Curcumin: From the Spice Rack to Supplement Superstar
Its golden color is unmistakable around the world today, however turmeric was once confined as a culinary staple to kitchens throughout Asia, Southeast Asia, and the Middle East. What was once simply regarded as a spice on the spice rack has become the “golden child” of the natural medicine cabinet. Researchers, consumers, and health practitioners alike now value turmeric and its key phytonutrient, curcumin, for its remarkable qualities that make it the centerpiece of many therapeutic interventions.
Turmeric is the common name for the rhizome of the Curcuma longa plant, native to Asia, which has many traditional uses:
- Main spice of curry dishes
- Ancient ways of dyeing textiles and food
- Antimicrobial preservative
- Insect repellant
This revered spice has a long history of use within the ancient medical philosophies of Ayurveda and Traditional Chinese Medicine as an herb to treat a wide variety of ailments including rheumatism, diabetic ulcers, anorexia, cough, and sinusitis, making turmeric among one of the original “superfoods.” It was not until researchers began to notice a decrease in certain cancers among people living in regions where turmeric is regularly consumed as part of their traditional diet, that the rest of the world began to recognize what Ayurvedic and Traditional Chinese Medicine practitioners already knew: turmeric has a long list of potential health benefits that may be therapeutically useful for nearly every malady, due in part to its anti-inflammatory actions.
How Are Inflammation and Chronic Disease Related?
Inflammation is an important action triggered by the immune system in response to injury or microbial threat. Inflammation has two phases: initiation and resolution. When the body is in balance, the resolution phase resolves the inflammatory cascade and brings the body back to homeostasis. However, when the resolution phase is inadequate, inflammation becomes chronic, triggering oxidative stress.
Oxidative stress and chronic inflammation are the mechanisms that unify the pathology of nearly all disease states. Because chronic inflammation and oxidative stress are the fundamental underlying causes of chronic disease, they represent an important therapeutic target for healing.
How Should Chronic Inflammation Be Addressed?
Traditionally, medicines have targeted the initiation phase of inflammation, seeking to block its effects. However, botanicals and natural agents can be used to modulate inflammation, reduce oxidative stress, and promote resolution of inflammatory cascades. This approach is a primary focus of integrative medicine protocols, as well as a major area of scientific investigation.
Curcumin has been shown to have strong antioxidant and anti-inflammatory effects in the body through a number of different mechanisms. One of its effects is to “dampen” the inflammatory response when inflammation is chronic by reducing, and in some cases blocking, the actions of key pro-inflammatory messengers including nuclear factor kappa beta (NF-kB) and tumor necrosis factor (TNF). Another way it reduces inflammation is by revving up nuclear factor E2-related factor 2 (Nrf2), a signaling pathway that boosts the body’s own production of anti-inflammatory molecules (like superoxide dismutase) and detoxification enzymes (like and glutathione S-transferase) to protect against oxidative damage and promote phase 1 and 2 detoxification. While it affects chemical messaging pathways, curcuminoids may also act directly as a free radical scavenger, reducing oxidative damage and stress. As an anti-microbial, curcumin can improve inflammation by helping to resolve underlying infection, which can be an inflammatory trigger. Curcumin has been shown to have antibacterial, antiviral and antifungal effects, as well as demonstrated activity as a biofilm disruptor.
Because curcumin functions in a wide variety of ways through different mechanisms to address inflammation, and because oxidative stress, chronic inflammation and chronic disease are so closely linked, curcumin’s potential benefit in any inflammatory-related condition is particularly significant. This can explain why it is so frequently used in integrative medicine protocols.
Curcumin and its Bioavailability
One long-standing issue with curcumin supplementation has been its notably poor absorption rate in the digestive tract, rapid metabolism and short half-life. This is why curcumin is typically combined with other herbs to enhance its absorption. Combining cucumin with piperine, a component of black pepper, irritates the gut lining, allowing for improved absorption of curcumin. Another common preparation is curcumin in a lecithin phospholipid, since curcumin is fat soluble. Compared to a standard mixture, the curcumin-phospholipid absorption rate is about 29-fold higher. A more novel formulation of curcumin combines the phytonutrient within a galactomannon soluble fiber matrix formulated from fenugreek seeds. Studies have shown that this combination increases curcumin bioavailability in humans significantly, by approximately 40-fold. In animal studies, the galactomannon-curcumin formulation was better able to cross the blood-brain-barrier, and the half-life of curcuminoids was extended significantly. Because galactomannon is not digested, it slowly releases curcuminoids, extending its effect and therefore its potential benefit.
Potential health benefits/therapeutic uses
Because curcumin is a potent inflammatory modulator, and most chronic diseases are inflammatory in nature, curcumin may have therapeutic uses and potential benefits for a wide range of all-too-common health conditions.
