How to win turmeric and its curcumin game?
Turmeric and curcumin – basic information.
Turmeric is a kind of herb scientifically called Curcuma longa. It is bitter in taste with a slight evocative fragrance of orange and ginger. Turmeric has manganese, iron, vitamin B6, fiber, copper, potassium, and other important nutrients. However, the main interesting active ingredient of turmeric is curcumin (about 2-5% of turmeric root).
Turmeric is one of the major ingredients of the Indian cuisine (also known as “Indian saffron”). Turmeric, with its main active ingredient curcumin, is a potent anti-inflammatory agent protecting against cancer and Alzheimer’s disease and cardiovascular diseases.
About benefits from turmeric phytochemicals you can read here.
Important at this point is that curcumin benefits overlap with nonsteroidal anti-inflammatory drugs (NSAID) like aspirin. For people who prefer not to take NSAIDs because of stomach issues or because of a preference for “natural” products, turmeric, with its curcumin, provides unequivocal benefits, not patented of course (what is sometimes important for supplements producers).
There is only one issue with curcumin – its bioavailability.
Bioavailability of curcumin.
The efficacy of turmeric and curcumin in mentioned above diseases has been proved by many clinical studies. This efficacy and safety make turmeric a potent compound for the treatment of wide range of human diseases. It is also safe even at higher dosages. However, low bioavailability of curcumin for years blocked a wide therapeutic use of turmeric.
The reason behind the low bioavailability of some compounds within the body is their low indwelling activity, or/and inactivity of metabolise compounds or/and their rapid removal from the body. In the case of curcumin, it has been found that main issues with bioavailability are related to low absorption and rapid metabolism. Also, curcumin hydrophobicity is not unhelpful and its solubility in body’s aqueous solutions arise a problem.
In general bioavailability of active compound depends on its:
- serum concentration and tissue distributions,
- rate of metabolism,
- half-life (excretion from the body).
In the case of curcumin bioavailability, the major consideration involves its low serum levels (caused by poor absorption of curcumin from the gut, fast metabolism and excretion from the body).
In recent study Yang et al showed that administration of 10 mg/kg of curcumin results in only 0.36 µg/ml of curcumin in the blood serum, which means very low absorption (Yang, K. Y.; Lin, L. C.; Tseng, T. Y.; Wang, S. C.; Tsai, T. H., Oral bioavailability of curcumin in rat and the herbal analysis from Curcuma longa by LC-MS/MS. J. Chromatogr. B Anal. Technol. Biomed. Life Sci. 2007, 853 (1–2), 183–9).
Fast metabolism of curcumin takes place in the liver, where absorbed curcumin undergoes conjugations like sulphation and glucuronidation. The major metabolic products of curcumin, glucuronides of tetrahydrocurcumin and hexahydrocurcumin, unfortunately, are less active as compared to curcumin itself.
Also, excretion of curcumin from the body is a significant factor, which decreases its bioavailability in the body. Some studies showed even 75% excretion of curcumin in rats (Wahlstroem B., Blennow G., A study on the fate of curcumin in the rat., Acta Pharmacol Toxicol. 1978, 43: 86-92).
Scientific studies show that the route of administration will have an important role to play in the absorption and metabolism of curcumin.
Improving bioavailability of curcumin in the body.
A problem with absorption and lifetime of any agent can be solved by using various solutions:
- adding adjuvants,
- creating liposomes, phospholipids and micelles,
- administering nanoparticles,
- providing hydrophilic carriers for lipophilic compounds.
Adjuvants generally improve the bioavailability of curcumin by blocking its metabolic pathway. For example piperine (present in black pepper) has the property to inhibit glucuronidation in the liver and intestine and thereby protects curcumin. Its usage can increase the bioavailability of curcumin in rats up to 154% (Shoba G, Joy D, Joseph T, Majeed M, Rajendran R, Srinivas PS., Influence of piperine on the pharmacokinetics of curcumin in animals and human volunteers., Planta Med. 1998, 64(4):353-6).
