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Astronaut nutrition: staying healthy for a year in space

The views expressed are those of the author and are not necessarily those of Scientific American.


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NASA astronaut Karen Nyberg, Expedition 36 flight engineer, gets some nutrients aboard the International Space Station. Photo courtesy of NASA.

When NASA astronaut Scott Kelly leaves the earth for his International Space Station mission in 2015, he won’t walk the aisles of a grocery store for a year.  To ensure he and other long-term astronauts stay healthy, NASA must make certain they have the proper food in tow.

I caught up with NASA nutritionist Scott Smith to see what NASA scientists are doing to prepare for missions like Kelly’s (and along the way picked up an astronaut recipe to try at home).

One essential nutrient NASA scientists have been studying in relation to long-term missions is iron.  People often cite the health implications of low iron, such as the fatigue-marked condition of anemia, and herald the benefits of high-iron foods, such as beef or spinach.  But a recent analysis of 23 astronauts’ blood and urine samples suggests the opposite issue may be the concern for extended spaceflight: not too little iron, but too much.

“In flight, you end up with more iron than you need because your blood volume contracts,” said Smith, who was also the main author for the study. “When you reduce your blood volume you have increased iron storage.”

Instead of boosting health, the extra iron may actually be causing bone loss, according to the research, which was published in the American Journal of Clinical Nutrition in May.  In other words, astronauts’ bone breaks down faster than new bone is made.  The study showed that an increased storage of iron correlated with increased bone loss in astronauts on missions ranging from two to eight months.

Bone loss is a major nutrition-related issue for astronauts on long-term missions, as they have been known to lose bone density at an average rate of 1 to 2 percent a month. These numbers may be meaningless until you compare them to the rate at which an elderly person loses bone, which is a mere 1 to 2 percent a year.  The decreased bone density means the astronauts have an increased risk of bone fracture once they return to earth, similar to the way an elderly person with osteoporosis is more prone to breaking bones.

While the effect of iron on bone loss may be less of a concern for an average, healthy person on earth, the prolonged weightlessness of spaceflight makes astronauts prone to lose bone mass, which means the further effect of nutrients like iron are an important consideration.

“One of our concerns is that the effect of diet on bone is likely greater the longer you’re up there,” Smith said, meaning the relationship between nutrients like iron and bone density loss is of special concern for long-duration missions, like Kelly’s yearlong space station mission.

“When we flew shuttle missions of two weeks, we always looked at those as just sort of camping trips; you can eat pretty much anything and get away with it.”

But once you reach missions of 30 days and above, Smith said proper nutrition becomes more important-whether it’s maintaining proper levels of iron or any other nutrient.

“As we approach longer space missions, initially extending from six months to 12, and someday beyond that, nutrition will play a critical role in the health and safety of crew members on these missions, and in the ultimate success of these next steps in space exploration.”

And if you want to test out a little of this astronaut nutrition yourself, check out this recipe, courtesy of NASA Space Food Systems Laboratory – it contains moderate iron and high protein:

NASA Mini Vegetable Quiche – adapted for small scale preparation

Ingredients:

4 whole eggs
3/4 cup canned low-fat evaporated milk, 2%
½ lb. fresh zucchini
4 oz. cream cheese
1 cup fresh mushrooms, sliced
½ cup Swiss cheese, shredded
Tops of 3 fresh green onions
1 cup corn flake crumbs
1 tbsp unsalted butter
1 tsp coarse grind black pepper
No-stick cooking spray

Instructions:

1.    Remove cream cheese from the refrigerator so that it can soften.
2.    Preheat convection oven to 275°F.
3.    Spray petite loaf pans with the no-stick cooking spray.
4.    Coat each compartment of the loaf pans with corn flake crumbs.
5.    Wash green onions and zucchini thoroughly.
6.    Trim ends from zucchini. Grate zucchini.
7.    Chop sliced mushrooms and the green onions.
8.    Place softened cream cheese into a bowl and beat until smooth.  Add evaporated milk to the cream cheese, a little at a time, mixing well after each addition.
9.    Add eggs to the cream cheese mixture and mix until thoroughly combined.
10.    Heat sauté pan over medium heat. Melt butter and sauté chopped green onions and mushrooms just until soft, about 5 minutes.
11.    Add black pepper to sautéed vegetables.  Mix well and set aside.
12.    Combine sautéed vegetables with zucchini and Swiss cheese; mix well.
13.    Combine vegetable mixture with egg mixture and mix well.
14.    Add vegetable quiche to each compartment until the compartment is almost filled to the top.
15.    Bake pans of quiche for approximately 25-27 minutes at 275°F (until internal temperature is 170°F).  The quiche will rise a bit during cooking and then fall slightly.  Cooked quiche may brown slightly on top.
16.    Allow quiche to cool before removing from pans.

 

References

1. Zwart, S.R., Morgan, J.L., & Smith, S.M. (2013) Iron status and its relations with oxidative damage and bone loss during long-duration space flight on the International Space Station. Am J Clin Nutr. 98 (1), 217-223.

2.(2012, August 24). Good diet, proper exercise help protect astronauts’ bones. Retrieved from http://www.nasa.gov/mission_pages/station/main/bone_study.html

Julianne Wyrick About the Author: Julianne Wyrick has a bachelor’s in biochemistry and is currently a master’s student in the health and medical journalism program at the University of Georgia, where she also writes about science for the Office of Research Communications. Find her on the web at juliannewyrick.com. Follow on Twitter @juliannewyrick.

The views expressed are those of the author and are not necessarily those of Scientific American.






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