Turmeric and Curcumin Simply Explained

1. What Is Turmeric and Curcumin?

Turmeric is the dried and ground rhizome of the plant Curcuma longa. This plant belongs to the ginger family. Curcumin is the yellow colorant in this rhizome. It belongs to the group of curcuminoids. Turmeric is traditionally used as a spice and for coloring.

2. Where Is It Found, and What Is It Made From?

Turmeric is found in spices as powder from the ground rhizome. Curcumin is obtained from this powder. There are extracts with a high curcuminoid content. Some products contain curcumin with piperine from black pepper. Others use a special phytosome form. Individual curcuminoids such as demethoxycurcumin and bisdemethoxycurcumin are also available. Hydrogenated curcumin is called tetrahydrocurcumin. Other Curcuma species such as zedoary and Javanese turmeric are not included. Ginger, galangal and the essential oil without curcuminoids also do not count.

3. What Does Turmeric and Curcumin Do? What Research Shows

Metabolism and Blood Values

For metabolism and blood values, several controlled studies (with a comparison group) showed improvements. These include fasting blood glucose 3716212238 and long-term blood glucose value 71622384748. Insulin resistance also improved in several controlled studies 33132475687. A randomized (participants assigned by lot) controlled study in healthy older people found increased blood glucose under a special curcumin preparation 58. Many studies do not state the form, curcuminoid content and duration of administration precisely, and information on manufacturer funding is mostly missing.

Inflammation-Related Conditions

In inflammation-related complaints, curcumin showed improvements in C-reactive protein in several controlled studies and meta-analyses (joint evaluation of many studies) 3412162128. Tumor necrosis factor-alpha, a messenger substance of inflammation, also decreased more strongly than under control in several studies 41221495057. Likewise, the erythrocyte sedimentation rate 283352626380 and the inflammatory messengers interleukin-6 449505760 and interleukin-1 beta 495060 improved. Two further controlled studies saw no difference in the inflammatory values overall 7288. When curcumin was given in addition to gum treatment, the gum value improved more strongly than with the treatment alone 1973. In rheumatoid arthritis, the rheumatoid factor, a typical blood value of this disease, decreased more strongly than in the comparison group 3380. Curcumin, curcuminoid-rich extracts, turmeric powder, curcumin with piperine, and phytosome forms were investigated. Findings from a meta-analysis of various polyphenols in rheumatoid arthritis cannot be attributed to curcumin alone 6. The findings come predominantly from small to medium-sized studies of varying form, dose, and duration, which limits the informative value.

Joints and the Musculoskeletal System

For joint and movement complaints, curcumin showed improvements in pain intensity in several controlled studies, predominantly in knee osteoarthritis 91720283644. Questionnaires on knee pain and knee function also showed better values than under a sham treatment 53644536466. Several controlled studies also found better function values than in the comparison group 416886 and, in rheumatoid arthritis, lower disease activity 28334080. Predominantly extracts with a high curcuminoid content were studied, partly in forms that reach the blood better, as well as a curcumin gel for the skin and hydrogenated curcumin 6468808689. Two controlled studies found no difference in pain and function compared with ibuprofen 46 or paracetamol 90. In rheumatoid arthritis and lupus, disease activity remained without a difference from the comparison group 27. Inflammatory values and joint inflammation in knee osteoarthritis also did not differ 88. Performance tests with curcumin gel also showed no difference 64. Some investigations used mixtures with Boswellia serrata, painkillers or cartilage agents. Such results cannot be attributed to curcumin alone 10131415. Many studies are small and short, the forms and additives are inconsistent, and information on manufacturer funding is mostly missing.

Absorption in the Body

Certain preparations increased absorption in several controlled studies. Micellar, water-soluble, and newly developed forms achieved more active substance in the body than conventional curcumin or a standard extract 798283. The highest blood levels were also higher with these preparations 798283. Curcumin packaged in fat or water particles (liposomal, nanoemulsified, micellar) was measurable in the blood 697172. An overview mainly of animal and laboratory studies suggests that curcumin is better absorbed in tiny carrier particles (nanocarriers). These results apply only to the respective preparation tested, not to curcumin in general. With five different preparations, there was no difference in free curcuminoids. The combination with piperine also did not differ from the standard extract 77. With three different amounts of turmeric powder, the curcumin level in the blood did not differ 85. Most studies were small and investigated healthy volunteers over a short period. Therefore, the informative value is limited despite the high number of controlled studies.

