Vitamin C and fatigue, how are they linked?

Ingredient Spotlight 8 June 2017

When we feel tired, we often tend to take vitamin C, either in the form of a dietary supplement or freshly squeezed fruit juice. The question remains…  does vitamin C have a real effect or placebo effect? To learn more, we have focused on the (many) physiological roles of the most famous of all vitamins.

A brief history of Vitamin C

Since Antiquity, scurvy has been described as a terrifying disease that was the scourge of sailors on long ocean voyages.  After a period of intense fatigue, the patient would show signs of swelling, bleeding, and decaying teeth, until he or she would then die from exhaustion.


In the 17th century, it was discovered that the consumption of oranges and lemons helped prevent and even cure scurvy.  However, it wasn’t until the beginning of the 20th century that scientists realized that scurvy was caused by a vitamin C or ascorbic acid deficiency (a-scorbic, which literally means “no scurvy”).

Did you know?

Only a few mammals are incapable of producing vitamin C: guinea pigs, some bats, large monkeys and … humans! This is due to a genetic mutation that occurred 40 million years ago, preventing glucose from turning into ascorbic acid.

Focus: what role does vitamin C play?

Some researchers have shown that not only is fatigue one of the first signs of vitamin C deficiency, but this symptom may be improved by taking vitamin C supplements. (EFSA Study).

This is not at all surprising when we look at the countless roles that vitamin C plays in our body!


  1. It is a powerful antioxidant that helps us fight against free radicals.
  2. It plays a role in hepatic detoxification, eliminating toxic products and toxins that “overburden” our body (see article: The liver: our body’s waste treatment plant).
  3. It promotes collagen production, improving the elasticity of our vessels and skin (this explains why individuals with vitamin C deficiencies tend to hemorrhage and have difficulties healing).
  4. It also helps produce carnitine, a molecule required for muscle effort and energy metabolism.
  5. It improves iron absorption in the digestive system, allowing for improved production of red blood cells which carry oxygen to our organs. Iron is also effective in fighting against fatigue and stimulating mental performance.
  6. Vitamin C helps ensure the proper functioning of the immune system and resistance to infections.
  7. It also plays a role in the production of certain neurotransmitters and certain hormones:
  • dopamine and noradrenaline, the neurotransmitters responsible for concentration, motivation and memorization.
  • adrenaline, the hormone that causes us to react when faced with an assault or acute stress.
  • thyroid hormones, which are essential to the proper functioning of our brain and energy production.


What are the daily requirements?

Our daily requirements for vitamin C are estimated at 200 mg/day, which is normally provided in a well-balanced and varied diet, as it is found in both fruits and vegetables.

Foods that contain the most vitamin C

Fruits: pineapple, cantaloupe, acerola berry, blackcurrant, strawberry, raspberry, citrus fruit, kiwi.

Vegetables: asparagus, broccoli, cauliflower, watercress, green pepper, potato, tomato.

Herbs: parsley.


Scurvy is making a comeback

Recent studies have shown that there new outbreaks of scurvy today at the heart of our rich and abundant civilization. Unfortunately, we are seeing cases of vitamin C deficiency in individuals living in extreme poverty or on the fringes of society, and who do not have access to a varied, well-balanced diet.


Yet in other cases, this condition is simply brought on due to poor eating habits. For example, Australian researchers have observed symptoms characteristic of scurvy in diabetic patients who eat too little fresh fruit and vegetables. Moreover, vitamin C is very sensitive to heat and is easily destroyed when cooked for too long…


There are also other very surprising cases, such as that of a young woman who only ate fast food…and the story of a 3 year old child who refused all food, except for whole milk!



  • The experience of ancient Egypt, Dr. Ann Rosalie David, Routlegde, 2000 page 41
  • D. J. Christie-David, J. E. Gunton, Vitamin C deficiency and diabetes mellitus – easily missed?, Diabetic Medicine, 2016.
  • EFSA. Scientific Opinion. EFSA Journal 2010; 8: 1815.
  • New Concepts in the Biology and Biochemistry of Ascorbic Acid, Mark Levine, M.D. N Engl J Med 1986; 314:892-902