Vitamin C

Feel free to make lemonade with the lemons that life gives you. Just don't go around selling it as a cure for cancer.

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Vitamin C, also known as ascorbic acid (chemical formula C₆H₈O₆), is a micronutrient, and likely the most common in supplements. Humans require it in small doses to promote normal bodily functions and to prevent the onset of pirate disease. It is found in fruits, vegetables and the artificial supplements obnoxious woo peddlers force on the unsuspecting masses in order to get their hard earned money.

The facts

Every human needs vitamin C in their diet, since it cannot be produced by the body. It's necessary for the production of collagen (a type of structural protein) and certain hormones. It also facilitates the body's natural responses when it comes to blood clotting and infections. Since vitamin C dissolves in water, the body can't store it for later use — the body absorbs what it needs and any excess is peed out. This is why it has to be consumed every single day.

The amount that a person needs depends on factors like age, biological sex, pregnancy and smoking:

Recommended daily intake of Vitamin C
Infants 0 to 6 months	40 milligrams
Infants 7 to 12 months	50 milligrams
Children aged 1 to 3	15 milligrams
Children aged 4 to 8	25 milligrams
Children aged 9 to 13	45 milligrams
Females aged 14 to 18	65 milligrams
Males aged 14 to 18	75 milligrams
Females aged 19 and over	75 milligrams
Males aged 19 and over	90 milligrams

Pregnancy and breastfeeding require an increased intake (as high as 120 milligrams for a breastfeeding adult) and smokers need an additional 35 milligrams everyday on top of their recommended daily intake. Seeing as how an average orange has around 53 milligrams of vitamin C in it, it's not particularly hard to hit the necessary targets without taking artificial supplements.

There is such a thing as an upper limit, though it's quite high, because of the whole water soluble thing. It's about 2,000 milligrams a day. Excessive consumption can lead to side effects, none of them positive (unless one considers stuff like vomiting, headaches and diarrhoea a positive).

The nonsense

“”75% of all cancer can be prevented and cured by vitamin C alone.

—Nobel Prize winner Linus Pauling, pulling numbers directly out of his ass

The promotion of vitamin C as a cure for various ailments has been going on for decades, but the most prominent advocate of the supplement was one Linus Pauling. From 1968 until his death in 1994, Pauling claimed that taking doses of vitamin C multiple times above the recommended limit set by medical authorities had numerous health benefits, such as the slowing of aging, the curing of the common cold and the treating of cancer. The doses that he advocated were in the thousands of milligrams; he claimed that he took around 12,000 milligrams a day when he was healthy and 40,000 milligrams when he had a cold.

Considering that he aged normally like the rest of us mere mortals, had regular colds and eventually died of cancer one might think that his claims shouldn't be of relevance to anybody. And yet, because of his prestigious academic background, Pauling was regularly held up by hacks as an authority on the subjects of nutrition and medicine. He was invited to give talks at events organized by health-food companies and practitioners of CAM treatments, published numerous books and articles on the powers of vitamin C and even set up his own "scientific institute", which spent most of its resources on producing pseudoscience and silencing his critics.

The popularity of vitamin C didn't die with Pauling; his ideas are still widely circulated by well known sources of woo, such as NaturalNews and Patrick Holford, as well as the small army of naturopaths, chiropractors and other assorted cranks. Are any of their claims backed by factual evidence?

Cure for cancer

No high quality evidence exists that would prove that vitamin C cures cancer. This isn't for lack of trying to find evidence though; there have been numerous studies carried out to examine the effects the vitamin might have on tumours. It's just that all the properly-designed experiments found that it's completely worthless and the dodgy experiments that the media occasionally makes a big song and dance about don't even have results that are all that impressive.

In the 1970s, Pauling and his colleague Dr Ewan Cameron published reports about two groups of cancer patients — the test group, made up of 100 cancer patients under the care of Dr Cameron, received 1,000 milligrams of vitamin C daily. Then the records of 1,000 cancer patients who were not treated with vitamin C were dug up from the hospital records — this was their "control group". Upon comparing their test group with their cherry picked control group, they concluded that (drumroll, please): in the patient group receiving vitamin C "there is a 3-fold increase in survival time, measured from the date when the cancer was pronounced untreatable." Oh. So they weren't cured? How disappointing… but, they lived longer than the control group, right? Well, no, actually. "The date when the cancer was pronounced untreatable" varied hugely between the test group and the control group, because they were done by different doctors. Dr Cameron's 100 hand picked patients were declared untreatable at much earlier stages of their cancers, compared to the 1000 control patients. The fact that test and control patients were not matched by the stages of their diseases was a big design flaw, to say the least. Three subsequent studies carried out by the Mayo Clinic sought to test Pauling's claims and concluded that when all interfering variables are eliminated, vitamin C does nothing beneficial to patients suffering from terminal cancer.

Cure for the common cold

Claims of vitamin C preventing or curing the common cold have also been rejected by high quality, peer-reviewed scientific papers. There have been dozens of studies examining the efficacy of vitamin C, given before a cold as a preventative measure or during a cold as a treatment. Some studies looked at taking vitamin C intravenously via injection, some orally in pill form. Regardless of timing, dosage or method of administration, vitamin C performed no better than the placebos and in the cases where the vitamin C group did see differences, the change in symptoms and reduced duration of sickness was so minuscule as to be statistically insignificant.

Cure for COVID-19

Japanese clinic selling both COVID tests and vitamin C

In early 2020 as COVID-19 was starting to sweep the globe, vitamin C was being touted as a cure for the scary new disease. These claims, made by people with PhDs in bullshit quickly went viral on social media, but luckily debunking them isn't particularly tedious, mostly because they have provided no credible evidence to back up their claims. Although the claim of "vitamin C is necessary for the immune system and the immune system fights COVID" is harmless enough, the idea that extra vitamin C will give someone an extra powerful immune system capable of fighting off a new viral disease is unfounded — even if the person making such a claim is cosplaying as a real doctor and offers to inject the damn thing directly into your bloodstream.

See also

• Vitamin D
• Megavitamin therapy