For decades, some people have embraced the idea that there might be major health benefits from taking vitamins in quantities well beyond the recommended daily requirement. The concept was very popular for a while in the media, but research findings to the contrary gradually made it virtually untouchable for scientists.
It is about a hundred years since vitamins first came to prominence. Described in the early days as "vital-amines", important for "vitality" (life), the public's knowledge was originally based on solid science. But from the 1940s, the information became conflicted as food manufacturers and later the dietary supplements industry took over much of the education on nutrition.
The rollercoaster remedyThe idea of miraculous healing properties from taking vitamins in much larger quantities has long been part of this line of thinking - largely thanks to a leading American scientist named Linus Pauling.
I have written previously in The Conversation about how Pauling, a double Nobel prize winner in chemistry and peace, became singularly committed in the 1960s and 1970s to the idea that megadoses of vitamin C could treat diseases from the common cold to cancer. Pauling pushed these claims through a combination of exaggeration and selecting only studies showing positive effects - with a helping hand from the manufacturers. The story is described very well here. Other scientists began debunking these claims as far back as the late 1970s, demonstrating not only that Pauling was wrong but also that taking oral vitamin or mineral supplements can often do more harm than good - including in the treatment of certain cancers. It soon reached the point that any idea of benefits from vitamin megadoses was considered dubious within the research community. Some of this was absolutely right, yet perhaps the backlash went too far. It overlooked some careful science that had hinted, in selected cases, that megadoses of vitamins may treat certain diseases after all. This is borne out by the new study I mentioned earlier, which has shown that taking high doses of vitamin C may help treat lung cancer and certain brain tumours. This follows on from previous work proposing to test the use of vitamin C in the treatment of ovarian cancer. The new findings come from research led by Dr Joshua Schoenfeld of the University of Iowa. The paper was published last month in the journal Cancer Cell, and showed that vitamin C does not fight cancer directly as a drug, but by rendering radiotherapy and certain chemotherapy treatments more effective. But where Pauling and his followers extolled supplements, Schoenfeld et al are proposing to directly infuse vitamin C into the patient's bloodstream. It builds on previous findings that showed that tablets taken orally will not deliver enough vitamin C into the body to be effective. The research has completed a first phase that found the treatment improving survival prospects in mice, and that the vitamin C is safe and tolerable in patients having radio-chemotherapy. But to stress, if there is a successful final outcome to these trials, any treatment would never involve vitamin C pills from the local pharmacy. It would require a well controlled intravenous infusion.