We have been advised for some time to increase the consumption of fruit and vegetables in the event of recurring virus epidemics involving the respiratory system. And even at the beginning of the Covid-19 epidemic, many scholars called for an increase in the need for Vitamin C to increase the body's immune defenses. However, the relationship between the digestive system and the respiratory system is not always perceived as a function of strengthening the immune system. Vitamin C is known to all and is contained in fresh and uncooked fruit and vegetables.
Vitamin C content of some foods of fresh vegetable origin (mg/100 g).
Fresh guava 243
Fresh currants 200
Fresh rocket 110
Fresh kiwis 85
Source: database CREATE.
Although vitamin C is very abundant in cabbage, peppers and chili peppers, as well as in parsley, unfortunately the naturally limited cooking or ingestion, as for parsley and chili peppers, does not in fact allow an adequate intake.
Vitamin C in plants has a short life; cold preservation processes, and even cooking by boiling, cause substantial losses that reach up to 100%. The losses are not homogeneous and vary according to the plant species, the cooking time and the temperatures reached.
The different vitamin C content at the end of the cooking process is exclusively dependent on the mask effect that the other cellular components exert on the molecule, including the content and nature of the soluble and insoluble fiber with which the plant cells are coated.
Vitamin C is made up of the single molecule of ascorbic acid, since we will be able to see that other vitamins are actually sets of molecules, each with a different power, but which together are able to exert their function synergistically on the human metabolism.
Ascorbic acid is a molecule capable of easily donating electrons; this simple function is essential for the defense of the cells of the human body, since free radicals from various environmental sources (smog, stress, smoke) exert their destructive action by subtracting electrons from biological systems, altering their efficiency. Biological damage is naturally alleviated, if not eliminated, when free radicals steal electrons from ascorbic acid rather than cellular structures.
Following the intake of foods containing vitamin C, this molecule is slowly released from its vegetable matrix during the digestive process and slowly absorbed into the blood, where it circulates in all parts of the body. A correct diet, without any need for dietary supplementation, is able to supply "electrons" useful for neutralizing the action of free radicals. The intake of 100-200 mg/g of vitamin C is an adequate contribution for the prevention of many pathologies, and using the data already tabulated, for example, 100 g of rocket and 100 g of kiwi are sufficient to satisfy this value .
Many certainties, not always definitive, have been reached regarding the ability of vitamin C to enhance man's immune defences. In fact, both monocytes and neutrophilic leukocytes accumulate vitamin C up to 50-100 times the concentration in blood plasma. Such a high accumulation has immediate protective effects on the functionality of the neutrophil leukocytes themselves.
Vitamin C stimulates neutrophilic leukocytes to leave the bloodstream, in which they circulate, to move (chemotaxis) selectively towards the part of the body from which significant signals of invasion by a pathogen have been emitted. Neutrophils engulf the pathogen within them and flood it with a cascade of free radicals capable of eliminating the aggressor. The radicals endogenous to the cell are exactly the same that smog, alcohol and stress produce inside the human body, since the immune system uses the same chemical mechanisms. The high content of vitamin C in neutrophils is decisive for limiting the oxidative damage that can be induced on the cells themselves by the free radicals produced against the engulfed invader, almost a sort of protection against "friendly fire".
Following the elimination of the pathogen, the neutrophilic leukocyte undergoes a programmed death (apoptosis) with the removal of all fragments from the inflamed site by the macrophages, which intervene in a subsequent phase by restoring the functionality of the invaded tissue. Also in this phase, vitamin C allows the perfect functioning of some enzymes (caspases) which regulate the apoptosis process. Moreover, vitamin C promotes the production of anti-inflammatory substances such as interleukin-10 or compounds with antiviral action such as interferon.
The action of stimulating the action of the immune system is closely related to the availability of vitamin C in the blood plasma; in a healthy subject with a varied diet with a prevalent vegetable composition, the immune system works efficiently, compatibly with the availability of other nutrients.
A weekly intake of the following foods can ensure a constant and adequate supply of vitamins without any need for supplements:
To increase the vitamin intake it is possible to season other dishes with fresh lemon juice and parsley. A condiment made with a total of 5 g of parsley and lemon juice contributes with a supplementary intake of 5.3 mg of vitamin C. It is preferable to consume fresh foods rather than centrifuged foods, since in the process of extracting the cellular content the dietary fiber is discarded plays an irreplaceable role in maintaining the balance of the intestinal microbiota.
In classical times many of the foods listed in the table were not available, however the use of sea fennel (Crithmum maritimum) was widespread.
Dioscorides, a Greek physician, makes extensive mention of it describing the "κρίϑμος... it is eaten cooked and also raw or preserved in brine" II, 157).
This plant species typical of the rocky coasts bordering the entire Mediterranean Sea basin shows a vitamin C content of approximately 70 mg/100 g of fresh product.
It lends itself very well to making fresh salads, but also added as a juice to give a note of color and to give more structure to pastas and risottos. The vegetable species was consumed on board ships, it was stocked up before long voyages as its antiscorbutic action was known.
