Dietician
Karolina Dobrowolska-Zrałka
Vitamin C, also known as ascorbic acid, is one of the most important microelements in the diet of each of us. It has antioxidant function, protecting cells against oxidative damage, is necessary for collagen synthesis - protein responsible for skin elasticity, blood vessels and connective tissue, and also supports the proper functioning of the immune system. Although we commonly associate it with citrus and supplements, the natural sources of vitamin C are much more diverse: from berry fruit, through legumes, to wild forest fruits. In conditions of everyday stress, environmental pollution and reduced immunity, it is particularly important to provide the body with the right amount of this vitamin. In this article, we will take a closer look at what vitamin C is, what are its main roles in the body, which fruits and vegetables provide it with it, what to look for to acquire it optimally and how to safely and effectively supplement it in different age groups. Thanks to practical tips, you will learn how to arrange a diet rich in ascorbic acid to enjoy health, better skin condition and increased resistance to infection.
What is vitamin C?
Vitamin C, i.e. L-ascorbic acid, is a water-soluble compound, which, unlike fat-soluble vitamins, is not stored in the body, and its excess is removed as urine. Discovered at the beginning of the 20th century, it quickly gained fame thanks to its antioxidant properties - it neutralizes free radicals that arise as a result of oxidative stress, toxins or UV radiation. Ascorbic acid is a cofactor of many enzymes, including Those responsible for lysine and proline hydroxylation during collagen synthesis, which translates into the correct structure of connective tissue. In addition, vitamin C participates in the transformation of amino acids, the synthesis of neurotransmitters (e.g. dopamine), as well as in the regeneration of other antioxidants, such as vitamin E. Lack of endogenous synthesis of ascorbic acid in humans means that its delivery from the outside is absolutely key to maintaining homeostasis and health.
Antioxidant properties of vitamin C translate into slowing the aging process, protection against DNA damage and support in the fight against chronic inflammation. Thanks to participation in the synthesis of collagen, vitamin C also affects wound healing, skin regeneration and preservation of tissue firmness. In conditions of severe oxidative stress - e.g. during intensive physical exertion, exposure to tobacco smoke or air pollution - the demand for this vitamin may increase, so it's worth paying attention to its regular and sufficiently high intake.
Role in the immune system
Vitamin C plays a key role in the proper functioning of the immune system. Promotes activation of T lymphocytes and phagocytosis of macrophages - cells responsible for absorbing and eliminating pathogens such as bacteria or viruses. Thanks to antioxidant properties, it protects immune cells against oxidative stress, which increases their vitality and effectiveness in the fight against infections. Ascorbic acid also supports the production of interferon - protein with antiviral effect, which limits the replication of viruses in the host cells.
Clinical studies show that proper consumption of vitamin C can reduce the duration of the cold and alleviate its symptoms, although it does not always prevent infections. A particularly beneficial effect is recorded in people exposed to intensive physical effort (athletes, soldiers) or in conditions of high mental stress. In addition, vitamin C strengthens the epidermal barrier and mucous membranes, which makes it difficult for pathogens to penetrate into the body. Thanks to the impact on the synthesis of collagen, it also promotes the rapid healing of mucous membranes microtraumas, reducing the risk of secondary infections.
The richest citrus fruit
Although many fruits provide vitamin C, citruses are the most popular thanks to taste and availability. Orange - a classic in our diet - contain an average of 50 mg of ascorbic acid in 100 g of fruit, which covers about 60% of the daily demand. Grapefruits provide approx. 40 mg/100 g, mandarins about 30 mg, and lemons and lime - between 30 and 50 mg per 100 g. Juice squeezed from fresh fruit, consumed immediately, is an excellent form of quick complement to vitamin C.
To maximize the benefits, it is worth consuming citruses in various forms - as a snack, addition to salads or desserts, as well as in the form of homemade jam (cooked briefly so as not to lose most vitamins) or smoothie. Combining various types of citrus fruits allows you to get a wide spectrum of bioflavonoids that interact with ascorbic acid, increasing its stability and bioavailability. What's more, citruses are a perfect complement to the diet in the autumn and winter months, when access to other fresh vegetables and fruits is limited.
Vegetables as source C
Although citruses are most often mentioned as sources of vitamin C, in vegetables its content can be equally impressive. Red pepper supplies up to 140 mg of ascorbic acid per 100 g, exceeding most fruit in this respect. Green pepper contains approx. 80 mg/100 g, while yellow peppers - approx. 120 mg. Broccoli and Brussels sprouts are another high content: up to 90 mg/100 g. Spinach, kale or kohlrabi supply from 40 to 60 mg vitamin C per 100 g of product.
