What is Vitamin C?

Vitamin C is a water-soluble vitamin which can be absorbed from the diet and in the form of a supplement.

But what is Vitamin C, what does it do in the body and more importantly, how can you make sure you are getting enough?

I will answer all these questions and more, to tell you everything you need to know about this very important vitamin.

Vitamin C is classed as one of the 13 ‘essential vitamins’ which are vital for your body to function optimally. It is also known as ascorbic acid, L-ascorbic acid or L-ascorbate.  If you are looking at multivitamin and mineral supplements you may also see it in the form of sodium ascorbate, calcium ascorbate or magnesium ascorbate but rest assured it is still Vitamin C!

Vitamin C is a water-soluble vitamin which means that it dissolves in water and can travel freely within our body. Vitamin C is not stored well within the body, unlike fat-soluble vitamins, and any excess is excreted. It is also not synthesised by our body which means that we need to consume it regularly in our diet to avoid deficiency.

Signs of Vitamin C deficiency

Most of us will be aware of scurvy, which is a severe Vitamin C deficiency.1 Scurvy was common in sailors spending long periods at sea without fresh fruit and vegetables: the historian Stephen Bown noted that ‘scurvy was responsible for more deaths at sea than storms, shipwrecks, combat, and all other diseases combined’2

But how do we know if we have a Vitamin C deficiency? Some of the signs and symptoms include swelling and bleeding of gums, hair loss and delayed wound healing. If you suspect that you have a Vitamin C deficiency speak to your doctor or healthcare professional for advice. 

Thankfully, Vitamin C deficiency is rare in developed countries and generally if you have a healthy, balanced diet which includes lots of Vitamin C rich foods you should consume sufficient Vitamin C in your diet3. However, there are many common factors which can lead to an increased risk of having a Vitamin C deficiency including being pregnant or breastfeeding, or smoking or drinking heavily. Vitamin C levels in older people and the very young may also need to be monitored more closely4. This is why it can sometimes be helpful to take a supplement.

Benefits of Vitamin C

Vitamin C has many functions within our body, including acting as an antioxidant; helping with wound healing; the maintenance of healthy skin through the production of collagen, and the maintenance of bones and cartilage and the production of blood vessels. All of this and it has a role in immune function and energy levels! So, you can see why it is classed as one of the ‘essential vitamins’.

Other health benefits associated with Vitamin C include the reduction of tiredness and fatigue5 whilst contributing to normal energy levels, and the absorption of non-heme Iron, Iron from plant-based sources, which will be of particular interest to vegans and vegetarians. 

But probably the most commonly known benefit of Vitamin C is the maintenance of the normal function of the immune system6.

Sources of Vitamin C

Now we know how important Vitamin C is for our bodies, where can we find it? What are the most Vitamin C rich foods?

The good news is that Vitamin C is readily available in fruits and vegetables. I think we all remember that citrus fruits are high in Vitamin C, especially oranges but did you know this includes lemons, grapefruits, and limes?  Other Vitamin C rich fruits are kiwi fruit, mangoes, strawberries, and blackcurrants. Vegetable sources of Vitamin C include sweet potatoes, peppers, Brussel sprouts and potatoes. So, you can see if you eat a varied diet, rich in fruits and vegetables, how easy it is to get Vitamin C from food unlike Vitamin D which has to be synthesised by sunlight or supplemented.

Find out more about Vitamin D.  

How much Vitamin C should I take?

To avoid deficiency and support your body’s Vitamin C requirements, how much Vitamin C do you need to take each day?

The NHS advises that the recommended daily amount of Vitamin C7 for adults over 19 years of age is 40mg for both males and females with no additional adjustments for smokers or during pregnancy and breastfeeding. However, these guidelines vary and show only the minimum daily requirement, so you may see supplements containing much more than these amounts.

Should I take a Vitamin C supplement?

