In earlier navigations, there were many cases of failure due to deficiency of vitamin and subsequent occurrence of scurvy.

• 但早期的远航，因饮食单调，缺乏维生素，发生“坏血病”而屡遭失败的事例颇多，然而郑和船队没有因缺乏维生素而发生坏血病这类疫情。