Enhanced Diet May Help Astronauts Adapt to Spaceflight

Eating healthily benefits the human body, both on Earth and in space. Just as a healthy diet can help improve athletic performance, a healthy diet could help astronauts better adapt to the stresses of spaceflight.

But, how might eating healthy change the physiology of astronauts? To find out, Grace Douglas, lead scientist for the Advanced Food Technology project at NASA’s Johnson Space Center, is conducting a study on the physiological effects of food aboard the International Space Station. The study is conducted through NASA's Human Research Program.

Fresh whole fruits and other food items float around NASA astronaut Chris Cassidy who, on Expedition 63, participated in a study to gauge how an enhanced diet affected his physiology. Credits: NASA

Douglas and other researchers are assessing how the current spaceflight diet — by any assessment a healthy offering — compares to an “enhanced” spaceflight diet: one packed with foods rich in nutrients such as flavonoids, lycopene, and omega-3 fatty acids. How does such a diet affect the immune system, the gut microbiome, and nutrition? These factors are known to influence each other, and researchers want to discover how.

Participants in the study receive a consultation before their mission to help in creating an enhanced spaceflight diet. This diet is generally more diverse in foods rich in bioactive compounds — specifically fruits, vegetables, and fish — than standard spaceflight fare. Although these foods must all be shelf stable for multiple years at room temperature, to be compatible with the food-system requirements of the space station, a variety of options are available, such as freeze-dried butternut squash or fish with mango salsa.

The study works like this: Participating astronauts consult with Douglas’ team to develop an enhanced diet that suits them. They stick to the enhanced diet aboard the space station, logging their food intake daily. Every week, participants discuss their diet with a member of Douglas’ team, who provides feedback about their dietary status and information to help them continually meet requirements. Blood, urine, saliva, and fecal samples are taken before, during, and after spaceflight. The team tracks changes in these vitals and samples over the course of the mission to pinpoint any observed benefits to a given astronaut’s health.

Eight individuals in total are needed for the study. Victor Glover, NASA’s SpaceX Crew-1 astronaut and Expedition 64 flight engineer, contributed during his recent stay aboard the space station. Expedition 63 astronaut Chris Cassidy already participated.

The results of the investigation will help NASA researchers determine how an enhanced diet affects human physiology and the way those physiological changes improve human adaptability to spaceflight. Results will also provide evidence for dietary interventions that support beneficial immune, microbiome, and nutritional outcomes for crews.

There’s another set of factors to consider: Future spacecraft will likely have a limited amount of interior space, which must support crews for longer missions. To sustain flight, heavy cargo may need to be kept to a minimum. When deciding what to bring, “food is often targeted for reductions, as it is one of the biggest mass and volume drivers on missions,” Douglas explained. “Many of the healthiest foods are also the least calorically dense. We need to provide evidence for food-system health and performance risk/resource trades to inform these program decisions.”