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There are three principal classes of macronutrients: carbohydrate, protein and fat. [1] Macronutrients are defined as a class of chemical compounds which humans consume in relatively large quantities compared to vitamins and minerals which provide humans with energy.
A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures such as hair, scales, feathers, or exoskeletons.
An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life forms, the nine amino acids humans cannot synthesize are valine , isoleucine , leucine , methionine ...
Some nutrients can be stored – the fat-soluble vitamins – while others are required more or less continuously. Poor health can be caused by a lack of required nutrients, or for some vitamins and minerals, too much of a required nutrient. Essential nutrients cannot be synthesized by the body, and must be obtained from food.
Organisms are able to detect nutrients through taste or other forms of nutrient sensing, allowing them to regulate nutrient intake. [16] Optimal foraging theory is a model that explains foraging behavior as a cost–benefit analysis in which an animal must maximize the gain of nutrients while minimizing the amount of time and energy spent foraging.
Essential fatty acids, or EFAs, are fatty acids that are required by humans and other animals for normal physiological function that cannot be synthesized in the body. [ 1 ] [ 2 ] As they are not synthesized in the body, the essential fatty acids – alpha-linolenic acid (ALA) and linoleic acid – must be obtained from food or from a ...
[1] [2] [3] Minerals are one of the four groups of essential nutrients; the others are vitamins, essential fatty acids, and essential amino acids. [4] The five major minerals in the human body are calcium, phosphorus, potassium, sodium, and magnesium. [2] The remaining minerals are called "trace elements".
Most foods contain a mix of some or all of the nutrient classes, together with other substances. Some nutrients can be stored internally (e.g. the fat soluble vitamins), while others are required more or less continuously. Poor health can be caused by a lack of required nutrients or, in extreme cases, too much of a required nutrient.