Turmeric has been the “blockbuster” nutrient on the superfood and supplement shelf in recent years.
Touted for its antiinflammatory and fat metabolising benefits, turmeric is said to help with everything from heart disease to Alzheimer’s to asthma, erectile dysfunction, baldness, sore throats and rheumatoid arthritis. A potent antioxidant, the ancient ingredient is even said to slow the ageing process.
Naturally, researchers have jumped on the turmeric bandwagon, hoping to develop its active ingredient, curcumin, into a drug. But, according to some research, claims about the spice have “duped” people and led “drug hunters astray”.
“Now, in an attempt to stem a continuing flow of muddled research, scientists have published the most comprehensive critical review yet of curcumin — concluding that there’s no evidence it has any specific therapeutic benefits, despite thousands of research papers and more than 120 clinical trials,” explains a Nature report on the review, titled “Deceptive curcumin offers cautionary tale for chemists”.
At least 15 articles on curcumin have been retracted since 2009 and dozens more corrected, said the authors of the report, published earlier this year in the Journal of Medical Chemistry. The authors concluded that “curcumin is an unstable, reactive, nonbioavailable compound and, therefore, a highly improbable lead”.
Why? Essentially, they argue that curcumin results in a false positive of chemicals, even lighting up under ultraviolet light (a typical method used to detect interaction between chemicals and proteins), despite being inactive.
“Much effort and funding has been wasted on curcumin research,” said Gunda Georg, co-editor-in-chief of the Journal of Medicinal Chemistry.
So does that mean all the turmeric lattes and curcumin supplements are worthless?
“It may very well be the case that curcumin or turmeric extracts do have beneficial effects, but getting to the bottom of that is complex and might be impossible,” Bill Zuercher, a chemical biologist at the University of North Carolina at Chapel Hill, told Nature.
“It’s a way more complex issue than that article makes it out to be, as that study focuses on the views of a couple chemists and isn’t a comprehensive review,” Kamal Patel, a nutrition researcher and the director of Examine.com, told Fairfax.
“On the one hand, several studies have been retracted in the past couple years, which is bad. On the other hand, most were by one particular author, and there are still many hundreds of studies out there [meaning that the retractions aren’t likely to be representative of the general body of literature].”
He adds that a set of false positives “in and of itself doesn’t negate the results of randomised controlled trials”.
“There are still many well-conducted trials that do show benefits,” Patel says.
Dietitian Melanie McGrice agrees that the spice, used for centuries in India as a disinfectant and treatment for sore throats, has worth.
“I don’t believe that this means that everyone needs to throw out their curcumin capsules, however, it may not be the miracle ‘supersupplement’ that it has been getting the reputation for lately,” McGrice says. “This is an important reminder that there’s still a lot that we don’t know, and there is still a lot of research that needs to be done before we know exactly how it’s best used.
“However, it doesn’t seem to cause any harm, other than to our hip pockets, so if people can afford it, and they enjoy the taste and colour, then adding some curcumin to your smoothie or latte is not necessarily a bad thing.”
Patel says he would still take turmeric for its health benefits.
“Personally, I wouldn’t take it for ‘general health’ or prevention indications, but trying it for certain specific conditions with moderate-to-high evidence (e.g. pain, inflammation, depression) can be a good idea,” he says.
“It can also be useful without the usual absorption enhancers [like fat], as a gut health supplement (since it will act within the gut, not get out into general circulation so much).”