How does vitamin C work?

 

Fortunately, vitamin C is very easy to obtain and we don't need much of it. The minimum dose required is 90 mg a day, which we can achieve with an orange or, better yet, with only 100 grams of spinach. A maximum dose of 2000 mg, two grams per day is recommended, but mainly because it can have a laxative effect, not because it is toxic. Also, find more helpful resources 

In addition, vitamin C is a cofactor, an enzyme helper, which is necessary for the production of collagen (skin, blood vessels, ligaments and bones) and the synthesis of the hormones adrenaline and carnitine (one of the molecules responsible for burning fat for energy.). Not surprisingly, people with long-standing scurvy (vitamin C deficiency) suffered from all the symptoms of collagen loss: bleeding gums, brittle skin and hair, and problems with wound healing. Without vitamin C, we fall apart. 

Fortunately, vitamin C is very easy to obtain and we don't need much of it. The minimum dose required is 90 mg a day, which we can achieve with an orange or, better yet, with only 100 grams of spinach. A maximum dose of 2000 mg, two grams per day is recommended, but mainly because it can have a laxative effect, not because it is toxic. 

Can I take too much vitamin C?

The toxicity of vitamin C is very low, and it has even been observed that even with high doses, the risk of kidney stones (oxalic acid) is a myth. Even doses of 100 grams per day are considered safe. But vitamin C tablets can only raise the level of this compound in the blood to a certain limit, around 0.22 nM, because the more we take, the less we can absorb and the rest is excreted in the urine. 

Oral vitamin C supplements have no effect on preventing colds or flu, a widespread myth that was disproved by a 2013 review of studies. It was found that in some cases the common cold lasted for less time, but could not be replicated in other experiments. There was one exception: supplementation with vitamin C prevented colds in athletes. This makes sense, since the stress of sports induces oxidation, which depletes our stores of vitamin C. It is normal for very active people to need more. 

This is not the case with cancer. Pauling and physician Ewan Cameron published a study in 1976 in which a very high dose (10 grams) of vitamin C was administered intravenously to cancer patients, and the treatment showed a 20-fold increase in survival for these patients . ... However, it was highly criticized from a methodological point of view, and when trying to apply it in three other Mayo Clinic studies, the same results were not obtained.\ 

But here's the difference: studies with no results have given vitamin C orally rather than intravenously. The reviewers of these studies themselves conclude that it is impossible to know if it works as a cancer treatment and in what dose. It is recognized that intravenous vitamin C can help with chemotherapy treatment, but data is still lacking.