Vitamin C: What Is, Important Functions, Daily Doses, and Sources

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What is Vitamin C?

Vitamin C, ascorbic acid, is essential for humans and other animal species. It plays several vital roles in the body. Vitamin C is found in various foods, especially fruits and vegetables.

Vitamin C (L-ascorbic acid, L-AA, or ascorbic acid) is significant in plant organisms. It is naturally and technically synthesized from sugar–D–glucose. Chemically pure, it is in the form of a water-solubleTrusted Source, slightly acidic powder.

Vitamin C synthesis

In the organisms of plants and animals, the synthesis of vitamin CTrusted Sourceproceeds through various pathways. In plants, glucose is directly metabolized. However, in animals, glucuronic acid is an intermediate metabolite. The name ascorbic acid comes from the word scorbutus, the Latin name for a multi-organ disease caused by vitamin deficiency in the diet. The dominant symptoms of scurvyTrusted Source, the most commonly associated clinical effect of vitamin C deficiency, are related to connective tissue pathology.

Vitamin C is a coenzyme involved in the forming of cross-links of tropocollagen, the basic building block of connective tissue – collagenTrusted Source. Vitamin deficiency blocks the development of the final collagen structure, which leads to: 

Vitamin C – health benefits and role in the body

Vitamin C is essential for survival. It’s a fact. The human body cannot synthesize it on its own, so we must constantly supply it from outside sources. It’s a bit different in the animal world. Most of them produce this compound themselves. 

Ascorbic acid has countless functions in the body. It enables the proper functioning of enzymes in many chemical reactions. Vitamin C participates in the synthesis of collagen, L-carnitine, and some hormones. The production of collagen is one of the most important functions of vitamin C. This protein is needed for bones, teeth, skin, and eyes to function properly. 

The body relies on vitamin C for various processes, including converting cholesterol to bile acidsTrusted Source. Additionally, it plays a critical role in the body’s antioxidant process. Ascorbic acid is one of the most popular antioxidant substances that fight free radicals. Free radicals are harmful molecules that can damage meaningful structures such as proteins and DNA. Vitamin C, as an antioxidantTrusted Source, neutralizes excess. 

The properties of ascorbic acid are also associated with increased iron absorptionTrusted Source, which is significant information, especially for people with iron deficiency anemia. Taking preparations with iron with vitamin C increases the absorption of these substances. Ascorbic acid also supports the proper functioning of the nervous systemTrusted Sourceand affects the immune systemTrusted Source.

Vitamin C is essential in cosmetology due to its two main benefits: it aids in collagen production and neutralizes free radicals. That’s why it is commonly found in various cosmetics and preparations used during specialized face and body treatments. It is needed to maintain a healthy complexion and also has a role in delaying the aging process of the skinTrusted Source

Excessive exposure to UV radiation can lead to oxidative stress and an overabundance of free radicals within the body. To combat this, ascorbic acid’s antioxidant properties can be utilized. Vitamin C helps to slow down photoaging of the skin, lowers the risk of discoloration, and has anti-inflammatory effects.

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Levorotatory vitamin C – does it exist?

Vitamin C is otherwise known as ascorbic acid or L-ascorbic acid. They are different names for the same substance. The myth of “left-turned” vitamin C probably stemmed from a misconception of the “L” symbol. However, it has nothing to do with optical rotation and does not mean that this vitamin is turned left. 

All drugs, supplements, or foodstuffs contain the same form of vitamin C. So, regardless of the marking on the packaging, whether as vitamin C, ascorbic acid, or L-ascorbic acid, we always deal with the same compound. 

The biologically active form of vitamin C we are talking about is dextrorotatory. Adding information about the levorotatory vitamin CTrusted Source on the labels of various preparations or drugs is a deliberate or unconscious duplication of the error. The levorotatory isomer of ascorbic acid is not a vitamin and is only used to preserve food.

