How does the immune system work, and what can I do to naturally boost mine? Are there specific nutrients, foods, or lifestyle changes that have been shown to improve immune function in scientific studies? Also, how do things like sleep and exercise impact immunity?
Sure, the immune system is your body's natural defense system. It comprises cells, tissues, and organs that work together to protect the body from harmful entities like bacteria, viruses, and toxins. 

There are two parts to the immune system: the innate immune system, which you are born with, and the adaptive immune system, which you develop as you're exposed to microbes or chemicals released by microbes.

A healthy diet is crucial for a strong immune system. Foods high in vitamins C and E, plus beta-carotene and zinc is key. These are found in a wide variety of fruits and vegetables, nuts, seeds, dairy products, and meat. Also, a healthy gut contributes to a strong immune system, so probiotic-rich foods can be beneficial.

Regular exercise can also contribute to good immune function. Keeping an active lifestyle can boost your immune system by improving blood circulation and allowing your immune cells to move throughout your body more freely.

Adequate sleep is also essential for your immune system to function well. Without enough sleep, the immune system might not have the energy necessary to fight off illness.

It's important to note that overly stressing your body, be it through extreme exercise or other life stress, can weaken your immune system. So balance is key when considering a healthy lifestyle that will boost your immune function.

However, these are general recommendations and individual health needs may vary. You should consult a medical professional for personalized advice.