Part I of the skeptical cardiologist’s intermittent efforts at exposing the dark underbelly of the “superfood” snake oil parade deals with turmeric.
This key ingredienet of curry, has been seized upon by the useless and dangerous supplement/vitamin/nutraceutical industry recently and a patient asked me if he should take it.
A Google search yields overblown titles such as
-The amazing health benefits of turmeric (MNN.com, a bogus website)
-6 Health benefits of Turmeric (Huffington Post, the health portion of which is full of hucksters)
-10 Proven Health Benefits of Turmeric and Curcumin (authoritynutrition.com, a bogus nutrition website)
-7 Powerful Turmeric Health Benefits and Side Effects (DrAxe.com, a bogus health website)
As I started researching turmeric I came across an outstanding summary of the topic on science-based medicine by Harriet Hall. I stopped the research and decided I would just put a link to that blog post on my site but never get around to it.
Today, however, another patient told me he was taking turmeric.
Consequently, I’m posting Harriet Hall’s article below in its entirety.
Turmeric: Tasty in Curry, Questionable as Medicine « Science-Based Medicine.
A correspondent asked me to look into the science behind the health claims for turmeric. He had encountered medical professionals “trying to pass turmeric as some sort of magical herb to cure us from the ‘post-industrial chemical apocalypse.’” It is recommended by the usual promoters of CAM: Oz, Weil, Mercola, and the Health Ranger (who conveniently sells his own superior product, Turmeric Gold liquid extract for $17 an ounce).
Turmeric (Cucurma longa) is a plant in the ginger family that is native to southeast India. It is also known as curcumin. The rhizomes are ground into an orange-yellow powder that is used as a spice in Indian cuisine. It has traditionally been used in folk medicine for various indications; and it has now become popular in alternative medicine circles, where it is claimed to be effective in treating a broad spectrum of diseases including cancer, Alzheimer’s, arthritis, and diabetes. One website claims science has proven it to be as effective as 14 drugs, including statins like Lipitor, corticosteroids, antidepressants like Prozac, anti-inflammatories like aspirin and ibuprofen, the chemotherapy drug oxaliplatin, and the diabetes drug metformin. I wish those claims were true, because turmeric is far less expensive and probably much safer than prescription drugs. It clearly has some interesting properties, but the claims go far beyond the actual evidence.
The Natural Medicines Comprehensive Database has reviewed all the available scientific studies and has concluded that it is “Likely Safe,” “Possibly Effective” for dyspepsia and osteoarthritis, and “Insufficient Reliable Evidence” to rate effectiveness for other indications, such as Alzheimer’s, anterior uveitis, colorectal cancer, rheumatoid arthritis, and skin cancer.
Mechanism of action
The “14 drugs” website says turmeric is one of the most thoroughly researched plants ever, with 5,600 peer-reviewed studies, 175 distinct beneficial physiological effects, and 600 potential preventive and therapeutic applications. They provide a database of 1,585 hyperlinks to turmeric abstracts. Naturally I can’t read all of them, but a sampling indicates that they are almost entirely animal and in vitro studies. The NMCD has conveniently provided a list of the most pertinent studies.
The pertinent preclinical studies, in animal models and in vitro, indicate that curcumin has anti-inflammatory properties; can induce apoptosis in cancer cells and may inhibit angiogenesis; has antithrombotic effects; can decrease the amyloid plaque associated with Alzheimer’s; has some activity against bacteria, Leishmania, HIV; etc. These effects sound promising, but animal studies and in vitro studies may not be applicable to humans. As Rose Shapiro pointed out in her book Suckers, you can kill cancer cells in a Petri dish with a flame thrower or bleach. Preclinical studies must always be followed by clinical studies in humans before we can make any recommendations to patients.
