Talk:Curcuminoid

Some Major Missing Information

See Aggarwal's very comprehensive review of curcumin. http://www.springerlink.com/content/q73308813202502m/. This is one of the most complex polyphenols in terms of its effects. Tons of pathways, many different and barely appreciated molecular actions. DFW Harvard Medical School —Preceding unsigned comment added by 207.180.129.233 (talk) 20:45, 15 September 2008 (UTC)

Curcumin web sites

Please add your favorite site, thas has reliable scientific references.

Here is one: http://examine.com/supplements/Curcumin/

"This page features 234 unique references to scientific papers".

88.192.39.165 (talk) 16:17, 20 January 2015 (UTC)

Deletion of dubious content

I have deleted a part of the lede as it is unreferenced, out of place, and conflicts with other articles here on the same subjects. The passage deleted is in bold:

"A curcuminoid is a linear diarylheptanoid, with molecules such as curcumin or derivatives of curcumin with different chemical groups that have been formed to increase solubility of curcumins and make them suitable for drug formulation. These compounds are natural phenols .."

The lede of the Diarylheptanoid article states:

"The diarylheptanoids are a relatively small class of plant secondary metabolites. .. They can be classified into linear (curcuminoids) and cyclic diarylheptanoids. The best known member is curcumin, .. "

A curcuminoid is a linear diarylheptanoid, and a diarylheptanoid is a plant secondary metabolite, and, as this article itself later makes clear, the chemicals used to increase solubility are not in themselves curcuminoids. Curcumin is a curcuminoid, as too is demethoxycurcumin, and bisdemethoxycurcumin - see e.g [Turmeric|Turmeric]].

I have edited the lede accordingly, but if the deleted passage is nevertheless correct and relevant is some manner, then that should be made clear by means of suitable contextualization and reference (and the other articles corrected accordingly) before adding it back in.

LookingGlass (talk) 11:26, 23 October 2021 (UTC)

Deletion of effect on IL-6 levels

My recent change was reverted due to "8 years out of date, WP:MEDDATE; no confirmation by a WP:MEDRS review". My questions regarding this are the following:

• Why isn't my reference a WP:MEDRS review?
• WP:MEDDATE states "These instructions are appropriate for actively researched areas with many primary sources and several reviews, and may need to be relaxed in areas where little progress is being made or where few reviews are published." and "In many topics, a review that was conducted more than five or so years ago will have been superseded by more up-to-date ones, and editors should try to find those newer sources, to determine whether the expert opinion has changed since the older sources were written." Based on this, my understanding is that editors should try to make an effort to find newer sources, but if none is available about a particular question, older sources are fine to keep. Since I could not find a newer source on this particular question (the effect of curcuminoid supplements on circulating IL-6 levels), why isn't my reference compliant with WP:MEDDATE?

Bendegúz Ács (talk) 08:07, 31 January 2024 (UTC)

The revert was based on several issues, including those noted in the article, giving doubt about the significance of the review: 1) there were limitations of study design mentioned, such as heterogeneous subject conditions, doses used, and duration of studies; 2) a review of low-quality studies produces a low-quality review - see WP:MEDASSESS, pyramids - the studies included in the review fall within the definition of primary research and unfiltered information, i.e., quality too low for the encyclopedia; 3) there are no high-quality MEDASSESS reviews or clinical guidelines (tops of the pyramids) confirming this 2016 report; 4) the MEDDATE issue applies because the conclusion of a curcumin effect has not been confirmed over the past 8 years. It has, in fact, been refuted by this 2019 review in the same journal, which stated that curcumin did not affect several inflammatory biomarkers.

The existing Research section gives standards for curcumin research quality which have not been addressed since 2017. By WP:BURDEN, adding more recent reviews would need to be convincing to overcome these concerns. Zefr (talk) 17:11, 3 February 2024 (UTC)

Thanks for the reply! I have compared the two studies (from 2016 and 2019) in depth and indeed, you are right that the earlier one is outdated and low-quality, as the later one reflects on the differences between them, and finds that some more recent RCTs were not included in the earlier one, and one trial included was not randomized, despite stating otherwise in the title.

