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Curry spice turmeric boosts memory by nearly 30%, eases depression, study finds

726 points| bcaulfield | 8 years ago |ac.els-cdn.com

386 comments

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[+] YeGoblynQueenne|8 years ago|reply
From the Wikipedia page on Curcumin (section Research):

  In vitro, curcumin exhibits numerous interference properties which may lead to 
  misinterpretation of results.[3][6][20] Although curcumin has been assessed in 
  numerous laboratory and clinical studies, it has no medical uses established by 
  well-designed clinical research.[21] According to a 2017 review of over 120 
  studies, curcumin has not been successful in any clinical trial, leading the 
  authors to conclude that "curcumin is an unstable, reactive, non-bioavailable   
  compound and, therefore, a highly improbable lead".[3]
The study claims to have studied a bioavailable forom of curcumin, Theracumin® but it uses a very restricted interpretation of "bioavailability":

  The use of adjuvants that block curcumin metabolism, or nanoparticles, liposomes, 
  phospholipid complexes, and other strategies have improved its bioavailability somewhat, 
  but only as defined as increased curcumin blood levels8,64–66 with minimum effects on   
  curcumin availability to the brain.
The study also notes its sample was small:

  The relatively small sample size in this study warrants caution in interpreting 
  our results and limits their generalizability. 
It just doesn't sound like their results are going to stand the test of time.
[+] dumbneurologist|8 years ago|reply
None of your criticisms from wikipedia pertain to this publication. The paragraph is essentially making the argument that a randomized, double blind (DB), placebo controlled (PC) clinical trial (RCT) is unlikely to show that curcurmin is effective. yet, the published article is exactly that, and shows a statistically measurable impact on a clinically meaningful endpoint: a direct refutation of the paragraph.

the fact the "interference properties" and being an "unstable, reactive, non-bioavailable compound" is subsumed by the study design.

  claims to have studied a bioavailable form of curcumin
This is not really relevant to the claim or conclusions. could it be that the bioavailability matters? maybe. could it be that curcurmin is a trick molecule to study? yes. but come what may, this is direct evidence (not proof) of a cause-effect relationship between this treatment and the outcome.

the only thing this effects is the chance that other forms of curcurmin will be comparable (and it might have consequences for regulatory status by the FDA).

  The study also notes its sample was small
This is a very weak criticism when the study is positive (i.e. shows an effect). when the sample size (and statistical power) of the study is small, you need a BIG EFFECT SIZE to be positive. The fact that the trial was positive actually means that it's more likely to be clinically important, because a big effect size means it protects memory in a dramatic way. This is like penicillin: in the pre-antibiotic era, how many cases of pneumonia do you need to treat in order to be satisfied that penicillin is effective? Not bloody many, because the effect size is so dramatic. Likewise for parachutes. few are the therapies that fall into this category, but when you have an inkling that one does following a DB, PC, RCT, you better pay attention.

So does it need to be replicated? definitely. does the sponsorship matter? definitely; they could have cheated in some way. until then does it make sense to prescribe this to seniors, or encourage them to increase curcurmin in their diet? quite possibly, given the presumably low rate of adverse effects.

Bottom line: this study is not the end-all be-all of curcurmin and memory, but there is legitimate early evidence that the emperor has clothes.

edits: mainly spelling, formatting

[+] mrguyorama|8 years ago|reply
>Because curcumin's anti-inflammatory properties may protect the brain from neurodegeneration

My very first question was: Please provide a possible physiological pathway for this. I'm so glad it was answered in the very first sentence. So many of these "Superfood does X" studies are just trials with 10 people over a month, with no explanation as to __how__ it could possibly happen. It significantly increases the skepticism I have whenever something like this comes up

I also did not know Turmeric had anti-inflammatory properties. I guess I have reading to do.

Also interesting that they used (what seems to be) a name brand supplement instead of Turmeric

[+] dumbneurologist|8 years ago|reply
I am a neurologist. this is actually the exact opposite of what you should care about, which is "does it work to treat ___"

In this trial, and 99% of other trials, there is no mechanism provided by the study, only a measurement of causality (which is the same thing as effectiveness).

