Twin acts as control sample for space nutrition study

While Scott Kelly is on a one-year mission aboard the International Space Station, scientists from NASA’s Nutritional Biochemistry Lab will track his nutritional status via blood and urine samples provided before, during and after the space missions. This information is compiled for all astronauts, but in Scott’s case there exists a ground-based control for comparison. His twin brother, Mark, will remain on Earth and has agreed to provide his biochemical profile.

Planning adequate nutrition for long journeys is nothing new. Centuries ago, scurvy — a severe depletion of Vitamin C — was a major health risk on board ocean voyages. But today’s explorers cross space with no chance of finding a palm-fringed island along the way. All nutritional needs must be met aboard.

“Nutrition is vital to the mission,” Scott M Smith, PhD, said. “Without proper nutrition for the astronauts, the mission will fail. It’s that simple.”

Smith and his colleagues at NASA’s Human Research Program research the requirements for long-duration spaceflight, and its unique challenges.

Astronauts tend to eat while in space due to being very busy and menu fatigue. The environment also impacts their nutrition needs: beyond microgravity, higher radiation exposure, higher atmosphere levels of carbon dioxide, temperature and humidity can all have profound effects on health, such as bone and muscle loss, cardiovascular degradation, impairment of immune function, neurovestibular changes and vision changes.

As mission durations increase and as NASA prepares for the journey to Mars, it is important to understand how the human body changes with longer exposures to microgravity and higher radiation doses. The Biochemical Profile project examines nutritional markers such as proteins, vitamins, minerals, bone markers, hormones, metabolites, immune function, antioxidants and general chemistry to better understand these changes.

The future of spaceflight includes human space exploration that will go beyond low-Earth orbit, such as a journey to Mars that could last as long as 30 months or more. The human body could experience several physiological effects in this prolonged environment including weight loss, fluid shifts, dehydration, constipation, calcium loss, potassium loss and motion sickness.

“The food system will be of utmost importance for combating these effects from long-duration missions,” Smith said. “But to be helpful, food must also be palatable, nutritious and safe, even after months in storage. If astronauts do not eat well, they will not receive the necessary nutrients to keep them healthy.”

Image caption: Astronaut Scott Kelly, Expedition 43, with carrots floating around him in the Node 1 module of the International Space Station. A table covered in other food packets is beside him. Credit: NASA; Terry Virts.