Omega-3 Fatty Acids, Rising Stars in Zero-G

Scientists look to space station for answers to nutritional health. Photo Credit/NASA

A sea food nutrient recently touted as a contributor to human cardiovascular health, omega-3 fatty acids, may also reign in the worrisome bone loss that accompanies long-duration human spaceflight.

Dr. Scott Smith and colleague Dr. Sara Swart, who lead NASA's Nutritional Biochemistry Lab at the Johnson Space Center, hope to investigate the prospect further in experiments aboard the International Space Station.

Smith explains the plausible connection that could also produce benefits for the elderly and others facing skeletal problems in a weblog post that summarizes work recently published in the Journal of Bone and Mineral Research.

The connection began to arise several years ago as a proposal to study whether omega-3 fatty acids, found in rich amounts in salmon, mackerel and other fish, would stem muscle loss, another downside to lengthy exposures to weightlessness. Omega-3 consumption had that benefit for cancer patients who were experiencing muscle loss.

However, funding for the proposed space muscle experiment was not forthcoming.

Smith and his associates then decided to research what he termed a "softer" link between omega-3 and bone loss with cell culture studies.

The results suggested that the fish nutrient suppressed the growth of cells that trigger bone loss. Though encouraging, the finding was not the breakthrough Smith was seeking. But it was enough for the nutritional lab to continue its pursuit.

In his post, Smith explains second and third events that strengthened the link.

The second involved human bed rest studies. The studies simulate weightlessness in volunteers who agree to spend weeks at a time confined to their beds, where their muscles and bones are minimally exercised.  A look at the diets of volunteers revealed that those who consumed more Omega-3 fatty acid exhibited smaller amounts of a marker, N-telopeptide, in their urine that signals bone loss.

Smith's team then looked for a correlation between the diets of astronauts after they returned from the space station and bone loss.  As they hoped, the researchers found that those who consumed more fish lost less bone.

However, the connection is still not rock solid.

Smith and his associates propose a controlled experiment, using two groups of astronauts while they are living and working aboard the station -- one group with a diet high in Omega-3 and a second with a control diet lower in the fish fatty acid.

A proposal for funding has been submitted.

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