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SKEPTOID BLOG:

Turmeric: What is it Good For?

by Stephen Propatier

June 2, 2016

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Donate The supplement industry historically is a conga-line of promoters selling unproven or disproven health products. Supplement claims are crank whack-a-mole for the most part—knock one down and another comes up. It is an industry that markets with a constant drone of miracle cures that fail to deliver the miracle. Turmeric is a newly popular herbal supplement. I see patients using it in ever-increasing numbers. Most of my patients are taking turmeric as an osteoarthritis remedy, but that is just the tip of the iceberg. Historically there have been rare exceptions to the failure of herbal supplements; let's take a look at turmeric and see if it's good for something other than a tasty dinner.

Turmeric grows wild in southeast Asia. It's commonly used as a flavor and color additive. Although it has a long history as a folk remedy, it is more commonly used as a spice. The plant's roots are boiled and then dried in hot ovens; eventually they are ground into a orange-yellow powder with a variety of uses in cooking.

Due to its folk remedy status it has been popularized as a medical remedy. There is a lot of research evaluating the possibility of a medical benefit. Most of the medical research focuses on the primary ingredient curcumin. It is assumed to be safe for consumption since it is commonly used as a spice, at least in those typically small amounts. So is there any good reason to suspect that turmeric has escaped prior detection by the medical industry?

Turmeric has many positive attributes ascribed to it. Evaluating claims critically you will see most of it is either implausible or mutually exclusive. Interestingly there is a large volume of research associated with turmeric. Promoters provide endless links to peer-reviewed research. I estimate one turmeric site alone offered at least 1,700 different research papers, which were all disappointingly similar. A random sample of 20 varied topics in the bibliography revealed exclusively in vitro research, meaning kind of test tube research, rather than demonstrations in living organisms. I decided to independently research turmeric and I found thousands of individual studies. Since I do not realistically have the time to review 30 years of research I used the Natural Medicine Comprehensive Database. It provides a list of the leading research claims.

Their evaluation of turmeric research is generous. The authors feel it might possibly be effective for upset stomach, and may have anti-inflammatory properties. I reviewed the best evidence as compiled by their authors, but it was sadly disappointing. Although I can agree that turmeric is probably a low-risk supplement, there were problems for gall bladder patients or surgical patients. The disappointing part stems from the quality of the research. There were failings commonly found in alternative medicine. The research was primarily in vitro, or they were preliminary studies without replication. Additionally, most of the research had results consistent with normal variation as opposed to significant findings. All the research suffers from a lack of replication. I have written extensively in a prior post about the common failings of preliminary or in vitro studies, and why less than 1% of substances with positive in vitro/preliminary research ever eventually result in anything useful.

There is one piece of research often quoted as proof of turmeric benefit as an anti-inflammatory. This was a study comparing it to diclofenac, an anti-inflammatory drug available by prescription. This poorly structured study fails to have proper controls and it used a faulty system for measuring results. The researchers took 80 people off of anti-inflammatory medications, rested them, and then put them on curicumin and diclofenac randomly. Although the administration of medication was blinded, the COX-2 monocyte samples from synovial fluid used to determine relative inflammation of the joint were un-blinded. This undermines controls for researcher bias in any way. There is a multitude of other issues as well: the subject numbers were too few, there were no baseline comparisons, and no patient reported symptoms. Needless to say, I was not impressed and wondered why they didn't just do a simple comparative study, double-blinded with three groups: one using diclofenac, one using curicumin, and one taking nothing. All you can glean from this study is that the "best research" is a disappointingly structured preliminary index study.

In my opinion this is huge red flag that turmeric is not effective. Anytime a promising substance has tons of research surrounding it, done over decades, yet has no replication or rigor, that combination is almost universally synonymous with "does not work," even though a casual glance might lead one to assume "All that research must mean there is something to it."

My answer is two-pronged. Normally, the progression of research is common with effective treatments. Lack of progression in research means that the results for more rigorous studies are withheld or unpublished. So repeating endless preliminary work is window dressing without substance. Secondly, constant retreading of preliminary work happens only when it is being done by researchers who either lack expertise or are deliberately trying to avoid further questions. Good research does not retread preliminary research when you have something promising. Replication of results would make turmeric very valuable. That substance would be snatched up by a pharmaceutical company, become drug patented, and be turned from a million-dollar supplement into a billion-dollar drug. That may sound cynical, but it is accurate to say that most supplements are produced by the supplement wings of pharmaceutical giants. So why do you think they don't move it from a less-profitable division to a more profitable one? If turmeric had been proven effective for any condition it would be a medical boon. Medicine is always hoping to find new treatments but historically very few available folk remedies have escaped evaluation. Most of the low hanging fruit (or roots, in this case) has been plucked.

