Turmeric is a spice used across the world. Curcumin is one of its key compounds that gives turmeric its color has a variety of biological mechanisms which provide therapeutic benefits for a range of conditions. Turmeric has been in use as food and medicine for thousands of years in the East and is a staple in the traditional Indian medical system, Ayurveda, as well as Traditional Chinese Medicine. Thousands of Western research studies further validate curcumin’s biological activities and benefits in the body.
Table of Contents
- What is turmeric?
- History of Turmeric
- Why take turmeric?
- How does turmeric work?
- Why take turmeric/curcumin?
- Health Benefits of Turmeric/Curcumin
- How to take turmeric?
- Turmeric essential oil
- Is turmeric/curcumin safe?
- What side effects are there?
- The bottom line on turmeric/curcumin
What is turmeric?
Turmeric, or Curcuma longa, is a gold-colored spice, popularly used in the Indian subcontinent for food preparation and as a therapeutic remedy. The spice is derived from the rhizome of the plant Curcuma longa, where rhizome refers to the underground plant stems that grow horizontally away the plant which can develop into new shoots. Thus, turmeric’s root-like appearance is not so different from that of ginger (which is also a rhizome). In fact, Curcuma Longa is in the Zingiberaceae family, or the “ginger family”. Curcuma itself refers to an entire genus of plants, from which other spices or wild turmeric may be extracted.
Curcumin is the primary chemical compound in turmeric. The spice’s yellow color and the majority of its therapeutic effects are attributed to curcumin [Aggarwal 2007].
Turmeric goes by many names: curcumin (the primary active ingredient), Haldi in Hindi, Ukon or Gajyutsu in Japanese, Ulgeum or Gangwhang in Korean, and Haridra in Sanskrit meaning “dear to Hari”, or Lord Krishna [Aggarwal 2007]. Many languages refer to turmeric by a name strongly resembling curcumin: kurkuma in German, cúrcuma in Spanish, kurkuma in Dutch, and куркума in Russian, just to name a few.
History of Turmeric
Turmeric’s history dates back thousands of years. Its utility in food to preserve freshness, its aesthetic contribution by adding color and its ability to improve flavor all made it a vital staple to eastern households. Its history is entrenched in Eastern life, and its use in Ayurveda and Traditional Chinese Medicine for a range of conditions is a testimony to its therapeutic benefits. In Ayurveda, turmeric is considered a stomachic (something that settles the stomach), a blood purifier and tonic. Traditional uses for turmeric include treating conditions like liver disorder, jaundice, urinary tract disease, cold, skin infection, wounds and inflammation [Aggarwal 2007].
Marco Palo referenced turmeric in 1280, in the context of his travels to China and India. Turmeric was “introduced” to the West on several occasions. The earliest introduction was in the 13th century when it was brought to the western world in the by Arab traders. However, it gained more traction upon being reintroduced by a Portuguese sailor, Vasco de Gama, who had traveled to India in the 15th century. Finally, during British rule in India, turmeric was combined with other spices to form the still widely popular, curry powder [Aggarwal 2007].
Today, there are thousands of published research studies and preclinical or clinical trials on turmeric and curcumin, evaluating its biological mechanisms and therapeutic uses for a range of health conditions.
Why take turmeric?
Turmeric, functioning as both a food and medicine, is beneficial to health as a preventative measure and as a treatment for some conditions. It is important to note that the treatment of any health condition should be approached with care and proper consultation of medical professionals.
There are many compelling reasons to add turmeric or a curcumin formulation to one’s diet, with the primary reason being its general protective properties. This may be attributed to its anti-inflammatory and antioxidant properties, as well as the range of other biological activities observed.
How does turmeric work?
Curcumin exhibits a variety of biological mechanisms through its anti-inflammatory, antioxidant, antitumor, anticancer, antiviral, antifungal, antispasmodic, antibacterial, and antivenomic activities. The majority of its therapeutic uses for the treatment and prevention of diseases is likely attributed mainly to its antioxidant and anti-inflammatory mechanisms.
Curcumin, one of the dozens of phytochemicals present in turmeric, is believed to be largely responsible for the therapeutic benefits of turmeric. Roughly 2-5% of turmeric is curcumin [Aggarwal 2007]. Today, many supplements focus on isolating curcumin separately, although studies have evaluated both the effects of turmeric and curcumin alone.
