By Dr Martie Conradie
MBChB (UP), Diploma in Child Health (SA), Diploma in HIV Management (SA)
During this time of year as the cold strikes, many people start taking more vitamins and supplements again. One of the vitamins that receives a lot of attention is vitamin C. Does it really help or are you pouring money down the drain?
A little bit about vitamin C
Vitamin C, otherwise known as L-ascorbic acid, is a water-soluble vitamin and is found in many foods, particularly in fruits and vegetables. Because it is water-soluble and after intake any extra is excreted in urine, overdosing is not such a big concern as it is with fat-soluble vitamins such as vitamin A, D, E or K.
The current recommended daily value for vitamin C is about 90 mg, but you might need a little bit more if you are fighting an illness and there are some factors that could influence how your body absorbs vitamin C which is why supplements often contain a higher dose.
An interesting fact is that humans do not have the capacity to synthesize vitamin C in contrast to many mammals, which makes it an essential vitamin for humans. Many species of mammals potentially have the capacity to increase their biosynthesis of vitamin C in times of need, but unfortunately you do not have that ability and when there is an increase in turnover in your body, such as when there is disease-induced inflammation, you can only compensate by an increased intake through foods or supplements.
It is not always practical for most people to consume the recommended number of servings of fruits and vegetables every day and it has been shown that only about 10-20 % of adults are able to attain this goal most of the time. With the reduction in fresh fruits and vegetables that are being consumed, many people actually do not get an adequate amount of vitamin C and the benefits of additional supplementation are becoming more apparent. A daily supplement has been shown to be a safe alternative although a healthy dietary intake should not be neglected.
Symptoms of a deficiency of vitamin C may include bleeding gums, scurvy, frequent bruising, poor wound healing and frequent infections.
Benefits of vitamin C supplementation
Vitamin C is well-known for its antioxidant properties and the ability to boost the immune system and protect your cells against the effects of free radicals. Free radicals are molecules produced when your body breaks down food or is exposed to tobacco smoke and radiation from the sun, X-rays or other harmful sources. Free radicals might play a role in heart disease, cancer and other diseases. For many years the effects of vitamin C on various diseases and body systems have been researched, but because of so many factors that influences its consumption, absorption and transport, not all the theories of vitamin C’s effects could be proven. But vitamin C has been linked to several health benefits:
- Although it has not been proven to prevent the common cold, it has been shown that by taking a vitamin C supplement regularly, the recovery time of colds can decrease by about 8 % in adults and 14 % in children and it can reduce the symptoms of a cold. This alone is a great reason to increase your vitamin C intake during this time.
- Vitamin C is important to improve the skin’s defence system by strengthening the skin’s barriers through its antioxidant properties.
- It could protect your memory and thinking as you age. It is suggested that vitamin C contributes to fighting off oxidative stress and inflammation near the brain and nerves which plays a role in development of dementia.
- Someone with high blood pressure, high cholesterol or an increased risk of heart disease may benefit from vitamin C supplementation. Although vitamin C should not be relied on alone as treatment for these conditions, it has been shown that ensuring an adequate intake of vitamin C in these diseases, may result in a slight lowering of the systolic blood pressure and unhealthy cholesterol values.
- Several studies have shown that vitamin C may reduce the uric acid levels in blood which is why it is deemed as beneficial, especially when taken by people regularly suffering from gout.
- It may prevent iron deficiency. Vitamin C supplements can help improve the absorption of iron from the diet. It helps to convert iron into a form that is easier to absorb into our bodies. This is a really beneficial effect, especially in people who follow a meat-free diet. Many children are prone to iron deficiency, which can even lead to concentration problems and vitamin C supplementation are valuable in these children.
A diet high in vitamin C is usually part of a healthy diet containing a lot of fruits and vegetables which are also contributing to good effects on health.
Our bodies cannot cope without enough vitamin C and therefore it is important to ensure adequate intake, whether through diet or supplementation.
