TOPIC INTRO
For thousands of years, the bright yellow spice of turmeric has given wonderful aroma and flavour to curries. But turmeric isn’t only about making food taste great. There’s been alot of health hype over a group of compounds that are found in turmeric – called curcuminoids – particularly one of them called Curcumin. Curcumin has been used in Chinese and Ayurvedic medicinal practices to treat inflammation, reduce the risk of cancer, relieve pain and generally improve the digestion process.
Turmeric has grown a big reputation as one of the so-called ‘super-foods’. Some celebrity chefs call Golden Lattes or Turmeric Tea “anti-inflammatory drinks”. So are these turmeric health claim true? Are revolutionary health benefits lying in your pantry? Do we need to take turmeric supplements? What does the science say?
We asked some top researchers around the world who study turmeric to share the facts and myths on this popular spice. Our goal in this review is to help you make better decisions next time you head to a grocery store or supplement aisle.
Here’s what we found…
Learn more with Consensus:
🍠Does curcumin have anti-inflammatory properties? 🕵️♀️Is there scientific evidence supporting turmeric as a treatment to reduce the risk of cancer? 💊Are turmeric supplements necessary to achieve its health benefits?NUMBERS
Meta-Index
100 Number of compounds in turmeric
3% proportion of turmeric that is made up of curcumin (the main compound with claimed medical benefits)
65% proportion of turmeric that is made up of carbohydrates
20% proportion of turmeric that is made up of oils, fat, fiber and minerals
10% proportion of turmeric that is made up of water
120 registered clinical trials of curcumin against several diseases
0 the number of successful double-blinded, placebo controlled clinical trials of curcumin by 2017
$1,300,000,000 Estimated global market-size of curcumin by 2025
ORIGIN STORY
Indian Saffron
For over 5000 years Turmeric has been in use in India, likely originating in western and southern India. Turmeric reached China’s coast in 700 AD and by the thirteenth century, Arab merchants were spreading the plant onto the European continent. Marco Polo described it during his legendary voyages via the Silk Route in 1280 AD. He was so impressed by turmeric, it was often called the “Indian saffron”.
Turmeric is a perennial rhizome that grows to about one meter in height above the ground. It is classified in the Zingiberaceae family, making a relative of fellow rhizome ginger. The rhizome is yellow due to the presence of the most bioactive compound; curcumin. It’s no surprise, therefore, that its scientific name is Curcuma longa L.
The name turmeric is derived from the Latin terra merita which translates to ‘meritorious earth.’ Some suppositions say the name might be from the Middle English words turmeryte or tarmaret. Today, turmeric is also widely cultivated throughout the tropics.
The underground stem is the most important part for human use. Curcumin has been used over the years in Chinese medicine, Ayurveda as well as Siddha medicinal practices. Apart from these medicinal uses, curcumin is used in dyeing foods and garments, giving them a rich yellow color.
Learn more with Consensus:
🌱Are plants in the Zingiberaceae family used for therapeutic purposes? 👍Is curcumin effective in traditional medicinal practices? 🍵Are there multiple applications of turmeric in food and medicine?
THE CONSENSUS
Does turmeric reduce inflammation?
83% Likely via 6 experts
Read the full answers to this question here. Inflammation is an important part of how the body defends and repairs itself. If something damages your cells, your body releases chemicals from your immune system which cause a response. Acute inflammation happens rapidly (swelling), typically within minutes but is typically of limited duration like when we cut ourselves or get bitten by a bee.
Chronic inflammation is different. It frequently starts with the same cellular response but becomes a residual condition that continues for months or years when the response to the immune system does not remove the problem. Sometimes the immune system can persistently order white blood cells to invade healthy tissues and organs, an inflammatory cycle linked to diseases like rheumatoid arthritis, cancer, asthma and even Alzheimer’s.
Turmeric has long been touted as an anti-inflammatory ‘super-food’ to help lower on-going inflammation in the body. If something in our kitchen cabinet can reduce this kind of inflammation, that would be revolutionary. So, what do the experts say?
Dr Cornelie Nienaber-Rousseau, nutrition scientist from NorthWest University shares a thorough review of the literature on this question here. In general, there is good evidence that curcumin (found within turmeric) has been shown to have anti-inflammatory properties. Dr Zorica Stojanovic-Radic, an expert from the University of Niš shares a long answer concluding there is “remarkable potential of this compound to reduce inflammation in conditions such as arthritis, osteoarthritis, various metabolic diseases as well as post-operative conditions”.
