Vitamins are essential in nutrition. What are they? What are their properties?
What is a vitamin?
Vitamins are organic molecules that must be obtained through diet. They are essential to the body because we are unable to synthesize enough of them. They have no energy value but are necessary for many reactions in the body.
In case of deficiency, the major functions of the body no longer function properly.
There are 13 vitamins:
- 4 are fat-soluble ( A , D , E , K )
- 9 are water-soluble ( B1 , B2 , B3 , B5 , B6 , B8 , B9 , B12 , C )
What are the properties of vitamins?
As stated previously, vitamins can be soluble:
- in fats (fat-soluble): vitamins A, D, E, K
- or water-soluble: vitamins B1, B2, B3, B5, B6, B8, B9, B12, C
These properties, as well as their sensitivity to heat, light, oxidation, and pH, determine their preservation during culinary preparations.
Which vitamins are heat-sensitive?
Vitamins A, D, E, B1 (++) and B5 and C are sensitive to heat, so cooking is likely to alter them.
Which vitamins are sensitive to light?
Vitamins A, D, K and B2 are very sensitive to light.
Vitamins E, B1, B6, B8, B9, B12 and C are sensitive but to a lesser extent than the previous ones.
Which vitamins are sensitive to oxidation?
Vitamins A, D, B9 and C are very sensitive to oxidation.
Vitamins E and K are sensitive, but to a lesser extent than the previous ones.
Which vitamins are pH-sensitive?
Vitamins A, D, B5 (++), B6, B8, B9, B12 (++) and C are sensitive to acidic pH (<7)
Vitamins D, E, K (++), B1 (++), B2 (++), B5 (++), B6, B8, B9, B12 (++) and C are sensitive to basic pH (>7).
What are the dietary sources of vitamins?
Generally, the different vitamins are grouped into the following food groups. However, within the same group, their concentrations can vary greatly.
| Meats, fish and eggs | Dairy Products | Cereals and Breads | Fruits and Vegetables | Fats | |
| Water-soluble vitamins | B1, B2, B3, B5, B6, B12 | B1, B2, B5, B6, B8, B12 | B1, B3, B5, B6, B8, B9 | B9, C | |
| Fat-soluble vitamins | A, D | A, D | K | A, D, E |
Can vitamins be toxic?
Vitamins, when taken in excess, exhibit different properties than those they possess at normal doses.
Certain vitamins, in high doses, have properties considered pharmacological: Vitamins A, D, B1, B3 and C
Furthermore, excessive consumption can have toxic effects, so it is important to respect the recommended intake and, in the case of using food supplements, to respect the dosage.
Safety limits have been set by health authorities to ensure safe intake.
Vitamins can be classified according to the risk of overdose:
A, D > B6 > K, B9 > E, B1, B2, B3, B5, B8, B12, C