For example, most don't have enough calcium. A good, cheap source is Tums 500 chewable tablets. Other conditions that might require supplementation include pregnancy, menopause, competitive athletics, and many acute and chronic illnesses. Consult a clinical nutritionist or a naturopathic physician. Chemically, there's no difference between the vitamin C in an orange and the vitamin C in a test tube.
Labels can be misleading.
If you spring for a brand that claims to deliver 100 percent natural whatever, you're usually wasting your money. Be sure to get the pure d-alpha form. And with folic acid, avoid the natural form and go with the synthetic. Synthetic folic acid is easier to absorb. Proponents claim that the process promotes absorption, and it does, but minimally.