Dr Pavla Jendelova, from the Czech Academy of Science goes into further detail about the ability of curcumin to reduce inflammation noting “Our research has shown that application of curcumin (turmeric) in rat experimental model of spinal cord injury can reduce activation of one of the proinflammatory pathways (NF-kB), which is activated after injury. This leads to reduction of pro-inflammatory cytokine TNF-a and further attenuation of inflammation.” However, she was keen to point out that the statement cannot be generalized, since they injected curcumin directly into the spinal cord. “It must be taken into account that curcumin is not water soluble and oral administration can have less profound effect” she says.
For arthritis, Dr Francesca Borelli, a pharmacologist from Italy, notes “meta-analyses, analyzing all randomized clinical trials performed to evaluate the clinical efficacy of turmeric and/or curcumin, concluded that there is some evidence that turmeric and curcumin are effective in patients with arthritis-related diseases and these effects are associated to a reduction of markers involved in the systemic inflammation”.
Others experts are very negative
But other experts are highly critical of the existing research. Dr Bart Roman says “there’s no evidence curcumin has any specific therapeutic benefits, despite thousands of research papers and more than 120 clinical trials“.
“The many papers on curcumin and turmeric claiming medicinal benefit are flawed. For example, the most common error is that they extrapolate observations on proteins or cells to observations on organisms. No sound evidence backs these extrapolations. There may be some local effects (e.g. on the stomach) but no significant systemic effects are to be expected. Curcumin and related compounds are poorly bioavailable”. In conclusion he says: “In an evidence-based health system, one must leave curcumin where it belongs: in the kitchen, not in the medicine cabinet”.
Other experts note it’s highly misleading to think that turmeric will help inflammation. Gideon Meyerwitz-Katz from the University of Wollongong makes the point: “By weight, turmeric is made up of about 3% curcumin…So, to get the amount of turmeric that you’d need to eat to get an active dose of curcumin..you would need to consume at least 24 grams a day of turmeric, which is about the size of a supermarket jar of the dried powder”. A typical Indian diet packed with many curries a day equates to ~2 grams of turmeric per day.
Learn more with Consensus:
😳Does inflammation play a role in chronic disease? 👄Is curcumin poorly bioavailable when taken orally? 🦵Has curcumin been shown to reduce inflammation in conditions like arthritis and osteoarthritis?
THE CONSENSUS
Does eating turmeric help prevent cancer?
57% Negative via 14 experts
Read the full answers to this question here. There have been various internet claims that turmeric can help prevent or treat cancer. It’s clear that turmeric as an anti-cancer medicine is “highly speculative” and “unproven” with a majority of experts sharing negative answers.
Some experts cite studies indicating anti-cancer properties for curcumin, but there is a long way to go in claiming it can prevent or lower the risk of cancer. Dr Seyed Moghaddam from the MD Anderson Cancer Centre in Texas writes: “There are some evidence and animal studies including one from our group that indicate an anti-tumor effect for curcumin, the main active substance in turmeric. However, due to its low bioavailability and absorption rate by the gastrointestinal tract, it needs to be used in a very high daily amount in order to provide a potential protective effect.” Dr Moghaddam says it’s unlikely to help prevent cancer because of “its broad and non-specific targeting effect on several essential biological pathways”.
Dr Gail Mahady from the University of Illnois notes a lack of clear clinical evidence on humans despite the several cell culture and animal studies suggesting that the curcumin found in turmeric has anticancer effects. Some ongoing trials are in the early phases of trying to determine the clinical benefit of curcumin in regards to preventing cancer. She emphasizes that the current clinical trials are more concerned with the pharmacokinetics and safety rather than efficacy. And even then, this attention is centered on curcumin as a compound and not turmeric as a whole.
All experts share the important bioavailability problem of turmeric/curcumin. Like for inflammation, one would need copious amounts of turmeric in their diet to get a dose of curcumin that can make a difference. Dr Keith Singletary, from the University of Illinois at Urbana-Champaign, stresses that “improvements in developing more bioavailable forms of curcumin may help in evaluating any potential health benefits of this spice in studies using typical dietary or culinary-relevant levels”.
