The Low-Down on Vitamin C

by Marissa Camilon, MD 2011 |

What it is? Where can you find it?

When we were kids, vitamin C lozenges were the equivalent of candy. Actually, they were even better than candy because they tasted great and they were healthy. As we grow older (and become more educated), we have to ask ourselves if this is really true.  Is all that delicious vitamin C actually good for our bodies?

Vitamin C, also called ascorbic acid, is a “water-loving” vitamin that, like other vitamins, cannot be made in your body and must be consumed as part of your diet. Luckily, vitamin C can be found in lots of foods (not just citrus fruits). Other sources of vitamin C include potatoes, brussel sprouts, broccoli, cauliflower, tomatoes, cabbage, strawberries and spinach. Once inside your body, vitamin C plays a role in a number of metabolic reactions, including making collagen, transferring fatty acids into specific parts of your cells, assisting in hormone production and helping your immune response.  It is also considered one of the “antioxidant” vitamins.

What happens when you don’t have enough of it?

The close relationship between vitamin C and one’s health has been known throughout history. European explorers who spent extended periods of time on the sea knew of the importance of citrus fruits during long shipping trips in the prevention of scurvy. Scurvy is the direct result of a deficiency of vitamin C. Without vitamin C, the body is unable to make adequate collagen.  No collagen means weak blood vessels and malfunctioning barriers throughout the body. This presents itself as bruising, bleeding of gums, joint pain and a decreased ability to heal wounds. There is also an associated general feeling of weakness, malaise and depression. Not our kind of party.  Today, scurvy is extremely rare, though it can be found in individuals who are severely malnourished, people living in poverty or individuals addicted to drugs or alcohol. Symptoms can present as early as 3 months without any vitamin C.

What happens when you have too much of it?

On the other hand, vitamin C overdosing can have negative effects on your body. It can cause diarrhea and bloating.  It can also cause a falsely positive test result if you are being evaluated for a lower gastrointestinal bleed. Last but not least, studies have shown that there may be a relationship between vitamin C toxicity and the formation of certain kinds of kidney stones. While we don’t currently have a clear cut answer, most physicians would suggest that people on dialysis and people who have a disposition to form kidney stones should not take large doses of vitamin C. Even more rarely, extreme doses of vitamin C can cause abnormalities in your heart’s rhythm (which can be fatal in some cases!).

What it is used for medically?

The medical use of vitamin C is difficult to study partly because vitamin C is so closely regulated by your body.  Trying to supplement vitamin C in those with a healthy, complete diet won’t be very useful because body’s ability to absorb vitamin C decreases as its stores are saturated. In addition, the patient population that would benefit from vitamin C happens to be the most unlikely to consume a supplement (i.e. severely malnourished, alcohol and drug users). So while supplementation of vitamin C can be extremely beneficial for specific populations, it is questionable whether it should be recommended for everyone.

We now know that vitamin C is not the super supplement that some people think it is. While we continue to search for a cure to cancer, we are fairly certain that vitamin C is not it.  Studies have shown that the antioxidant properties of vitamin C can reduce the damage caused by oxygen radicals but that vitamin C does not have any effect on the development of cancer. What about cataracts?  The verdict here is mixed. While older studies have shown that there may be a reduction in the severity of cataracts in those who take vitamin C, more recent studies have shown the opposite results.

Does anyone else benefit from Vitamin C?

Don’t get us wrong. Vitamin C does have some beneficial effects for individuals with a balanced, healthy diet.  Individuals with anemia, or a decrease in the amount of red blood cells in one’s body, benefit from vitamin C supplementation. In those who have iron-deficiency anemia, taking vitamin c as an addition to iron therapy can increase the amount of iron absorbed in a given meal and improve the long-term effect of iron therapy. In individuals with end-stage renal disease who are on hemodialysis, studies show that vitamin C can increase hemoglobin concentration and other blood factors that can improve their anemia.

What about the Common Cold?

Vitamin C is more widely know for its use in the treatment of the common cold. Once you start feeling a bit of the runny nose or sore throat, you start popping those tasty vitamin C chew tabs. What does the scientific data say about this common practice?   Studies have shown that vitamin C taken after the start of symptoms has no impact on how long the symptoms will last.  However, they may be some evidence to suggest that vitamin C can prevent the common cold (although this prophylactic effect is more pronounced in individuals who are highly active in arctic conditions…strange, we know).

While we’re continue to clarify the full scope of vitamin C’s healing powers, its hard to say whether we should have everyone in the entire population sucking on these delicious vitamin C drops.  Can you really tell that you’re about to have a cold before actually starting to have those symptoms, Nostradamus?  For now, we know that vitamin C can be of benefit for specific medical conditions, from anemia to scurvy.  While we continue to sort out the trust behind the magic of vitamin C, if you’re really interested in vitamin C supplementation, we recommend a delicious Florida orange. Your body will absorb exactly what you need as long as you give it a healthy, comprehensive diet, and send the rest out to sea.

Questions? E-mail the author:


  1. Arroll B. “Non-antibiotic treatments for upper-respiratory tract infections (common cold).” Respir Med. 2005, 99(12): 1477-84.
  2. Deved V, Poyah P, James MT, Tonelli M, Manns BJ, Walsh M, Hemmelgarn BR. “Ascorbic acid for anemia management in hemodialysis patients: a systemic review and meta-analysis.” Am J Kidney Dis. 2009. 54(6): 1089-97.
  3. Douglas R, Hemilia H, Chalker E, Treacy B. “Vitamin C for preventing and treating the common cold.” Cochrane Database Syst Rev, 2007. 18(3):CD000980.
  4. Gaziano JM, Glynn RJ, Christen WG, Kurth T, Belanger C, MacFayden J, Bubes V, Manson JE, Sesso HD, Buring JE. “Vitamins E and C in the prevention of prostate and total cancer in men: The Physicians’ Health Study II randomized controlled trial.” JAMA, 2009. 301(1): 52-62.
  5. Jacques PF, Chylack LT, Hankinson SE, Khu PM, Rogers G, Friend J, Tung W, Wolfe JK, Padhye N, Willett WC, Taylor A. “Long term nutrient intake and early age-related nuclear lens opacities.” Arch Ophthalmol, 2001. 119(7): 1009-19.
  6. Lykkesfeldt J, Poulsen HE. “Is Vitamin C supplmentation beneficial? Lessions learned from randomized controlled trials.” J Nutr, 2010: 103(9): 1251-9.
  7. Reuler JB, Broudy VC, Cooney TG. “Adult Scurvy” JAMA, 1985: 253 (6): 805-7.
  8. Teucher B, Olivares M, Cori H. “Enhancers of iron absorption: ascorbic acid and other organic acids.” Int J Vitam Nutr Res. 2004. 74(6): 403-19.


08 2010

Comments are closed.

WordPress SEO