I have spent some more time looking for reliable and up-to-date WP:MEDRS reviews investigating the effects of curcumid/curcuminoid supplementation on various biomarkers and/or diseases. Here's a list of the studies I found:

1) dermatologic conditions: https://pubmed.ncbi.nlm.nih.gov/38085369/

• the abstract states: "grade of recommendation C or D. Further research is required to determine optimal dosing and treatment parameters of turmeric" - low grades of quality and inadequate research disqualify this source.
  • Is there any Wikipedia policy and guideline that says only a certain level of recommendation is qualified to be included or meets WP:MEDRS? If there isn't any, I think a wider consensus would be needed to disqualify such sources. Also, the study contains grade B recommendations too: "Psoriasis, cesarean section scar, and pruritus received grade of recommendation B." What do you mean by "inadequate research"? Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

2) MAFLD: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10001478/

• the limitations discussed in the last paragraph of the Discussion raise doubts about the quality of this analysis; it is not a good MEDRS source.
  • Does WP:MEDRS say anything about limitations? If not, I think a wider consensus would be needed to disqualify otherwise eligible sources based on their discussed limitations. Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

3) https://www.nature.com/articles/s41598-023-33023-3

• same concern - too many limitations, especially for the low quality of studies conducted in Iran
  • What counts as "too many" limitations? Why would the studies in the review have low quality? Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

4) PCOS: https://pubmed.ncbi.nlm.nih.gov/36387924/

• this is a limited analysis on a relatively small sample; it would not qualify as a MEDRS source
  • What do you mean by "limited"? If it's only the sample size, isn't that already accounted for by the statistical analysis (determining significance)? In general, are Wikipedia editors supposed to disqualify sources based on a small sample size? Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

5) knee osteoarthritis: https://pubmed.ncbi.nlm.nih.gov/36261810/

• "low quality and substantial heterogeneity" - in an altmed journal - not acceptable
  • Same comment as for source 2) about judging limitations: Does WP:MEDRS say anything about limitations? If not, I think a wider consensus would be needed to disqualify otherwise eligible sources based on their discussed limitations. Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

6) kidney: https://pubmed.ncbi.nlm.nih.gov/35649583/

• unacceptable altmed journal
  • Does WP:MEDRS (or other Wikipedia policy/guideline) talk about altmed journals? If not, I think a wider consensus would be needed to disqualify otherwise eligible sources based on being published in such journals. Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

7) https://www.sciencedirect.com/science/article/pii/S1756464622004662

• too many limitations identified in the Discussion
  • What counts as "too many" limitations? Does WP:MEDRS say anything about limitations? If not, I think a wider consensus would be needed to disqualify otherwise eligible sources based on their discussed limitations. Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

8) COVID-19/inflammation: https://pubmed.ncbi.nlm.nih.gov/36799442/

• Phytotherapy Res is not a MEDRS source - no suggestion of such use in reputable publications
  • Does WP:MEDRS (or other Wikipedia policy/guideline) talk about what journals are allowed, apart from predatory journals? If not, I think a wider consensus would be needed to disqualify otherwise eligible sources based on being published in such journals. Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

9) inflammation: https://pubmed.ncbi.nlm.nih.gov/36804260/

• unconvincing results; not a MEDRS source
  • What do you mean by "unconvincing"? Does WP:MEDRS (or other Wikipedia policy/guideline) talk about a source having to be "convincing" or how to judge that? Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

10) https://pubmed.ncbi.nlm.nih.gov/34378053/

• weak underlying studies; not a MEDRS source
  • What do you mean by "weak"? Does WP:MEDRS (or other Wikipedia policy/guideline) talk about a source having to be not "weak" or how to judge that? Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

11) rheumatoid arthritis: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10264675/

• limited, unconvincing results; too many limitations
  • What do you mean by "limited" and "unconvincing"? What counts as "too many" limitations? Does WP:MEDRS say anything about limitations? If not, I think a wider consensus would be needed to disqualify otherwise eligible sources based on their discussed limitations. Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