Digestion

In women with severe obesity, curcumin alleviated gastrointestinal complaints such as belching and constipation more than a sham treatment 75. In children with autism, gastrointestinal complaints and an inflammation value in the stool decreased under curcumin 63. In ulcerative colitis (a chronic intestinal inflammation), a joint evaluation and two reviews of small studies saw indications of a benefit, especially in addition to standard treatment 404243. A review saw a possible effect in irritable bowel syndrome and chronic inflammatory bowel diseases 37. In irritable bowel syndrome, a joint evaluation found a favorable but not confirmed effect 26. A small randomized study found no difference in gastrointestinal symptoms 81. In fatty liver and liver stiffness, the values improved in a randomized controlled study 60. In periodontitis (gum inflammation), curcuminoid gel or curcumin gel improved the gum values 7684. The findings are based predominantly on small studies with short duration. Information on manufacturer funding is mostly missing. The forms studied ranged from curcuminoid-rich extract to curcumin with piperine and phytosome form to mixtures with other substances. Mixtures cannot be attributed to curcumin alone. An herbal preparation with turmeric lowered an intestinal bacterium and constipation 54. Curcumin with piperine reduced the severity of a fatty liver 59. A curcumin-Boswellia phytosome mixture alleviated bloating and abdominal pain 61.

Tolerability and Safety

For this area, 13 controlled studies and 2 joint evaluations with a total of 1732 participants were evaluated. Several controlled studies and reviews described curcuminoids, curcumin in phytosome form and hydrogenated curcuminoids as well tolerated 3739576780. Liver and kidney values remained unremarkable under curcumin 48. Liver enzymes remained unchanged under micellar curcuminoids 72. Laboratory values and vital signs did not differ from placebo 65. Meta-analyses and reviews found no increase in adverse events under curcumin 5252641; in a large randomized study over two years, side effects were rare and mild 45. A meta-analysis on curcumin and Curcuma longa extract in various forms of arthritis found no differences in safety endpoints 9. A meta-analysis on Curcuma longa, also as a mixture with Boswellia serrata, found no differences in adverse events 13. A systematic review (ordered summary of all studies) found no differences between curcuminoid formulations and painkillers in satisfaction, treatment adherence and rescue medication 15. The findings apply to the forms studied — powder, extract, phytosome form and individual substances. Because of the mostly short study duration and the very different preparations, they can be transferred to long-term use only to a limited extent.

Other Investigations

For cognition, several studies found improvements 2324305558, while individual controlled studies showed no difference 2474. For depression 1825295070 and anxiety 1825, several studies also found improvements. The forms ranged from turmeric powder to phytosome; mixed preparations with resveratrol or green tea extract cannot be attributed to curcumin alone 11. Overall, the robustness is high. But the preparations, formulations and target values are very different. Therefore, no uniform statement can be made. It remains open which form and which curcuminoid content are effective for which target value.

4. How Was Turmeric and Curcumin Taken in the Studies?

Various forms were tested in the studies. These included ground turmeric powder, extracts with a high curcuminoid content and curcumin with piperine from black pepper. Curcumin in phytosome form, individual curcuminoids and hydrogenated curcumin were also studied. Some of the investigations tested mixtures with other plant substances, Boswellia serrata or painkillers. Such results cannot be attributed to curcumin alone. Form, curcuminoid content and duration of administration were not stated precisely in many studies.

5. Is Turmeric and Curcumin Safe? Side Effects in the Studies

Curcumin was well tolerated in most studies 25395767. Under a Curcuma domestica extract, abdominal pain occurred less often than under ibuprofen 46, other studies reported more gastrointestinal complaints under curcumin 8247478. As an infusion, liposomal curcumin temporarily changed the shape of red blood cells at higher doses 69.

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