As an older woman with bone density issues, vitamins B-12 and D3 are on my list of "must take" from my doctors, and they do blood tests to be sure the levels are high enough. The rest of it is subjective (the only other one you mentioned I take is probiotics - I take a simple lactobacillus because I don't eat yogurt every day.)

My elderly Labrador retriever gets a daily dose of glucosamine and chondroitin because the vet's Rx dogfood that contains extra is way expensive. I give him a good quality OTC dogfood for elderly dogs and supplement to bring it up to the level in the vet food. A lot of things we know about human health was initially tested by vets in our pets. I don't know if vets were ahead of the curve with the arthritis treatments, but it is of interest to a lot of people. You may be skeptical of their efficacy, but there is a lot of ongoing research looking into it.

Many American foods have supplements added, and in some instances, it is overkill. And I can't think of the last time I ate a box of commercial cereal. I don't eat many processed foods that have extra vitamins added. I use a little bit of milk, that has vitamin D, but that's about it.

This is a recipe thread, and one recipe for poor health is too much processed food.