Vitamin C is what’s known as a ‘water soluble vitamin’.  This means it is soluble in water, and the body doesn’t store it so you need to consume it regularly. 

Vitamin c

The most well-known source of vitamin C is probably fruit, specifically oranges.  However, vitamin C is found in all citrus fruits, strawberries, peppers, blackcurrants, broccoli, brussels sprouts and potatoes.  Basically, if you try to eat as many different colours of fruit and vegetables, you’ll be doing great!  You know the slogan for Skittles (the sweets) “Taste the rainbow”, well if you use that’s slogan and attribute it to fruit and vegetables instead, you’ll be sorted! 

Now I’m going to talk a little about why vitamin C is so important.  Humans don’t make their own vitamin C because we don’t need to.  Our bodies have adapted to get our vitamin C from fruit and vegetables.  Animals who are carnivorous make their own vitamin C, which is how they can get away without eating plant foods (Milton, 2003).  The fact is for humans fruit and vegetables are so important that we could actually die from not eating them due to a vitamin C deficiency disease called Scurvy (Milton, 2000, 2003)!  Scurvy is a potentially fatal disease (Scurvy, 2017b).  Symptoms of Scurvy include;

  • Feeling weak and tired all the time
  • depression
  • Severe joint or leg pain
  • Swollen, bleeding gums – sometimes your teeth can fall out
  • Development of red or blue spots on the skin, usually on your shins
  • Bruising easily (Scurvy, 2017a)

The main thing is that Scurvy leads to impaired immunity, so if you are very deficient in vitamin C you are more susceptible to picking up infections that can be potentially fatal, like Pneumonia.  Approximately 10mg of vitamin C per day is enough to prevent scurvy.(Carr and Maggini, 2017), this is a miniscule amount considering there is around 50mg of vitamin C in 100ml glass of orange juice! 

The Recommended Daily amount of vitamin C from the European Food Safety Authority (EFSA) is different depending on age, but as vitamin C is a water-soluble vitamin and your body doesn’t store it, it’s very difficult to take too much from food.  Your body just gets rid of the excess.  The table below shows the different recommendations depending on age.

Table 1: Daily recommendation for vitamin C (EFSA, 2019)

Children 1-3 years20mg/day
4-6 years30mg/day
7-10 years45mg/day
11-14 years70mg/day
15-17 years90mg/day
≥18 and pregnant105mg/day
≥18 and lactating155mg/day

Surprisingly, vitamin C deficiency is actually quite common in Western society despite supply and availability of foods rich in vitamin C are supposed to be sufficient (Carr and Maggini, 2017).  A vitamin C plasma level of less than 23µml/L is deemed deficient, and vitamin C deficiency is one of the leading nutrient deficiencies worldwide, particularly in low-middle income places, but not uncommon in high income areas either (Rowe and Carr, 2020).  The main causes for vitamin C deficiency are;

  • Poor dietary habits (eating a lot of processed foods and very little or no fruit and vegetables)
  • Lifestyle or life-stages that limit the intake of vitamin C or increase the requirement.  Smokers, drug abusers and alcohol abusers require more vitamin C than those who don’t smoke, drink or do drugs)
  • Various diseases that increase inflammation in the body and cause the requirement for vitamin C to increase
  • Exposure to pollution which causes the requirement to increase
  • Economical reason (Carr and Maggini, 2017)

