A recent systematic review of the alleged health benefits of curcumin show that, yet again, hype based on “traditional use” is not a reliable guide.
Curcumin is a spice that makes up about 5% of turmeric, a yellow spice used in many curries. It is also a traditional herbal treatment. The health claims made for curcumin are numerous – WebMD has this entry:
Other preliminary lab studies suggest that curcumin or turmeric might protect against types of skin diseases, Alzheimer’s disease, colitis, stomach ulcers, and high cholesterol. Based on lab studies, turmeric and curcumin might also help treat upset stomach, scabies, diabetes, HIV, uveitis, and viral infections.
The systematic review had two main findings:
No double-blinded, placebo controlled clinical trial of curcumin has been successful. This manuscript reviews the essential medicinal chemistry of curcumin and provides evidence that curcumin is an unstable, reactive, nonbioavailable compound and, therefore, a highly improbable lead.
Let’s take the second point first, bioavailability. In order for a drug to be useful when taken orally it has to have adequate bioavailability. This means it needs to be relatively stable, it has to be absorbed in adequate amounts through the GI tract, and then it has to survive a first pass through the liver and be distributed in the body in such a way that it gets to its target tissue is sufficient concentration to have a clinical effect.
Any one of the steps could be a fatal flaw for a potential drug or compound. Most substances do not have all the properties necessary to be an effective treatment. Pharmaceutical companies spend a lot of time and resources studying the pharmacokinetics and pharmacodynamics of drug candidates, and often tweaking them in an attempt to give them the properties they would need to be an effective treatment.
Most herbs do not have these properties. They therefore fail as a therapeutic agent out of the gate. The authors of this review found that studies of curcumin show it does not have the overall bioavailability to be an effective treatment for anything.
Why, then, are there literally thousands of studies with curcumin or turmeric? It is because there is apparently a different set of rules for studying substances that have a traditional use and that are already being hyped to the public as having health benefits.
http://theness.com/neurologicablog/index.php/curcumin-hype-vs-reality/
