Take lots of dietary supplements? You may have increased cancer risk, says new meta-study


Bad news for Ray “these 150 pills a day will help me live long enough to see the Singularity” Kurzweil.


Another one on the pile. Meta Studies, reviews, and many studies for over a decade have been showing vitamin supliments were at best totally useless and at worst actively harmful. Ben Goldacre was writing about this some what regularly back when I was in college ~2005. The vaguer “dietary suppliments” have an even worse track reccord.


Not even Vitamin D in winter, for people who live in extreme northern climates?

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Vitamin D is one of the few supplements that seems still worth taking if you don’t see the sun enough, as its very hard to get enough of the right kind of D3 with a normal healthy diet.

Omega 3 (as EPA and DHA) seems also possibly worthwhile if you don’t eat enough fish. Non-fish-based Omega 3s, such as in flax seeds or added to chicken feed for eggs, don’t have nearly as high bioavailability.

A very good resource with thousands of peer-reviewed citations and a sometimes-easy to understand chart listing the kind and strength of research on lots of suppliments can be found at examine.com. (Though it’s slightly targeted towards weight lifters and gym buffs.)


Wow, a crappy article about a crappy article about a crappy article - none of which link to the actual paper. The whole summary of which:

found that high doses of certain vitamin supplements were linked to increased odds that a person would develop certain kinds of cancer.

is rendered meaningless by not stating what the “certain” (lol) supplements are alleged to be. How is this any more meaningful than saying that “food may be bad for you” or “drugs may be bad for you”? Taken in the abstract (as it were) it assumes equivalence between everything which can be considered a “supplement”.

Maybe the paper is out there somewhere to read, I’ll try this evening. But just this short commentary is distinctly unhelpful.


So is the term “dietary supplement” more or less specific than “natural food”?

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Well, they do give some examples further down. More would be nice, but it’s not entirely as general as that.

Byers found that people who took high doses beta carotene supplements had an increased risk for lung cancer. Selenium supplements were associated with skin cancer. Men who took vitamin E had an elevated risk for prostate cancer. Folic acid, a B vitamin, taken in excess could lead to an increased risk for colon cancer.

Also, if you want more definite medical advice based on these studies, you should probably ask a doctor rather than getting all of your information from a CBS News article…


I didn’t say I was looking for advice. I was looking for reports from this study. The article links to these:

The sciencedaily article cites its link to: “The above story is based on materials provided by University of Colorado Cancer Center.” leading to this page:

…instead of the University of Colorado Cancer Center. Now I am on the UCCC site and still don’t see the article.

As opposed to a medical practitioner? I only wanted to read the report from this study, instead of merely being told about it.

But you clicked.

So what?

Bait: successful!

Succeeded at what, exactly? Is this like “Ha-ha, made you look!” or the “burning bag of doggy-doo” game?

I miss my 1990s internet of rampant academia, rather than dumb games of hide-the-content.

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In this particular case, a dietician or oncologist might be good sources.

I could be wrong, but… it looks like this might not be from a single study, but rather a discussion of various studies that happened on Monday at the AACR Annual Meeting.


All I know is I want some of them vitamin skittles in that picture!


That’s a case of a specific deficiency. Which is the exception. Folate for pregnant women is another classic. But you should know for sure you have (or are at risk for) a deficiency and just suppliment that one thing. And a lot of the big ones are covered by “enriched” foods. Like milk or milk substitutes with added vitamin d, or iodised salt.

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Not really. Fish oil. Herbal remedies. Protein powders. Energy drinks. And vitamins all fall under the category.

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It has been many years, but I recall thinking that rise of Anti-Oxidant-Everything might result in an increase in cancers in some individuals… I don’t recall the specifics, but a couple papers that I read at the time seemed to indicate that cells exposed to antioxidants tended to undergo DNA repair rather than letting the cell die (apoptosis). This might sound like a good thing, but it is mistakes in DNA repair that can lead to cancer (just letting a few cells die has no real impact on well being). Ah, here’s a short article: Antioxidants Suppress Apoptosis
This mentions how beta-carotene and vitamin E might have a negative effect on those with existing cancers or pre-cancerous cells:

Antioxidants, by preventing oxidant-mediated damage to diverse targets (DNA, RNA, proteins, and lipids), may play a protective role in healthy individuals with no existing cancer cells that must be eliminated; however, by inhibiting apoptosis, these same antioxidants may exert a cancer-promoting effect in cancer patients and in individuals with precancerous DNA changes. Inhibition of apoptosis by antioxidants may explain why, in several studies in heavy smokers, vitamin E and β-carotene enhanced carcinogenesis in the lung (33)

This link only has the abstract for a paper on a similar topic:
The benefits and hazards of antioxidants: controlling apoptosis and other protective mechanisms in cancer patients and the human population. - PubMed - NCBI


a meta-analysis of 12 trials involving more than 300,000 people

So far, alas, all we have is a press release publicising Byers’ talk to the AACR, and the word “meta-analysis” does not appear.
All the press release does is re-hash some of the earlier studies, and since each studiy found something different (one study implicating beta-carotene, another implicating folic acid), and since none of the results are replicated, this is still at the junk science level. U-Col clickbait.

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As far as I can tell in the last five years or so I’ve been interested in Science Based Medicine and Skepticism and critical thinking, the term “Dietary Supplement” pretty much means “something we want to sell as medicine, without having to do research.”