Recent attention-grabbing headlines have been suggesting that curry powder – and in particular one of its most prominent ingredients, turmeric – are the newest and most exciting trend in curing cancer. Most of the hype has been due to the publication of a case report published in the British Medical Journal illustrating the case of a myeloma patient who had been unresponsive to all other forms of chemotherapy and who achieved long-term stabilization of her condition by taking concentrated curcumin. Curcumin is a natural phenol – a chemical compound produced by plants. In particular, high concentrations of it are found in the root of Curcuma longa, also known as turmeric. The root is often dried, turned into a powder and consumed as a spice in several Asian dishes – including of course as a key ingredient to several curries. However, the turmeric powder one buys at the supermarket (or at the health-food store) is a completely different thing from the pure chemical compound that the patient in the case report used after chemotherapy had failed to give any positive results. In fact, curcumin makes up about 3% of traditional turmeric powder (and naturally a much smaller fraction of curry powder). Since the dosage outlined in the case study in question is 8 grams of curcumin per day, the patient would have had to eat about 266 grams of pure turmeric powder every day, which is about 6 full bottles of the ground spice. Since there are no studies on the potential toxicity of the spice being consumed in such large doses, consuming 6 whole bottles of turmeric a day every day for several months would not only be incredibly impractical but also potentially really dangerous. This also means that 1 teaspoon of turmeric (which is about 3 grams) has less than one-tenth of a gram of curcumin – which makes the idea that eating a single portion of curry is “good for you” mathematically ridiculous.
However, the fact that there is not enough curcumin in curry to carry any of the benefits shown in the case report does not mean that curcumin itself is not a promising candidate as a cancer drug. In fact, reports such as the one recently published in the BMJ are pushing more and more serious research into the potential beneficial effects of curcumin for patients with cancer. For example, Professor Karen Brown from the University of Leicester in England is receiving funding from Cancer Research UK, one of the most important funding bodies in the world, to further investigate the role of curcumin in treating tumors. Her studies have real potential to clarify whether curcumin is beneficial and if so at what dosages. If this is indeed found to be the case, understanding how curcumin affects cancer cells can help us develop slightly modified forms of the compound that might be exponentially more efficacious or to develop completely new drugs that mimic the effect of curcumin. This is certainly not the first time that a compound naturally found in nature has been taken on board by western medicine and improved chemically to be used as a safer and better drug. For example, willow tree leaves contain salicin, which has historically been used to relieve pain. Modern chemists subsequently discovered that the part of the molecule that was responsible for the pain relief was eventually metabolized to salicylic acid and therefore started prescribing salicylic acid directly as a pain reliever. Nowadays, salicylic acid (also known as aspirin) is one of the most popular over-the-counter medications in the world. At the same time, digoxin (which is a type of medication commonly prescribed to people with heart conditions) has been developed starting from foxglove extract, which has been known for centuries as a poison (since it decreases the heart rate, which can be therapeutic in those whose heart is beating too fast but can be fatal to people whose heart beats normally).
In conclusion, modern medicine often takes chemical compounds from the natural world and there is certainly reason to be optimistic that curcumin will be one of them in the future. The claims that this is unlikely to happen because “Big Pharma” cannot make money out of developing a natural compound that cannot be patented are simply ridiculous. While of course turmeric root cannot be patented, a highly effective compound designed around the basic structure of curcumin most certainly can (Bayer made a colossal fortune out of producing aspirin in the last century). However, there is still a long way to go before curcumin can become a clinically-tested drug, mostly because of the thorough process that any compound (natural or not) must go through before it is considered safe and effective beyond reasonable doubt. Unfortunately (or perhaps, fortunately), science is not simply a collection of “things that have worked sometimes” like perhaps the health section of some news organisations. We look forward to more comprehensive and thorough studies on the effect of curcumin on cancer cells – there are certainly plenty of good reasons to be very optimistic that one day curcumin-derived compounds might open up new avenues for the treatment of cancer patients.