The authors may think they know based on other, prior, basic science research (as they are postulating here), but it does not affect the conclusions of the trial ( whether they do or don't (or even if they are wrong).

Obviously it's intellectually satisfying to understand WHY, but it's not as important as "is it true?"

[+] blacksmith_tb|8 years ago|reply
For all the claims of bioavailability, I was surprised to see that Theracumin(R) doesn't seem to contain piperine[1] or any perines (which are usually in curry powder courtesy of black pepper). The 90mg dosage also seemed low, I have been taking 500mg of 95% extract daily for a couple of years.

1: https://www.ncbi.nlm.nih.gov/pubmed/9619120

[+] bcaulfield|8 years ago|reply
Looking through the comments, I'm really glad I posted the paper itself to HN, rather than the various writeups of it.
[+] maxxxxx|8 years ago|reply
Turmeric has helped me quite a bit with my inflamed joints after learning about it at a yoga ashram. Now I cook a lot with it. What i have noticed though is that supplements do nothing for me. I only feel a difference when it's fresh powder or even better ground from a root.

I have done several experiments where I stopped taking it. Every time my joints got worse and then better after resuming cooking with Turmeric.

No idea how it works but it seems to work.

[+] jeffshek|8 years ago|reply
I post this whenever HN brings up a comment about supplements -- but I created a site to help track people trying out a lot of supplements and how it impacted health and sleep.

HN and QuantifiedSelfers find this as a niche site to record correlations and habits for self improvement.

https://betterself.io/ (Open sourced)

[+] rdlecler1|8 years ago|reply
This is how science works. You start with an anomalous discovery. Publish it, write a grant to do more research.
[+] 40acres|8 years ago|reply
More it more I'm learning that inflammation is a huge problem in modern health. I'd be very interested in a list of anti-inflammatory foods, supplements and behaviors.
[+] neeleshs|8 years ago|reply
I agree. "How" is a difficult question to answer, and involves basic research. "X does Y" studies need a hypothesis, a bunch of test subjects, and some statistical wrangling. Far easier than basic research. I'm now at a point to take all statistical studies with a pinch of salt. Molecular studies are more interesting and while micro and may miss the macro picture, are more promising.
[+] stordoff|8 years ago|reply
Not to say it's not useful (a plausible method of action + weak evidence is more suggestive that further study is needed than weak evidence alone, and that understanding could lead to further developments), but the question of does this work is far more important, and can be answered without knowing the how.
[+] vondur|8 years ago|reply
I vaguely remember reading that the physiology of acetaminophen is still not completely understood. I doubt we will be lucky to figure this one out quickly. I also remember reading that the level of dementia in India is much lower than western nations and turmeric was thought to be part of the reason for that.
[+] kumarvvr|8 years ago|reply
Im from India. Whenever I get a throat infection, my grandmother gives be a spoonful of turmeric powder mixed with very hot milk, no sugar.

Till date, it has not failed once to cure the inflammation/infection/pain. The infection is gone within a day or atmost a couple of days.

[+] IntronExon|8 years ago|reply
Given what we’re learning about the impact of gut microbiome on CNS, immune system, and other systems I wonder if the GI effect is it, but with secondary effects related to activity of bacterial colonies.
[+] hannob|8 years ago|reply
Small study, probably not preregistered (didn't find anything about it in the description). Likely Publication Bias or p-hacking. I'm starting to get interested when it's been independently replicated.
[+] sov|8 years ago|reply
> Small study

Almost entirely irrelevant, provided it's properly powered--and based on the effect size and p-values, it is. Furthermore, for an 18 month trial, 40 people is larger than most.

> probably not preregistered

I mean, true, and we should definitely promote pre-reg, but, 1. so few are preregistered that I'm not sure it's prudent to disregard a study based on this and 2. it's an academic study, neither a clinical trial nor a public-health decree--not a typical study type that necessitates pre-registration.

> Likely Publication Bias or p-hacking.

What? You're arrived at this conclusion based on... the fact that it's "small" and you couldn't find preregistration about it?