12) metabolic syndrome/inflammation: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10376715/

• limited, unconvincing results; too many limitations
  • What do you mean by "limited" and "unconvincing"? What counts as "too many" limitations? Does WP:MEDRS say anything about limitations? If not, I think a wider consensus would be needed to disqualify otherwise eligible sources based on their discussed limitations. Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

13) general human disease: https://www.mdpi.com/1422-0067/24/5/4476

• limited, unconvincing results; too many limitations; MDPI journal suspected of predatory publishing
  • What do you mean by "limited" and "unconvincing"? What counts as "too many" limitations? Does WP:MEDRS say anything about limitations? If not, I think a wider consensus would be needed to disqualify otherwise eligible sources based on their discussed limitations. According to Unreliable/Predatory Source Detector, MDPI is a borderline source, which, in my understanding, means that studies published in it are not automatically disqualified as WP:MEDRS. Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

In order to prevent future reverts, I would appreciate if you could check if any of these has any similar issues that would prevent them from being used as WP:MEDRS sources on Wikipedia.

14) Since you also mention clinical guidelines, I have also tried to find one that is up-to-date, and the best I could find is a long summary/review ([1]) from the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board on curcumin supplementation's effect on cancer. Do you think the current main content on the page could be extended to be brought more in-line with some of the content from this document? In particular, its summary points are like this: "Results from early-phase trials of curcumin-containing products in the chemoprevention of colon, oral, and hepatic carcinoma appear promising. However, the findings from these early trials have to be confirmed in well-powered trials evaluating safety and effectiveness as indicated by modulation of clinical outcomes." Bendegúz Ács (talk) 18:25, 12 February 2024 (UTC)

• "Early-stage" is the key term - the studies to date are considered to be low-quality, primary research which does not meet the standards of MEDRS for the encyclopedia.
  • The review I linked does not mention anything about low quality. One of its major points is that research "appears promising", which seems to be entirely missing from the content of the current Research section. I think adding more information on this, while of course continuing to point out the various limitations/early phase, would be a great improvement to the page. Bendegúz Ács (talk) 17:53, 21 February 2024 (UTC)

  Bendegúz Ács - respectfully, I already invested considerable time reviewing all these low-quality sources and am not going to elaborate on them further. If you wish to have the thoughts of other editors, I suggest posting a discussion at WP:RSN. Zefr (talk) 19:51, 21 February 2024 (UTC)

I numbered the sources to facilitate any followup discussion. A unanimous conclusion is that curcuminoid studies to date are typically of low-quality with many design flaws that make reviews on them also low-quality, and are commonly published in non-clinical, low-ranking journals, far from the standard expected for WP:MEDASSESS, left pyramid. Zefr (talk) 22:41, 12 February 2024 (UTC)

Bendegúz Ács, 3 of the reviews you cited were by Frontiers (publisher), 2 were alternative medicine journals, we wouldn't cite these journals on Wikipedia. Some of the of reviews you cite said they utilized bioavailability-enhanced curcumin, some did not. In regard to the former this isn't something the general population are consuming. Curcumin has a poor bioavailability. As for reviews what you have cited is not high-quality.

In the middle east a lot of authors are obsessed with publishing papers on something called "functional foods", i.e. [2]. Similar to this topic, they often turn out review papers every month on polyphenols but nothing new is presented. We read about all kinds of miracle anti-disease effects from these foods but when you read the results of the paper there is nothing conclusive. I have said this before but if you go looking it is always the same names in the papers. Years ago I was fooled by this kind of research. There is a group of researchers in the middle east that have an obsession with doing these type of reviews but it is all low-evidence. They have a different idea over there on what evidence-based medicine is. The conclusions of the papers are nearly always the same, "additional studies are required to confirm such findings" due to heterogeneity and limited evidence, or an uncertain claim of "might". These foods might do this or they might do that. There is no good long-term evidence. One of your reviews from Frontiers admits this [3]. It's basically the same thing every-time. The studies are always short-term (usually 3-6weeks) and they do not really show anything significant.

