- Development of the growing organism
- Bioregulatory function
- Precursors or coenzymatic constituents
Vitamins can be classified according to their chemical-physical characteristics; the most traditional differentiation is that of solubility (water-soluble vitamins and fat-soluble vitamins), but there is no lack of distinctions on molecular resistance to heat (thermolabile vitamins and thermostable vitamins), on reactivity to light (photosensitive vitamins and photoresist vitamins) etc.
Being micronutrients of great nutritional value, the intake of vitamins SHOULD be constant in order to avoid any form of vitamin deficiency; however, their intake with food (and sometimes also their metabolic demand - see ascorbic acid [protective against infections] in winter), varies according to the season.It should also be remembered that ignoring the recommended rations for taking vitamins increases the chances of running into a deficit or (in the case of supplementation or pharmacological administration) a nutritional excess.
; on the other hand, the EXCESS of vitamins can also lead to definite toxicity reactions hypervitaminosis.
As anticipated, vitamins are a group of MICRO-nutrients that boast a "wide range of functions; it follows that, by virtue of their heterogeneity, their metabolic requirements also differ significantly between molecules. In other words, the recommended rations. some vitamins are all different from each other.
etc.To meet the needs of the general population, the various research institutes have carried out numerous studies, both experimental and statistical; certainly, the most authoritative bibliographic sources are the American RDAs (Recommended Daily Allowance) and the Italian LARNs (Recommended Nutrient Intake Levels for the Italian population, composed and modified by the S.I.N.U .: Italian Society of Human Nutrition); which is why, to the question "How many vitamins to take?", we will respond with the values disclosed by our national body: the LARN of S.I.N.U.
The scheme shown below is almost comparable to that of the LARNs; however, some values (such as those of vitamin E and vitamin K) are the result of arithmetic products between unit coefficients and other reference parameters (such as the "total intake of vitamin F [essential fatty acids - AGE] or the weight body "physiological") suggested by the text itself.
- mg of PP with the diet = 6.6 every 1000kcal introduced with the diet = 6.6 * (kcal with the diet / 1000).
The same indications can be applied to vitamins B1 and B2, through the products:
- mg of B1 with the diet = 0.4 every 1000 kcal introduced with the diet = 0.4 * (kcal with the diet / 1000)
- mg of B2 with the diet = 0,6 every 1000 kcal introduced with the diet = 0,6 * (kcal with the diet / 1000)
The amount of vitamin B6 is calculated on the basis of 15 mg / gram (g) of protein (about 15% of the energy intake is protein in both children and adults).
Vitamin A is in µg of Retinol Equivalents, but remember that 1µg of retinol = 6 µg of beta-carotene = 12 µg of other active carotenoids (NB. Beware of vitamin A supplementation in pregnancy!).
To cover the needs of vitamin D it is sometimes necessary to use fortified foods or complete with a supplementary supplementation.
