So, Linus Pauling is apparently the hot topic of the day. Janet’s already discussed a bit about the whole “wacky older scientist” phenomenon over at Adventures in Ethics and Science, while the first post cited gives you a bit of the background of Linus Pauling, bringing in two new studies on the topic of vitamin C as a treatment for cancer. Since Janet’s covered a bit more of the philosophy and sociology of the topic, I just thought I’d weigh in a bit on the science of the issue, particularly since Lee makes it seem as if Pauling has been unfairly maligned.
Here’s what Lee claims happened to Pauling:
In essence, he challenged the established notions of nutrition, particularly regarding vitamin C.
Well, not really. It’s much more than that, as he notes later:
Consequently, he proposed that “megadoses” of vitamin C could effectively treat several illnesses, most notably cancer and the common cold, and published a few books to popularize these ideas. In 1973, he formed the Linus Pauling Institute of Medicine, where he performed multiple experiments to verify his claims.
Books to “popularize” his ideas, before they were accepted by the mainstream scientific community. Sound familiar? His own Institute, where he performed experiments (hey, performing any experiments puts him a step above the Discovery Institute, at least). Now, I don’t really think Pauling was as bad as the hacks as the DI, but I do think he was guilty of over-selling his own results, particularly when others were failing to replicate them. This is really where the trouble starts starts–when others couldn’t replicate the results, and Pauling and his supporters remained adamant.
It’s curious – if Pauling’s original experiment demonstrating vitamin C’s anti-cancer effects was based on both oral and intravenous vitamin C supplementation, why did the subsequent studies attempting to “replicate” his findings forego testing both routes? When they couldn’t replicate Pauling’s results, why wasn’t their methodology challenged? It seems increasingly plausible that if anyone had bothered to notice and correct these fundamental oversights, Pauling’s reputation would have been redeemed and a potentially valuable cancer therapy might have gained mainstream acceptance much sooner.
I don’t know much about the studies carried out right after the original 1976 Pauling paper that Lee links, but let’s discuss the methods in Pauling’s own paper first. According to the methods, patients received vitamin C intravenously for only 10 days, then “orally thereafter.” So the IV portion was but a small component of the study, which lasted for as long as a year or more. Most of this time the patients were on oral “megadoses;” so is it surprising that most future research in this area concentrated on this method of delivery? And if the method of delivery was known to be so important, why didn’t Pauling or one of his researchers point that out to the folks working on the larger studies? Seems like a bit of ad hoc reasoning to me.
And have no doubt–this has been an incredibly active area of study. Doing a PubMed search using the key words “vitamin C cancer” brings up 2651 items (399 reviews alone). Even adding “intravenous” to that still brings up 41 papers, including 4 reviews. “Vitamin C and intravenous” alone (without necessarily including cancer) brings up 480 papers, including some which seem to involve cancer but were missed in the first search. It’s not as if research into this topic stopped with Pauling 30 years ago, and has suddenly been re-discovered.
Additionally, the new studies cited are intriguing, but not exactly groundbreaking. The PNAS study cited is an interesting in vitro study that certainly may have clinical applications, and if it works, great. Several pilot studies have already been published showing it’s fairly safe for humans at the therapeutic levels needed to kill tumor cells, and larger studies examining efficacy will likely follow. (The other study cited is a case report of 3 cancer patients who improved after receiving IV vitamin C–an interesting observation, but as noted in the commentary, ” these are only 3 individual cases of very different types of cancer, and in each case there is a possible alternative explanation for the positive outcome.” Doesn’t mean the findings are meaningless, but just that like many preliminary findings, they should be taken with a grain of salt until larger studies confirm the results.
And this brings me back to Pauling. Indeed, his work in this field is often synonymous with quackery, or a tale of caution when it comes to knowing where your expertise lies–and where it doesn’t. Does that mean he could still be right–and megadoses of vitamin C could be beneficial? Sure. It’s also unfortunate that snake oil salesman such as Matthias Rath, who was affiliated with the Linus Pauling Institute, continue to trade on Dr. Pauling’s name. So while all this is unfortunate, what I see here is a bit more like the mythology of Barry Marshall’s ostracism–complete now with the potential happy ending of Pauling’s “vindication.” Again–call me closed-minded, but I’ll wait for the evidence.