Curcumin is the bioactive constituent from turmeric, which experts use for seasoning, pigment, and herbal medicine in food. Experts consider it as the most common nutraceutical used in pharmaceutical, supplement, and food domains as a result of its several health benefits. When consumed as a drug, supplement, or food, it consists of antioxidant, anti-inflammatory, antimicrobial, anti-parasite, and anticancer activities. Experts determine its toxicity by conducting clinical studies for analyzing its safety in terms of consumption, even at relatively high levels.
It’s biological mechanisms, and low toxicity have resulted in an effective nutraceutical ingredient for application in functional foods. But, there are many hurdles that formulators need to mitigate while incorporating curcumin into commercial products. The low water solubility, mainly under acidic and neutral conditions, chemical instability in neutral and alkaline conditions, rapid metabolism by enzymes in the human body, and limited bioavailability are the significant complexities found during formulations of curcumin which brings complexities during absorption in the body. Hence, doctors ingest a minimal amount of curcumin into the bloodstream. Therefore, there is a need for overcoming such obstacles in the absorption of curcumin within the bloodstream.
The complexity of curcumin in absorption within the bloodstream
Pure curcumin is an orange and yellow colored crystalline material that is available in powdered form. Experts consider its chemical composition a labile hydrophobic substance which is evolving with low water solubility, mainly under acidic or neutral conditions showing complete protonation. Also, poor chemical stability in alkaline conditions and low bioavailability in case of lower bioaccessibility and chemical transformation due to presence of metabolic enzymes in the gastrointestinal tract contributes to its slower absorption rate. Curcumin is also susceptible to chemical degradation when stored in the body during the condition of light, high temperatures, and alkaline conditions. During acidic conditions, curcumin shows stability towards chemical degradation while constituting low water solubility that enhances crystallization and sedimentation in aqueous delivery systems 1. Hence, these obstacles complicate the absorption of curcumin within the bloodstream when ingested as pharmaceuticals, supplements, and functional food products.
Curcumin is lipophilic and contributes to its poor absorption. Most dietary compounds absorb within the digestive tract and do not reach the colon. Hence, one can increase the curcumin concentration in the large intestine through appropriate ingestion. Poor water solubility is a significant issue that hinders the delivery of curcumin to non-enteric organs. The limitations in the solubility and absorption result in lowering the bioactivity of curcumin within non-enteric organs. This complexity is further increases b implicating the understanding that curcumin may not be much effective due to its parent molecule. Still, the doctors determine the effectiveness in some cases due to its metabolites. Most curcumin particles are suggested to get metabolized in the liver and later converted into curcumin conjugates and degradation products 2. The current inconsistencies in curcumin are due to its lack of stability, short retention time, and limited reports on curcumin’s metabolites and conjugates.
Overcoming curcumin complexities in body absorption
Experts have undertaken several approaches for mitigating the complexities of curcumin in terms of absorption. The most effective means of protecting curcumin from chemical degradation is by increasing the water dispersibility and improving its bioavailability through modern encapsulation technologies 3. The incorporation of curcumin into edible nanoparticles or microparticles enhances the absorption rate of curcumin, which can be later used to be integrated into food or supplement products 4. The colloidal particles used for the same are assembled from food-grade ingredients involving surfactants, phospholipids, lipids, proteins, polysaccharides, and minerals, using spontaneous or directed processes. Different types of colloidal particles have been used to improve the solubility of curcumin while integrating as micellar aggregates, liposomes, emulsion droplets, solid lipid particles, and biopolymer particles 5.
- 1.Kharat M, Du Z, Zhang G, McClements DJ. Physical and Chemical Stability of Curcumin in Aqueous Solutions and Emulsions: Impact of pH, Temperature, and Molecular Environment. J Agric Food Chem. Published online February 16, 2017:1525-1532. doi:10.1021/acs.jafc.6b04815
- 2.Hoehle SI, Pfeiffer E, Sólyom AM, Metzler M. Metabolism of Curcuminoids in Tissue Slices and Subcellular Fractions from Rat Liver. J Agric Food Chem. Published online January 13, 2006:756-764. doi:10.1021/jf058146a
- 3.McClements DJ, Decker EA, Park Y, Weiss J. Structural Design Principles for Delivery of Bioactive Components in Nutraceuticals and Functional Foods. Critical Reviews in Food Science and Nutrition. Published online June 16, 2009:577-606. doi:10.1080/10408390902841529
- 4.Zhang Z, Zhang R, Decker EA, McClements DJ. Development of food-grade filled hydrogels for oral delivery of lipophilic active ingredients: pH-triggered release. Food Hydrocolloids. Published online February 2015:345-352. doi:10.1016/j.foodhyd.2014.10.002
- 5.McClements DJ, Decker EA, Weiss J. Emulsion-Based Delivery Systems for Lipophilic Bioactive Components. J Food Science. Published online October 2007:R109-R124. doi:10.1111/j.1750-3841.2007.00507.x