Curcumin has a range of biological activities including: anti-bacterial, antioxidant, anti-inflammatory, lipid-lowering, hepatoprotective (liver health), antitumor, anticancer, antiviral, antifungal, antispasmodic and antivenomic. Most of the therapeutic effects of curcumin are attributed to its antioxidant and anti-inflammatory properties.
Curcumin itself refers to one of the three curcuminoids in turmeric. Curcuminoids are the natural phenolic coloring compounds in the rhizomes of Curcuma Longa. These three curcuminoids are: curcumin I diferuloylmethane, curcumin II or demethoxycurcumin, and curcumin III or bisdemethoxycurcumin. It’s yet unclear which of these offer the most potent biological activity, as studies have so far found conflicting evidence. Curcumin may refer to all three curcuminoids or to the first one, diferuloylmethane. Most formulations of curcumin are predominantly made up of curcumin I [Aggarwal 2007].
Curcumin and curcuminoids exhibit a variety of beneficial mechanisms. They lower cholesterol, reduce platelet aggregation, and inhibit the proliferation of cancer cells and even improve digestion [Aggarwal 2007].
It’s also worth noting that curcumin metabolizes differently based on whether it is consumed orally or taken intravenously [Aggarwal 2007]. The implications being that studies finding significant results from intravenous administration of curcumin may not be applicable in situations where turmeric is taken orally (i.e. as a supplement).
One of the key mechanisms behind turmeric’s therapeutic use is its anti-inflammatory activity. Inflammation is associated with a huge range of conditions and diseases. Studies show that turmeric, and curcumin especially, exhibit anti-inflammatory properties [Aggarwal 2007].
One in vitro study found curcumin inhibited the expression of a certain inflammatory enzymes [Lantz 2005]. Another in vitro study on human cells found curcumin inhibited a particular kind of protein associated with inflammation [Singh 1995]. Various studies on rats provide evidence that curcumin boasts anti-inflammatory properties [Joe 2000] [Joe 1994].
One of the key mechanisms by which turmeric fights inflammation is in its suppression of prostaglandins synthesis. Prostaglandins are compounds which play a key role in generating the inflammatory response. Increase in the synthesis of prostaglandins may influence cancer and tumor growth. Curcumin seems to suppress the induction of certain proteins (COX-2), which are the key enzymes in creating prostaglandins [Menon 2007].
Turmeric’s potent antioxidant activity is another explanation for why it is effective in treating some conditions. Why does antioxidant activity matter? The body strives to maintain an equilibrium of oxidants and antioxidants. When this is thrown out of balance, in favor of oxidation, oxidative stress occurs. Although the body itself aims to create this balance, it is not infallible. Oxidative damage occurs, particularly with age and age-related disease.
Curcumin functions as an antioxidant through several known mechanisms. The simplest mechanism to understand is its ability to protect cells from peroxidative damage. Curcumin does so by scavenging reactive free radicals that cause this damage [Menon 2007].
Various studies have explored the chemopreventive and anticancer effects of curcumin. These includes studies on cancers of the skin, stomach, intestine, colon, mammary gland, liver, prostrate, bone, bone marrow, brain, breasts, head, neck, lungs, pancreas and ovaries. Turmeric has been observed to suppress the proliferation of tumor cells by several mechanisms, including inducing certain genes which help suppress tumors [Aggarwal 2007].
Why take turmeric/curcumin?
The known mechanisms of curcumin, outlined above, indicate that supplementing with it (or turmeric) may a beneficial treatment for several conditions, particularly those linked to inflammation or oxidative stress. Such conditions may include neurodegenerative diseases (Alzheimer’s), liver disease, diabetes, AIDS, autoimmune diseases, and psoriasis.
Thus, turmeric (and curucmin supplements) may be a compelling dietary addition to both those who are already healthy (for its preventative and anti-aging benefits), as well as those currently undergoing some health condition or disease. It’s especially interesting to note that even for conditions such as smoking, curcumin may still provide benefits. One study found that rats who had nicotine-induced lung toxicity supplemented with curcumin experienced its protective effects. Curcumin regulated the damage through its antioxidant properties (by modulating lipid peroxidation) and boosted the antioxidant defense system [Kalpana 2004].