This you cite [4], is a review on curcumin and inflammatory markers published in Cytokine. I don't know much about this journal, I had never heard of it before. It should be noted however that another review in the journal Pharmacological Research found no effect [5].

You should ask yourself why most mainstream medical and nutritional journals are not publishing reviews on this topic. It's because there is no good evidence currently. Psychologist Guy (talk) 21:12, 26 February 2024 (UTC)

Thanks for the reply. My main issue is that this reasoning is neither consistent with WP:MEDRS, nor any other Wikipedia guideline I know of.

"3 of the reviews you cited were by Frontiers (publisher), 2 were alternative medicine journals, we wouldn't cite these journals on Wikipedia.": WP:CITEWATCH gives explicit instructions for both MDPI and Frontiers Media to "Evaluate on a case by case basis", which is far from "we wouldn't cite these journals on Wikipedia.".

I don't fully understand the first part of your second paragraph. What is the exact problem? What do the facts that the research comes from the Middle-East and that it is about "functional foods" have to do with its quality?

What do you mean by "low-evidence"? If stating that more research is needed or finding high heterogeneity was problematic, shouldn't we include that in WP:MEDRS?

"They have a different idea over there on what evidence-based medicine is.": Do you have any proof for this?

Not all of the RCTs in these meta analysis were that short. For example, one of them ([6]) lasted for 3 months. But then again, if length is an important factor, shouldn't that be mentioned in WP:MEDRS?

As for the other review you referenced, it is because that one ([7]) came out 4 years prior, and as per WP:MEDDATE, we should prefer the newer source.

My understanding here is that the curcuminoid/curcumin/turmeric supplementation doesn't have as strong an effect on any particular disease as a direct medication would have, which can be a reason why "most mainstream medical and nutritional journals" prefer those. But it can be due to other factos, maybe the researchers who published these studies were more familiar with those particular journals. I also tried to look at some more well-known nutritional journals, and they do seem to publish some studies: [8], [9].

Overall, based on the studies I linked above, it seems to me that curcumin does have some, statistically significant effect, and adding this information would improve Wikipedia. So I would argue that there is good evidence, even if it is not necessarily strong. I would also only add the concrete findings of these studies, maybe even with attribution (e.g. "A 2023 meta-analysis of RCTs found that turmeric/curcumin supplementation reduces levels of inflammatory markers, including CRP, TNF-α, and IL-6."). Bendegúz Ács (talk) 22:29, 26 February 2024 (UTC)

You need to ask yourself, what consistent evidence are you presenting? Your MO seems to be just going onto pubmed and finding any systematic review you can find to prove a beneficial health effect for curcumin. Nothing you are presenting here is consistent in finding or strong evidence. As stated I can relate to this type of faulty thinking in the past. When I was an early editor on this website I had a poor understanding of evidence-based medicine. We see it with many new users. It seems you are a beginner to this and you are in the same boat as I was years ago. I used to do the same to what you are doing now, just throwing out any random beneficial finding from any single review.

It took me 4 or more years to work out I was wrong and understand the basics of evidence-based medicine. Then I realized most of this type of research is very weak, none of it has been replicated and most of it is in shoddy journals. If you look at the totality of the evidence it is only early days with speculations, not concrete findings. We need consistent data and replication, you have not provided that. Look at it this way, what do health medical organizations say about curcumin? WP:MEDORG. I have not seen any recommending people to take these supplements because there is no good evidence. If you want to believe Frontiers and MDPI are high-quality that is up to you, but these are usually removed from Wikipedia quickly because they are not high quality.

