What does 'essential' indicate in relation to dietary substances?

The term 'essential' in relation to dietary substances signifies components that the body cannot synthesize on its own and therefore must be obtained through the diet. This includes essential amino acids, essential fatty acids, and certain vitamins and minerals. If these substances are not included in a person’s dietary intake, it can lead to deficiencies and various health issues, as they are crucial for various bodily functions, growth, and overall well-being. For example, while the body can produce some amino acids, it cannot produce the nine essential amino acids that must be ingested through food sources. Thus, the requirement for these nutrients to be supplied by diet underscores their critical role in maintaining health and is why they are classified as ‘essential.’