Final answer:
The term 'natural' on dietary supplements doesn't guarantee safety or that it's essential. Essential nutrients, like Vitamins A and K, must be obtained through the diet as the body cannot synthesize them and they are necessary for health.
Step-by-step explanation:
The term "natural" when used to describe dietary supplements does not imply that the supplement is safe, essential to the functioning of the cells, or anything in particular. It is simply a marketing term that has not been closely regulated by the Food and Drug Administration (FDA). Dietary supplements can contain a variety of ingredients and not all of them are necessarily 'natural' in the way consumers might assume.
Essential nutrients are those that cannot be synthesized by the body and are necessary for proper body function. For example, vitamins such as Vitamin A and Vitamin K are fat-soluble vitamins that are essential nutrients. Vitamin A is needed for maintaining connective tissues, while Vitamin K is crucial for the process of blood clotting. These essential nutrients must be obtained through diet.