Additionally, curcumin has anti-cancer, anti-bacterial, anti-fungal and anti-viral properties. These allow it to inhibit a range of viruses. For this reason, supplementation with curcumin may provide therapeutic benefits with regards to the prevention of certain conditions [Jennings 2020].
However, it’s important to note that curcumin has low bioavailability. Certain formulations significantly increase the amount of curcumin actually absorbed and used by the body.
Health Benefits of Turmeric/Curcumin
A significant body of evidence demonstrates that curcumin is an effective therapeutic treatment for a range of conditions, as well as a potentially potent preventative measure to fight aging. Curcumin may be an effective aid in a range of conditions including inflammatory, chronic, and infectious diseases.
Turmeric, and its primary active ingredient, curcumin, may have potent therapeutic benefits for a huge range of health conditions and diseases. Here, we cover just a portion of this spectrum, focusing on its general anti-inflammatory capabilities, anti-aging influence, and potential for the treatment of neurodegenerative diseases and skin conditions.
Turmeric/curcumin is used for many health issues beyond this list, such as those in the visualization above: cancer, cardiovascular disease, diabetes, cystic fibrosis, and depression. Curcumin also possesses a range of protective properties, one of which is anti-toxicity, thus making it potentially beneficial against chronic arsenic exposure and alcohol intoxication.
Thousands of Western research studies coupled with the teachings from Ayurveda and Traditional Chinese Medicine demonstrate that turmeric/curcumin has many uses for one’s health, far too many to effectively cover in this brief article.
Based on its potent antioxidant and anti-inflammatory, as well as success in animal studies, curcumin may be a promising anti-aging agent.
Turmeric may be beneficial simply as an anti-aging agent. Free-radicals play a key role in aging. Over time, as the defense systems weaken, free radicals accumulate, damaging DNA and other parts of the system. By add antioxidants to the diet, one may conceivably increase their life expectancy [Menon 2007] [Harman 1992] [Greenstock 1993].
One study found that aging rats supplemented with curcumin over month had less lipid peroxidation and less accumulation of age-pigment lipofuscin, both of which are known to increase with age. The rats also had an increase in antioxidant defense enzymes [Bala 2006]. Simply put, this means that curcumin reversed the age-related changes in the brains of these rats.
By protecting against oxidative damage and improving measures of the aging brain, curcumin may slow typical brain aging, as well as help resolve age-induced oxidative damage [Cole 2007].
Significant evidence (in human trials and in vitro experiments) demonstrate that curcumin is an effective treatment in a range of inflammation-related conditions. Many conditions fall into this category including post-surgery healing, inflammatory bowel diseases, osteoarthritis, wound healing and inflammation of the eye.
The anti-inflammatory activity of curcumin makes it a potent therapeutic treatment and preventative measure for a range of health conditions and diseases that are worsened by inflammation. Below, we dive into the studies showing curcumin’s efficacy in some of these conditions. However, the list of relevant conditions is likely much larger than is covered here.
At 400mg 3x daily for 5 days curcumin significanty reduced post-operative inflammation for men who had just had surgery. Not only did it bring down inflammation but it worked even better than another comparable drug [Satoskar 1986].
One study found a particular formulation of curcumin to be effective in the long-term management of osteoarthritis. Those who took 1g/day of Meriva tablets experienced significant improvements to their clinical and biological measures for osteoarthritis after 8 months [Belcaro Cesarone 2010]. The formulation used here was Meriva® Curcumin Phytosome™, standardized to contain 18-22% of total curcuminoids . The same authors ran a shorter 3-month study using 200mg/day of Meriva, and found it to be effective in the management and treatment of osteoarthritis, even in the shorter timeframe and with lower dosage [Belcaro Cesarone Dugall 2010].
