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Comment by ellyagg | Hacker News Reader

As always, the devil is in the details. Different vitamins have different effects, they aren't just "antioxidants". Showing that one vitamin supplement is harmful doesn't remotely prove that others aren't beneficial because antioxidants.

This article makes sweeping generalizations that vitamin supplements "don't work" based on a couple of studies on beta-carotene. Many of us already thought beta-carotene supplementation would be worthless. And I bet once they do a study of vitamin E supplementation, it will also be worthless or harmful. On the other hand, you're not going to find a study proving vitamin C supplmentation is harmful. And I very much doubt if they did an isolated study on non-beta-carotene vitamin A, they'd find harmful effects.

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> On the other hand, you're not going to find a study proving vitamin C supplmentation is harmful.

But I don't think that you'll find a good study that says that it's beneficial, either, unless you had a deficiency.

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edit: and megadoses could certainly turn out to be harmful...

"[...] Take vitamin C, Pauling’s preferred supplement. At the correct dose, vitamin C neutralises highly charged free radicals by accepting their free electron. It’s a molecular martyr, taking the hit upon itself to protect the cellular neighbourhood.

"But by accepting an electron, the vitamin C becomes a free radical itself, able to damage cell membranes, proteins and DNA. As the food chemist William Porter wrote in 1993, '[vitamin C] is truly a two-headed Janus, a Dr Jekyll-Mr Hyde, an oxymoron of antioxidants.'

"Thankfully, in normal circumstances, the enzyme vitamin C reductase can return vitamin C’s antioxidant persona. But what if there’s so much vitamin C that it simply can’t keep up with supply? Although such simplifying of complex biochemistry is in itself problematic, the clinical trials above provide some possible outcomes."

"A study published in 2007 from the US National Cancer Institute, for instance, found that men that took multivitamins were twice as likely to die from prostate cancer compared to those who didn’t. And in 2011, a similar study on 35,533 healthy men found that vitamin E and selenium supplementation increased prostate cancer by 17%."

They do cite quite a few articles that show negative effects of specific vitamins.

That study used 400UI of vit E, which is more than 10x the RDA. Mega-dosing is what's dangerous. Good multivitamins use a fraction of that dose.

The BBC article is merely clickbait.. People love to jump on the 'vitamins are actually dangerous' bandwagon. if you do a bit of digging into the studies they're quoting you'll find that their claims are unjustified.

"Mega-dosing is what's dangerous. Good multivitamins use a fraction of that dose."

The problem is that a lot of multivitamins (and supplements in general) have doses which are all over the place, and megadoses are quite common. You'll also find many reviews and testimonials that swear to the efficacy of any given dose of these supplements. On top of that, many doctors recommend that people take "a multivitamin", without any further guidance as to the ingredients or their dosage. Finally, a lot of people don't trust doctors and believe in alternative medicine, naturopathy, or what have you, from which they'll often hear recommendations to megadose because allegedly, the RDA's are set way too low (for a variety of reasons, depending on the supplement).

There's a lot of conflicting medical advice out there, and for the average consumer (who may have a host of medical issues, or suspected issues) it's not always as clear as "just take the RDA".

A study of 350000 is almost certainly just a survey.

It's not a stretch that there are other correlations at play here. People who feel sick or lethargic try vitamins.

My doctor told me to take Vit E due to some bad liver numbers. Two months later the numbers were significantly closer to normal, so it seems like Vit E supplements are doing something for me...

Possibly influential on your doctor's recommendation for specific, limited conditions [1].

I would not generalize this to the average person, however, due to evidence of harm (such as hemorrhagic stroke [2] and increased mortality [3] )

1 = https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2928471/

2 = https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2586922/

3 = https://www.ncbi.nlm.nih.gov/pubmed/15537682

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