Before trying a new supplement, I always check on potential interactions with other supps, or with RX or OTC meds, and also if it may be contraindicated for any issues.

One of the things I was taught during my studies was that just because something is "natural" doesn't mean it is harmless - and similarly, just because something is prescribed, doesn't mean it will not cause problems too.
We need to keep ourselves well informed and make wise decisions.

I have a question on this. From what I've seen, the dietician will use the determined information on a fruit or vegetable etc to determine how much vitamins or minerals are in the food. Then use this to determine an adequate intake based on a meal plan. While I do believe the science to determine information is accurate, I also believe, that it can vary from specimen to specimen. It can also vary from the same farm year over year. For example, the amount of minerals in an avocado, isn't it possible and probable that over time as the tree makes avocado's that are picked that the soil gets depleted of those minerals? Unless the farmer practices incredibly good farming techniques, it is likely that the quantity of minerals etc can diminish over time and vary from one tree to another. So if the initial information is not accurate, how can we get a good meal plan?

Good thought process... Many soils are depleted, or chemical fertilizers and various sprays are used.. plus the harvesting , storage, practices.. before it gets to a store.. .
I try to read labels. See where things come from or produced..
Same for supplemts and vitamins.. And check brand ratings , purity etc..