Inflammatory bowel diseases (IBD) & irritable bowel syndrome (IBS)
1.1-1.6g/daily for 2-3 months of curcumin improved health for those suffering from inflammatory bowel disease. This study did lack a control group and was small (10 people total), but still provides promising results [Holt 2005]. Another, much larger-scale study with 500 volunteers with irritable bowel syndrome (IBS), demonstrated that 72mg or 144mg of a standardized turmeric extract (Cynara) daily for 8 weeks improved IBS. Abdominal pain decreased by >20% in both treated groups, among other improvements. However, the drawback of this study is that it lacked a placebo control group [Bundy 2004].
One of the most compelling studies regarding curcumin’s use in inflammatory bowel disease was conducted on individuals suffering from ulcerative colitis, a type of IBD distinguished by inflammation and ulcers in the digestive tract. As with IBD in general, those suffering from ulcerative colitis face numerous painful and uncomfortable side effects such as abdominal pain, diarrhea, and bloody stools. Curcumin was not only effective in treating this IBD, but was more effective than the placebo in preventing relapse in patients. Those in the treatment group took 2g/day of curcumin for 6 months. It’s important to note that both those in the treatment and “placebo” groups also took mesalamine or sulfasalazine (typical treatments for the condition) [Hanai 2006].
Due to both antioxidant and anti-inflammatory properties, among others, curcumin is a powerful agent in progressing wound healing at numerous stages of the process [Panahi 2019]. In various studies performed on rats topical application of curcumin significantly accelerated healing time of various wounds [Akbik 2014]. In fact, curcumin is one of the most widely used Ayurvedic herbs for wound healing [Biswas 2022].
Inflammation of the eye
Some studies demonstrate that curcumin supplementation reduces discomfort and helps treat eye conditions, particularly anterior uveitis, or inflammation of the eye.
One study found that 600mg 2x daily of Meriva-formulated curcumin for 12-months reduced eye discomfort and relapse for those suffering from anterior uveitis [Allegri 2010].
Another, older study, found that 375mg 3x daily of curcumin for 12 weeks helped reduce inflammation of the iris, although the results were better when combined with another treatment. This study did lack a control group and was relatively small [Allegri 2010].
Neurodegenerative diseases (Alzheimer’s)
Based on its known biological mechanisms and small-scale human trials, curcumin may be a promising therapy for the treatment of neurodegenerative diseases like Alzheimer’s and Parkinson’s.
Curcumin targets at least eight known anti-amyloid mechanisms that contribute to the development of Alzheimer’s. Thus far, few clinical trials exist evaluating it as a therapy or preventive medicine. Its use as a preventative measure is based predominantly on its understood mechanisms, and not yet on any long-term studies.
Two studies exist evaluating the use of curcumin to treat existing Alzheimer’s. One double-blind 24-week study Alzheimer’s patients were treated with 2 or 4g/day of curcumin. However, no significant changes were observed in the treatment group [Ringman 2012]. One double-blind 6-month trial evaluated 1 or 4g/day of curcumin for 50+ year Chinese patients with memory or cognition issues and who likely had Alzheimer’s. Some measures did not differ significantly at different doses (1 vs 4g/day), but the curcumin treatment overall appeared to significantly reduce amyloid aggregation, a key mechanism in treating Alzheimer’s [Baum 2008].
How does curcumin help with Alzheimer’s? It appears to be effective by its anti-inflammatory and antioxidant properties, as well at its mechanisms which limit amyloid plaques. The limiting of these plaques is important because these plaques are one of the hallmark’s of Alzheimer’s and disrupt cell function. Studies on rodents confirm that curcumin reduces oxidative damage and cognitive deficits (in rats receiving toxic beta-amyloid, which mimics Alzheimer’s progression) [Frautschy 2001]. Such findings have also been confirmed in vivo with mice [Yang 2005].
Additional evidence indicates that curcumin may be a promising area of further exploration for its use in other neurodegenerative conditions like Parkinson’s and Huntington’s disease [Cole 2007].
Studies suggest that curcumin has therapeutic benefits for a range of skin conditions including vitiligo (loss of skin color in patches), psoriasis and acne. Particularly relevant is curcumin’s anti-inflammatory properties, which likely explains why it is so effective in treating some of these conditions.
Additionally, milk thistle is another natural health remedy beneficial for skin health. Black seed oil is another, which may be beneficial for psoriasis.