The need for vitamin C

The dosage of vitamin CTrusted Sourcevaries depending on gender, age, general health, lifestyle, presence of chronic diseases, and exposure to stress. It increases in people who smoke cigarettes and live in constant tension, as well as in pregnant women and breastfeeding mothers. In smokers, the need for ascorbic acid increases by about 40% compared to the general guidelines in a given age group. It is also higher in athletes and people who train for a long time and have intense training. 

How many mg of vitamin C per day do we need?

The Institute of Medicine (Food and Nutrition Board) recommends the following daily dose of vitamin CTrusted Sourceper day:

infants from birth to 6 months40 mg
children from 7 to 12 months50 mg
children from a year to 3 years15 mg
children from 4 to 8 years25 mg
children from 9 to 13 years45 mg
boys from 14 to 18 years75 mg
girls from 14 to 18 years65 mg
men older than 19 years90 mg
women older than 19 years75 mg
pregnant women80-85 mg
lactating women115-120 mg

Sources of vitamin C

The daily requirement for vitamin C can be met by eating enough vegetables and fruitsTrusted Source. A rich source of this compound is parsley, paprika, acerola, wild rose, blackcurrant, kiwi, and citrus fruits. For example, 100 g of blackcurrants is about 180 mg of vitamin C. Peppers of the same weight have about 140 mg of ascorbic acid, and oranges are about 50 mg. 

With a rational diet, healthy people should not have any difficulties in providing the body with the necessary dose of vitamin C in food. However, it is worth knowing that this substance is a very unstable compound.

Vitamin C: What Is, Important Functions, Daily Doses, and Sources

Only cookingTrusted Sourcevegetables or fruits deprives them of vitamin C by about 50%. It is not only sensitive to heat but also to light. That is why, to protect its effectiveness, skin care products with vitamin C are typically packaged in dark jars or vials.

Vitamin C also becomes partially inactive during intensive defrosting or heating of foodTrusted Source. Since this substance is well soluble in water, instead of boiling in water, steaming is preferable. Keeping vegetables and fruits for too long or storing them in inappropriate conditions also deprives them of vitamin C. It is better to extend the shelf life of such products by freezing them if possible.

Is synthetic or natural vitamin C better for the body?

The available studies do not show significant differences in the bioavailability of vitamin CTrusted Sourcetaken from food compared to synthetic ascorbic acid. For a long time, there was a belief that vitamin C would be much better absorbed in its natural form, from vegetables or fruits, than from tablets. The current state of knowledge contradicts this. 

So, regardless of whether we take synthetic or natural vitamin C, the same chemical compound with very similar biological activity gets into the body.

Deficiency symptoms

Vitamin C deficiency can occur primarily in the elderly, those living alone, using a poor, monotonous diet, living with chronic stress, or smoking cigarettes.

Symptoms associated with vitamin C deficiencyTrusted Sourceinclude:

Scurvy, a disease, can develop if there is a significant lack of vitamin C in the body. Currently, it is practically absent in developed countries. Scurvy is characterized by:

The importance of vitamin C cannot be overstated as it helps in maintaining the overall functioning of the body, boosts the immune system, and supports the circulatory system. A deficiency of this essential vitamin can significantly affect different aspects of our lives. Research has shown that cancer patients and those with thyroid disorders often have insufficient levels of vitamin C. Additionally, individuals with dermatological diseases have lower levels of this vitamin in their skin. Inflammation caused by acne, psoriasis, or atopic dermatitis can lead to increased consumption of vitamin C due to intensified oxidative processes in the skin.

Vitamin C – when should you use it?

As mentioned above, ascorbic acid has many positive benefits for our bodies. Continue reading to dispel some myths.

Does vitamin C reduce the risk of colds and flu? 

Vitamin C has been used mainly to prevent and treat the common cold.Trusted Source There is a widespread belief that ascorbic acid increases immunity and protects against the development of the disease. 