Preliminary clinical research
There are preliminary pilot studies in humans suggesting that:
- it does not change mental state examination scores in Alzheimer’s
- it might improve symptoms in anterior uveitis
- it might stabilize some markers of colorectal cancer in some patients with treatment refractory colorectal cancer
- high doses may decrease the number of aberrant crypt foci in smokers with abnormalities detected on colonoscopy
- it might reduce some symptoms of rheumatoid arthritis and might be more effective than diclofenac
- it might relieve odor and itching associated with skin cancers
Clinical research on turmeric is being funded by the National Center for Complementary and Alternative Medicine (NCCAM), but the NCCAM website is not very encouraging. Under the section What the Science Says, it reads:
- There is little reliable evidence to support the use of turmeric for any health condition because few clinical trials have been conducted.
- Preliminary findings from animal and other laboratory studies suggest that a chemical found in turmeric—called curcumin—may have anti-inflammatory, anticancer, and antioxidant properties, but these findings have not been confirmed in people.
- NCCAM-funded investigators have studied the active chemicals in turmeric and their effects—particularly anti-inflammatory effects—in human cells to better understand how turmeric might be used for health purposes. NCCAM is also funding basic research studies on the potential role of turmeric in preventing acute respiratory distress syndrome, liver cancer, and post-menopausal osteoporosis.
Turmeric is generally considered safe, but high doses have caused indigestion, nausea, vomiting, reflux, diarrhea, liver problems, and worsening of gallbladder disease. The NMCD warns that it may interact with anticoagulants and antiplatelet drugs to increase the risk of bleeding, that it should be used with caution in patients with gallstones or gallbladder disease and in patients with gastroesophageal reflux disease, and that it should be discontinued at least 2 weeks before elective surgery. Purchasers of supplements are not given that information.
The “14 drugs” website recommends that everyone:
use certified organic (non-irradiated) turmeric in lower culinary doses on a daily basis so that heroic doses won’t be necessary later in life after a serious disease sets in.
There is no evidence to support any part of that recommendation. And the scientific evidence for turmeric is insufficient to incorporate it into medical practice. As with so many supplements, the hype has gone way beyond the actual evidence. There are some promising hints that it may be useful, but there are plenty of promising hints that lots of other things “may” be useful too. Since I have no rational basis for choosing one over another, I see no reason to jump on the turmeric bandwagon. On the other hand, I see no compelling reason to advise people not to use it, as long as they understand the state of the evidence well enough to provide informed consent and know that they are essentially guinea pigs in an uncontrolled experiment that makes no attempt to collect data. I will keep an open mind and stay tuned for further evidence in the form of well-designed clinical studies in humans.
So, the bottom line on turmeric, our “snake-oil du jour” is
-there is nothing to support its use for any health condition
-potential dangerous side effects
-interacts with legitimate prescription meds
-crucial ingredient in curry
My advice-DONT”T TAKE IT!
7 thoughts on “Snake Oil Du Jour: Turmeric”
With all due respect, I have to share with you my turmeric (plus ginger) story. I am an early 50s female with a 15 year history of hypertension and a bad family history of deaths from myocardial infarction, congestive heart failure (both systolic – maternal grandmother – and diastolic – mother), and ischemic stroke.
I have been under the care of a highly respected cardiologist for my hypertension for the past 14 years or so. He has tried Losartan potassium, 25 and then 50 mg/day, which worked marginally for a couple of years, then stopped working, to the point that he accused me of noncompliance. Since my mother died recently, I had been taking 25 mg of Lopresor per day, primarily to combat frequent pvcs that I had apparently acquired from the stress – neither it not anything else I have taken has had any effect on that.
My doctor is not a fan of supplements of any kind, I hasten to add, though his nurse confided to me that she takes 1000 mg of turmeric per day.
I also suffer from obesity, asthma, psoriasis and insulin resistance, though not diabetes. I have been diagnosed by an endocrinologist with metabolic syndrome. In the past five years I have taken several courses of high dose corticosteroids to fight my other health issues, which also contributed to weight gain. I came down with the flu and bronchitis and went off the beta blocker because of its bad effects on my breathing. The only medications I was taking were a Z-pack, Singulair 10mg, and an albuterol inhaler as needed – no bp meds.
