E300 - L-ASCORBIC ACID
L-ascorbic acid (enantiomer more known as vitamin C) is a water-soluble antioxidant vitamin that covers multiple functions in the body, and which is widely used as an additive in foods.
The history of ascorbic acid is related to that of the disease called scurvy, a pathology due to the vitamin C deficiency demonstrated by James Lind in 1747 and published six years later.
The ascorbic acid is particularly contained (40-150 mg / 100 g of product) above all in the citrus fruits, in the kiwis, in the berries, in the spicy peppers, in the raw peppers, in the rocket, in the broccoli, in the brussels sprouts, in the dog rose etc.
In plasma the vitamin circulates 90-95% as ascorbic acid and 5-10% as dehydroascorbic acid.
Vitamin C is stored in small quantities in the tissues of the body, in particular in the adrenal and in the liver; not all, however, is stored in the body and the excess is eliminated in the urine.
Ascorbic acid is a water-soluble, acidic compound, which occurs in the form of crystals. It is a vitamin that suffers enough from light, humidity and air; these factors should therefore always be monitored to avoid loss of vitamin C in foods.
The food industry, from an economic point of view, uses the natural-identical form; this vitamin is very soluble both in water and in alcohol and is able to counteract the reaction between amines and nitrites, which leads to the formation of dangerous N-alkyl-nitrosamines. In addition to this function, vitamin C is very useful in flour maturation processes.
Vitamin C, taken with the diet, is absorbed respectively in the mouth, in the stomach and above all in the small intestine, thanks to a passive diffusion process dependent on sodium. It is a very efficient system and it is especially so for low concentrations of vitamin C.
The strong antioxidant action of vitamin C and its ability to keep vitamins A, E, folic acid and Thiamine (B2) stable, is exploited by industries (as such or in the form of sodium, potassium and calcium salt) as additive in various foods.
Ascorbic acid salts are:
- E301 SODIUM L-ASCORBATO
- E302 CALCIO L-ASCORBATO
- E303 DIACETIL-5, 6-L-ASCORBIC ACID
- E304 ASCORBILE PALMITATO → indicates an ESTER FORMED FROM THE UNION OF ASCORBIC ACID WITH A FATTY ACID (PALMITICO OR STEARICO). It is used in oils (excluding olive oil) and in fats to avoid rancidity. It acts as an adjuvant in the antioxidant activity of natural tocopherols.
- POTASSIUM ASCORBATE has been removed from the list of EU approved additives.
Consuming high concentrations of vitamin C contributes:
- to decrease uric acid levels, with a preventive effect against hyperuricemia (serum concentration of uric acid> 6 mg / dl) and gout
- to increase iron absorption by reduction of Fe (3+) to Fe (2+)
- to the synthesis of collagen in the body
- to the regenerating action of vitamin E by the transfer of an electron to the α-tocoploxylic radical.
- to protect the body with an antihistamine action
- to reduce the number of intestinal nitrosamines and various oxidizing compounds (the superoxide radical, hypochlorous acid and hydroxyl radicals).
- to several chemical reactions essential for our body, including the synthesis of carnitine, the hydroxylation of lysine and proline (for the synthesis of collagen) and the synthesis of bile acids.
A deficiency of vitamin C, as we said just now, can lead to the appearance of scurvy, a disease that causes a reduced synthesis of collagen and intercellular cementing substance. This deficiency causes alterations in the blood vessels, with the consequent manifestation of bleeding (sometimes even leading to a picture of iron deficiency anemia), slowing down of wound healing, gingivitis with dentin alterations and bone osteoporosis. In children, growth arrest may also occur.
In addition to these pathologies, the insufficiency of vitamin C levels also seems to favor atherosclerosis due to oxidative stress (not opposed by the antioxidant action of this vitamin) and the collapse of blood vessels (due to lack of or reduced collagen synthesis in the blood walls).
DOSE RECOMMENDED BY LARN:
For the adult, the minimum amount of vitamin C needed to prevent the onset of scurvy is about 10 mg / day; however, it is recommended to consume a higher quantity than that indicated as "minimum quantity".
In Italy, a level of 60 mg / day for men and women is recommended, equal to that recommended in the American RDA (National Research Council, 1989).
But we must also pay attention to situations that differ from the physiological one.
For example, recent studies have shown that smokers have a double requirement of vitamin C due to the increased (more than 40%) metabolic turn-over of that vitamin.
In the nurse, due to the amount of vitamin secreted with milk, the recommended and recommended levels should be higher (30 mg / day more). In addition to the nurse, even during pregnancy it is estimated that the daily requirement increases by about 10 mg.
In the case of infants, the recommended amounts are based on the vitamin C content of breast milk, and are set at about half of those recommended for adults (20-30 mg / day).
For the following ages, on the other hand, the recommended doses are gradually increased with increasing body weight, until reaching those of adulthood.
Ascorbic acid is harmless in small doses (usual doses), but if you consume it in too high doses (> 10 g per day) you could get diarrhea and / or kidney stones.
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