It turns out that L-ascorbic acid supports the immune system, but it is not entirely clear how. Secondly, the available scientific data rather conclusively confirm that vitamin C supplementation does not protect against the appearance of the disease. It slightly reduces the duration of cold symptoms. 

However, athletes have observed a positive impact on disease prevention using ascorbic acid. This could be due to the body’s increased need for vitamin C during intense physical activity.

Vitamin C: What Is, Important Functions, Daily Doses, and Sources

Ascorbic acid and cancer

Another application of vitamin C is cancerTrusted Sourcebecause it has been noticed that cancer patients tend to have lower levels of ascorbic acid. This leads to the query of whether addressing these deficiencies can enhance one’s health.

The available research results do not give a clear answer. Taking vitamin C by cancer patients allowed them to obtain an anti-cancer effect in some patients. However, we still do not know enough to determine the effect of using vitamin C infusions in patients with specific cancers. So far, no evidence would confirm the effectiveness of using this substance in cancer. There are also reports of the effect of vitamin C supplementation on blood vessels and cardiovascular diseases. However, more research is needed.

Vitamin C – just supplementing?

Ascorbic acid supplements can be taken by people whose diet is unlikely to meet the daily requirement for this compound – for example, the ones with a diet low in fruits and vegetables. SmokersTrusted Sourceand people who exercise very intensively should also look at the meals they eat, and if necessary, reach for appropriate preparations with vitamin C. The groups of patients mentioned above, most at risk of deficiencies of this substance, may also benefit from its supplementation.

What dose of vitamin C is best?

Based on guidelines for dietary supplements, the suggested daily intake of ascorbic acid should not exceed 1000 mgTrusted Source. Taking excessive amounts of vitamin C is not medically necessary and can have negative effects on the body. 

The body copes with too much of this substance by excreting it in the urineTrusted Source. However, its excess leads to increased excretion of oxalate and uric acid, which promotes the formation of kidney stones. It is dangerous for people with a tendency to their development or those suffering from kidney stonesTrusted Source

Vitamin C used in high doses can also cause digestive ailments, such as diarrhea and abdominal pain. High doses of ascorbic acid should also not be taken by people who are prone to accumulate iron in the body and patients with gastric ulcer disease. 

To ensure optimal absorption without burdening the body, it is advised to use lower amounts of vitamin C that align with the recommended daily doses of ascorbic acid. This way, the body can absorb almost all of the vitamin C without any unnecessary strain.

Vitamin C – review of different supplements

Vitamin C is a component of many pharmacy preparations. It has a different dose and form. Some supplements are available in the form of extended-release capsules. Does this form provide a better effect of ascorbic acid? This is rather unlikely. Although there were few studies on this subject, the available ones did not show differences in the absorption of ascorbic acid from a regular tablet or capsule and from the extended-release form. 

vitamin cin different forms

Liposomal vitamin CTrusted Sourceis also becoming popular. When enclosed in liposomes, substances are absorbed more effectively. This procedure is used in many cosmetics. Liposomes enable better penetration of active substances through the layers of the skin. As for oral vitamin C preparations, too little data is available to conclude that they are more effective than a regular tablet.

There is ascorbic acid in different chemical compounds forms like potassium ascorbateTrusted Source, sodium ascorbateTrusted Source, or calcium ascorbateTrusted Source. Sometimes they are recommended to people who use ordinary ascorbic acid irritates the delicate gastric mucosa. However, sodium ascorbate is not the best compound for people suffering from hypertension, due to the significant amounts of sodium. Hypertensive patients who need to limit the amount of potassium should not take potassium ascorbate. Patients with renal insufficiency should also watch out for these forms. Therefore, when choosing vitamin C in a form other than ordinary ascorbic acid, pay attention to the content of additional minerals.

Vitamin C is commonly used in numerous immune, cold, and flu remedies. When using several preparations at the same time, it is worth paying attention to whether ascorbic acid is not present in several of them and whether we do not exceed the recommended daily dose.

Sources

November 22, 2023
12 minutes read
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