> I'm starting to get interested when it's been independently replicated.

Yeah, if only there were another trial that showed a positive cognitive effect of bioavailable curcumin... https://www.ncbi.nlm.nih.gov/pubmed/25277322

I mean, the title of this post is by far the most wrong thing about this article, as...

1. it's not turmeric, it's curcumin, which is about 2% of turmeric by mass (so, you'd need to eat ~4.5g turmeric daily to match study doses).

2. curcumin doesn't even have any reasonable bioavilability by itself, so they're using a bioavailable analogue.

[+] pytonslange|8 years ago|reply
It was registered as a clinical trial (https://clinicaltrials.gov/ct2/show/NCT01383161?term=NCT0138...). If you are concerned about p-hacking and replicability, what should worry you is that the outcome measures posted during registration are rather vague, i.e. ".. show less evidence of cognitive decline (as measured with neuropsychological assessments)"

At baseline, they performed an extensive neuropsychologist test battery, including a bunch of subtests:

  -Trail Making Test A
  -WAIS-III Digit Symbol Substitution
  -WAIS-III Block Design Test
  -Rey-Osterrieth Complex Figure Test (copy)
  -Trail Making Test B
  -Stroop Interference
  -F.A.S.
  -Buschke-Fuld Selective Reminding Test [SRT]
  -Wechsler Memory Scale-3rd Edition [WMS-III] 
  -Verbal Paired Associations I
  -Benton Visual Retention Test
  -Buschke-Fuld SRT
  -Rey-Osterrieth Complex Figure Test [recall]
  -WMS-III Verbal Paired Associations II
  -Boston Naming Test
  -Animal Naming Test
The outcome measures they report are:

  -TMT-A
  -SRT
  -BVMT-R
I would be _very_ surprised if those were the only tests they performed at followup after a 18 month (expensive) clinical trial. If these measures had been specified as the only outcome measures of interest, noone would question the results. But, when it was not registered, and when no other measures are reported, not even in the supplementary, the reader is left to wonder why that is.
[+] soneca|8 years ago|reply
Great "credibility check". There should be a "nutriction facts table" for scientific papers quoted at articles. Sample size, preregistration, replication, p-value.

At least a practice to include that in the abstract

[+] piyh|8 years ago|reply
If every study on tumeric, tea, chocolate, and coffee was fully accurate we'd all be immortal by now.
[+] roystonvassey|8 years ago|reply
This is becoming an increasingly worrying trend - to bunk any analysis with a comment on 'small sample size, biases' that somehow moves to the top of the comment pile.

Statistically, there is no such thing as a 'small sample size', in isolation. It is always related to the power and effect that the researchers want to work with.

Moreover, even if a study is statistically insignificant, it DOES NOT mean that the opposite conclusion is true. It might often merit some further examination of cultural and historical trends. In this case, for instance, turmeric has been used for medicinal properties in Asian cultures for centuries. Theories of evolution suggest that this wouldn't be the case (and it would've died a natural death), if there wasn't some merit.

[+] piracy1|8 years ago|reply
It's possible, but I think (not that I'm an expert) that this is not the first piece of evidence to suggest this. A year or two was recently speaking with a researcher who studies Alzheimer's and he had told me about how in cultures where more curry and turmeric was consumed there was significantly less Alzherimer's. I'll try to find a source for this and update my comment.
[+] EnderWT|8 years ago|reply
Examine.com has a page for curcumin. They cite 5 sources with notable impacts on reducing depression, but they summarize with this:

"Curcumin seems to be somewhat more effective than placebo in reducing symptoms of depression. It may take 2-3 months to see any outcomes. Skepticism is warranted though, as the studies comparing curcumin to placebo were not well designed and produced effect sizes not too far apart, even though the differences were statistically significant."

https://examine.com/supplements/curcumin/#hem-depression

[+] loeg|8 years ago|reply
Results too good to be true, as well :-).
[+] dumbneurologist|8 years ago|reply
agree that replication is important and that it's too early to believe fully, but when a study size is small and you still find a difference, then it implies the effect size is large.

If you meet statistical significance, then diminishing n means increasing clinical significance.

