Vitamin C’s role in health

- and why are certain exposed groups at risk of deficiency: new report

Vitamin C’s role in healthVitamin C plays a key role in our energy turnover, immune defense, connective tissue, wound healing, antioxidant protection, cardiovascular health, brain, and a host of different enzyme processes. An English population study has shown that having low blood levels of vitamin C is associated with poor physical condition and that may spawn a number of different symptoms. The researchers behind the study also found that people from lower social classes, smokers, men, and older people in general are more likely to be deficient. Alcohol abuse, sugar abuse, stress, and poisoning may also increase the need for the nutrient, which means that many people may benefit from taking a supplement or improving their diet. The big question is how much vitamin C do we actually need for optimal health?

Vitamin C supports the collagen in our connective tissue, which is vital for the structural integrity of blood vessels, skin, gums, cartilage, and bones. In the old days, thousands of sailors were affected by scurvy, the classic vitamin C deficiency symptom, and they died of internal bleeding. Prior to this advanced stage of the disease, they developed symptoms like fatigue and mental disturbances. Although scurvy is very rare in the developed countries, subclinical scurvy is quite common. This condition results in symptoms like bruising, poor wound healing, impaired immunity, muscle pain, atherosclerosis, fatigue, and depression. Vitamin C also goes under the name ascorbic acid.

Most animals are able to synthesize vitamin C and can cover their own needs. However, humans, apes, guinea pigs, and bats have lost this ability through evolution, so they depend on dietary sources of the vitamin.

The purpose of the new study and how it was conducted

The new study had two aims: One was to look at the risk factors of vitamin C deficiency. The other was to study the relation between blood levels of vitamin C and the physical condition of the general population.
The participants were recruited from the EPIC-Norfolk population trial. A total of 30,445 men and women aged 40-79 were included in the study. They were asked to fill in questionnaires with information about their physical and mental health, including details about energy levels, life experience, vitality, social status, work conditions, pain, functional and emotional limitations, and self-perceived health status. The score in each category was based on the participants’ self-perceived well-being. Each participant received a score from zero to one hundred, where one hundred represented excellent health, and a score of zero represented the exact opposite.
Blood levels of vitamin C were measured several times during the study period for each participant. Specific vitamin C deficiency was defined as levels below 11 µmol/L, while suboptimal levels were in the range between 11- 28 µmol/L, and adequate levels were 28 µmol/L or higher.

Having low social status, being male or elderly increases your risk of being deficient

The study revealed that the vitamin C-deficient participants were primarily from lower social classes, had no education, were male, were older, smoked, and were physically inactive. Needless to say, participants that did not take supplements were also more likely to lack vitamin C.

  • The participants that lacked vitamin C had poorer health by various accounts. More specifically, the study revealed that:
  • Eating sufficient quantities of fruit and vegetables, which are rich in vitamin C, is associated with better self-reported health
  • The participants without education were three times as likely to lack vitamin C as the participants with an education
  • Men were more than four times as likely as women to lack vitamin C
  • Participants that were physically inactive were twice as likely to lack vitamin C in comparison with the physically active ones
  • Participants who lacked vitamin C were more tired and had worse health
  • Although scurvy is rare, subclinical scurvy is rather common. This may lead to a variety of symptoms that affect quality of life
  • People who lack vitamin C should eat more fruit and vegetables or take supplements

Study limitations

According to the study, there was no link between excessive alcohol consumption and lack of vitamin C in the blood. This contradicts previous research that shows a clear relation between excessive alcohol consumption, subclinical scurvy, and scurvy.
The differing results may be a result of study limitations. The study was based exclusively on voluntary participants with enough surplus to engage in the project, which could mean that these individuals’ health could be slightly better than the health of the general public. The study is published in Nutrients.

Vitamin C deficiencies are widespread

Lack of vitamin C is rather common. An earlier study, CHALICE, from New Zealand showed that 62 percent of 50-year-old people from all income groups have insufficient blood levels of vitamin C. Several studies have demonstrated that the majority of Danes fails to adhere to the official dietary guidelines, which recommend eating six servings of fruit and vegetables daily – preferably vegetables that are a rich source of vitamin C.
Deficiency and poor utilization of vitamin C may be caused by unhealthy eating habits, stress, smoking, poisoning, lesions, ageing, and a large consumption of alcohol and narcotic drugs. Sugar is also a culprit. It just happens that sugar and vitamin C compete for the same cellular entry channels. The more sugar you consume, the more the effect of vitamin C is reduced.

Vitamin C content in foods (mg/100 grams)

  • Parsley 308
  • Red bell pepper, raw 191
  • Broccoli, raw 121/frozen 56
  • Orange 60
  • Apple and carrot 8

How much vitamin C do we need?

The official recommendation (reference intake level) for vitamin C in Denmark is 80 mg for adults and children older than 11 years. Experts are not certain how much we really need, as the absorption of vitamin C from food and supplements differs from one person to another.
If you are healthy and avoid stress, sugar, tobacco, and stimulants, it may be possible to get enough vitamin C by following the official guidelines, possibly helped with a multivitamin.
In any case, exposed groups such as people with chronic stress, smokers, older people, drug abusers, and pregnant and breastfeeding women should get more than the officially recommended amount of vitamin C. Regular multivitamins normally contain 80-100 mg, while specific vitamin C supplements often contain over 500 mg. It is a good idea to take non-acidic forms of vitamin C such as calcium ascorbate that are gentle toward the stomach.


Stephen J. McCall et al. Plasma Vitamin C Levels: Risk Factors for Deficiency and Association with Self-Reported Functional Health in the European Prospective Investigation into Cancer-Norfolk. Nutrients 2019

Hara Estroff Marano. Psychology Today 2018

Pernille Tveden-Nyborg og Jens Lykkesfeldt. Vitaminer til hjernen. Aktuel Naturvidenskab, nr. 4 2016

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