The better positive effect of piperine has been shown in humans. Also, other adjuvants (like genistein, quercetin, tangeretin, silibinin) have similar properties (Grill AE, Koniar B, Panyam J., Co-delivery of natural metabolic inhibitors in a self-microemulsifying drug delivery system for improved oral bioavailability of curcumin., Drug Deliv Transl Res. 2014, 4(4):344-52).
Phospholipids, micelles and liposomes
Having regard to the hydrophobic properties of curcumin, liposomes seem to be a nice solution for its delivering and adsorption. Also, a typically high loading capacity of liposomes can be important for effective transport curcumin to the blood plasma stream. Actually, an evaluation of the efficiency of liposomal curcumin administration over the free curcumin intake is still under active research process.
It seems to be a good solution to use micelles created from phospholipids. Many studies suggest that the absorption of curcumin in this form increases significantly its bioavailability and this is a promising solution for wider medical use of curcumin (Liu A, Lou H, Zhao L, Fan P., Validated LC/MS/MS assay for curcumin and tetrahydrocurcumin in rat plasma and application to pharmacokinetic study of phospholipid complex of curcumin., J Pharm Biomed Anal. 2006, 24;40(3):720-7; Peng S, Zou L, Liu W, Li Z, Liu W, Hu X, Chen X, Liu C, Hybrid liposomes composed of amphiphilic chitosan and phospholipid: Preparation, stability and bioavailability as a carrier for curcumin., Carbohydr Polym. 2017, 156:322-332).
Other, recently popular option is to administer polymer based nanoparticles (with size less than 100 nm) with encapsulated curcumin (S. Bisht, G. Feldmann,S. Soni, R. Ravi, C. Karikar, A. Maitra, A. Maitra, Polymeric nanoparticle-encapsulated curcumin ("nanocurcumin"): a novel strategy for human cancer therapy., J Nanobiotechnology. 2007; 5).
This form of curcumin, called nanocurcumin, has been found to have the similar biological activity (the same anti-oxidant and anti-inflammatory effects) as that of free curcumin. Experiments show that curcumin is released from nanoparticles within about 12 hours.
Also a formulation of curcumin with a combination of hydrophilic carrier, cellulosic derivatives and natural antioxidants significantly increases curcuminoid appearance in the blood in comparison to unformulated standard curcumin (R. Jäger, R. P. Lowery, A. V. Calvanese, J. M. Joy, M. Purpura, J. M. Wilson, Comparative absorption of curcumin formulations, Nutrition Journal, 2014, 13:11).
Best and easy practices – how to win?
The main reason behind the low bioavailability of curcumin in the body is its hydrophobicity (low water solubility) and its fast metabolism. Bioavailability of curcumin can be enhanced by increasing its solubility in water and by protecting curcumin molecules or by inhibiting enzymes and processes result in transformation curcumin to less active derivatives.
There are some strategies for increase bioavailability of curcumin and which can be used on daily basis:
- eating turmeric in fatty compositions (for example with an addition of coconut oil, flaxseed oil, olive oil or yolk), which support absorption of curcumin by a liposomal mechanism.
- eating boiled turmeric as a part of warm meals (for example warm milk with turmeric called golden milk), where increased temperature enhances curcumin extraction and solubility.
- eating turmeric together with black paper (or bioperine – extract from black paper), which means protection curcumin from glucuronidation in intestine and liver with piperine.
- eating turmeric together with fruits or vegetables or cider (contains a high level of quercetin), which means protection curcumin from sulfation by sulfotransferase (inhibited by quercetin).
- eating turmeric with extract of the milk thistle seeds (silymarin) containing silibinin, which means protection of curcumin by inhibiting uridine glucuronyl transferases.
- taking supplements with enhanced bio-availability of curcumin (in the form of encapsulated curcumin or nanoparticles contains curcumin).
- taking formulations with phytosomes (liposomes that contain curcumin and often piperine) like products: Mervia, BCM-95, Curcumin C3 Complex and Longvida.
Manufacturers and suppliers of curcumin: