A compound found in red wine, resveratrol, could be the key to helping explorers stay fit on long space voyages, according to a recent Harvard study. Published in Frontiers in Physiology, the study offers a means of preserving muscle strength in reduced gravity.
Getting to Mars will take its toll
Using current technology it would take around 9 months to get from Earth to Mars, according to NASA. But the challenge is not just one of technology, such a long journey can result in physiological effects on astronauts.
Loss of muscle mass is just one problem potential Mars explorers will face on such a journey. Bones also weaken in low gravity and weight-bearing muscles tend to be hit first and to a greater extent.
The soleus muscle in the calf is particularly susceptible to this problem.
Dr. Marie Mortreux, lead author of the NASA-funded study at the laboratory of Dr. Seward Rutkove, Beth Israel Deaconess Medical Center, Harvard Medical School said: "After just 3 weeks in space, the human soleus muscle shrinks by a third."
"This is accompanied by a loss of slow-twitch muscle fibers, which are needed for endurance," she added.
Harvard researchers wondered if there might be a way of staving off this problem so they would be able to actually stand and walk on the other side.
The researchers may have found the answer
Mars has around 40% of Earth's gravity and this could still be highly detrimental to astronauts if their muscle and bone mass have degraded to a great extent. To mitigate this something would need to be done to make sure they can walk, or even stand, on the red planet.
"Dietary strategies could be key," says Dr. Mortreux, "especially since astronauts traveling to Mars won't have access to the type of exercise machines deployed on the ISS."
After some research using rats in simulated Mars-like gravity, the team appears to have found a good candidate - resveratrol. This is a compound commonly found in grape skin and blueberries that have been widely investigated for its anti-inflammatory, anti-oxidative, and anti-diabetic effects.
This chemical has also been shown to extend the lifespans of mice.
"Resveratrol has been shown to preserve bone and muscle mass in rats during complete unloading, analogous to microgravity during spaceflight. So, we hypothesized that a moderate daily dose would help mitigate muscle deconditioning in a Mars gravity analog, too."
Under controlled conditions, the team found that administering the chemical slowed down rat muscle-weakening significantly. In fact, it was even able to restore weakened muscles to pre-simulated Mars gravity conditions.
It should be noted, however, that the protection was not complete. It was not able to entirely rescue average soleus and gastrocnemius fibers cross-sectional area or calf circumference.
More work needs to be done
As promising as these results were, more work still needs to be done before it can be considered a "magic bullet" for long space flights. For example, what are the reasons for non-complete protection of muscle mass seen in test rats?
"Resveratrol treatment promotes muscle growth in diabetic or unloaded animals, by increasing insulin sensitivity and glucose uptake in the muscle fibers. This is relevant for astronauts, who are known to develop reduced insulin sensitivity during spaceflight," said Dr. Mortreux.
The anti-inflammatory effects of resveratrol could also help to conserve muscle and bone, and other anti-oxidant sources such as dried plums are being used to test this, adds Dr. Mortreux.
"Further studies are needed to explore the mechanisms involved, as well as the effects of different doses of resveratrol (up to 700 mg/kg/day) in both males and females. In addition, it will be important to confirm the lack of any potentially harmful interactions of resveratrol with other drugs administered to astronauts during space missions."
The original study was published in the journal Frontiers in Physiology.