This paper you link to [10] says curcumin has poor bioavailability and high doses are required. High-doses that are not well tolerated and don't really show us much, there is no long-term evidence and 3 months is not long-term. In the conclusion of that paper it says "There has been a major interest in the creation of functional foods and beverages that are fortified with curcumin due to its perceived health benefits. However, there are many challenges associated with incorporating curcumin into commercial foods and beverages because of its low water solubility, poor chemical stability, and low bioavailability." As stated it has very poor bioavailability. They are currently testing the use of curcumin in cancer treatment but as the National Cancer Institute notes "the evidence is currently inadequate to recommend curcumin-containing products for the treatment of cancer" [11]. Inadequate evidence pretty much sums up this entire discussion. The evidence you are presenting is inadequate.

CRP is C-reactive protein. We have a Wikipedia article on C-reactive protein, if you are really interested in that topic then maybe edit there because it looks like the article is in need of attention. We shouldn't cherry-pick one weak review. If you had 2 or 3 reviews in good journals supporting this finding you would have a better case. Psychologist Guy (talk) 01:15, 27 February 2024 (UTC)

The consistent element across these sources is that curcuminoid/curcumin/turmeric supplementation does have a statistically significant effect on human health, unlike what the current Curcuminoid#Research section implies ("Laboratory and clinical studies have not confirmed any medical use for curcumin"). But I think the best addition would be to report on the concrete findings of these studies, including the concrete circumstances in which the supplementation was applied. For example skin conditions, such as psoriasis, cesarean section scar, and pruritus for the first study.

"any single review": I found 13 reviews, so it is not just a "single" review.

"none of it has been replicated": all of the meta-analyses I am proposing include several individual studies (RCTs), which means that the findings of each of them have been replicated by the others. The whole point of a meta-analysis is to show that the findings have been replicated.

"shoddy journals": as I have said before, the journals are not considered unreliable according to WP:CITEWATCH.

"I have not seen any recommending people to take these supplements": this may be true, but WP:MEDRS does not require that medical organizations have to say something about a particular health effect. Calcium_supplement#Cancer is a great example of how both the official recommendation and the research findings can be presented together.

"these are usually removed from Wikipedia quickly because they are not high quality.": if this is the case, we should just ban/deprecate them, in order to avoid unnecessary reverts that occur when editors are not aware of this unwritten rule.

I did not bring up those 2 studies as WP:MEDRS sources in my last comment, but I still do not see why my original 13 reviews would not qualify as WP:MEDRS sources.

"The evidence you are presenting is inadequate.": I am not in any way suggesting that curcuminoid/curcumin/turmeric supplementation has been proven to have any effect on cancer. The reviews I am proposing are about inflammation and some other diseases, often with a focus on related biomarkers.

I would be happy to improve that article as well. I think arguably the most useful addition would be about in which ways CRP can be reduced, but that also needs WP:MEDRS, thus I first need to understand which sources are okay to use as WP:MEDRS and which ones are not.

To take CRP as an example:

• [12] did not find a significant effect in people with chronic kidney diseases, based on 9 studies
• [13] did not find a significant effect in people with COVID-19, based on 8 studies
• [14] found a significant effect in all people (WMD: -0.58 mg/l, 95 % CI: -0.74, -0.41), based on 66 RCTs
• [15] found a significant effect (MD = -0.93, 95% CI [-1.33, -0.53]) in people with rheumatoid arthritis, based on 6 RCTs
• [16] found a significant effect (MD = - 1.24, 95% CI: -1.71 to -0.77) in people with metabolic syndrome, based on 2 studies

We could either only include the most inclusive study ([17]) to talk about the effect on CRP, or all of them, with appropriate qualifications about the study groups (chronic kidney diseases, COVID-19, rheumatoid arthritis, metabolic syndrome). Bendegúz Ács (talk) 21:54, 27 February 2024 (UTC)

Bendegúz Ács - I don't agree with your apparent conclusion here that changes are warranted to the curcuminoid article (the discussion on possible revisions belongs on this talk page). There is no consensus at RSN and the arguments for including your proposed sources are only opinions by two other editors. Reasoning:

1) the topics of your interests are outside of mainstream scientific agreement (WP:MEDSCI) for having any anti-disease effects by curcuminoids, and therefore are WP:UNDUE and WP:FALSEBALANCE to be included in the article.

