The human body is a complex system, requiring energy to carry out its myriad of metabolic processes. To maintain its functions, the body needs a constant supply of nutrients. An appropriately balanced diet with essential nutrients goes a long way toward promoting a healthy lifestyle. The main nutrients essential for the human body include carbohydrates, fats, proteins and vitamins.
Carbohydrates
Carbohydrates are sugars that the body uses as its main energy source. They are naturally occurring in plants and are present in manufactured foods such as starches. They are also found in legumes, grains, fruits, vegetables and breads. The Mayo Clinic recommends getting about 45 to 65 percent of your daily calories from carbohydrates. However, you should limit the amount of liquid sugars, like those contained in sports drinks and sodas, and minimize consumption of refined sugars, like those in white bread, french fries and high-sugar breakfast cereals.
Dietary Fats
Excess fat can predispose to cardiovascular heart disease and stroke, as well as complications of obesity, but a small amount of fat in the diet is useful for the body. Fats are important for the maintenance of the immune system, to facilitate the absorption of certain vitamins from the gut and to maintain the health of cell membranes. Dietary fats are an important source of energy to infants and toddlers. Some fats can be harmful for your health, however. You should limit consumption of saturated fats, like those in butter and lard, and avoid trans fats, such as those in margarine and vegetable shortening.
Proteins
Proteins are part of the structure of every cell in the body. They are part of skin, muscle cells and glands, and they are important for the body's growth and development, as well as for its healing processes. Proteins are also enzymes, which are specialized compounds that the body utilizes to facilitate many metabolic reactions. Dietary proteins are contained in animal foods such as meats, poultry, fish and dairy products. According to MedlinePlus, two to three servings of protein are enough for the adult daily diet.
Vitamins
Each vitamin has a specialized role to play in the human body. For example, vitamin A is important to the retina, the pigment in the eye that allows for vision; vitamin E is important for skin health; vitamin D is important for the maintenance of calcium levels and bone health; and vitamin C is important as an antioxidant, defending the body against noxious substances. A diet rich in fruits and vegetables is usually enough to provide for daily vitamin requirements.
