Begin with the idea that inflammaging is one of the four programs of self-destruction which take over our bodies later in life. Quelling the body’s inflammation is one of the best anti-aging strategies we have, and curcumin is the most effective herbal anti-inflammatory agent we know. It couldn’t be clearer…
But look below the surface, and things are more ambiguous, more complicated as usual. Yes, I believe that curcumin has a place in a longevity program, but how much to take? and in what form? These are questions that only get more difficult in the light of hundreds of studies, some with results that are contradictory in crucial ways.
The first mystery about curcumin is that there is a long tradition of turmeric root in Ayurvedic and Oriental medicine, yet hardly any curcumin is absorbed from the stomach. Are there other compounds in the turmeric root that facilitate absorption of curcumin? Or maybe curcumin is not the only beneficial ingredient in turmeric. There is a lot of literature documenting the metabolic effects of curcumin, but only one study I could find that compared curcumin to whole turmeric (and some of its reported findings were so strange that it makes me suspicious of everything in this paper).
First, the benefits:
Curcumin acts by a similar mechanism to aspirin and other NSAIDs, inhibiting COX chemistry that promotes inflammation. In addition, curcumin suppresses the action of NFkB, a signaling chemical that promotes inflammation, and increases in prevalence as we age, to our detriment. This is theoretical ground for believing that curcumin can do something that aspirin does only weakly, so curcumin may have benefits even for those who are already taking daily aspirin or ibuprofen. There are also some rodent experiments [ref, ref] suggesting that aspirin + curcumin is better than aspirin alone.
I have written that anti-inflammatory supplements are the easiest and surest longevity program currently available. Surely curcumin finds a place in this program.
Curcumin has been demonstrated to kill cancer cells grown in the lab [ref, ref, ref, ref]. In mice and rats, oral curcumin has been shown to prevent cancer [ref, ref, ref], and in humans there have been some small epidemiological studies. A search of ClinicalTrials.gov produced 97 studies, about a third of them involving cancer. Cancers of the digestive tract are most likely first targets, because of the difficulty of getting curcumin into the bloodstream.
Evidence that curcumin protects against AD is even stronger than for cancer. There has been extensive experimentation with cell cultures [ref] and with rodents [ref], and in addition there is the human epidemiology, linking consumption of curry spices to protection against AD. Age-adjusted incidence of AD is far lower in India than in America ([Ref] compiled separately for people with different alleles of the gene APO-E) and the difference has been statistically linked to eating curry [Ref]. Often I am skeptical of cross-cultural comparisons, because so many differences are difficult to untangle, but in this case, understanding of the underlying biochemistry is so strong that I think the attribution to curry is probably warranted.
Since turmeric is only about 10% of curry, and curcumin is only a few percent of turmeric, and curcumin absorption in blood tests is less than 1%, it would be predicted that the amount of curcumin that is absorbed by people who eat curried foods ought to be too small to matter, and yet it doesmatter. I take this to mean that there is something we don’t yet understand about turmeric’s mechanism of action. In addition, there is at least one known synergy between turmeric and other spices that might be eaten with it: black pepper increases the staying power of curcumin in the bloodstream (more below).
For the last decade, it has been acknowledged that osteo arthritis, like rheumatoid arthritis, is better described as an auto-immune disease than as a wearing-away of cartilage. This would seem to be a natural application for curcumin, but study has just begun. [Example]
Curcumin and cardiovascular disease
Also: whole turmeric is a vaso-relaxant [ref]. This means that eating turmeric might protect against heart disease in the near term. In other columns, I’ve tried to make the distinction between slowing the aging process and cutting the immediate risk of mortality. Of course, both are valuable. Aspirin, for example, slows aging by damping inflammation, and also cuts the risk of stroke and heart attacks in the near term by reducing blood clots. In that curcumin is an anti-inflammatory agent, it may slow the aging process. To the extent that curcumin makes arteries more pliable, curcumin might also lay claim to reducing mortality, and by a different mechanism from aspirin, so that we might hope the effects (aspirin + curcumin) are additive.
Warning: Telomerase inhibitor
Part of the mechanism by which curcumin kills cancer cells is to inhibit telomerase. Does curcumin also inhibit telomerase in healthy cells? We need telomerase to keep our stem cells healthy into old age, so this is potentially a pro-aging function of curcumin. I have found no data on the effect of curcumin on telomerase expression in healthy, non-cancerous cells.