To preserve as much vitamin C as possible when preparing meals, it is worth reaching for light thermal treatment: brother the paprika or broccoli, cook in steam, and eat leafy vegetables partly raw, e.g. in salads. Thanks to this, we not only keep valuable nutrients, but also enrich the diet with fiber, folic acid and antioxidants present in vegetables. For people who want to conveniently supplement your vitamin C diet, we recommend the Supersonic Food product - Collagen Beauty Drink, combining ascorbic acid with collagen and other ingredients supporting skin and joint health.
Absorption of vitamin C - what affects?
The absorption of vitamin C is actively carried out in the small intestine with specific transporters, the effectiveness of which depends on the concentration of ascorbic acid in the light of the intestine. At low doses (up to 200 mg), absorption reaches up to 80-90%, while with doses above 1 g, bioavailability decreases at once. Therefore, it is better to spread the daily consumption into several smaller portions, instead of taking high doses once.
The health of the digestive tract also affects bioavailability - diseases such as celiac disease or leaky intestine can limit absorption. Smoking and high levels of oxidative stress increase the demand for vitamin C, reducing its concentration in tissues. Cooking in a large amount of water and prolonged thermal treatment lead to a loss of up to 50-70% ascorbic acid. To prevent this, it is recommended to steam, short processing time and consume raw vegetables and fruits when possible.
Supplementation and daily doses
The recommended daily intake (RDA) of vitamin C for adult women is 75 mg, for adult men - 90 mg. Pregnant and nursing women have increased demand (85–120 mg), and smokers should take an additional 35 mg per day due to higher oxidative losses. Children between 1 and 3 years of age need about 15 mg, and at the age of 4-8 - 25 mg. During periods of increased incidence, severe stress or intensive sports training, dose may be increased to 200-500 mg per day.
Vitamin C supplements are available in the form of tablets, capsules, powders or water soluble forms. The best absorption effects are obtained at doses not exceeding 500 mg once and distributing the dose to at least two portions of the day. Excess ascorbic acid is excreted in urine, but at very high doses (> 2 g/day) there may be gastrointestinal ailments, so you should stick to the recommended doses and consult supplementation with a doctor or dietitian.
Sources
- National Institutes of Health (Nih) - Vitamin C Fact Sheet for Health Professionals.
- European Food Safety Authority (EFSA) - dietary reference values for vitamin C.
- World Health Organization (WHO) - Vitamin and Mineral Requirements in Human Nutrition.
- Polish Society of Dietetics - recommended consumption of vitamin C.
- Levine, M. et al., "Vitamin C: ITS Role in Immunology and Health", Journal of Clinical Nutrition, 2021.
FAQ
What are the best vegetable sources of vitamin C except citruses?
The richest vegetable carriers of ascorbic acid are red pepper (approx. 140 mg/100 g), broccoli (approx. 90 mg/100 g), Brussels sprouts (up to 85 mg/100 g), kale and spinach (40-60 mg/100 g). Wild rose and blackcurrants provide up to 200-300 mg/100 g, which makes them real leaders in the content of vitamin C.
Does cooking always reduce the content of vitamin C in dishes?
Yes, long -term thermal treatment in water leads to a loss of 50-70% ascorbic acid. To preserve as much vitamin C as possible, it is worth cooking steamed vegetables, blanch them briefly or consumed raw in salads and smoothies.
What factors increase the demand for vitamin C?
Smoking, intensive physical effort, oxidative stress caused by air pollution and gastrointestinal disease increase losses and reduce vitamin C, which is why in these situations increased doses are recommended, up to 200-500 mg per day.
Is excess vitamin C harmful?
Vitamin C is water soluble and its excess is excreted in the urine. However, gastrointestinal problems such as diarrhea or abdominal cramps may occur at very high doses (> 2 g/day), so it is better to stick to the recommended doses.
How to support the absorption of vitamin C from a diet?
The absorption of vitamin C does not require fats, but it is worth consuming it together with bioflavonoids (present in citrus peels, green tea leaves) and avoid long -term cooking. The distribution of consumption into several portions during the day increases bioavailability.
Does vitamin C help in the treatment of colds?
Regular consumption of vitamin C may reduce the duration of the cold and alleviate the symptoms, especially in people exposed to intensive physical effort. However, it does not prevent infections completely, so it is worth combining a diet rich in vitamin C with other prevention methods.
What vitamin C supplements are the most effective?
Water -soluble forms, such as ascorbic powder, sparkling tablets or liposomal forms of vitamin C, which can ensure higher bioavailability and milder effect on the digestive tract, are best absorbed.
Looking for a nutritious and filling meal?
Discover Supersonic Smart Meal! A nutritious meal you can prepare in seconds!
