Vitamin D deficiency creeps up on people, and causes all sorts of health problems to their bones, to their gradual decay of their immune systems, or loss of immune function, and probably some problems with their mood and health, their mental health.
维生素D的缺乏会在不知不觉中 对人体的骨骼造成各种各样的问题， 导致免疫系统的逐步衰退 或者免疫机能的丧失 也有可能对心情 还有精神的健康 造成影响。