Currently, most of the scientific papers reporting the biological effects of turmeric/curcumin represent preliminary in vitro data, obtained with biochemical assays or on cell culture models. Therefore, the real therapeutic application in cancer prevention or treatment is still unknown. There is however, a great need for new drugs that are effective, but have less deleterious side effects – so lets hope that curcumin progresses to a stage where the evidence is clear. So far, the consensus is clear that turmeric is unlikely to give benefits relating to cancer.
Learn more with Consensus:
🐌Have any studies shown an anti-tumor effect for curcumin in animal models? 🔎Is there clear clinical evidence that curcumin can prevent cancer in humans? 👨⚕️Are improvements in the bioavailability of curcumin needed to evaluate its potential health benefits effectively?
CALCULATIONS
Can you get enough curcumin via diet alone?
Extremely Unlikely.
Curcumin is the compound of primary scientific interest. So is it possible to get enough curcumin from diet alone? One study found a big range in the curcumin content of various curry and turmeric powders in grocery stores. For example in the US, Tone’s curry powder contained 0.5% curcumin by weight, yet McCormacks pure turmeric powder contained 2.5% curcumin by weight. If we take pure turmeric powder as an example, how many curries and turmeric lattes would you need?
30 Curries a day
A typical family-size pot of curry contains about one teaspoon of turmeric (~2 grams of turmeric). Taking a curcumin concentration of turmeric as 3%, one serving of serving of curry (one pot serves 4) equates to ~15 mg of curcumin. The starting point for most scientific studies that use curcumin are at least 500mg per day. So that would mean we would need to eat over 30 serves of curry per day to reach the equivalent curcumin amount used in most scientific studies.
30 Turmeric Lattes a day
Turmeric latte recipes typically have one quarter of a teaspoon (~ 0.5 grams of turmeric) – equating ~15 mg of curcumin in one turmeric latte. So that would mean we would need to drink at least 30 cups of turmeric lattes to reach the equivalent curcumin amount used in most scientific studies (>500mg).
Beyond the basic calculation above, as noted above, most curcumin in scientific studies are also combined with other compounds to ensure the body utilises it – since most curcumin passes through our digestive system without doing anything.
Learn more with Consensus:
🏃Does curcumin supplementation have health benefits? 🧘🏻♀️Does curcumin supplementation improve health outcomes? ®Is the quality of turmeric powders consistent across different brands?
ANALYSIS
Are turmeric supplements worth it?
Unlikely.
Many experts reiterated that consumption of turmeric to obtain curcumin by itself in the amounts normally present in diets would not be beneficial, due to the quantity and poor bioavailability. The calculations above demonstrate the virtual impossibility of obtaining reasonable amounts of curcumin via a diet alone. So what about supplements?
Supplements of high-dose turmeric/curcumin extracts are widely available, but still don’t solve the problem of bioavailability shared by experts. Most of the turmeric/curcumin supplement will pass through the digestive system without a health benefit.
Improvements in developing more bioavailable forms of curcumin supplements via nano-formulations combinations may help in evaluating any potential human health benefit in the future. However given the added potential risk of side-effects in taking high-dose supplements in general, the potential benefit in our view does not warrant supplementation.
In India, hundreds of millions of people enjoy a turmeric rich diet. The average intake of turmeric in the Indian diet is approximately 2-2.5 g for a 60 kg individual which corresponds to a daily intake of approximately 60-100 mg of curcumin. Although this is theoretically 5-10 times less than those used in scientific studies and may have little benefit due to poor bioavailability, it’s pretty clear this amount of turmeric in a daily diet (2-2.5g) is a safe and tasty amount for the vast majority of people.
Learn more with Consensus:
🍴Is curcumin bioavailability a significant challenge in dietary supplements? 💆🏻♀️Do typical dietary curcumin levels have significant health effects? ⚡Are there adverse effects associated with high-dose curcumin supplementation?
CONCLUSION
Four reasons to remain skeptical on turmeric health claims
Turmeric is claimed to help a variety of health conditions from weight-loss and mood to diabetes and heart disease. While experts confirm that curcumin (found in turmeric) has anti-inflammatory properties, there are some very big caveats that everyone should know about that have been shared by many experts on Metafact:
1. Turmeric doesn’t contain much curcumin
Turmeric is the spice we eat, while curcumin is the active ingredient with potential anti-inflammatory effects. But only ~3% of turmeric is made up of curcumin. The vast majority of science has been on curcumin – not turmeric. When turmeric is cooked as part of a curry or soup for example, its chemical components can change. Experts say it’s unknown what effects cooking does on the potential benefits relating to curcumin/turmeric.
