Nutrition in Space - Plans for the new millennium

As the new millennium approaches, we are planning exciting things in the Nutritional Biochemistry Laboratory here at the Johnson Space Center. Our studies on board the Mir Space Station revealed the exciting potential for future studies on the International Space Station. Both Dave Wolf and Andy Thomas monitored their food intake weekly, using a computerized food frequency questionnaire (see Field Journal dated 1/20/98). We are also hoping to use these protocols for the International Space Station. We plan to determine crew nutritional status before their missions, providing dietary counseling if deficiencies are noted. Food intake will again be monitored during the mission with real-time feedback from the ground. Body weight (mass) will be measured before flight, while on orbit, and on return to Earth. On mission completion, nutritional status will again be monitored to assess recovery in the post-flight period.

Nutritional status assessment is critical for making sure that our crewmembers are healthy before, during and after long missions. A case in point is the assessment of Vitamin D levels. Vitamin D is important for bone and calcium health on the ground and during space flight. We get most of our vitamin D from dairy products and from sunlight exposure. Because the spacecrafts are heavily shielded to reduce astronauts' exposure to harmful radiation, exposure to the sun is limited on orbit. We have also learned from previous studies, that crewmembers' vitamin D levels are frequently decreased during the winter months in Russia, as compared to studies in sunny Houston. Star City, Russia, is about the latitude of Alaska and receives limited sunlight during winter. This can be significant as astronauts will complete some training in Russia. Knowing the vitamin D status in crewmembers before flight gives us a chance to make sure that they leave Earth with adequate stores.

We are always on the lookout for techniques that can help assess crew health 'on the spot'. Such information, taken together with what we know about food intake and body weight, can offer amazing opportunities for telemedicine (long distance medical treatment) as we move into the 21st century. Indeed, it will be interesting to develop and investigate new methods for determining crew health before, during and after the long International Space Station missions, as they will give us added insight into the effects of space flight on the human body.

One of the areas that we are particularly interested in is bone health during long missions. Bone loss represents one of the greatest challenges for future space travel. We have completed studies of bone health as part of our nutritional assessment protocols and as the main focus of life sciences research studies on board the Mir Space Station. These latter studies have looked at the effects of long missions on indices of bone health in blood and urine samples. In addition, we have looked at the effect of space flight on calcium kinetics, that is, the movement of calcium throughout the body with special interest in bone. We are planning to continue these studies on board the International Space Station (see http://www.faseb.org/asns/calcium.html). We may also have a chance to look at the early effects of space flight so that we can determine whether or not these effects are gradual or sudden. Our understanding of these factors will help us to determine countermeasures, or ways to prevent or reduce the loss of bone, during long missions.

Our planned studies for the International Space Station are good examples of the research process in action. First, we developed a research question (e.g., What are the effects of space flight on bone health?) Second, we looked at what has been done in this area (e.g., We reviewed published studies) and did some preliminary studies of our own. Third, we began our current process of collecting data. This is by no means a trivial matter, especially in the space program. Getting enough study participants has its obvious challenges, and then there are the additional challenges of doing science in space. These include special hardware for collecting biological samples (blood, urine and saliva), as well as storage volume and power issues on board the spacecraft. We are in the process of studying additional crewmembers, the studies planned for International Space Station will be a splendid opportunity for this.

Next on our agenda will be data analysis. This will include measuring the amounts of hormones and other chemical components in the biological samples and then organizing all of the data. Finally, we will summarize the data and draw conclusions from which we can perhaps make general statements about our findings. By understanding what goes on with bone and calcium during space flight, we may be able to better understand bone diseases, like osteoporosis, here on Earth.

Nutrition is involved in many aspects of health that are affected by space flight - including immune function, bone health, antioxidant status and body composition. We have much to learn about the role of nutrition during long missions. Full realization of the role of nutrition will be critical to future planetary exploration in the new millennium.