[+] platz|8 years ago|reply
What is the power & effect size?
[+] Karupan|8 years ago|reply
Personal anecdote: was born and brought up in south India and my grandma used to make me drink turmeric + ground black pepper milk every night. It was a standard practice to serve it with black pepper, even though I’m sure they didn’t really know about bioavailability. Kids were forced to drink it when they have the flu.

Used to hate it as a kid, but of late I’ve been looking to replace one coffee/tea with turmeric milk.

[+] gopalv|8 years ago|reply
> was born and brought up in south India and my grandma used to make me drink turmeric + ground black pepper milk every night

I grew up in a part of South India with a fairly high natural background radiation (thorium, mostly) and I did wonder if the practice boosted survival via accidental cancer protection from an alpha decay environment.

Natural selection is weird because the goal of taking turmeric might have nothing to do with the survival advantages.

[+] Florin_Andrei|8 years ago|reply
Just curious: what's the amount of each ingredient that goes in one drink?
[+] glangdale|8 years ago|reply
For those commenting on bioavailability, black pepper supposedly makes it more bioavailable:

https://examine.com/supplements/curcumin/

It's an interesting result, but they do note that the subpopulation is somewhat self-selected: "Only approximately 15% of the screened volunteers were included in the study, and our recruitment method yielded a sample of motivated, educated, physically healthy subjects concerned about age-related memory problems. The sample, therefore, was not representative of the general population. "

[+] nwah1|8 years ago|reply
Black pepper increases bioavailability of everything by inhibiting your cytochrome p450 enzymes, which increases your vulnerability to toxins.
[+] flipp3r|8 years ago|reply
Very interesting to see this posted. In Japan its ingredients are used in an anti-hangover drink, this youtube video https://youtu.be/Ij_aJI5O9Rs goes somewhat deeper into it, where the poster tried a combination of it and pepper to strengthen the effect.
[+] sturmen|8 years ago|reply
Note: this was a relatively small sample (40 total, split in half for placebo/not), who were elderly people who already have "mild" memory problems, and given a concentrated turmeric derivative rather than just sprinkling it over food.

In summary: very cool, and I'd offer these curcumin supplements to anyone 50+ but sprinkling turmeric on your breakfast cereal ain't going to do much for high schoolers.

[+] mikeleung|8 years ago|reply
There are side effects to be aware of taking curcumin together with other medications:

"Medications for diabetes (Antidiabetes drugs) Interaction Rating: Moderate Be cautious with this combination. Talk with your health provider. Turmeric might decrease blood sugar in people with type 2 diabetes. Diabetes medications are also used to lower blood sugar. Taking turmeric along with diabetes medications might cause your blood sugar to go too low. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.

Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others."

Turmeric might slow blood clotting. Taking turmeric along with medications that also slow clotting might increase the chances of bruising and bleeding.

Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates) Interaction Rating: Moderate Be cautious with this combination. Talk with your health provider. Some medications are changed and broken down by the liver. Turmeric might decrease how quickly the liver breaks down some medications. Taking turmeric along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking turmeric talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications that are changed by the liver include some calcium channel blockers (diltiazem, nicardipine, verapamil), chemotherapeutic agents (etoposide, paclitaxel, vinblastine, vincristine, vindesine), antifungals (ketoconazole, itraconazole), glucocorticoids, alfentanil (Alfenta), cisapride (Propulsid), fentanyl (Sublimaze), lidocaine (Xylocaine), losartan (Cozaar), fexofenadine (Allegra), midazolam (Versed), and others."

https://www.rxlist.com/turmeric/supplements.htm#Interactions

[+] dahidahi1|8 years ago|reply
Turmeric has been used in India since ancient times. There are many references to it in Ayurveda - the Indian/Hindu medical sciences. Ayurveda believes in using food as medicine to non only prevent a large majority of human diseases, but also to cure several of them — all with almost zero side effects. Turmeric is just one such extremely powerful & healthy food item that Western science seems to be playing catch up on. Many others like black pepper, honey, asafoetida (hing), coconut oil, copper utensils, cloves, cardamom, mustard seeds, neem (gold), milk, clarified butter (ghee). So, expect more things to come out from the research of Western labs, knowledge that is common to most grandmothers in India for ages. But the other aspect is that we are slowly losing all that because Indians try to mimic the West in almost everything they do & nowadays do not trust our own sciences like Ayurveda etc, even at the risk of debilitating side effects.

