Dr. Soon Sue Rene, Senior ENT Specialist, Farrer Park Hospital explains the benefits that vitamin C brings as well as the limitations of this vitamin’s efficacy.
Vitamin C is also known as ascorbic acid and widely associated with citrus fruits. According to Britain’s National Health Service (NHS), adults aged 19-64 would require 40 mg of vitamin C daily and this amount should likely be obtained from dietary intake.
As vitamin C cannot be stored in the body, a daily intake is required.1 In addition, vitamin C is classified as an antioxidant.
Antioxidants, to put it simply, benefit the body by mitigating the damage that could be done to our cells. As one might be able to infer from the name, an antioxidant addresses the reactions from the presence of oxygen.
This process and the benefit that vitamin C brings is shown when vitamin C helps the function of white blood cells in their role of combating infections.
Dr. Soon explains, “Vitamin C boosts the role of white blood cells such as phagocytes and neutrophils by allowing these to travel to the site of an infection in a process called chemotaxis. This is followed by phagocytosis which is the engulfing of the organism responsible for the infection. A reactive oxygen species is then produced which would kill this organism.
“Also, as an antioxidant, vitamin C helps protect the surrounding cells from damage by the reactive oxygen species generated by the white blood cells.”2
It is this process that primarily contributes to how vitamin C increases the body’s immunity.
Anecdotally, this follows what can be called “loading up” on vitamin C in anticipation of having a cold or to consume vitamin C supplements so as to ward off falling ill or stay healthy.
In line with popular belief, vitamin C can hold many benefits for us. Dr. Soon says, “Vitamin C is necessary for the growth, development, and repair of body tissue.
“It is involved in many functions of the body, including the formation of collagen, absorption of iron, proper functioning of the immune system, wound healing, and maintenance of cartilage, bones, and teeth.”
And this popular belief resonates with a number of Dr. Soon’s patients as she attests, “Many of them take vitamin C supplements which are readily available for children and adults.
“These supplements can be tasty and come in a variety of forms such as pills, effervescent tablets, gummies, and chewables. Even sweets come with claims of having vitamin C.”
While it appears that vitamin C is a cure-all, questions might remain about this vitamin’s ability to fight the common cold or lessen the severity of the associated symptoms that most would like to avoid.
And as we respond to the evolving challenges of the Covid-19 pandemic, suggestions have been raised as to whether vitamin C has a beneficial role to play.
On this question, Dr. Soon gives us a clear-eyed view. She explains, “Currently, there is no conclusive evidence that Vitamin C can prevent or cure the common cold.3 There are a few small studies that show that Vitamin C may decrease the duration and severity of symptoms in a small minority of patients.”4
In other words, while evidence has been found of vitamin C’s efficacy in aiding the immune system, the effectiveness of employing vitamin C against the common cold is not backed by medical research.
This is the moderated view when we add up the benefits of vitamin C versus what we can apply based on what medical and scientific studies have revealed.
Moving on to suggestions that vitamin C can be helpful in treating a Covid-19 infection, Dr. Soon cautions that according to guidelines from the National Institutes of Health of the United States, there is insufficient evidence for or against the usage of vitamin C for the treatment of Covid-19 for both hospitalized and non-hospitalized patients.
Dr. Soon adds, “For non-hospitalized patients, the disease is probably mild so they are less likely to experience severe inflammation and oxidative stress. So it is not recommended.
“As for hospitalized patients, the data has not borne out the theoretical benefits of vitamin C and has not shown the reduction of Covid-19 complications in these ill patients.”5
It may come as a surprise that one can consume enough vitamin C purely from the intake of food, barring exceptional circumstances. And this means that the consumption of vitamin C supplements cannot be said to be necessary.
According to research from Sampson Regional Medical Center, “Vitamin C is naturally found in fresh fruits and vegetables; for example, grapefruits, oranges, lemons, limes, potatoes, spinach, broccoli, red peppers, and tomatoes. Up to 90% of vitamin C is consumed in the form of vegetables and fruits.”6
As for how much vitamin C we would need, Dr. Soon points to the same research that the current recommended daily dosage without a deficiency for a number of separate groups would be: up to 45 mg for children; 90 mg for men; 75 mg for women; and 120 mg for lactating women.
Of note is a key finding from Sampson Regional Medical Center’s research that is tied to the relationship between vitamin C and collagen.
On this finding, Dr. Soon explains that vitamin C is important in the formation and crosslinking (for forming bonds) of collagen from pro-collagen. The latter is termed the precursor in this process; what would eventually become collagen.
On the significance of collagen as pointed out in this research, Dr. Soon says, “There are different types of collagen and these are found in skin, tissues, blood vessels, and even bones. Without collagen, the skin would not be healthy, the blood vessels can bleed, and our bones can become brittle.
“And for wound healing, vitamin C is certainly important as it involves the formation of healthy collagen.”
In the case of experiencing bleeding occurring from one’s blood vessels, this condition is scurvy which is famously linked to surgeon James Lind of the British Royal Navy who in 1747 determined to find out the cause of the condition as reported in many sailors.
The cure, as concluded then, was to consume oranges and lemons. These fruits are, of course, a good source of vitamin C.
Currently, the NHS of Britain advises that the condition can be easily treated with adding vitamin C to one’s diet along with the option of consuming vitamin C supplements.
Most of those treated would usually start to recover in the span of 48 hours and fully do so in the space of 2 weeks.7
2 Carr AC, Maggini S. Vitamin C and Immune Function. Nutrients. 2017 Nov 3;9(11):1211. doi: 10.3390/nu9111211. PMID: 29099763; PMCID: PMC5707683.
3 Hemilä H, Chalker E. Vitamin C for Preventing and Treating the Common Cold. Cochrane Database Syst Rev. 2013 Jan 31;2013(1):CD000980. doi: 10.1002/14651858.CD000980.pub
4 PMID: 23440782; PMCID: PMC8078152. 4 Hemilä H. Vitamin C and Infections. Nutrients. 2017 Mar 29;9(4):339. doi: 10.3390/nu9040339. PMID: 28353648; PMCID: PMC5409678.
6 Maxfield L, Crane JS. Vitamin C Deficiency. [Updated 2022 Oct 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493187