For decades, some people have embraced the idea that there could be major health benefits to taking vitamins in amounts far beyond the advised daily requirement. The concept has been very popular for some time in the mediabut the results of research to the contrary gradually made it virtually untouchable to scientists.
Yet it’s now making a comeback of sorts, thanks in part to new discoveries showing that high doses of vitamin C can treat cancer. As we will see, however, there are some important caveats here – as well as obstacles to exploiting the various potential health benefits of other vitamin treatments. It’s a cautionary tale about the dangers of black-and-white thinking and how things are rarely as simple as they make them out to be.
About a hundred years ago vitamins came into prominence. Describe originally referred to as “vital amines,” important for “vitality” (life), public knowledge was originally based on solid science. But 1940sinformation became confrontational as food manufacturers and later the dietary supplement industry took over much of nutrition education.
An example of this advice that lives on to this day is the idea that we need to supplement our diet with additional vitamins and minerals. This has been extremely profitable for everyone in this industry, from producers of breakfast cereals to vitamin pills. The food supplement sector was worth US$205bn (£160bn) last year and is predicted reach nearly $280 billion by 2024.
The roller coaster cure
The idea of the miraculous healing properties of taking vitamins in much larger amounts has long been part of this line of thinking – thanks in large part to a leading American scientist named Linus Pauling.
I have already written in The Conversation how Pauling, double Nobel Prize in Chemistry and Peace, was singularly committed in the 1960s and 1970s at the idea that megadoses of vitamin C could treat illnesses ranging from the common cold to cancer. Pauling pushed these claims through a combination of exaggeration and selecting only studies showing positive effects – with help from the manufacturers. The story is very well described. here.
other scientists began to demystify these claims from the end of the 1970s, demonstrate not only that Pauling was wrong, but also that taking vitamin or mineral supplements by mouth can often do more harm than good – including in the treatment of certain cancers. It quickly reached the point where any idea of the benefits of megadoses of vitamins was considered dubious within the research community.
Some of that was spot on, but maybe the backlash went too far. He neglected careful science who had hinted, in selected cases, that megadoses of vitamins could treat certain illnesses after all.
This is confirmed by the new study I mentioned earlier, which showed that taking high doses of vitamin C can help treat lung cancer and certain brain tumors. 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 to research led by Dr. Joshua Schoenfeld of the University of Iowa. The article was published last month in the journal Cancer Cell and showed that vitamin C does not directly fight cancer as a medicine, but by making radiation therapy and some chemotherapy treatments more effective.
But where Pauling and his followers touted supplements, Schoenfeld et al propose infusing vitamin C directly into the patient’s bloodstream. It builds on previous findings that have shown that tablets taken by mouth will not provide enough vitamin C in the body to be effective.
The research has completed an initial phase which found that the treatment improves survival prospects in mice and that vitamin C is safe and tolerable in patients having chemoradiotherapy. But to emphasize, if there is a positive end result to these trials, any treatment will never involve vitamin C pills from the local pharmacy. This would require a well-controlled intravenous infusion.
The path to follow
This research is an example of meticulous science that dissects the reality of vitamins from fiction. I am optimistic that new discoveries using megadoses will be made in the future. High doses of vitamin C can also be used to treat pain postherpetic neuralgia, a nerve condition linked to shingles; while preliminary results suggest it may also help treat blood poisoning (sepsis).
Megadoses of other water-soluble vitamins have also been proposed, including the administration of vitamin B3 as a treatment for damaged nerve endings (peripheral neuropathies) after a promising study on rats.
There’s probably also undiscovered potential among the fat-soluble vitamins — A, D, E, and K — but megadoses can be dangerous. Too much vitamin A can damage the liver, for example; while too much vitamin D may cause everything from fatigue and tinnitus to heart arrhythmias due to excess calcium in the blood.
In such cases, the answer could be to design molecules providing the equivalent of a hyperdose of vitamins but in a very targeted way to reduce the side effects. This is what I have been working on with colleagues from the universities of Aberdeen and Durham, as explained in the staple below.
We are designing new compounds that activate only part of the vitamin A response via the retinoic acid receptor, without triggering other receptors. It should be possible to obtain similar results for other vitamins with receptors, including vitamin D.
In conclusion, it seems that the pendulum swung too far in the other direction in reaction to Pauling. Schoenfeld et al have shown how very precise and careful science can extract the benefits of vitamin supplementation. This is certainly not a new argument for taking oral supplements, but it’s worth watching this space to see what emerges next.