Vitamin C (ascorbic acid)

What is it

Vitamin C or ascorbic acid is a water-soluble vitamin to which numerous functions are recognized: it facilitates the absorption of iron, contributes to the protection of cells from oxidative stress, counteracts the proliferation of free radicals.

It is necessary for the body to synthesize collagen, a substance capable of strengthening bones, cartilage, muscles and blood vessels. It also participates in the synthesis of carnitine, a molecule that allows the use of fats as an energy source by transporting them inside the energy plants of the cell (the mitochondria), and in the metabolism of the amino acid tyrosine, and has an important antioxidant action. As a result, together with other micronutrients, vitamin C is essential for cellular well-being.

It is also believed that through a mechanism still not fully understood, vitamin C strengthens the immune system, also intervening in allergic reactions by enhancing immune responses.

Food sources

Vitamin C is widely present in vegetables and fruits; Among the main sources are:

• citrus fruits (such as lemon, oranges and mandarins)
• kiwi
• strawberries
• blackcurrant and other berries
• fruits and vegetables with a dark or intense color, such as cherry, papaya, turnip
• dark leafy vegetables (broccoli, watercress, spinach, cabbage, but also cauliflower)
• tomatoes
• Peppers
• potatoes.

Unfortunately, this precious vitamin can be easily deteriorated both by food preservation treatments and by cooking; The heat damages it, and can be easily lost when boiling in water. It is also easy to lose good quantities even when washing food and it can also be damaged by oxygen.

To keep the properties of vitamin C contained in food active, it is necessary to avoid prolonged cooking and it is preferable to consume fresh fruit and vegetables, which should be kept away from light and heat, but not frozen. Those who need to take a lot of vitamin C for food, therefore, may have to change at least in part their habits regarding cooking and food storage.

However, food is not the only source of vitamin C. In fact, there are several products on the market that promise to provide significant doses of this micronutrient, such as lemon essential oils and rosehip-based supplements; in the latter, the supposed benefits of vitamin C are often accompanied by that of bioflavonoids, substances of natural origin that, if taken in sufficient quantities, could have a positive effect on the well-being of tissues and the body.

It is also sold in the form of supplements – usually in capsules, tablets or sachets – in which it is combined with other important nutrients, such as magnesium and potassium. There are also certain categories of foods in which some vitamins, including C, can be added by the manufacturer, for example milk, orange juice or some breakfast cereals.

Activity

Thanks to its positive action on collagen synthesis it is able to strengthen blood vessels, helps heal wounds and bone fractures and keeps teeth and gums healthy tags. The action of strengthening the functioning of the immune system that vitamin C exerts is known; it would also seem to be involved in various beneficial aspects for the health of the central central nervous system .

Often, for example, these antioxidant and collagen synthesis promoting properties are used to justify its addition to cosmetic products for skin care (on which it would even exert a protective function against wrinkles ) and lips, even if being not very stable, vitamin C degrades in a short time, unless complex and studied precautions are taken.

Other relevant functions are related to the absorption of iron and the production of red blood cells: it is therefore useful in the treatment of anemia.

In particular, it can be used to increase the bioavailability of non-heme iron , i.e. the one present in foods of plant origin. In fact, unfortunately, the absorption of this form of iron is less efficient than that of heme iron, typical of foods of animal origin (such as meat).

For this reason it is often recommended to season vegetables sources of iron (such as spinach) with lemon juice: the vitamin C present in the latter makes it easier to absorb vegetable iron.

As far as the immune defenses are concerned, vitamin C deficiency was first of all correlated with pneumonia, but numerous studies have then associated it with the ability to alleviate or prevent various other infections of bacterial or viral origin, or caused from protozoa.

C , most of the time, it is recommended to take fresh foods rich in vitamin C, which would be able to improve the symptoms of the disease.

A final activity of vitamin C is its usefulness in supporting the reduction of stress and fatigue , both physical and mental. A balanced dose of vitamin C would help, according to some studies, in the prevention of some common symptoms of stress, such as fatigue and headaches .

Shortage

Since ancient times, a serious lack of vitamin C has been associated with scurvy , a disease characterized by capillary fragility and hemorrhage, skin problems, tooth loss due to collagen deficiency.

In the past, scurvy was very common among sailors due to inadequate nutrition, in particular, a lack of fruit and vegetables. Its first symptoms are lack of appetite, apathy and anemia ; later the problems due to the lack of collagen also begin to appear, such as bleeding from the gums and subcutaneous Hemorrhages , tooth loss, muscle pain and capillary fragility.

Even if scurvy has now almost completely disappeared in industrialized countries, a lack of vitamin C can still manifest itself with digestive difficulties, epistaxis (nosebleed), anemia and slow wound healing.

Furthermore, vitamin C deficiency is associated with an increased risk of mortality due to cardiovascular disease.

Overdose

However, it is advisable not to exceed the recommended daily dose , also because very high doses can cause gastrointestinal disturbances and can favor the formation of Kidney Stones .

Recommended doses

The recommended daily requirement of vitamin C for a healthy life varies according to age, but also differs between women and men:

Smokers should double the dose.

If necessary, supplementary intake by mouth can be recommended tags. Vitamin C intake can be increased through special food supplements or simply by modifying one’s diet to introduce additional natural sources of vitamins; intramuscular, intravenous or subcutaneous administration is an option in case malabsorption is suspected due to various problems in the digestive processes.

In case of scurvy the daily dose necessary to deal with the situation can increase a lot, reaching amounts between 300 mg and 1 g per day.

Precautions

Even vitamin C, if taken through supplementation, can have contraindications . High doses of vitamin C are not recommended in patients with renal insufficiency . Caution is advised while taking vitamin C and medications that can damage the kidneys due to an increased risk.

In addition, supplementation with vitamin C in high doses is contraindicated in the presence of diagnosis of thalassemia, G6PD deficiency, sickle cell anemia and hemochromatosis, and should be avoided both immediately before and immediately after angioplasty.

Other conditions that make it necessary to seek advice from your doctor before taking vitamin C are kidney stones and diabetes.

Furthermore, even when taking vitamin C it is important to pay attention to the appearance of side effects. In particular, seek medical help right away if you have symptoms that suggest an allergic reaction, such as a rash, difficulty breathing, and swelling of the face, lips, tongue, or throat.

Also, stop taking vitamin C and see a doctor if you experience joint pain, weakness or tiredness, weight loss, stomach pain, chills, fever, trouble urinating (increased urgency, pain or difficulty ), blood in the urine, or severe pain in the side or lower back.

Lighter heartburn, cramps and stomach discomfort, nausea and diarrhea are the most common side effects of taking vitamin C.

It’s also important not to abruptly stop taking vitamin C after a long period of high-dose treatment; in fact, symptoms similar to those of a deficiency could appear, such as gum bleeding, severe tiredness and bluish-red spots at the level of the hair follicles. Symptoms that may in turn require specific therapies.

Finally, remember that some over-the-counter medicines can interact with vitamin C, as can other vitamin or herbal products. As with any other food supplement, therefore, also in this case it will be advisable to keep the possible simultaneous intake of other drugs under control.

For this reason, before taking it, it is good to consult with your doctor without forgetting to discuss possible interactions; likewise, if you use vitamin C-based products before starting a new drug it is good to check for any interactions, and smokers should be aware that smoking can reduce the effectiveness of vitamin C.