Guest blog post by Ozcan Esen
A nutritious and safe food program for space flight has been started by The U.S. human space flight programs (Lane and Schoeller, 1999, Smith, Zwart, Kloeris, Heer, 2009), which provides physiological adaptation to weightlessness and psychological adaptation to extreme environments against the negative effects of space flight.
Percentage of micronutrients (carbohydrate, protein, and fat) of USA baseline diet is suitable for space flight. The menu of The International Space Station (ISS) consists 50% of carbohydrate, 17% of protein, and 30% of fat (Smith et al., 2009).
Although previous data indicated that energy intakes were lower during flight than pre-flight, actually in-flight and pre-flight energy requirements are similar (Lane and Schoeller, 1999; Smith et al., 2009).
According to The World Health Organization, energy requirements in-flight are similar with ones for moderately active individuals. Thus, it has been utilised standard for menu planning.
In-flight and pre-flight energy requirements are similar or in some case, even higher due to increased exercise according to doubly labelled water technique (Lane and Schoeller, 1999; Smith et al., 2009). In addition, Recently, the study that is about energy expenditure on long-duration flights has been started on the ISS with a European Space Agency–sponsored.
Protein and muscle
Muscle mass, volume and performance decreases under microgravity either in short or long flights (Smith et al., 2009). Studies that used stable isotope technique showed that protein synthesis went up and even protein breakdown went up more.
Therefore, there is an increase whole-body protein turnover in short duration flight. In the long duration flight study (more than 100 days), Stein et al. (1999) have suggested that decrease in protein synthesis of 6 astronauts is associated with insufficient energy intake).
Bone and muscle
Recently, the study that applied resistive exercise to prevent bone loss demonstrated sufficient energy, protein, and vitamin D have to be used to keep bone mineral density after 6 months of space flight (Smith et al., 2012). However, dietary factors may provide optimisation of bone health.
For instance, consumption of high sodium intake increases bone resorption markers during inactivity such as bed rest (Frings-Meuthen et al., 2011), which could activate osteoclasts by inducing via a low-grade metabolic acidosis (Frings-Meuthen et al., 2011).
Potassium bicarbonate supplementation can be used to reduce this effect on bone resorption (Buehlmeier et al., 2012). Additionally, bone turnover may be influenced by the rate of consumption of dietary protein and potassium. Animal protein includes more sulphur-containing amino acids while it includes less potassium-containing amino acid than plants.
Oxidation of sulphur-containing amino acids might cause a low-grade metabolic acidosis and therefore bone resorption. Reducing the rate of animal protein to potassium provides to compensate this resorption (Zwart, Hargens, and Smith, 2004).
Vision-related issues have been presented as another important aspect of space flight by the ISS (Zwart et al., 2012). Despite it is suggested that prolonged exposure to the effects of cephalad fluid shifts causes it, changes in the folate- and vitamin B-12–dependent, 1-carbon metabolic pathway involving homocysteine, cystathionine, 2-methyl citric acid, and methyl malonic acid may lead to it (Zwart et al., 2012).
Anatomic or physiologic sensitivity to environmental stressors such as fluid shifts or response to cabin CO2 might be affected due to differences in this pathway.
Space Food Development
Early the U.S. Air Force School of Aerospace Medicine developed space foods as dehydrated foods and cubes. Then, they developed their formulation, processing, and packaging specifications with the U.S. Army Natick Laboratories.
The food used on Mercury and Gemini flights was only form of dried food, with most products requiring water for rehydration. On Apollo flights, reversibly compressed freezedried foods were also developed in addition to thermostabilized pouches, canned fruits, and irradiated meats were added (Lane et al., 2013).
Skylab conducted the first metabolic study conducted in space. Food quality was greatly developed compared with previous missions. A freezer and refrigerator allowed use of frozen and refrigerated foods. Consequently, consumption of nutrient was close 100% (Lane et al., 2013).
ISS had pre-packaged food, containing high sodium. Thus, NASA has developed 90 foods to decrease sodium intake to 3000 mg/d because of aforementioned high sodium intake causes bone loss and potentially vision changes (Cooper, Douglas, and Perchonok, 2011).
The future mission is to Mars. It would last roughly 2.5 (6 months for going, 18 months for Mars surface mission and 6 months for return) years with current technologies. because of the lack of gravity prepackaged food will be used during flight but, this complicates food production and processing.
ın the surface time, a combination of pre-packaged food and growing foods methods may be used. Thus, much research is required to set up nutritional standards and a safe and palatable food system (Cooper et al., 2011; Lane and Schoeller, 1999; Smith et al., 2009).
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- Buehlmeier, J., Frings-Meuthen, P., Remer, T., Maser-Gluth, C., Stehle, P., Biolo, G., & Heer, M. (2012). Alkaline salts to counteract bone resorption and protein wasting induced by high salt intake: results of a randomized controlled trial. The Journal of Clinical Endocrinology & Metabolism, 97(12), 47894797.
- Cooper, M., Douglas, G., & Perchonok, M. (2011). Developing the NASA Food System for Long‐Duration Missions. Journal of food science, 76(2), R40-R48.
- Frings-Meuthen, P., Buehlmeier, J., Baecker, N., Stehle, P., Fimmers, R., May, F., … & Heer, M. (2011). High sodium chloride intake exacerbates immobilization-induced bone resorption and protein losses. Journal of Applied Physiology, 111(2), 537-542.
- Lane, H. W., & Schoeller, D. A. (Eds.). (1999). Nutrition in spaceflight and weightlessness models (Vol. 24). CRC Press.
- Lane, H. W., Bourland, C., Barrett, A., Heer, M., & Smith, S. M. (2013). The role of nutritional research in the success of human space flight. Advances in Nutrition: An International Review Journal, 4(5), 521-523.
- Smith, S. M., Heer, M. A., Shackelford, L. C., Sibonga, J. D., Ploutz‐Snyder, L., & Zwart, S. R. (2012). Benefits for bone from resistance exercise and nutrition in long‐duration spaceflight: evidence from biochemistry and densitometry. Journal of Bone and Mineral Research, 27(9), 1896-1906.
- Smith, S. M., Zwart, S. R., Kloeris, V., Heer, M. (2009). Nutritional biochemistry of space flight. New York: Nova Science Publishers.
- Stein, T. P., Leskiw, M. J., Schluter, M. D., Donaldson, M. R., & Larina, I. (1999). Protein kinetics during and after long-duration spaceflight on MIR. American Journal of Physiology-Endocrinology And Metabolism, 276(6), E1014-E1021.
- Zwart, S. R., Gibson, C. R., Mader, T. H., Ericson, K., Ploutz-Snyder, R., Heer, M., & Smith, S. M. (2012). Vision changes after spaceflight are related to alterations in folate–and vitamin B-12–dependent one-carbon metabolism. The Journal of nutrition, 142(3), 427-431.
- Zwart, S. R., Hargens, A. R., & Smith, S. M. (2004). The ratio of animal protein intake to potassium intake is a predictor of bone resorption in space flight analogues and in ambulatory subjects. The American journal of clinical nutrition, 80(4), 1058-1065.