So why has the research stagnated? The combination of easy-on-the-stomach and good-for-inflammation is a pharmaceutical gold mine: safe, effective, and better than current drugs in use. It would be widely used without question. None of this means absolutely that turmeric is useless, rather it is tremendous red flag that it underperforms.

A quick Google search will reveal another glaring red flag for pseudoscience. Turmeric is promoted as a safe and effective treatment for an impossibly large number of maladies. An abbreviated list of medical issues that turmeric is recommended for: anti-inflammatory, anti-coagulant, anti-platelet, anti-depressant, cholesterol lowering, antioxidant, deep vein thrombosis prevention, myocardial infarction prevention, dementia, memory loss, cancer, diabetes, irritable bowel syndrome, Crohn's disease, ulcerative colitis, psoriasis, eczema, rheumatoid arthritis, scleroderma, and chronic pain. The hallmark of quack treatment is the cure-all treatment.

Far too many alternative medicine treatments offer such panaceas. The items on that list are extremely varied medically. You have cancer, genetic diseases, neurological dysfunction, psychological illness, all with vastly differing causes and mechanisms of action. The truth is that anything which claims to be a wonder drug for such an incredibly varied list of problems is impossible. The human body just doesn't work that way.

Turmeric also has potential side effects. Reasonable evidence exists that it can give you gall bladder problems at high doses and may thin your blood. It should be avoided as a concentrated supplement prior to any surgery since it may have anticoagulant properties.

If you point at a drug and say X substance has Y problem it is because it has good research behind it. Remember that a drug has a history, that at one time it was a promising substance that had unknown dosage, side effects, and toxicity. If doctors started using Drug X when it was a promising substance rather than a proven drug it would just mean rolling the dice with your life. When you are taking something that you know nothing about, that ignorance does not make it safer. Unknown is just that: unknown. It does not in fact makes it less dangerous than a drug. Additionally, calling something a supplement yet promoting it as a drug because you lack evidence doesn't make it a better option. It just makes your claims less reliable. Claiming that turmeric is safe merely because it is naturally derived and doesn't have any good research is just plain wrong. "Natural" does not at all mean "safe" or "effective."

For example, the anticoagulant warfarin (a.k.a. Coumadin) was originally derived from sweet clover. Sweet clover was unknowingly causing livestock to die from internal bleeding when they grazed on it. It was a mystery that perplexed farmers who didn't realize for decades. When they eventually determined that the clover was the cause it was initially used as a rat poison. Eventually, with proper research it evolved into a drug that saves lives. Although natural, it was not safe until it was properly researched and dosed. Compare this to the pain medication acetaminophen, commonly called Tylenol in the United States. It is a completely synthetic compound derived in the laboratory. Yet it is arguably one of the safest of all available pain medications today. So a preliminary natural plant without dosing and research equals rat poison, and good solidly researched synthetic chemical equals safe drug. The point is this, tagging something as all natural is a marketing trick to make you feel good, distracting consumers from possible severe risks. The moral of the story is simple: an unknown natural substance is always more dangerous than a drug because the risks are unknown. All pharmacoactive substances have a downside. Natural doesn't equate with no risk. It is illogical to assume that nature doesn't want to kill or injure us, because more often than not it does.

Turmeric is a food additive for both color and flavor. We know that at those dosages it seems safe. What we don't know is if it really does anything at those doses. We also don't know if it has any benefits, dangers, how much it takes to get the supposed benefits, and we don't know how much is dangerously too much.

I can't recommend turmeric as a medical treatment. It is an unknown with many worrisome red flags and volumes of poor quality research. Its major appeal seems to be the appeal to nature fallacy, which is demonstrably false. But I can recommend turmeric as a spice. I have personally researched it and give it the Skeptoid blogger Seal of Approval. I recommend you try it. Here is one of my favorite Curry Chicken recipes, and for you vegetarians out there a nice Sweet Potato and Curry soup. Dose your food according to taste!

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You can follow me at Twitter @steveproacnp for a daily dose of skeptical nursing.

Disclaimer: This post is my personal opinion, it is not a substitute for medical care. It is for informational purposes only. Information on the Skeptoid blog is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified healthcare professional regarding any medical questions or conditions. This post does not reflect the opinion of my partners, professional affiliates, or academic affiliations. I have no financial conflicts of interest to disclose.

by Stephen Propatier

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