Psoriasis is a disease of the skin, the most common kind being plaque psoriasis, which causes dry, itchy skin in raised patches (the plaque). Some studies indicate that curcumin may be a beneficial therapeutic treatment for the treatment of psoriasis.
One study found that an alcoholic gel with 1% curcumin applied daily for 3-4 weeks helped improved the untreated plaque psoriasis of six patients by 25-70%. The placebo group saw no improvements, or even a worsening of the condition [Heng 2000].
One study found that patients with psoriasis treated with both topical steroids and a 2g/day of curcumin formulation (Meriva) experienced a greater improvement to their psoriasis than those taking the steroids alone. Furthermore, the levels of IL-22 serum (which plays a major role in the development of psoriasis) were significantly reduced for those on the curcumin supplement [Antiga 2015].
Another study explored the oral consumption of curcumin for psoriasis vulgaris. Patients took a 1.5g 3x daily of a curcuminoid C3 complex with 95% curcuminoids for 12 weeks. Although the response rate was low, the results were still promising. Further research is necessary to identify how effective oral consumption alone of curcumin may be for psoriasis [Kurd 2008].
In the case of vitiligo, a condition characterized by patches on the skin lacking color, curcumin used in addition to UVB therapy was found to be more effective than the UVB therapy alone. Although the study was small, it showed that curcumin helped the skin to “repigment”, with results seen after 8 weeks. The cream used was a commercially available curcuminoid cream, with the primary ingredient tetrahydrocurcuminoid in a special medium to help it to absorb into the skin better (called phosphatidylcholine liposomes) [Asawanonda 2010].
Curcumin is a promising therapeutic agent for the treatment of acne, thanks to its antimicrobial and anti-inflammatory properties. Although no reliable human trials yet exist, the evidence thus far is suggestive of its therapeutic benefits. Future studies are necessary to understand how to effectively use curcumin for acne.
One study experimented with different formulations of curcumin, and found a particular mixture effectively inhibited the growth of S. epidermidis, a possible pathogen in the development of acne vulgaris [Liu 2012]. The same authors also found that curcumin inhibited the growth of P. acnes [Liu 2013]. It’s important to note that A) inhibiting bacterial growth is only one part of acne treatment and B) these findings combined curcumin with other ingredients (for example, lauric acid).
A study on rats further confirms these findings. Rats treated with curcumin and lauric acid liposomal gel had a ∼2 fold reduction in comedones count and pro-inflammatory cytokines compared to placebo [Madan 2018].
How to take turmeric?
Turmeric may be taken as a part of the diet. In this case, general advice dictates to consume turmeric with fats and pepper, mimicking its traditional consumption in Indian cuisine and reflecting the contemporary methods used to make curcumin more bioavailable. For example, the advice to take curcumin with a fatty meal is based on the fact that curcumin is fat soluble, therefore consuming it with a fatty meal enhances absorption. The addition of pepper is to stimulate the gastrointestinal system, further aiding absorption [Stohs 2020]. Alternatively, curcumin may be specifically supplemented using encapsulated curcumin or curcumin formulations.
There are three key components to the supplementation of curcumin (which apply to most supplements):
- Formulation/Extract Type
Dosage refers to how much of the supplement to take (mg, g), duration refers to how long (weeks, months, years) and formulation refers to different ways curcumin is combined with other compounds to enhances it bioavailability.
Although much research has been dedicated to turmeric’s therapeutic use, there are still many unknowns regarding its use. This includes optimal dosage, bioavailability and the details of how to use it to prevent or cure certain diseases. It may also be that other compounds in turmeric, besides curcumin, may provide therapeutic benefits. Despite the research and historical knowledge at hand, a great deal yet remains to be understood [Aggarwal 2007].
Dosage & Duration
The majority of evidence on curcumin is based on relatively large daily doses (1-2g/day or more) and over timeframes of ~3 months or longer.
The majority of studies explore the effects of sizable doses of curcumin, somewhere along the lines of 2g/day or more. It may be that some therapeutic benefits are still realized at lower doses (which would be more reflective of traditional use of turmeric). The effectiveness of different doses for particular conditions is yet unclear.