Side fact: An American company tried to patent turmeric & almost got away with it. This had to be fought by the Indian government to prevent (or nullify) the patent application.

[+] blambljoob|8 years ago|reply
The wikipedia for curcumin suggests that it is not bioavailable. The results of this study are attributed to the supplement Theracurmin, which is a bioavailable form of curcumin. So maybe don't bother increasing your turmeric intake based on this study.

Lots of people won't realize that though, and by the time this research gets through the news cycle people will be buying turmeric in bulk. Good time to buy stocks in turmeric producers?

[+] jmckib|8 years ago|reply
So is this outdated now?

> The review goes into four examples for which details are available, all of them complete wipeouts, and those would seem to serve as good proxies for the rest given that no curcumin trial has ever reported any convincing positive results.

http://blogs.sciencemag.org/pipeline/archives/2017/01/12/cur...

[+] mtw|8 years ago|reply
For every turmeric study claiming health benefits, I can also find a study finding none. It's one of the most controversial subject. Read several papers at least before deciding anything. It's even less clear when you try to evaluate curcumin vs turmeric.
[+] xiaopanga|8 years ago|reply
Did no one read the last bit on the people who did the research? there seems to a clear conflict of interest in this paper. " Dr. Small also reports having served as an advisor to and/or having received lecture fees from Allergan, Argentum, Axovant, Cogniciti, Forum Pharma- ceuticals, Herbalife, Janssen, Lundbeck, Lilly, Novartis, Otsuka, and Pfizer. Dr. Heber reports receiving consult- ing fees from Herbalife, and the McCormick Science Institute.The manufacturer of Theracurmin, Theravalues Corpora-tion, provided the Theracurmin and placebo for the trial,funds for laboratory testing of blood curcumin levels, and funds for Dr. Small’s travel to the 2017 Alzheimer’s As- sociation International Conference for presentation of the findings"
[+] jtwebman|8 years ago|reply
30 total people with 15 on placebo seems like a very small sample size to me but a great study to maybe get funding for a bigger one for sure.
[+] reubenswartz|8 years ago|reply
Don't know about the study-- it seems interesting but like more research is needed-- but I do know that if you throw a little turmeric on your broccoli or cauliflower or whatever, before you roast, the veggies come out extra delicious. My kids will even eat them without complaining. ;-)
[+] ggm|8 years ago|reply
And in late breaking news, sales of bleach and clothes whitener are up worldwide as turmeric is discovered to be a potent yellow dye for clothes...
[+] relyks|8 years ago|reply
I'm surprised no one has mentioned here that there's been research on using Turmeric as an antidepressant. It's known to increase BDNF in the brain, the same protein generated during aerobic exercise. BDNF is one of the reasons exercise is so beneficial for mental health.

"Antidepressant-like effects of curcumin in WKY rat model of depression is associated with an increase in hippocampal BDNF" (https://www.sciencedirect.com/science/article/pii/S016643281...)

"Effects of curcumin on brain-derived neurotrophic factor levels and oxidative damage in obesity and diabetes" (http://www.nrcresearchpress.com/doi/10.1139/apnm-2013-0133)

[+] AdmiralAsshat|8 years ago|reply
Glanced at the study. The supplement appeared to be 90mg of curcumin, taken twice daily.

A quick google search says there are about 15 mg per tablespoon. That would mean you'd need to eat about 6 tbsp of turmeric to get a comparable amount. Probably even more so, since I don't think turmeric is pure curcumin. For reference, the average curry or other dish using turmeric in my household takes about 1 tbsp, so at a glance I would consider it impractical to get that much naturally through your food.

My next curiosity would be whether a smaller amount can show similar benefit, or whether it needs to be at a level only available in a supplement.