Offering an exploratory natural medicine session!
For many reasons.
It is almost impossible to get adequate nutrients from the soil in the US from over farming. Basically that means you need to eat more fruits and vegetables to get the same nutrient content that would've been in the same food 30 years ago. So, many Americans are overweight...but actually malnourished!
Also, our bodies are unique and adaptive, when we are in a disease state, our body wants to heal, it knows how to heal, but it may need more nutrients or "a little help" to properly do its job.
In addition, as we age and are exposed to more toxins in our diet and environment, we may need help removing them from our body. There are many natural and safe ways to supplement our diet to help in this process.