Whilst we have learnt that if we have a healthy, balanced diet we should consume enough Vitamin C daily, it is hard to always maintain a healthy diet with the demands of day-to-day life. We have also learnt how many functions Vitamin C is involved with in our body and that it is an ‘essential vitamin’, but because it is not stored in our bodies and we can’t synthesise it, we need to consume it daily. For an ‘essential vitamin’ it does make it tricky for us to know if we are consuming enough of it!

So, to answer the question, there are some groups of people for whom taking a daily supplement would be an advantage. This includes heavy drinkers8, smokers, picky eaters, or those who find it difficult to consume a diet that is high in fruit and vegetables. Additionally, Vitamin C supplements can be useful during pregnancy9, and at times of stress10 which I think we can all relate to.

Optibac offers a product containing 80mg of Vitamin C, Immune Support, providing all of your daily requirements. It is vegan, gluten and dairy-free and suitable for use in pregnancy and whilst breastfeeding.

What happens if I take too much Vitamin C?

Taking high doses of Vitamin C, over 1000 mg daily, can irritate the gastro-intestinal tract, tummy, and result in symptoms such as stomach pain, flatulence and even diarrhoea11 which is why we recommend speaking to your doctor or healthcare professional if you want to take significantly more than the minumum daily requirement.

Reassuringly, these symptoms are only temporary whilst taking high doses of Vitamin C and will stop shortly after the high doses are stopped.

Who should not take Vitamin C?

Although Vitamin C is an essential vitamin there are some situations when it is not advisable to supplement with it, due to interactions with certain medications. There are also certain medical conditions where it may be appropriate to monitor Vitamin C intake. If you are taking medication or have serious or chronic health conditions, you should speak with a doctor or healthcare professional for further guidance and for personalised advice before taking any supplement.

I hope this has helped you learn more about this essential vitamin and its role within our body. Check out the other articles in this series: Added Nutrients

You may also find the following article of interest:

How to Take Care of your Immune System


  1. Valdés F. (2006). Vitamina C [Vitamin C]. Actas dermo-sifiliograficas97(9), 557–568. https://doi.org/10.1016/s0001-7310(06)73466-4
  2. https://www.sciencehistory.org/distillations/the-age-of-scurvy
  3. NHS: Vitamin C (2022). Retrieved 14 March 2022, https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-c/
  4. Lykkesfeldt, J., Michels, A. J., & Frei, B. (2014). Vitamin C. Advances in nutrition (Bethesda, Md.)5(1), 16–18. https://doi.org/10.3945/an.113.005157
  5. 5.Hemilä H. (2017). Vitamin C and Infections. Nutrients9(4), 339. https://doi.org/10.3390/nu9040339
  6. 6.Carr, A. C., & Maggini, S. (2017). Vitamin C and Immune Function. Nutrients9(11), 1211. https://doi.org/10.3390/nu9111211 Immune function7.
  7. NHS: Vitamin C (2022). Retrieved 14 March 2022, https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-c/
  8. Maxfield L, Crane JS. Vitamin C Deficiency. [Updated 2021 Jul 18]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493187/
  9. Rumbold A, Ota E, Nagata C, Shahrook S, Crowther CA. Vitamin C supplementation in pregnancy. Cochrane Database of Systematic Reviews 2015, Issue 9. Art. No.: CD004072. DOI: 10.1002/14651858.CD004072.pub3. Accessed 16 March 2022.
  10. Bettina Moritz, Ariana E. Schmitz, Ana Lúcia S. Rodrigues, Alcir L. Dafre, Mauricio P. Cunha,The role of Vitamin C in stress-related disorders,The Journal of Nutritional Biochemistry,Volume 85,2020,108459,ISSN 0955-2863,https://doi.org/10.1016/j.jnutbio.2020.108459.
  11. Padayatty, S. J., & Levine, M. (2016). Vitamin C: the known and the unknown and Goldilocks. Oral diseases22(6), 463–493. https://doi.org/10.1111/odi.12446

Author: Louise Mason BA Hons, Dip CNM Nutritional Therapist, Dip CNM Naturopath, mANP