On Oct. 10, U.S. astronaut David Wolf, who recently began a four-month stay on the Russian Mir space station, beamed down the first in-flight record of a diet eaten in space.
Created by public health epidemiologist Gladys Block, the record is a weekly intake questionnaire designed specifically help the crew to counter the effects of extended weightlessness.
For the first time, food and liquid intake can be systematically measured and modified while an astronaut is in space, said Block, whose dietary assessments are widely used by nutritional scientists. The space diet evaluation includes a formula for translating Wolf's weekly food log into measures of calcium, sodium, iron, fluid, calories and protein.
"We've never been able to do this in real time before," said Block, a professor in the School of Public Health. "If ...Wolf's fluid intake is low, the flight surgeon can say, 'You've got to drink more water.'"
Block said scientists hope to have an impact on such possible consequences of extended space flight as kidney stones and bone loss.
Long-duration space flight has serious effects on the human body, including loss of weight, bone and muscle; changes in blood cells, and increased risk of kidney stone formation, according to Scott M. Smith, nutritional scientist with NASA's Johnson Space Center in Houston, who receives the results of Wolf's weekly questionnaire.
Smith said these physiological hazards, particularly the risk of bone loss, will increase significantly with the extended space flight envisioned for the International Space Station, due for inauguration in 1998.
"In my opinion, bone loss is one of the most critical things we must fix before we can do anything like send humans to Mars," said Smith.
Experience with three decades of space flight has shown that individuals vary greatly on bone loss, said Smith. Some astronauts have recovered completely, while others have not yet returned to pre-flight levels.
The total diet available on Mir comprises approximately 250 food items, about half of which are Russian foods. Daily menus are created for astronauts, but they often swap foods or otherwise change the diet while in flight, said Smith.
The questionnaire of 50 to 60 items took several months to develop, but it takes only 10 minutes to answer, Block said.
Pre-flight ground tests with NASA volunteers demonstrated the ability of such a brief questionnaire to help estimate fluid and nutrient intake thought to be critical for health during space flight.
The volunteers ate a space station diet while living in a capsule for 60 days.