-preserving drug to limit such effects. But on longer missions, like a human spaceflight to Mars, stronger bone-forming drugs that require injections could be needed, which would take up valuable cargo space.

Kevin Yates at the University of California, Davis, and his colleagues used a soil bacterium to transfer a gene that produces a variant of the human version of parathyroid hormone (PTH) into lettuce. The same variant is commonly used as a drug to stimulate bone formation. The researchers screened a number of modified lettuce plants and observed that the most productive specimens produced 10 to 12 milligrams of PTH per kilogram. An astronaut could get all the PTH they need by eating 380 grams of the lettuce per day.

Yates and his team think that they will be able to improve on the initial results, which they presented today at the American Chemical Society Spring 2022 conference in San Diego, California. They hope that extracting medicine from produce grown from seeds in space could become the norm for future missions.

“This is a new way of thinking and solving problems for space exploration,” says Yates. “Typically in the past it’s been abiotic solutions – just package stuff up and fly it with you or have consumables that you use up and have more sent to you from Earth.”

Yates also speculates the lettuce could be used to treat osteoporosis on Earth too, where the condition is seen in millions of people.

“In principle, it could be [useful] in terms of treating osteoporosis,” says David Reid at the University of Aberdeen, UK. But the use of a hormone that builds up tissue like PTH might be unnecessary, he adds. “You can usually, unless it’s very profound, get away with other drugs which prevent bone breakdown, rather than a bone-forming drug.”

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