So, what do people who smoke, do drug, abuse alcohol, are exposed to pollution regularly or have a medical condition that causes their body to have to deal with ongoing inflammation have in common?  Why do they require more vitamin C than someone else?  The answer is free radicals.  Free radicals attack important structures in the body leading to cell damage which causes disease. Targets of free radicals include all kinds of molecules in the body. Among them, nucleic acids, lipids and proteins, which are major structural molecules, are the main targets (Lobo et al., 2010).  You may have heard the word ‘Antioxidant’ before, but what are they and why are they so important for good health?  Antioxidants helps defend the body from these nasty free radicals.  Plants make their own antioxidants to protect their structures from free radicals, we make some but not nearly enough to protect our bodies from the many free radicals attacking daily, and if free radicals breach our defences, they cause damage leading to a wide variety of diseases (Benzie, 2003).  That’s where the importance of eating plant foods comes in.  Back in the stone age our diets were mainly plant based so we got most of our antioxidants from plants (Benzie, 2003).  Our bodies didn’t have to evolve much because plants done most of the work with regards to our antioxidant defence system, so we became dependant on them.  Now if we don’t eat them our health suffers immensely (Benzie, 2003).  I remember reading (quite recently) about a 17-year-old boy from the UK who went permanently blind from eating no fruits or vegetables for several years.  He basically lived on a diet of chips, Pringles, processed white bread, processed ham and sausages from primary school age because he didn’t like certain textures.  He is now permanently blind due to severe b=vitamin and mineral deficiencies caused by poor diet (Teenager goes blind after years of no fruit or vegetables, 2019).  Understandably getting children to eat their fruits and vegetables can be difficult if they are fussy eater.  You probably are just happy if they eat anything at all!  It is important to get them eating different fruits and vegetables at a young age and experimenting with different textures.  Just persevere, and don’t make eating them a chore.  Involve the children in the preparation of meals, maybe even start growing your own vegetable and get the kids to help! 

Finally, if Vitamin C, plays an important role in immunity, could it help prevent or treat Covid-19?  There are some trials testing this theory, but as Covid-19 is still relatively new like vitamin D there is no conclusive evidence supporting whether it could be used as a treatment for Covid-19 patients, or as a preventative.  What we do know is that the main ‘high risk’ group for becoming very ill with Covid-19 are the elderly, people with chronic illnesses such as diabetes and people who are overweight or obese.  It has been shown that these people usually have lower vitamin C serum levels than normal due to excess inflammation which increases the vitamin C requirement (Feyaerts and Luyten, 2020).  Drug abusers and alcoholics also have lower than normal vitamin C serum levels (Feyaerts and Luyten, 2020).  Studies have shown that 1-2mg/day of vitamin C can lessen the severity and duration of the common cold.  Ongoing clinical trials should hopefully provide more definitive evidence as to whether vitamin C has any effect on Covid-19 (Feyaerts and Luyten, 2020).

My advice to whether it’s to protect against Covid or not, look at the facts.  Vitamin C strengthens your immune system and being deficient in it makes you very ill.  It’s not difficult to get your recommended amount of vitamin C per day if you eat a balanced diet with fruit and vegetables. 


Benzie, I.F.F. (2003) Evolution of dietary antioxidants. Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology, 136(1) 113–126.

Carr, A.C. and Maggini, S. (2017) Vitamin C and Immune Function. Nutrients, 9(11). Available from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5707683/ [accessed 27 October 2020].

EFSA (2019) Dietary Reference Values | DRV Finder Available from https://www.efsa.europa.eu/en/interactive-pages/drvs [accessed 12 December 2019].

Feyaerts, A.F. and Luyten, W. (2020) Vitamin C as prophylaxis and adjunctive medical treatment for COVID-19? Nutrition, 79–80 110948. Available from http://www.sciencedirect.com/science/article/pii/S0899900720302318 [accessed 27 October 2020].

Lobo, V., Patil, A., Phatak, A. and Chandra, N. (2010) Free radicals, antioxidants and functional foods: Impact on human health. Pharmacognosy Reviews, 4(8) 118–126. Available from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3249911/ [accessed 29 October 2020].

Milton, K. (2000) Back to basics: why foods of wild primates have relevance for modern human health. Nutrition (Burbank, Los Angeles County, Calif.), 16(7–8) 480–483.

Milton, K. (2003) Micronutrient intakes of wild primates: are humans different? Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology, 136(1) 47–59.

Rowe, S. and Carr, A.C. (2020) Global Vitamin C Status and Prevalence of Deficiency: A Cause for Concern? Nutrients, 12(7). Available from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7400810/ [accessed 29 October 2020].

Scurvy (2017a) Available from https://www.nhs.uk/conditions/scurvy/ [accessed 29 October 2020].

Scurvy: Symptoms, Risk Factors, Treatment, Recovery, and More (2017b) Available from https://www.healthline.com/health/scurvy [accessed 24 November 2019].

Teenager goes blind after years of no fruit or vegetables (2019) Available from https://www.irishtimes.com/news/health/teenager-goes-blind-after-years-of-no-fruit-or-vegetables-1.4006165 [accessed 29 October 2020].

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