Below is a complied list of doses used in the studies discussed above. In general, most studies rely on a minimum of 1g/day, with many at 2g/day or more. Contemporary studies tend to use curcumin formulations, such as Meriva.
The timeframe is generally 3 months or longer. For long-term chronic issues or inflammation (like inflammation of the eye or treatment of osteoarthritis), studies go even longer, 8 months to one year.
- 600mg 2x daily of Meriva formulation for 1 year, for inflammation of the eye [Allegri 2010]
- 1g 2x daily of Meriva formulation for 12 weeks, for psoriasis [Antiga 2015]
- 2 or 4g/day of Curcumin C3 Complex for 24 weeks, for Alzheimer’s (results not significant) [Ringman 2012]
- 1 or 4g/day of curcumin for 6 months, for Alzheimer’s [Baum 2008]
- 1g/day of Meriva formulation for 8 months, for osteoarthritis [Belcaro Cesarone 2010]
- 200mg/day of Meriva formulation for 3 months, for osteoarthritis [Belcaro Cesarone Dugall 2010]
- 1.1-1.6g/day of curcumin for 2-3 months, for inflammatory bowel disease (IBD) [Holt 2005]
- 72mg or 144mg/day of a standardized turmeric extract (Cynara) for 8 weeks, for IBS [Bundy 2004]
- 2g/day of curcumin for 6 months, for IBD [Hanai 2006]
- 400mg 3x daily for 5 days, for post-operative inflammation [Satoskar 1986]
Formulations of curcumin enhance its naturally low bioavailability. There are plenty on the market, some of the most popular being phytosome-formulated (Meriva patented) and piperine-formulated (black pepper).
On its own, curcumin has low bioavailability, meaning only a fraction of it may be absorbed and utilized by the body. Combining curcumin with other ingredients or compounds greatly enhances its absorption. The evidence is yet unclear which formulation is the best, because studies are predominantly conducted on rats or small-scale human studies with great variability. Overall though, formulations markedly improve bioavailability of curcumin as compared to unformulated, plain curcumin.
Below we dive into three particular formulations, but there are many more including Theracurmin (27x absorption, allegedly), Longvida (67x allegedly), Biocurcumax or BCM-95CG, CurQfen, NovaSol, CurcuWin, micronized curcumin, Curcumin C3 Complex + Bioperine, Cavacurmin and MicroActive curcumin [Mathew 2018] [Jamwal 2018].
Although the precise best formulation is yet to be determined, it is likely the case that any formulation will provide better absorption than unformulated curcumin or turmeric.
Phytosome Formulation (Meriva)
Certain formulation and methods of consumption of turmeric (or curcumin) lead to significantly faster and better absorption. Most notably among these are phytosome-formulated curcumin supplements (brand name Meriva). Precisely how much better Meriva is than nonformulated curcumin is still hard to tell, as reports range significantly. Some reports claim that 450mg of Meriva formulation is absorbed as well as 4g of unformulated curcuminoids (making it ~9 times more absorbed), but this is not yet proven [Jurenka 2009]. One study on rats found the Meriva curcumin formulation was somewhere between 3 and 20 times more bioavailabile than unformulated curcumin [Marczylo 2007]. Another study, conducted on humans, found that curcuminoid absorption was 29 times better for Meriva than for unformulated mixtures [Cuomo 2011]. This “29x better” is often what is referred to as its success when comparing Meriva to basic curcumin.
The phytosome formulation is not limited to curcumin, and has, in fact, been applied to a range of herbal extracts because of its ability to enhance the supplement’s ability to cross the lipid-rich biomembranes and actually reach circulation. Phytosome complexes were developed in Italy and have been around since the 1980s. Many extracts exist with the phytosome complex including Ginkgo biloba, milk thistle, green tea, ginseng, licorice, and horse chestnut [Semalty 2010].
Black Pepper Formulation
Taking curcumin with piperine, the key compound in black pepper and long pepper, significantly enhances the bioavailability of curcumin by as much as 20 times. Some studies on the human consumption of curcumin support this idea. Supplementing 2g of curcumin with 20mg of piperine improved absorption 20-fold in one small human study [Shoba 1998]. It’s helpful to note that piperine is the main active constituent of bioperine, which is also seen in some formulations [Jamwal 2018].
