Nutritional supplements are designed to support nutrition and not to replace eating whole, dense, live, properly prepared and stored foods. Supplements include vitamins, minerals, herbal preparations, protein bars and powder, sleep and stress aids, etc. You name the problem and some company will offer you a supplement. Not all supplements are of high quality regarding purity, dosage, third party testing and certification, and pharmacologic activity during metabolism. Many poor quality supplements are not absorbed and are excreted without any benefit to the body.