Nutrients are essential for the sustenance of life on Earth. They are fundamental to all biological processes performed by all species of organisms and for their structural growth. Nutrients such as fatty acids, vitamins, minerals, etc. are necessary and must be obtained on a regular basis through dietary supply. However excess consumption of nutrients can lead to nutrient toxicity. Nutrients are divided into two categories- micronutrients and macronutrients. Nutrition deficiency can result in various health conditions such as obesity, diabetes, metabolic syndrome, osteoporosis and many others. This book on nutrients provides in-depth knowledge of some of the key concepts and theories while also examining the modern advancements in this field of study. From theories to research to practical applications, case studies related to all contemporary topics of relevance to this field have been included herein. Constant effort has been made during the compilation of this book to enhance the understanding of the difficult concepts of nutrients, their structures and functions as easy and informative as possible, for the readers.