2. Curcumin is not easily utilised by the body
Once digested, the body can’t make use of much curcumin. Bioavailability is the ability for the body to utilise the active ingredient, and curcumin isn’t easily absorbed by the small intensine, while its structure can be changed when it binds with other proteins in the gut. Because of this, most studies have needed to combine curcumin alongside other compounds like piperine that help the body utilise it. Since curcumin passes through our digestive system, most of any additional supplementation is wasted and ineffective.
3. Studies funded by supplement manufacturers
As part of our review, Dr Cornelie Nienaber-Rousseau summarised the results of one study that found good evidence of reducing pain and inflammation-related symptoms – the study even suggested turmeric extracts/curcumin to be “equivalent to using ibuprofen and diclofenac sodium without the gastrointestinal symptoms associated with the conventional drugs in those with arthritis especially osteoarthritis.” The problem however, is that this study was funded and authored by researchers from a supplement company. Like most supplements, studies generally only get funded by industry and there is good evidence of biases relating to industry-funded research. That doesn’t mean they are worthless, just that we need to have other non-industry funded research before drawing solid conclusions.
4. Super-food panaceas
One big red flag in evaluating health-related claims related to foods and supplements, is when a product or blogger claims benefits for a diverse array of conditions from cancer, weight loss, mood to arthritis. In established science, no compound or medicine is a cure-all. If something claims to be a panacea for all things, it’s likely fake-science. Turmeric is one of those supplements to remain wary of.
Learn more with Consensus:
🤼Is curcumin the primary active ingredient in turmeric with potential health benefits? 👩🏻🔬Are the health benefits of turmeric supported by scientific evidence? 🙅🏻Are there biases in industry-funded research on dietary supplements?
TOP ANSWER
Does turmeric help?
Gideon Meyerowitz-Katz: A public health expert from University of Wollongong in Epidemiology, Public Health, Diabetes
Extremely Unlikely. As has been noted a number of times, there is good evidence of reasonable certainty that curcumin, a compound that is present in turmeric, has some anti-inflammatory properties. There is some debate that this is true, but overall it’s likely to improve inflammation in some way.
The issue is, how much curcumin? And does that mean that turmeric does, itself, reduce inflammation?
By weight, turmeric is made up of about 3% curcumin. An active dose – the amount needed to see a benefit in people – of curcumin varies, but is usually somewhere between 200-1,000 milligrams per day. So, to get the amount of turmeric that you’d need to eat to get an active dose of curcumin, you multiply by 33, making an active dose of turmeric about 6-30 grams per day.
However, there’s another problem – curcumin isn’t very bioavailable, which means your body only absorbs about 25% of the curcumin from the turmeric that you eat. So we have to take our number and multiply by 4, which means that the lowest amount of turmeric you’d have to eat to get an active dose of curcumin is 24 grams a day, which is about the size of a supermarket jar of the dried powder. This low estimate is also a bit misleading, because studies that use these low doses of curcumin usually have formulated a special supplement that is more bioavailable, which is very different to just eating turmeric.
This is a problem – curcumin may reduce inflammation, in sufficient doses, but eating 24-120 grams a day of turmeric is a bit of a different question. Overall, it’s unlikely that turmeric reduces inflammation as part of most people’s diets, unless they are eating truly vast quantities of the spice.
Learn more with Consensus:
🔧Is curcumin a significant component of turmeric? ↪️Does curcumin supplementation provide health benefits? 🧎🏽♂️Does curcumin have therapeutic effects on inflammatory diseases?TAKEAWAYS
- Some evidence that curcumin, a compound found in Turmeric, has anti-inflammatory properties
- However dietary or supplemental turmeric is unlikely to help inflammation or other health conditions due to low proportions of curcumin along with very poor bioavailability (passes through the body without utilisation)
- Nanoformulations that help with targeted bioavailability will better help evaluate the real effectiveness in humans
- Until then, enjoy your curry or turmeric lattes, but don’t expect meaningful health benefits from them