Human: My doctor says I have a vitamin D deficiency. What does this mean and how can I treat it? Assistant: 
Vitamin D is important for bone health, immunity, and other bodily functions. It helps the body absorb calcium from food and supplements are available to help with deficiencies. Your doctor may suggest you take a supplement or talk to your dietitian about ways to increase your intake of vitamin D-rich foods such as fatty fish, fortified dairy products, and eggs.