Initial assessment of the nutritional quality of the space food system over three years of ambient storage

Abstract

Processed and prepackaged space food is the main source of nutrition for crew aboard the International Space Station, and likely will continue to be the main source of nutrition for future exploration missions. However, very little information is available on the nutritional stability of space foods. To better understand their nutritional stability, 24 micronutrients were measured in 109 space foods stored over 3 years at room temperature. Our analysis indicated that potassium, calcium, vitamin D, and vitamin K concentrations in the food may not be adequate to meet the recommended daily intake requirements even before storage. Decreases in vitamins A, C, B₁, and B₆ were observed during storage. Notably, vitamins B₁ and C may degrade to inadequate levels after 1 year and 3 years, respectively. This assessment suggests that different technological approaches will be required to stabilize processed foods to enable spaceflight missions over 1 year.

Fig. 1

Expected vitamin delivery for aging space diet consumed according to the ISS Standard Menu. Total concentrations of vitamins D and K as well as calcium and potassium are below recommended intakes post-processing. Vitamin C and B₁ may degrade to inadequate concentrations within 3 years of 21 °C storage; vitamins A, B₆, and B₁₂ decline but sufficient concentrations remain after 3 years. Beverages were excluded from this analysis because they are not currently part of the standard menu, and are only selected based on crew preference

Fig. 2

Vitamin C concentrations in space foods over 3 years of 21 °C storage generally declined from the initial concentration. The rate of decline was most dependent upon the primary food matrix and formulation. Note: Increases in content from the initial concentration in fortified products is likely due to encapsulation, which can impede complete chemical detection until the encapsulation itself degrades over time

Fig. 3

Comparison of vitamin B₁ stability in breads and meats after 3 years of 21 °C storage. Vitamin B₁ concentrations in breads were sustained at higher levels than B₁ concentrations in meats. Multiple factors, including processing, food matrices, and fortification may have contributed to the difference in stability over time