Vitamin C

by Kat Matina March 6, 2020

We all know about vitamin C: to fill up on energy at the end of winter, to fight against the flu and colds in the bad season, etc. Its uses in our daily lives are numerous. But what about the real effectiveness of vitamin C? Be careful, this article may surprise you...

Vitamin C Overview

Vitamin C is a water-soluble vitamin (i.e. it dissolves in water) also known as L-ascorbic acid. It used to be synthesized directly by the human body, but over the course of evolution, our bodies have lost their natural ability to manufacture this very useful vitamin. Today, we must therefore find our vitamin C intake externally.

Vitamin C is absorbed primarily through the small intestine, but also, to a lesser extent, through the mouth and stomach. It is highly present in white blood cells, the pituitary gland, the adrenal glands and the brain.

Did you know?

Long before its discovery and isolation, vitamin C was known indirectly through the symptoms caused by its deficiency, recorded for several thousand years and described in particular by Aristotle.

But it was only in 1928 that it was isolated by Albert Szent-Gyorgyi. How? Thanks, so to speak, to the scurvy contracted by sailors deprived of fruit and vegetables during long periods of crossings and which often led to death.

The outcome remained fatal until the 18th century when it was discovered that eating lemon prevented the disease. The way to isolate vitamin C was opened…

Medicinal properties of vitamin C

Cold and flu conditions

Vitamin C has been traditionally used for hundreds of years to combat winter illnesses such as flu and colds. It is also widely taken as self-medication, and provides effective protection in the renewal of white blood cells , the body's internal protectors against viruses, bacteria and other undesirables.

Heavy metal poisoning

Vitamin C is said to be effective against excessive concentrations of heavy metals in the blood , such as lead, but also cadmium or mercury. Smokers, who are particularly prone to this type of poisoning, could benefit from the detoxifying function of vitamin C.

HIV syndrome

Ascorbate (or vitamin C) is said to have the effect of stopping the replication of HIV in the body. We will know more by looking more closely at the scientific studies conducted on this subject, which continues to be rather controversial.

Cancer

Vitamin C is also said to have anti-tumor action. In fact, it suppresses one of the essential enzymes in glucose metabolism, which would have the consequence of killing certain types of cancer cells.

Vitamin C is known to reduce the duration of pneumonia, but also to prevent cardiovascular diseases and certain cognitive disorders.

Scientific research on vitamin C

According to a meta-analysis, and contrary to what one might commonly think, doses of vitamin C, whether 200 mg or much higher with 2000 mg, prove NOT to reduce colds or flu in “normal” subjects. On the other hand, it has been proven that the consumption of vitamin C reduces flu and colds by half in people already subjected to significant physical stress , such as in cases of excessive fatigue or intensive practice of a sport (1) (2).

Studies of heavy metal poisoning cases seem to show similar results. Animal research shows that vitamin C helps eliminate lead and mercury and reduces cadmium toxicity (3). In humans, studies show that doses greater than 500 mg of vitamin C can reduce lead levels in the body in people who are already poisoned, but does not act preventively in “normal” subjects in contact with heavy metals (4).

Finally, since the 1970s, multiple studies have been conducted to evaluate the effects of vitamin C on different types of cancer. The different studies have obtained contradictory results, which seem to be explained by the difficulties that scientists have in precisely understanding the mechanisms of action of vitamin C.

In fact, it seems that oxidative stress induced by high doses of vitamin C causes an inhibition of GAPDH, enzymes involved in glycolytic metabolism. Cancer cells survive precisely on a high level of this enzyme. Thus, the decrease in the production of GAPDH leads to the death of certain cancer cells.

Studies are currently underway to confirm this mechanism of action and the usefulness of vitamin C in cancer (5) (6).

Finally, it appears that vitamin C may have very positive effects on the HIV virus. Some studies have shown that vitamin C may be more effective than AZT in suppressing the HIV virus in infected cells, and even in cells where the virus is still latent (7).

This discovery has been and still is controversial, and some scientific bodies criticize these studies for the fact that they are based on results concerning in vitro cells, and not on human subjects. The authors agree with the need to confirm these observations on humans, but at the same time proclaim the difficulty encountered in financing such tests.

According to them, the pharmaceutical industry would slow down the progress of science, because vitamin C is not patentable and would not allow to generate profit... It would seem however that other teams of researchers have carried out clinical trials on people with HIV, trials which would confirm the effectiveness of vitamin C (8). A subject which deserves to be followed closely.

Dosage and side effects of vitamin C

Recommended daily allowances (RDAs) range from 40 mg per day for newborns to 120 mg per day for a healthy adult.

However, it is completely harmless to consume up to 1000 mg of vitamin C per day. Beyond this, there is a risk of overdose, which can lead to the formation of kidney stones, the onset of diarrhea, stomach cramps or other digestive disorders.

Although supplementation can be helpful, it is always advisable to look for the nutrients we need in our diet. The table presented here gives you some guidelines for adopting a diet rich in vitamin C.

Food	Portion	Vitamin C intake
Bell pepper	½ cup	101-166 mg
Kiwi	1 fruit	75 mg
Orange	1 fruit	70 mg
Mango	1 fruit of about 200 g	57 mg
Broccoli	½ cup	42-54 mg
Grapefruit	½ fruit	42 mg
Green peas	½ cup	31 mg
Cauliflower	½ cup	29 mg

Vitamin C, take it at the right time!

The conclusion of our research seems clear: consuming vitamin C has beneficial effects on health, but when taken at the right time. It would seem that vitamin C does not reveal its virtues on healthy subjects, and therefore would not have any real preventive action.

On the other hand, it is recommended to ensure that you consume enough, just as supplementation can be very useful in the event of health concerns.