Nutrients act at the cellular level ensuring the functioning of tissues and organs. Each group has its specific biochemical function—which will be covered later.
It is recommended to follow the guidelines of a health professional who can identify the existence of nutritional deficiencies and include foods and/or supplements in the diet.
INDISPENSABLE GROUPS OF NUTRIENTS FOR THE BODY
The groups of nutrients that are part of a healthy and balanced diet are carbohydrates, proteins, fats, vitamins and minerals.
According to the Food Guide of the Brazilian Population, the macro and micronutrients should be included in all meals in adequate proportions.
The nutritional needs of each individual can vary according to age group, physical conditioning, changes in the structure of the gastrointestinal tract, presence of diseases, among other factors.
Thus, pregnant women need a greater supply of folic acid to ensure the formation of the baby’s neural tube. Preschool children need zinc, manganese and iron to be willing in physical and mental activities.
Adults need diversified nutrients in general, as they often have a busy routine, with no fixed mealtimes, little time for physical activity and work overload.
Vitamins are classified as micronutrients because the body only needs small doses of them.
They are essential for the functioning of the body because they participate in the metabolism of carbohydrates, lipids and proteins. These nutrients can vary in the amount to be ingested according to age, sex, health status and nutritional deficiency.
The lack of vitamins can cause serious disturbances, as well as an excess of them in the diet. See more details below:
1.1. VITAMIN A
It is found in dark green and yellow vegetables and has an antioxidant function, protecting cells against free radicals.
1.2. D VITAMIN
It is the only vitamin that is not usually added to the diet, however, some patients require supplementation to ensure minimal levels.
1.3. VITAMIN E
The natural and rich sources of vitamin E are vegetable oils and seeds. It is a natural antioxidant and is associated with all structures that have lipids present.
1.4. VITAMIN K
It is extremely important for blood clotting processes, and its absorption is dependent on the presence of fats in the diet. It is found in green vegetables, fruits, dairy products, vegetable oils, meats and cereals.
1.5. COMPLEX B VITAMINS
Among the main Complex B vitamins they are:
- vitamin B1 (thiamine) is essential for the metabolism of carbohydrates, and its deficiency causes loss of appetite and constipation, which may progress to depression, tremors and nervous system dysfunction;
- vitamin B2 (riboflavin) is important for lipid metabolism and its deficiency leads to inflammation of the tongue, corners of the mouth and desquamation dermatitis;
- vitamin B3 (niacin) is essential in the synthesis of some enzymes that catalyze neurotransmitter precursor substances, such as tryptophan, which gives rise to serotonin, one of the well-being hormones;
- vitamin B6 (pyridoxine) participates in protein metabolism, while vitamin B12 is important for fixing the heme group in blood cells. Its deficiency is associated with anaemia.
1.6. VITAMIN C
One of the essential nutrients for humans is vitamin C, as it participates in the synthesis of collagen, adrenaline, bile acids, iron absorption and bone metabolism. It is present in fruits and vegetables, such as orange, lemon, acerola, kiwi, strawberry, guava, broccoli and yellow pepper.
They are represented by zinc, copper, calcium, magnesium and iron. They participate in intracellular processes, the transmission of nerve synapses, oxygen supply, among other functions.
Excessive intake of minerals can cause intoxication and require medical help. Learn more about them:
Zinc is a component of several enzymes that participate in energy and carbohydrate metabolism, in addition to protein synthesis and degradation. It also participates in sperm formation and keeps the pancreas functioning properly. It is present in chicken meat, oysters, liver, wheat germ, among others.
Copper is important for cell function, for the synthesis of melanin (a substance that gives skin colour) and for iron metabolism. It is widely distributed in seafood, liver, whole grains, nuts and chocolate.
Calcium is essential for the maintenance of bone health throughout life, being recommended for the primary and secondary prevention of osteoporosis.
In addition to milk and dairy products, calcium can be found in tofu, broccoli, spinach, chickpeas and oats.
O magnesium is crucial for muscle contraction and relaxation, protein and energy production, clearing blood vessels, and appears to be a natural tranquillizer.
Insufficient amounts of this mineral can lead to muscle cramps, hypertension and cardiac arrhythmias. It is present in walnuts, cashews, beans and lentils.
Iron is a fundamental mineral for the proper growth and development of the body, functioning of the cardiovascular system, maintenance of the defence system, brain activation, among others.
It is present in oysters, tofu, beef liver, egg yolks and green vegetables.
Fats are the most important nutrients for energy storage and providing thermal insulation.
They are essential components of biological membranes and are particularly important for the development of the brain and retinal structures.
Fats are classified as saturated and unsaturated, the latter being subdivided into mono and polyunsaturated. Learn more about these nutrients and their differences:
1. SATURATED FATS
All animal fats are included (from meat, butter and lard, for example), palm oil, cocoa butter and coconut oil.
The sum of saturated fat intake should not exceed 10% of total daily calories due to the increased risk of dyslipidemia and, consequently, cardiovascular disease.
1.2. MONOUNSATURATED FATS
Monounsaturated fatty acids are present in olive oil, avocados and oilseeds (almonds, walnuts and chestnuts). These nutrients have antioxidant properties, which help to increase good blood cholesterol and stabilize biological membranes.
1.3. POLYUNSATURATED FATS
Fatty acids are important for the maintenance of life. Therefore, the daily recommendation is around 6 to 10% of the total calories ingested.
They are responsible for maintaining cell membranes, forming hormones and lowering bad cholesterol levels in the blood. They are present in fish, linseed, soy, corn and sunflower oil.
Carbohydrates, when digested, are broken down in the small intestine by various types of enzymes, such as sucrose, which turn them into glucose.
There are two types of carbohydrates: simple and complex. Below are the differences:
2.1. SIMPLE CARBOHYDRATES
A good example is table sugar, which is present in products such as candies, sweets and sweets in general. Simple carbohydrates deliver glucose (the body’s fuel) into the bloodstream quickly—usually no more than 30 minutes.
They are not very suitable, as the amount of energy generated runs out quickly, cause excitability and, in excess, can be transformed into fat.
2.2. COMPLEX CARBOHYDRATES
They are represented by foods based on wheat, tubers, rice and pasta in general. They provide a large amount of glucose, however, slowly and gradually.
They should also be consumed in moderation, as excess turns to fat – and this is a risk factor for obesity and related diseases.
The consumption of whole carbohydrates is recommended due to the presence of fibres, which are the parts of vegetables that resist the digestion process and help in the intestinal function, protecting against various diseases.
Proteins are responsible for transporting vitamins into cells, tissue composition, neuron synapse transmission, part of muscle contraction, blood coagulation, and other functions.
Proteins should make up 10 to 35% of the diet. When digested, they are degraded into amino acids.
They are present in all types of meat, eggs, milk and dairy products – these foods contain all the essential amino acids, in other words, that the body does not produce.
Plant foods, with the exception of soy, are incomplete in terms of amino acids and require combinations of grains and legumes to supply these elements.