Absorption and the fundamental mechanisms of action
It seems to be a common experimental finding that, after dosing a subject with turmeric or curcumin, no curcumin can be detected in the blood – and yet the full therapeutic benefit is being realized [Examples 1, 2, 3]. In some studies, curcumin could easily be found in urine samples, but was undetectable in the blood. This situation suggests to me that something basic may be missing from our understanding of the metabolic chemistry of turmeric and curcuminoids. Curcumin was identified more than 200 years ago as the active ingredient in turmeric, and most research up to this date has been designed and interpreted as though nothing else mattered but delivery of curcumin into the blood and thence into the body’s cells. But perhaps there are metabolites that we have yet to identify, or perhaps a combination of chemicals acts synergistically.
A great deal of work has been done in recent years that is narrowly focused on delivery strategies that raise measured levels of curcumin in the blood. This activity is commercially motivated. Here is a promising herb that is cheap* and un-patentable, so companies are clamboring to distinguish their products with proprietary processing for increased absorption. But it may be that we don’t know enough yet to be sure that curcumin is all that matters, or that higher blood levels for longer times translate into better effectiveness.
Two issues of bioavailability are discussed in this this 2007 review: First, inability to cross the stomach lining into the blood; second, the liver efficiently removes curcumin from the blood and breaks it down before it can be effective. Liposomes address the first issue. A liposome is a microscopic bubble of edible oil (“lipid”) which can carry a small quantity of chemical payload across the stomach wall. Piperine (a chemical constituent of ordiary black pepper) addresses the second issue [ref], slowing breakdown of curcumin in the liver. A phytosome is a liposome that contains a payload of multiple chemical species, and phytosomes are commercially available that combine curcumin with piperine.
Three formulations of curcumin with enhanced bio-availability are sold as Mervia, BCM-95and Longvida. All three use liposome microencapsulation, and include different proprietary ingredients and processes. Dr Trutt describes the three, and recommends Longvida, based on indirect reasoning: Longvida has the most credible data for getting curcumin into the bloodstream, and only curcumin has been shown in lab tests based on cell biology to protect against Alzheimer’s Disease. He may be right, but I would like to see some human or animal studies, since there are often surprises in the inference from cell culture to whole animal.
I wish there were more research on components of turmeric, together and separately; less on curcumin in isolation. I wish there were more research with health and longevity as measured outcomes, less emphasis on blood levels of curcumin.
Until we have much better understanding, I’m going to suggest that whole turmeric with black pepper is the most conservative path to supplementation. It tastes great with eggs.
The bottom line
Turmeric, with its main active ingredient curcumin, is a potent anti-inflammatory agent with evidence suggesting that it can lengthen human life span, while protecting against cancer and Alzheimer’s disease, and possibly cardiovascular disease as well. Most of the benefits overlap with aspirin/NSAID. For those who prefer not to take NSAIDs because of stomach issues or because of a preference for “natural” products, turmeric provides unequivocal benefits. And even if you are already taking NSAIDs, there are probably some additional benefits from turmeric.
Large quantities of turmeric are the most conservative and the cheapest form. If you’re thinking in terms of daily supplementation, teaspoonsful of turmeric may be the least convenient form; but if you like Indian cooking, it may be the most convenient way to dose yourself with turmeric.
Turmeric has a long and venerable history, and it is not entirely clear how the different chemical components of turmeric might interact. Eating turmeric with a small quantity of black pepper greatly increases the body’s uptake.
There is research to indicate that curcumin is the most important active ingredient, and concentrated curcumin can be taken conveniently in a pill that is twenty times smaller than the portion of whole turmeric from which it is derived. Absorption into the body is still an issue, and there are various commercial formulations of curcumin that claim to have resolved this issue, supported mostly by in-house studies.
If you are taking telomerase-activation supplements, then there is potential for curcumin to interfere with their action. Whether this is a serious problem is not known, but to be safe you may want to alternate telomerase activation with curcumin, for example on a cycle of 3 to 8 weeks.
Thanks to Steve Ellis of Edible Science for suggesting that I look into curcumin, and providing references and links. The views expressed here are mine and not his.
This post originally appeared on Josh’s blog here: http://joshmitteldorf.scienceblog.com/2014/05/01/turmeric-curcumin/