维生素学

例句：

1. 1. Vitamin A is essential for good eyesight and skin health.
   维生素A对良好的视力和皮肤健康至关重要。
2. 2. Researchers are studying the effects of vitamin supplements on human health.
   研究人员正在研究维生素补充剂对人类健康的影响。
3. 3. The importance of vitamin D in bone health cannot be overstated.
   维生素D在骨骼健康中的重要性不容忽视。