Space dietitians have discovered that increasing fruits, vegetables, and fish in the diets of astronauts — compared to their standard rations — can provide multiple health and performance outcomes.
A study published in Scientific Reports details the results of participants' samples of saliva, urine, blood, and stool, as well as completed cognitive assessment tasks throughout missions simulated in an Earth-based training module.
Sixteen people took part in the experiment into the effects of the new diet on would-be space voyagers.
The paper argued that long-duration spaceflight was known to affect human health, and spacecraft size and power constraints limit what can be lofted beyond our planet.
NASA Johnson Space Center Advanced Food Technology lead scientist Grace Douglas and her colleagues investigated the difference in the impact of two diets on 10 men and six women.
Four individuals participated in each of the four 45-day missions in NASA’s Human Exploration Research Analog, a three-story habitat designed to serve as an analog for isolation, confinement, and remote conditions in exploration scenarios.
One group were fed the enhanced diet while another got the standard Nasa rations. The enhanced diet included an increased number of servings and a variety of fruits and vegetables, along with more fish and sources of omega-3 fatty acids. The standard spaceflight diet is currently used on the International Space Station, and meets most dietary requirements, the authors said.
The booster diet included six servings of fruits and vegetables per day and between two to three servings of fish per week as well as other healthy foods.
The study found that the new diet could benefit astronauts, even on short space missions.
"Subjects consuming the enhanced space flight diet had lower cholesterol levels, lower stress, better cognitive speed, accuracy, and attention, and a more stable microbiome and metatranscriptome [gene expression of microbes within natural environments] than subjects consuming the standard diet," the study said.
The results indicate that a spaceflight diet rich in fruits, vegetables, and omega-3 fatty acids produces significant health and performance benefits even over relatively short durations, the authors argued.
"Further investigation is required to fully develop dietary countermeasures to physiological decrements observed during spaceflight. These results will have implications for food resource prioritization on spaceflight missions," the study said.
A handy NASA guide [PDF] to space nutrition describes how even missions as early as the Mercury program — an Apollo precursor which ran from 1958 to 1963 – helped contribute to the development of space food.
"They tested the physiology of chewing, drinking, and swallowing solid and liquid foods in a microgravity environment," NASA said.
In the Apollo Moon missions, rehydratable food was encased in a plastic container referred to as the spoon bowl. "Water was injected into the package through the nozzle of a water gun. After the food was rehydrated, a pressure-type plastic zipper was opened, and the food was removed with a spoon.
"The moisture content allowed the food to cling to the spoon, making eating more like that on Earth," the space agency said.
On Apollo flights, foods and drinks reconstituted with either hot or ambient water included coffee, bacon squares, cornflakes, scrambled eggs, cheese crackers, beef sandwiches, chocolate pudding, tuna salad, peanut butter, beef pot roast, spaghetti, and frankfurters.
After they touched down on the lunar surface, the astronauts were able to tuck into the Moon's plentiful supply of cheese*.
- Note, the Moon is not made from cheese. ®