By Joanna Wolstenholme
Mistletoe is everywhere is Cambridge – look up into the trees and you will often spot dense balls of twigs sprouting from a branch. But other than its mystical and romantic connotations, does mistletoe actually have any clinically proven medical use?
Rudolf Steiner is credited with being the first to raise a link between mistletoe and cancer, admittedly on a rather dubious basis. His school of thought, anthroposophy, followed the maxim, ‘like cures like’. Mistletoe, like cancer, is a parasite, and so it of course follows that mistletoe will be able to cure cancer.
However, clinical trials prompted by many people following Steiners advice, have had mixed outcomes. In several trials, cancer patients treated with various forms of mistletoe preparations have had fewer side effects, better symptom relief and survived longer after beating the cancer. However many of these trials were flawed as they had major weaknesses, such as studying just a few patients and lack of information about mistletoe dose. There are also some side effects (but then what cancer therapy doesn’t have side effects?) such as inflammation at the injection site, headache and fever.
Yet one compound found in mistletoe that may not be so welcome is its lectin, which is similar in structure to the castor bean lectin, the infamous ricin (that of the end of the umbrella to kill a journalist fame). As with many medicines that come with plants, the answer will be to identify the useful active agent produced by mistletoe and find a way to either purify it or synthesise it artificially. Until that point, however, it serves as a reminder of how powerful plant chemicals can be – for good and harm!