Adverse effects vitamin C
Vitamin C can not cause a lot of side effects because the body does not store it. In very rare cases there might be a few adverse effects, such as:
- Gastrointestinal problems – nausea and diarrhoea
- Kidney stones – this is because vitamin C is excreted through your kidney and when very high doses have to be excreted for a long time, it could result in oxalate crystal deposition
However, these basically never occur when high amounts are consumed through food sources and only very rarely occurs when too much vitamin C supplementation is taken. Most reports mention that side effects are more likely to occur if you take more than the tolerable upper limit of 2 000 mg every day. If you might suffer from these effects, you simply have to cut back on your supplement dose.
People who must take a bit more care with vitamin C supplements include people who suffer from conditions in which iron build-up are a problem, such as haemochromatosis, or people who use the following medicines:
- Aluminium: vitamin C can increase the absorption of aluminium from medications such as phosphate binders which contains aluminium
- Protease inhibitors: this is a type of antiviral medicine and therefore, especially in people who live with HIV, it is important to discuss supplements with your doctor. Vitamin C is important, also for people living with HIV, but intake has to be controlled
- Warfarin: very high doses of vitamin C might reduce your response to this anticoagulant
- Chemotherapy: there is a concern that the antioxidant effect might reduce the effect of certain types of chemotherapy drugs, and it is advised that you discuss supplements with your doctor
Food sources rich in vitamin C
Fruits and vegetables are the best sources of vitamin C. Some sources known to be high in vitamin C include citrus fruits, berries, tomatoes, broccoli, peppers, spinach, potatoes, kiwi fruit and guavas. If five varied servings of fruit and vegetables are consumed a day, you are likely to get in more than 200 mg of vitamin C.
Vitamin C is not naturally present in grains, but some breakfast cereals are fortified with it.
Due to prolonged storage and by cooking, much of the vitamin C content of food may be reduced. This is another reason people have started to lean toward rather adding a vitamin C supplement to their day. Steaming may lessen cooking losses, but the best is to consume raw sources.
Ensure your intake of vitamin C is adequate in order for you to benefit from the amazing effects this tiny molecule has. May you stay healthy during this cold season.
- Fenech M, Amaya I, Valpuesta V, Botella MA. Vitamin C Content in Fruits: Biosynthesis and Regulation. Front Plant Sci. 2018;9:2006.
- Vitamin C. A fact sheet for health professionals. National Institutes of Health. Available from: https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/
- Blaszczak W, Barczak W, Masternak J, Kopczyński P, Zhitkovich A, Rubiś B. Vitamin C as a Modulator of the Response to Cancer Therapy. Molecules. 2019 Jan 28;24(3)
- Ashor AW, Brown R, Keenan PD, Willis ND, Siervo M, Mathers JC. Limited evidence for a beneficial effect of vitamin C supplementation on biomarkers of cardiovascular diseases: an umbrella review of systematic reviews and meta-analyses. Nutr Res. 2019 Jan;61:1-12.
- 7 Impressive Ways Vitamin C Benefits Your Body. Healthline. Available from: https://www.healthline.com/nutrition/vitamin-c-benefits
- The benefits of vitamin C. WebMD. Available from: https://www.webmd.com/diet/features/the-benefits-of-vitamin-c#1
- Vitamin C. Mayo Clinic. Available from: https://www.mayoclinic.org/drugs-supplements-vitamin-c/art-20363932
- Chambial S, Dwivedi S, Sharma P. Vitamin C in Disease Prevention and Cure: An Overview. Indian J Clin Biochem. 2013 Oct; 28(4): 314–328. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3783921/#__ffn_sectitle
- Stewart JS, Booth CC. Ascorbic acid absorption in malabsorption. Acta Gastroenterol Belg. 1964;27:567–568
- Abdullah M, Jamil RT, Attia FN. Vitamin C (Ascorbic Acid). StatPearls Publishing LLC. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499877/#_NBK499877_pubdet_