Turmeric Oil Formulation
Another patented formulation, Biocurcumax, combines curcumin with turmeric oil. It’s reported to improve bioavailability roughly 7-fold. It was also about 6 times better than a the compared curcumin-lecithin-piperine formula [Antony 2008].
Topical application of curcumin
For various skin conditions such as wound healing or psoriasis, curcumin may be most effective when applied topically. The bioavailability of curcumin is still relevant, even for topical application. Although some studies don’t find a significant difference among different formulations (when applied to rats for wound healing), certain formulations do seem to access the cells at the wound site better [Akbik 2014].
One potentially advantageous way to use curcumin topically is its formulations as nanoparticles, although these are yet to be proven on humans [Akbik 2014].
A relatively low concentration may suffice. For example, one study found that an alcoholic gel with 1% curcumin applied daily for 3-4 weeks helped improve psoriasis [Heng 2000].
Turmeric essential oil
Overall, studies suggest that turmeric essential oil has anti-inflammatory and antioxidant activity. No human studies have yet been conducted with the consumption of turmeric essential oil. However, studies on rats thus far indicate it’s safe and may be beneficial.
One in vitro study found that crude organic extracts of turmeric inhibited inflammation, with respect to one of the key cytokines involved (TNF-alpha) [Lantz 2003]. Another in vitro study similarly found that the essential oil from waste leaves of turmeric inhibited the production of pro-inflammatory cytokines. The oil was also effective when topically applied on mice with induced skin inflammation [Kumar 2018]. Turmeric essential oil has in vitro antioxidant activity, and was found to significantly reduce acute and chronic inflammation for mice when taken orally [Liju 2011]. Large doses, even up to 5g/kg (in rats) of turmeric essential oil for single administration, or 0.5g/kg/day for daily, had no adverse effects [Liju 2013].
Is turmeric/curcumin safe?
Curcumin is considered safe, even in high doses [Soleimani 2018]. Long-term studies (3 months) administering up to 8g/day have demonstrated that curcumin isn’t toxic, even at high doses [Hsieh 2001]. Curcumin is particularly attractive as a treatment for conditions because of its oral safety and long history of use.
It’s worth noting that at some doses (perhaps at 2-4g/day), one may experience side-effects, such as gastrointestinal disturbances [Carroll 2011].
What side effects are there?
Some side reported side effects (particularly from high doses, 2g/day or more) include gastrointestinal upset, heat intolerance and hot flashes [Kurd 2008] [Carroll 2011]. In general, few adverse side effects are reported.
Due to the range of biological activites that curcumin enables in the body, it may interact with certain conditions. It’s particularly important for those with existing conditions or diseases (diabetes, heart conditions, etc.) to consult a reliable health professional before using curcumin as a therapeutic intervention.
Some concerns circulate about curcumin decreasing iron levels. One study found that mice supplemented with curcumin did experience a decrease in iron, however this appears to be more of an issue with those already with low iron stores or anemia [Jiao 2009] [Jiao 2006]. Its influences as an iron chelator are not necessarily negative, as this influence may contribute to its anticancer activity. However, it may also mean that curcumin could also contribute to the development of anemia in patients with marginal iron status.
The bottom line on turmeric/curcumin
Turmeric’s key active component, curcumin, is associated with a range of biological mechanisms with therapeutic benefits. It may help treat a variety of conditions including inflammation-related conditions, osteoarthritis, IBS, skin conditions, Alzheimer’s, Parkinson’s, wounds, lung or liver disease, and infection from certain diseases. Curcumin’s most relevant biomechanisms are its potent anti-inflammatory and antioxidant actions, as well as its antitumor, anticancer, antiviral, antifungal, antispasmodic, antibacterial, and antivenomic activities.
The most important thing to know about curcumin is that it has low bioavailability, meaning that only a fraction of how much you consume will be absorbed by the body. Much progress has been made in formulating curcumin to increase its bioavailability. Although curcumin can be supplemented by adding more turmeric to the diet, curcumin makes up only a small fraction of turmeric (<5%) and it’s unclear how well it absorbs compared to formulated curcumin. Thus, curcumin formulations are likely more beneficial than unformulated curcumin or turmeric alone.