Final answer:
Essential nutrients in human nutrition are substances that the body cannot synthesize in sufficient amounts and therefore must be obtained from the diet. These include specific amino acids, fatty acids, vitamins, and minerals that are critical for various bodily functions.
Step-by-step explanation:
The best definition of essential when discussing human nutrition is nutrients that must be obtained from food. The human body is incapable of synthesizing essential nutrients in adequate amounts, therefore it is crucial to consume these nutrients through our diet. These include certain amino acids, fatty acids, vitamins, and minerals. While macronutrients such as carbohydrates, proteins, and lipids are needed in larger quantities, micronutrients such as vitamins and minerals are required in smaller amounts, but they are no less important.
Essential nutrients play a key role in various bodily functions including energy production, cell and tissue synthesis, and maintenance of overall health. Since these nutrients are vital for normal body functioning and cannot be made by the body itself, they must be provided by a varied and balanced diet that includes all food groups to ensure all nutritional needs are met.