The human body is a complex machine, full of metabolic processes, and like all machines, it requires fuel. Nutrients are the fuel and raw material of our body. The essential ones, are those we must consume, such as proteins, carbohydrates, fats and oils, vitamins, minerals and water.
Proteins are made of amino acids, small units necessary for growth and tissue repair. After water and maybe fat, protein is the most abundant substance in the body.
Animal foods such as meat, fish, poultry, milk and eggs are rich in protein. Other sources of protein are vegetables such as beans, peas, nuts, bread and cereals.
Starches and sugars are carbohydrates, the main source of energy in the body. Carbohydrates make up about 60% of our daily diet. Rice, wheat, maize and potatoes are rich in carbohydrates. They have earned a bad name, because it is believed that make you "fat", however, they are important and good in food. Only an excess can cause weight gain.
Sugars are not essential nutrients. They provide energy (calories), but not nutrients. So sugar is called "empty calorie". Occasional sweets are not harmful to a healthy and active person, but too much sugar can cause tooth decay when they're eaten between meals, especially sticky snacks that adhere to teeth.
Fats and Oils
They are a concentrated source of energy. Despite the belief, dietary fats are necessary for a good health. They are the vehicle of some vitamins, and also body fat protects vital organs, and helps to maintain body temperature.
Fats also delay hunger, because a food mixture that contains fat remains longer in the stomach. The recommendation is to choose the good types of fats, as the vegetable; they won't give us cholesterol and are ideal to include in our diet in moderation.
Eat a variety of foods ensures you are getting enough vitamins. All living things need vitamins for growth and health. The body cannot produce them in sufficient quantities, so they must be adquire by food. Each vitamin has specific roles to play. Many of the reactions in the body require several vitamins, and the lack or excess of any of them can interfere with the function of another.
Fat-soluble vitamins: These are the A, D, E, and K vitamins. They are digested and absorbed with the aid of the fat found in the diet.
Vitamin A: is necessary for strong bones, good vision and healthy skin. It is found in dark green and yellow fruits and vegetables.
Vitamin D: is essential for children because it helps calcium and phosphorus to form straight bones and strong teeth. With direct sunlight on the skin, the body can make its own vitamin D. Babies and young children often need a vitamin D supplement. It is routinely added to most milk during processing.
Vitamin E: helps protect vitamin A and red blood cells. It's found in a variety of foods, and almost everyone has enough.
Vitamin K: is a vitamin that is made inside human body - by bacteria living in the intestinal tract. Small amounts are also found in the green leaves of spinach, kale, cabbage and cauliflower and also in the pig liver.
Fat soluble vitamins can be stored in the body for long periods. Is stored mainly in the adipose tissue and liver.
The vitamin B group helps maintain healthy skin and proper functioning of the nervous system. B vitamins also help convert carbohydrates into energy.
The vitamin C or ascorbic acid is needed for the construction of connective tissue that holds cells together body. Vitamin C is essential for healthy teeth, gums and blood vessels. It also helps the body to absorb iron.
These water-soluble vitamins are not stored in the body for a long time. Good sources should be eaten every day.
Minerals are neither animal nor vegetable, are inorganic. Almost all foods contribute to the consumption of essential varied minerals.
Iron: Most minerals are easily available in the quantities required by the body, however, iron can be harder to get, especially for children under 4 years and adolescent girls and women in childbearing age, since they need more iron than a normal diet can provide. Iron helps the formation of red blood cells, also helps the blood to carry oxygen from the lungs to every cell in the body. Rich sources of iron are meat, liver, especially egg yolks and green vegetables.
Calcium: Everyone at every age needs calcium. This mineral builds bones and teeth, and it is necessary for blood clotting. The best sources are milk and hard cheese. Others are green leafy vegetables, nuts, and small fish - like sardines - with bones.
Phosphorus: Phosphorus works with calcium to build strong bones and teeth. Other important minerals are sodium, potassium, iodine, magnesium, zinc, and copper.
Water is necessary for life, it is actively involved in many chemical reactions and it transport other nutrients. It helps regulate body temperature, as well as a vehicle to remove debris. The recommended daily intake of water is about two liters daily.