Italians are big consumers of vitamin C. More than thirty years after Pauling's first books, despite the dry denials by conventional medicine, the "myth of ascorbic acid - a cure-all for all ills" is struggling to fade. There are those who recommend it in a completely disinterested manner for the precious benefits experienced in the first person, those who improvise as scholars and researchers, and even those who raise conspiracy hypotheses about alleged attempts to blur their therapeutic properties.
As for ascorbic acid, a dietary intake of 60/90 mg a day is considered sufficient to meet the needs of an adult in good health. All in all, this is a ridiculously small quantity, easily replaceable with the simple daily consumption of a kiwi or an orange.
As for vitamin C supplements, according to ministerial guidelines, the daily dosage cannot exceed 1, 000 mg of ascorbic acid (one gram per day).
How much vitamin C do you take through supplements?
According to the theory of official medicine, a varied and balanced diet is able to provide all the nutrients necessary for the proper functioning of the organism on its own. The same thing also applies to the athlete, who, despite "more consumption", is led to eat more richly, thus increasing the contribution of various nutrients.
| Did you know that ... |
According to the thesis so to speak healthy, by virtue of the precious antioxidant properties of ascorbic acid, regular and constant integration of quantities varying between 180 and 1000 mg per day (0.18 / 1 gram) is recommended.
To tell the truth there are also those who - referring to the most famous former consumer of ascorbic acid, the aforementioned Linus Pauling - get to consume it in "industrial" quantities, in the order of 6-18 grams per day (the dosage is established by searching for repeated tests for the maximum quantity that can be taken without gastrointestinal disorders occurring).
Again according to official medicine, the maximum daily intake limit, which most likely presents no risk of adverse effects in most healthy subjects, is 2000 mg. This threshold refers to the total intake of vitamin C (foods plus possible supplementation). The most important side effects that can appear at higher doses include headache, sleep disorders, facial flushing and gastrointestinal disorders (stomach acid, nausea, vomiting and diarrhea).
Ultimately, therefore, if we want to rely on the advice of official medicine, the integration of vitamin C is not necessary, but not even dangerous, unless we take real megadoses. Since the truth is often in the middle, most experts favor this practice, recommend daily dosages ranging from 180/360 to 500/1000 mg / day.
Ascorbic acid and its salts: the many names of vitamin C
Often, among non-experts it is not clear that "L-ascorbic acid" is simply a synonym of "vitamin C" (while D-ascorbic acid does not carry out a vitamin action). Imagine what happens when these people hear about aspartate, potassium, calcium and so on.
As the word itself says, ascorbic acid is an acid, and as such it can react with a base (eg sodium carbonate or potassium) forming a salt; this property is used in the industrial field to produce - through rather simple reactions and techniques - the salts of ascorbic acid. These products take the generic dome of mineral ascorbates and compared to pure vitamin C they are distinguished by a lower degree of acidity.
Absorption and bioavailability of ascorbic acid
The gastro-intestinal absorption of ascorbic acid occurs by simple diffusion and active transport. At low concentrations the active form predominates, while in the presence of high concentrations this mechanism becomes saturated and the contribution of passive diffusion becomes important.
At normal intake levels, a proportion of ascorbic acid varying between 70 and 95% of the ingested dose is absorbed. This percentage can however vary, even to a considerable extent, in relation to the dosage taken, moving towards 100% when the intake is particularly low and even falling below 20% when ascorbic acid is taken at very high doses (12 g) . On the basis of these physiological evidences, fractionating the supplementary intake of vitamin C in several doses, to be taken at mealtimes, could theoretically increase the intestinal absorption of vitamin C. Once intestinal absorption has improved, one collides with a another obstacle, represented by the renal reabsorption threshold. If the plasma concentrations are too high, in fact, the excess vitamin C is rapidly removed from the body through the urine; it is therefore important, always in theory, that gastro-intestinal absorption is gradual. In this way, the little vitamin C that enters the circulation makes it possible for it to be picked up by needy cells, without accumulating too much, with the risk of being eliminated with urine. Not surprisingly, a university lecturer remembered in an ironic way that taking ascorbic acid at particularly high dosages is an excellent strategy to increase the cost of one's urine.
Is there a form of ascorbic acid better than the others?
Although the classic marketing rules have now been overturned, the offer, as we know, always follows the demand. On the market, therefore, we find numerous products based on vitamin C, among whose ingredients appear very often "strange" terms, such as sodium ascorbate, potassium ascorbate, bioflavonoids and so on. The pure form, ascorbic acid, may be unpleasant to the palate due to the bitter taste. Furthermore, due to its acidity, it can be badly tolerated at the gastric level. The main advantage of pure ascorbic acid is that it is the most concentrated form, in which each gram of product contains a gram of vitamin C. According to many experts in the field - who have no economic interests in promoting the purchase of alternative forms - ascorbic acid is without a doubt the formula with the best cost / benefit ratio.
As for ascorbates, the main limit is related to the additional mineral intake, which may be contraindicated for some categories of individuals. One gram of sodium ascorbate, for example, provides 889 mg of ascorbic acid and 111 mg of sodium. Megadoses of sodium ascorbate can therefore excessively increase the sodium intake, resulting however harmless for healthy people but potentially dangerous for those who follow diets poor in this mineral. In this case, potassium ascorbate should be preferred, which for each gram of ascorbic acid supplies the body with 175 mg of potassium. Unlike sodium, potassium has a diuretic action; even in this case, an additional intake does not cause particular problems to healthy people, but can be particularly dangerous for individuals with kidney diseases or with potassium-sparing diuretics. Calcium ascorbate brings 114 mg of calcium to the body every 1000 mg of ascorbic acid, and as such can help prevent osteoporosis (it should not exceed 2, 500 mg of calcium per day overall). Other common salts of ascorbic acid are magnesium ascorbate, manganese ascorbate, zinc ascorbate and molybdenum ascorbate.