2) in none of the suggested sources is there discussion of a mechanism of effect, efficacy (dose-response evidence), or specificity (shown by a potential blocking agent) - as other publications state, curcumin is a "false lead" in research, with no conclusions possible about its potential pharmacological effects in vivo.

3) the content and sources you suggest represent writing for the wrong audience, and potentially would mislead general encyclopedia users into believing curcumin has medicinal effects - see WP:MEDMOS

4) concerning use of curcumin as a candidate therapeutic for any disease, there is a) no endorsement of research for or adoption by any reputable international or national clinical organization, b) no approval as a prescription drug by any national regulatory agency, and c) no patent opportunities for any curcuminoid compound for any type of drug development. Zefr (talk) 21:59, 4 March 2024 (UTC)

Thanks for picking up the discussion again!

"only opinions by two other editors": what do you mean by this? Both the other editors and I have provided reasoning as to why the sources I found are WP:MEDRS.

1) I have multiple questions about this:

• How can we establish what the current "mainstream scientific agreement" is about a particular topic? Isn't WP:MEDRS supposed to cover this?
• What is included in "anti-disease effects" - for example, are effects on biomarkers included?
• Why would WP:UNDUE/WP:FALSEBALANCE apply to recent, research paper secondary sources in a Research section?

2) It is true that these meta-analysis don't describe the mechanism of action. However, if this is important, I can try to find some other papers that do. What do you mean by efficacy? These reviews don't focus on the dosing, but why would this invalidate their results? As for specificity, if you worry about side effects or safety profile, most of these reviews examine that question. For example, the first one has a whole section on it ([18]).

3) I would state no more and no less than what the reviews found. How is that misleading?

4) a) I don't think this is true, for example see these grants by the NIH ([19], [20]) and the page from the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board ([21]).

b) Of course, I am not claiming in any way that curcuminoids/curcumin/turmeric is an approved drug. But this doesn't mean it can't have health effects.

c) "No patent opportunities" doesn't mean it can't have health effects, either.

Bendegúz Ács (talk) 20:43, 6 March 2024 (UTC)

Bendegúz Ács, curcuminoids/curcumin/turmeric have poor bioavailability and are poorly absorbed by the small intestine, they also go through a reductive and conjugative metabolism in the liver. They have not shown they have beneficial health effects, we don't have any good data to be making a claim like that.

This paper on arthritis you cite is fringe science [22] and as the same as many of the other papers you cite is calling for more trials on the topic because there is no good data right now. We can't just cite one weak biased review. We need replication and strong consistent findings. If there was any strong evidence that curcumin had significant anti-disease effects then the health and medical organizations around the world would be recommending it. Authorities that have looked at diet and arthritis do not recommend it. Here is what the British Dietetic Association says "There is no scientific evidence to support the use of antioxidant vitamins or mineral supplements in the treatment of RA" [23]. The Arthritis Foundation tells people to eat fish, vegetables and whole grains [24]. There is no mention of curcuminoids/curcumin/turmeric. It should also be noted that diet is not a substitute for pharmaceutical treatments but the general reccomended diet advice is common sense stuff eat lots of vegetables, whole grains and reduce saturated fat [25]. Why not just go with what the medical authorities say? As Zefr says above no clinical organization is claiming curcuminoids have anti-disease effects.

There is an interesting article here "scientists are keen to emphasise that these trials are very much in the exploratory stage, and even if they produce positive results, far more proof will be needed before curcumin can be officially recommended for cancer patients" [26]. Basically as stated before, you have no good evidence right now for your claims. There is no strong data that curcumin is beneficial. The trials are only in the exploratory stage, why not wait until we have more data? I am afraid I don't want to be involved in this discussion anymore. I have seen the same happen at taurine and many articles related to polyphenols. My advice would be to edit other articles. I admire your enthusiasm, you have made some good edits elsewhere on this website. I wouldn't waste anymore time on this specific article, if you ignore medical consensus you will be reverted. Psychologist Guy (talk) 22:15, 6 March 2024 (UTC)