I recently got new health insurance, along with a primary care physician who ordered a large battery of bloodwork and other tests. My total cholesterol was 201 and my fasting glucose 101. I tested high for a marker for insulin resistance. I had a vitamin D deficiency.
I also had a sleep study, which diagnosed severe obstructive sleep apnea.
My blood pressure on a good day was in the 150s over the low 90s, all time high being 191 over 108.
I am a professional singer and on a trip two years ago managed to defeat a severe case of allergic sinusitis by taking a turmeric supplement along with my Singulair. I had also discovered by accident that a turmeric/ginger supplement can completely clear inflamed areas on my hands where topical steroids and all manner of medicated creams, and even prednisone, had failed.
I started taking the turmeric/ginger supplement, two 500 mg capsules per day, to give me an alternative to steroid treatment of the bronchitis. My bronchitis inflammation never made it past the very top of my chest, and a spot of inflammation on my right hand, of about 4 months’ duration, has cleared.
But the biggest surprise was that my blood pressure at my most recent primary care appointment was 102/73! I thought it must be inaccurate or an equipment malfunction, but at my cardiologist’s office for a nuclear stress test, I started at 141/94, after a long and stressful drive to the office. At the height of the stress test my bp was 151/100, then after the test immediately dropped to 138/82.
Turmeric is supposed to help with insulin resistance, and I find myself craving sugar, but I have noticed my clothes are appreciably looser. Is it helping?
I take the turmeric/ginger capsule with an 1140 mg dose of fish oil, as I had read that it helps bioavailability. I am not naming brands as I don’t want you to think I am a pitchwoman, but they are available on request.
Ok, well that’s my story. Believe it or disbelieve, as you wish. But I think this combination of supplements has at least earned a closer look.
You seem like a very reliable historian as we doctors like to say and I can tell you’re not pitching a supplement. I’m happy that you’ve found some relief from your medical issues with turmeric/ginger. I’m a firm believer in going with what clearly helps the patient (as long it is not hurting in some other way). If you are monitoring your BP and find it in a good range after taking the supplement by all means keep it up. But please keep monitoring your BP. It’s amazing how much BP randomly fluctuates in my patients ( and me) and at some point you may find it is persistently elevated even with the T/G and will require a prescription BP med with proven efficacy in large numbers of patients.
A friend has PSC with associated IBD. She uses turmeric 2x day to control symptoms of IBD. Anecdotal maybe, but https://www.researchgate.net/profile/Hiroyuki_Hanai2/publication/6696893_Curcumin_Maintenance_Therapy_for_Ulcerative_Colitis_Randomized_Multicenter_Double-Blind_Placebo-Controlled_Trial/links/56cda8e108ae059e3753264c.pdf and http://pubs.rsc.org/en/content/articlehtml/2012/fo/c2fo30097d point to efficacy. BTW she buys it for $7/kilo from a culinary supplier. I think a lot more study would help to verify or debunk ‘natural’ remedies but I don’t think drug companies will take it up as there no patents to gain.
I love that you post stuff like this. Merci!
Thank you, when I looked at this some time ago, some of your more well known professional “colleges”, ie Drs. Andrew Weil, Oz and others were recommending it for different reasons and one could find web sites touting it for whatever ails one. It also has the mystic appeal of being a major part of Siddha medicine (whatever that means). In any case, it is being touted as a super food and your skeptical enlightenment is welcomed.
Have you looked at nano delivery of curcumin? It’s touted to be much better absorbed. I tried the stuff for several months. Perhaps it was coursing around my system in its tiny way, but I never discerned any kind of difference from before or after in my random uncontrolled trial of one. I quit it, if only to salve my bank account.
If you’re selling a particular kind of snake oil and you have a lot of competitors selling what appears to be similar it seems a common technique to promote your particular kind is to claim some modification that makes it different and superior to all the others on the market. This might involve some chemical modification or addition of something to help its absorption or prevent its breakdown. In the end it is all marketing, hype and snake oil.