BASIC PRINCIPLE OF NUTRITION

May 31st, 2008 -- Posted in Calories, Carbohydrates, Fat, Nutrients, Protein | No Comments »

Nutrition is the set of processes by which the living being used, transforms and incorporates into its own structures substances it receives from the outside world. This way you get energy and can repair and build organizational structures, and regulate metabolic processes. These chemicals, called nutrients found in food: proteins, carbohydrates, lipids, vitamins, minerals, trace elements and water. Human beings need to live energy (calories), water, and about forty nutrients from 8 to 10 essential amino acids derived from proteins, essential fatty acids, carbohydrates, thirteen vitamins and eighteen elements of the periodic table, in addition to hydrogen, carbon , Nitrogen and oxygen, all obtained from food.

The concept of balanced diet :

The diet is the set of substances we eat normally and that allow us to maintain an adequate state of health and an ability to work. A diet is correct when quantitatively provides adequate energy, allows the maintenance or achievement of ideal weight and provides all the vitamins and minerals in amounts not less than 2 / 3 of the recommended dietary intake (RDA) (DSA hyper caloric below 1500 calories not guarantee).

Nutrients are any substance contained in foods and that it is necessary to live and keep us in health. Nutrients are those essential that the body can not synthesize (from others) and, therefore, depends entirely on your food intake.

The nutrients that provide energy and are called macronutrients are:

1) Protein

2) Fat

3) Carbohydrates.

The percentage contribution of the macronutrients the total calories should read:

– 50 to 55% carbohydrates

– 30-35% fat. (15-20% monounsaturated)

– 10-15% protein.

Table 1. Food balanced:

Nutrients energy Kcal. contributing per gram Needs gr / kg / day rate on total calories

Protein 4 0.8 - 1 10-15%

Fat 9 1 30-35%

Carbohydrates 4 3 - 5 50-55%

If deepened a bit more on the needs of these nutrients energy, we can say:

a) The proteins provided by 8 to 10 essential amino acids. The needs of a healthy adult and sedentary are approximately 0.8-1 g / kg / day of proteins. At least 50% of the protein must be ingested animal, richer in essential amino acids. The rest must be complete vegetable protein, which have the advantage of being poor in cholesterol and saturated fat (20g protein found in 100 grams of meat = 100 = 1.5 grams of fish eggs middle = 80 grams of vegetable in = 100 grams of raw nuts = 75 g pulp = 250 grams of rice = 200 grams of bread).

b) Carbohydrates. The recommended daily intake to a healthy adult and sedentary is 3 to 5 g / kg / day, or approximately 200-300 g / day. There are 2 kinds of carbohydrates in foods:

Simple: they are mono-and disaccharides sweet taste and rapid intestinal absorption. The refined sugars should not represent more than 10% of total energy.

Complex (Polysaccharides): little sweet taste and intestinal absorption slower. Starch is the most abundant.

c) Fats, which provide us with essential fatty acids. Depending on the degree of unsaturated (double bonds) of these fatty acids, and the length of its chain (number of carbon atoms), the fatty acids in food presented different properties:

1. The saturated fatty acids (no double bonds) are most important: the butyric (8:0) = lauric (12:0), myristic (14:0), palmitic (16:0) and stearic (18:0). All animal fats are rich in them, which give them the solid, but some vegetable fats like coconut and palm hearts are as well. These saturated fatty acids are the most adversely affect the levels of cholesterol and other lipids, and complex mechanisms are the most beneficial arteriosclerosis. Myristic and palmitic are the most aterogenicos.

2. The polyunsaturated fatty acids (several double bonds in their chain) of food are essentially within two rounds:

a) Omega 6: (when the first double bond is in sixth place) whose main representative is linoleum acid (essential), which is in the seed oils. Its consumption can lower levels of total cholesterol, replace the saturated fat. The double bonds can oxidize ( “rancidity”), and also saturated in the presence of hydrogen and a catalyst, changing its configuration to cross. For mechanism of saturation are obtained margarines.

b) Omega-3: fish, mostly blues, are polyunsaturated fatty acids essential omega-3. Representatives most abundant in this series are lanoline (18:3), docosahexaenoic (22:6) and eicosapentaenoic (20:5). They are hipotrigliceridemiantes (down triglyceride levels that so often are high in the diabetic.) And have an action antiagregante and vasodilator.

The consumption of polyunsaturated fatty acids present in seed oils, nuts and blue fish has been proved beneficial (especially when they replace saturated fat) in preventing atherosclerosis, but its excess (especially when providing supplements to pharmacological high doses) can have harmful side effects, such as to promote the oxidation of cellular events that underlie events such as ageing, atherosclerosis, and even predisposition to cancer.

3. The mono unsaturated fatty acid (a single double bond: C18: 1) is the most abundant oleic acid, present in olive oil, avocados and olives, and in smaller amounts in other foods such as eggs and pork. The olive oil exerts interesting changes in the lipid profile: decrease of LDL cholesterol, with maintenance and / or promotion of HDL, reducing the oxide particles and lipoproteico decline in the aggregate (the effects of different fats on the lipid profile are reflected in Table 2). Resist higher temperatures without altering its composition and thus is the most suitable for cooking and especially frying.

The influence of total calories and the type of fatty acid on the lipid profile are summarized in the following table:

Table 2: effect of different types of fat on serum cholesterol and triglycerides.

Total cholesterol and LDL cholesterol HDL Triglycerides

Total fat —

Cholesterol —

Saturated Fat —

Monounsaturated fat or —

Polyunsaturated fatty or —

Excess calories —

c) 13 vitamins

Hidrosolubles: 8 B vitamins and vitamin C.

Liposoluble: vitamins A, E, D and K.

d) 20 minerals: calcium, phosphorus, magnesium, iron, manganese, zinc, copper, cobalt, chromium, molybdenum, iodine, fluorine, sodium, potassium, chlorine, sulfur, selenium, nickel, tin and silicon.