Macronutrients and Micronutrients: Essential Roles in Human Health
Macronutrients
In nutrition, macronutrients are those nutrients that supply most of the body’s metabolic energy. The main ones are carbohydrates, proteins, and fats. Others include alcohol and organic acids. They differ from micronutrients like vitamins and minerals, as these are needed in small amounts to maintain health but not for energy.
Life is sustained by food, and substances in foods on which life depends are the nutrients. These provide energy and building materials for many substances that are essential for the growth and survival of living things. A nutrient is a substance used for the body’s metabolism and must be taken from the environment. Non-autotrophic organisms (heterotrophs) acquire nutrients through the food they eat. Methods of food intake are variable; animals have an internal digestive system, while plants externally digest nutrients and then absorb them. The effects of nutrients are dose-dependent.
Organic nutrients include carbohydrates, fats, proteins, and vitamins. Inorganic chemicals like minerals, water, and oxygen can also be viewed as nutrients. A nutrient is essential for an organism when it cannot synthesize it in sufficient quantities and must be obtained from an external source. Nutrients required in large quantities are called macronutrients, and those required in smaller quantities are called micronutrients.
Types of Human Nutrients: Macronutrients
Macronutrients are defined in various ways:
- The chemical elements humans consume in large quantities are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
- Classes of chemical compounds humans consume in large quantities and which provide energy, such as carbohydrates, proteins, and fats or lipids.
- Calcium, salt (sodium chloride), magnesium, and potassium (along with phosphorus and sulfur) are sometimes added to the list of macronutrients because they are required in relatively large quantities compared to other vitamins and minerals. They are sometimes referred to as macrominerals.
Macronutrients
Nutrients required in large quantities by the human body also provide the energy required for various metabolic reactions, tissue building, systems, and maintenance of general body functions. Among them:
Carbohydrates
Carbohydrates are organic compounds consisting of carbon, hydrogen, and oxygen. They vary from simple sugars containing from 3 to 7 carbon atoms to very complex polymers. They are classified by the number of sugar molecules: monosaccharides (like glucose and fructose), disaccharides (e.g., sucrose and lactose), oligosaccharides, and polysaccharides (such as starch, glycogen, and cellulose).
The main source of carbohydrates in the diet originates in plant foods, except for lactose (milk sugar). Plants such as cereals, fruits, vegetables, and table sugar.
Proteins
Proteins are organic compounds made up equally of carbon, hydrogen, and oxygen but also contain about 16% nitrogen, with sulfur and occasionally other elements such as phosphorus, iron, and cobalt.
Dietary protein is involved in tissue protein synthesis in anabolic processes to build and maintain body tissues. The main sources of protein are animal foods and some vegetable foods, such as legumes.
Lipids
Lipids consist of a glycerol molecule attached to three fatty acids. They are a heterogeneous group of compounds, including regular fats and oils. From a chemical standpoint, fatty acids are straight chains of hydrocarbons that end with a carboxyl group at one end and a methyl group at the other end.
The main sources of food are animal fats and vegetable oils.
Micronutrients
Micronutrients are substances necessary for metabolic processes the body needs in small doses. In animals, this includes vitamins and minerals, and the latter are divided into minerals and trace elements. The latter are required in even smaller doses.
In plants, all are minerals. They have been able to study them well in soilless culture through a form of growing crops without planting outdoors that could affect the results. It was discovered that some elements are required in such low proportions that fertilizer does not contain them in their formulation and can provide them due to the impurities they contain. In some cases, such as sodium, it can be provided only by touching a leaf of a plant. The sweat contains enough salt from fingers and makes the effect of a foliar fertilizer.
Micronutrients do not always need to be provided daily. Vitamins A, D, or B12 can be stored in the liver to meet the needs of periods longer than a year. In fact, in poor countries, children are provided a yearly pill that covers all their needs for vitamin A in that period.
Some micronutrients in plants are sufficient to be supplied once in a lifetime, just to the content of it is in the seed. To produce a deficiency, several generations should be cultivated in the absence of this mineral.
Some of the most important micronutrients are iodine, iron, and vitamin A, which are essential for physical growth and resistance to infection.
Iron and vitamin A are found naturally in food, and iodine should be added to staple foods such as salt in many countries. In Colombia, salt is fortified with iodine.
Other micronutrients include zinc, folic acid, calcium, and all the vitamins and minerals.