We go to an Alternative M.D. once a year. He has many other degrees as well including Nutrition, Chiropratic, etc. One way to see what you’re deficient in is through bloodwork. And as far as what is “used” by the system, depends on the brand you are taking.
Also, recently my chiropractor began with a line of supplements. I have found that it is good to have background knowledge on your own as well, and “partner” with your nutritional practitioner. I’ve been studying nutritional supplements for many years.
Personally, currently taking, Multi Vit & Mineral, Omega’s, Cal/Mag, Folic, Vit D, CoQ10, Dig Enzymes, Green Stuff and Red Stuff (yummy), NAC, ProBiotics, and a new Immune boosting supplement that you can only get through a healthcare practioner which contains: Licorice, Ginseng, Skullcap, Ashgawhanda…