I recently encountered a website touting the “tremendous’ health benefits of Turmeric. Having been intrigued, I decided to look into the background of its claims.
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. You probably know turmeric as the main spice in curry. 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 disease, 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.. Whenever one encounters such excessive claims that sound “too good to be true”, that’s exactly what they usually prove to be.
The Natural Medicines Comprehensive Database has reviewed all the available scientific studies and has concluded that turmeric is “Likely Safe,” “Possibly Effective” for dyspepsia and osteoarthritis, with “Insufficient Reliable Evidence” to rate effectiveness for other indications, such as Alzheimer’s disease, colorectal cancer, rheumatoid arthritis, and skin cancer.
Mechanism of action
The pertinent preclinical studies, in animal models and in vitro, indicate that curcumin, the presumed active ingredient in turmeric, has anti-inflammatory properties; can induce apoptosis (death) in cancer cells and may reduce microscopic changes of Alzheimer’s brains; has antithrombotic effects; and displays activity against some bacteria,. These effects sound promising, but animal studies and in vitro laboratory studies may not be applicable to humans. Although you can kill cancer cells in the laboratory with a flame thrower or bleach, animal studies must always be followed by clinical studies in humans before we can make any recommendations to humans.
Preliminary clinical research
Preliminary pilot studies of turmeric in humans suggest the following:
- it does not change mental state examination scores in Alzheimer’s
- it might improve symptoms in anterior uveitis (eye inflammations)
- it might stabilize some markers of colorectal cancer in some patients with treatment refractory colorectal cancer
- high doses may decrease the number of aberrant focal abnormalities detected on colonoscopy
- it might reduce some symptoms of rheumatoid arthritis.
Clinical research on turmeric is currently 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 states:
- 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 other diseases..
I might add parenthetically that NCCAM has, in its entire history, produced virtually nothing that might alter our current practice of science-based medicine.
Turmeric is generally considered safe, but high doses have caused indigestion, nausea, vomiting, acid reflux, diarrhea, liver problems, and worsening of gallbladder disease. 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 it should be discontinued at least 2 weeks before elective surgery. Purchasers of supplements are not given that information.
The scientific evidence for turmeric is insufficient for managing any human health problems. As with so many supplements, the hype has far exceeded the evidence, and this serves only to separate the public from its money. Although there are some promising hints that this substance may be useful, there are plenty of promising hints that lots of other supplements “may” be useful too. Given this monumental lack of substantive evidence, I see no reason to jump on the turmeric bandwagon. Stay tuned for further evidence, however, in the form of well-designed clinical studies in humans. Once in a very long while, we accidentally encounter a really effective drug such as quinine or aspirin, but usually we wind up instead in the “snake oil pit.”