Vitamins are organic compounds essential to the organism and serve as vital nutrients in limited quantities. Organic chemical compounds are called vitamins when they are difficult for humans to produce in sufficient amounts and must be obtained from food. The term, therefore, depends on the circumstance and the organism. For example, ascorbic acid (vitamin C) is a vitamin for humans but not for most other animals, and biotin and vitamin D are needed in the human diet only under certain circumstances. Nutritional supplements are important to treat some health problems. It is known that vitamins are important in our bodies because they have different functions that help keep our bodies functioning correctly. They help us resist infections and maintain the health of our nerves, and many of them help our bodies obtain energy from food, and others help blood clot properly. This book is an addition to the scientific library because it contains modern information distributed in five chapters by researchers known for their competence and scientific experience.