Macronutrients: what they are, types and functions in the human body.

A summary of the main types of macronutrients and their main characteristics.

Macronutrients are one of the most important concepts in the world of health and nutrition. Let's see what they are, what their types are and how they influence the functioning of our organism.

What are macronutrients and what is their importance?

From a nutritional point of view, macronutrients are those compounds that provide the majority of the body's metabolic energy.. These are carbohydrates, fats and proteins.

We must bear in mind that this is a merely utilitarian grouping, because although all these nutrients are composed of molecules of an organic nature, they have little to do with each other beyond the energy contribution they provide for human beings.

Even so, like all classificatory criteria, this way of grouping foods is immensely useful in the nutritional field. If you want to know the particularities of each of the macronutrients and what is the role they play on our physiological well-being, stay with us.

The terminological conglomerate that refers to diet and health is increasingly present in the general population. The World Health Organization estimated that in 2010, 20% of the adult population and 10% of children had some kind of obesity-related disorder. In 2016, these figures reached more than 650 million people.

Therefore, it is not at all strange to learn that the leading cause of death in high-income countries is heart disease. This type of information is not merely anecdotal, as it makes it clear that it is necessary to know in depth the distribution of calories in our diet, what is best for us to eat and what to limit. Again, it is not a matter of prohibiting but of knowing, since few foods are truly harmful. As they say, control is the key.

Types of macronutrients

Having delineated the importance of dietary knowledge on the part of the general population, it's time to dive into the world of macronutrients. Read on, as we dissect each of the groups in depth with interesting facts and statistics.

1. Carbohydrates

Carbohydrates or carbs group a series of biomolecules that are composed mainly of carbon, hydrogen and oxygen.. It is necessary to emphasize that these macronutrients are the main source of energy for the human being, since they are the fuel for 50 to 80% of the daily metabolic expenditure of a relatively active person.

Beyond being an excellent source of immediate energy, carbohydrates are an integral part of our physiology. are an integral part of our physiology and genes.carbohydrates: our species has about 10 grams of carbohydrates per kilogram of tissue, and the pentoses that give rise to each of the nucleotides in our RNA and DNA chains are simple carbohydrates.

We can divide carbohydrates into monosaccharides, disaccharides, oligosaccharides and polysaccharides according to their chemical structure. Nor do we want to turn this space into a complex lesson, so we will limit ourselves to saying that monosaccharides are the simplest molecules and polysaccharides the most complex, the latter being made up of chains of more than 10 monosaccharides.

Special mention should be made of the monosaccharides and disaccharides considered as free sugars, since they are the most complex group of molecules.They are the most controversial group of carbohydrates. Here we find galactose, fructose or glucose among others, which are usually found in fruits or artificially added in sweet products.

The World Health Organization recommends that only 5% of daily nutritional energy should come from these sources, as they have been shown to have an oxidizing activity that promotes cellular aging, in addition to other more immediate effects such as the formation of cavities.

On the other hand, other carbohydrates such as starch (a polysaccharide) are excellent nutritional elements. This is found, for example, in potatoes, rice, corn, cereals and fruit. We must bear in mind that carbohydrates make up the majority of the dry weight of vegetable matter, so we are dealing with the most abundant nutrient on Earth.

2. Proteins

In the next group we have proteins, a series of linear macromolecules formed by chains of amino acids.. From a nutritional point of view, it is estimated that they should not represent more than 15% of the daily caloric intake of the individual. In most western countries meat is the most consumed protein source, since together with milk and certain cereals it represents 75% of the proteins consumed in the diet.

Beyond what many people believe, protein is not a macromolecule only linked to the animal kingdom, since vegetables such as lentils, chickpeas and many others also produce them. In recent years, products such as red meat and processed meats (such as hamburgers and sausages) have come under the spotlight, as they have been classified as "potentially carcinogenic" and "confirmed carcinogenic" respectively. What does this mean?

It has been observed that the consumption of 50 grams of processed meat per day increases the risk of colorectal Cancer by approximately 18%, which is why they have been categorized as confirmed carcinogenic compounds. This is due to the fact that, during their production, harmful compounds such as N-nitroso and polycyclic aromatic hydrocarbons are formed during production.. Red meat does not present such a clear direct correlation with carcinogenic processes, but it is still suspected that it can also favor them.

Even so, proteins are necessary for the development of tissues, for the maintenance and repair of the body, for enzyme production and many other vital processes, so we cannot reject their consumption in any way. For this reason, alternative protein sources to red or processed meat, such as chicken, turkey, tuna and a diverse group of legumes that can be combined in a delicious way in the diet, are increasingly on the rise.

3. Fats

Finally we have the group of fats, a generic term that designates several kinds of lipids, a series of organic molecules that are mainly made up of carbon and hydrogen.. Surprising as it may seem, nutrition experts recommend that 20 to 30% of daily calories should come from fat, i.e. more than protein.

For a large part of the general population, the term "fat" refers to tallow from animal tissues, but this is an erroneous preconception. Unsaturated fats are good for the human body, as they are an excellent source of energy and are found naturally in vegetable oils, nuts, fish such as salmon or trout and dairy products such as yogurt or cheese.

The problem comes when we approach the field of unsaturated or trans fats, i.e., those found in pastries, fried and other ultra-processed foods. The consumption of fats must be balanced and of natural origin.This type of processed food is clearly associated with heart disease and other ailments.

It is not surprising that the United States breaks obesity records on an annual basis, since more than 36% of the caloric intake of a US resident is fat, especially unsaturated fats. On the other side of the coin are several countries in the global South, where daily fat intake rarely exceeds 8-10% of the total metabolic requirement. We are therefore not surprised to learn that more than 821 million people suffer from hunger.

Summary

These last lines have thrown up a key idea that we would like to emphasize: none of the macronutrients is bad if ingested in the right quantities.. Even the most dubious terms such as fats are essential for the diet and the metabolic expenditure of the organism. In general, we can affirm that more than half of the energy obtained in the diet should come from carbohydrates such as starch (always limiting free sugars), approximately 15% should come from animal or vegetable proteins, and the remaining 20-30% from fats, especially unsaturated fats of natural origin.

This does not mean that we should categorically reject processed meats because of their carcinogenic potential or ultra-processed foods because of the "empty calories" they contain. Emotional well-being is as important as physical well-being, and therefore, becoming a slave to dietary numbers is never a good idea: control is the key.

Bibliographic references:

• Distribution of macronutrients and food sources in the Spanish population: results obtained from the ANIBES scientific study. Retrieved October 11 from http://www.fen.org.es/anibes/archivos/documentos/ANIBES_numero_7.pdf.
• World hunger continues to increase, warns a new report from the UN World Health Organization (WHO). Retrieved October 11 from https://www.who.int/es/news-room/detail/11-09-2018-global-hunger-continues-to-rise---new-un-report-says.
• Macronutrients: carbohydrates, fats and proteins, FAO.org. Retrieved 11 October from http://www.fao.org/3/w0073s/w0073s0d.htm#:~:text=%20carbohydrates%20are%20compounds%20that,of%20starch%20and%20diverse%20az%20C3%BAcarbs.
• Obesity and overweight, WHO. Retrieved October 11 from https://www.who.int/es/news-room/fact-sheets/detail/obesity-and-overweight.
• Reducing free sugars intake in adults to reduce the risk of noncommunicable diseases, WHO. Retrieved October 11 from https://www.who.int/elena/titles/free-sugars-children-ncds/es/.