Just because something is natural and plant-based doesn’t mean it’s necessarily safe. Those who are pregnant, have gallstones, or are susceptible to kidney stones may want to moderate their turmeric consumption.
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Following flax and wheatgrass, turmeric is the third best-selling botanical dietary supplement, racking up $12 million in sales, and sales are increasing at rate of 20%.
Curcumin is a natural plant product extracted from the turmeric root, used commonly as a food additive, popular for its pleasant mild aroma and exotic yellow color, considered unlikely to cause side effects. Just because something is natural, though, doesn't mean it's not toxic. Strychnine is natural; cyanide is natural. Lead, mercury and plutonium are all elements—can't get more natural than that. But turmeric is just a plant. Plants can't be dangerous. Tell that to Socrates.
In considering the validity of the widely accepted notion that complementary and alternative medicine is a safer approach to therapy, we must remind ourselves and our patients that a therapy that exerts a biologic effect is, by definition, a drug and can have toxicity. It cannot be assumed that diet-derived agents will be innocuous when administered as pharmaceutical formulations at doses likely to exceed those consumed in the diet.
Traditional Indian diets may include as much as a teaspoon of turmeric a day, which is the equivalent of about this much fresh turmeric root. If you look at the doses of turmeric that have been used in human studies, they range from less then just a 16th of a teaspoon a day up two tablespoons a day for over a month. Whereas the curcumin trials have used up to the amount found in cups of the spice, around 100 times more than what curry lovers have been eating for centuries.
Still without overt serious side effects in the short-term, but if one combined both high dose curcumin with black pepper for that 2000% bioavailability boost, that could be like consuming the equivalent of 29 cups of turmeric a day. That kind of intake could bring peak blood levels up around here, where you start seeing some significant DNA damage in vitro.
So just incorporating turmeric into your cooking may be better than taking curcumin supplements, especially during pregnancy. The only other contraindication cited in the most recent review was the potential to trigger gallbladder pain in individuals with gallstones.
If anything, curcumin may help protect liver function and help prevent gallstones by acting as a cholecystokinetic agent, meaning it facilitates the pumping action of the gallbaldder to keep the bile from stagnating. In this study they gave people a small dose of curcumin, about the amount found in like a quarter teaspoon of turmeric and using ultrasound were able to visualize the gallbladder squeezing down in response, with an average change in volume of about 29%. Optimally, though, you'd want to like squeeze it in half, so they repeated the experiment with different doses. And it took about 40 milligrams to get a 50% contraction. That's about a third of a teaspoon of turmeric every day. On one hand that's great—totally doable, but on the other hand I'm thinking wow, that's some incredibly powerful stuff. What if you had a gallbladder obstruction? if you had a stone blocking your bile duct and you eat something that makes your gallbladder squeeze that could hurt like heck! So patients with biliary tract obstruction should be careful about consuming curcumin, but for everyone else these results suggest that curcumin can effectively induce the gallbladder to empty and thereby reduce the risk of gallstone formation and ultimately even gall bladder cancer.
Too much turmeric, though, may increase the risk of kidney stones. As I mentioned in a previous video, turmeric is high in soluble oxalates, which can bind to calcium and form insoluble calcium oxalate, which is responsible for approximately 75% of all kidney stones, so the consumption of even moderate amounts of turmeric would not be recommended for people with a tendency to form kidney stones. Such folks should restrict the consumption of total dietary oxalate to less than 40 to 50 mg/day, which means no more than at most, a teaspoon of turmeric. So for example those with gout are by definition, it appears, at high risk for kidney stones, and so if their doctor wanted to treat gout inflammation with high dose turmeric, then that's where curcumin supplements might come into play, because to reach high levels of curcumin in turmeric form would incur too much of an oxalate load.
If you are going to take a supplement, how do you choose? The latest review recommends purchasing from Western suppliers that follow recommended Good Manufacturing Practices, which may decrease the likelihood you're buying an adulterated product.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ariel Levitsky.
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This is the last installment of a 6-part video series on the power of spices in general and turmeric in particular. I started out discussing the role spices play in squelching inflammation and free radicals in Which Spices Fight Inflammation? and Spicing Up DNA Protection. Then out of the lab into the clinic with attempts to test the ability of turmeric extracts to treat joint inflammation with Turmeric Curcumin and Rheumatoid Arthritis and Turmeric Curcumin and Osteoarthritis. My last video, Boosting the Bioavailability of Curcumin, discussed ways to improve the absorption of these anti-inflammatory and antioxidant compounds.
I wish there was more science on wheatgrass. I just had that one unhelpful anecdote in my video How Much Broccoli Is Too Much? There is good science on flax though. See:
More on gallbladder health can be found in my video Cholesterol Gallstones. And those who are susceptible to kidney stones should try to alkalinize their urine by eating lots of dark green leafy vegetables (but then shouldn’t we all :). See Testing Your Diet with Pee & Purple Cabbage.
Based on this new science on turmeric (lots more to come!), I now try to include it in my family’s daily diet.
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