- Diabetes and Diabetes-Related Complications: The anti-inflammatory and antioxidant properties of curcumin can inhibit the enzymes that contribute to diabetes and drive secondary diabetes-related complications, such as alpha-glucosidase and aldose reductase. Curcumin may also prevent or slow the progression of diabetes-related complications, like retinopathy, neuropathy, vascular diseases, nephrology, and liver disorders. Type 2 diabetes often coexists with obesity, and curcumin has been shown to reduce markers of oxidative stress in obese people.
- Inflammatory Bowel Disease: A feature of Inflammatory Bowel Disease (IBD) is relapsing chronic inflammation, resulting in oxidative stress, white blood cell infiltration, and the up-regulation of pro-inflammatory cytokines, such as NF-kB. Downregulating NF-kB is a target for many IBD drug therapies. Studies have found that certain preparations of turmeric extract reduced inflammation by increasing anti-inflammatory transcription gene activity, such as IL-10. Oral curcumin has been found to block the actions of TNF, cyclooxygenase-2 (COX-2) and other markers of inflammation, and appears to decrease cellular damage to the colon without any toxic effects.
- Arthritis and Rheumatoid Arthritis (RA): Treatment strategies for arthritis-related pain and joint inflammation usually include non-steroidal anti-inflammatory drugs (NSAIDs) because they are COX-2 inhibitors that combat pro-inflammatory prostaglandins and thromboxanes. Curcumin has been used to treat arthritis symptoms because it too is a COX-2 inhibitor that has been found to decrease pain and inflammation as effectively as pain medication in many studies. In rheumatoid arthritis (RA), oxidative stress contributes greatly to joint destruction and is generally treated with NSAIDs. Curcumin treatment has been shown to down-regulate or inhibit mediators of RA inflammation and joint damage, including COX-2, prostaglandin E2, IL-6, NF-kB and TNF-a. In fact, when compared to a common RA medication, curcumin treatment was found to offer the best improvement in RA disease activity scores and American Collage of Rheumatology scores, which are used in studies to evaluate RA symptoms and disease progression.
- Neurodegenerative Diseases: Age-related neurodegeneration is associated with a decrease in antioxidants and an increase in persistent, low level oxidative damage to DNA, proteins and lipids in tissues and cells, which accumulate in neurodegenerative diseases. Curcumin has been found to offer neuro-protection through its free radical scavenging actions and by inhibiting nitric oxide synthase and lipid peroxidation. It may also modulate the cascade of oxidative stress in neurodegenerative diseases that results from mitochondrial dysfunction, inflammatory cytokines, COX-2 and damage from heavy metal accumulation. A major benefit to curcumin for neuroprotection is its ability to cross the blood-brain-barrier. Curcumin has been found to suppress gene transcription for inflammatory markers that interact with Alzheimer’s disease-related amyloid-b-proteins, such as TNF-a, IL-1b and IL-8. In animal models, curcumin was able to decrease amyloid-b and oxidized proteins in the brain. Other animal studies have demonstrated the ability of curcumin to increase brain derived neurotrophic factor (BDNF), which is responsible for neurogenesis and, to a large degree, neuroplasticity.
- Cardiovascular Disease and Stroke: Curcumin appears to have a multi-directional effect against cardiovascular disease and its contributors. On the one hand, curcumin is a potent anti-inflammatory compound that can suppress the production of pro-inflammatory molecules, like IL-1, IL-8 and TNF-a. On the other hand, curcumin has been observed to induce mild oxidative stress, leading to an “adapted stress response” in cells that stimulates cellular antioxidant defense mechanisms. Curcumin been shown to lower total cholesterol, increase HDL cholesterol levels, inhibit platelet aggregation, as well as suppresses inflammatory mediators in vascular smooth muscle cells, protecting against cardiovascular disease, coronary events and stroke. Curcumin may also protect against stroke epigenetically by influencing gene expression, though exact mechanisms are not yet clear.
- Cancer Prevention and Therapy: Curcumin has been found to have a therapeutic and preventative role for a wide variety of cancers, including colorectal, pancreatic, liver, lung, breast, uterine, ovarian, bladder, renal, kidney, prostate, brain, non-Hodgkins lymphoma, and leukemia. It appears to be toxic to cancer cells and yet protective to healthy cells, partially due to curcumin’s strong antioxidant capacity. Human studies have shown that high doses (up to 12,000 mg per day) of curcumin taken orally is safe and tolerable. There are several key mechanisms that make curcumin effective against cancer, including its effects on signaling pathways that control inflammation, angiogenesis, tumor growth, metastasis, invasion, and apoptosis. Curcumin may block the effects of carcinogens by inhibiting NF-kB, which is activated by most carcinogens and triggers the expression of inflammatory molecules like COX-2, lipoxygenase 2 (LOX-2), inducible nitric oxide synthesis (iNOS), TNF-a, proinflammatory cytokines, and chemokines. Several phase I and II clinical trials have been conducted to examine the efficacy of curcumin in the treatment of cancer with promising results. Because curcumin has multi-molecular targeting mechanisms, it presents as an important chemopreventive and possibly chemo-therapeutic phytonutrient.
- Anti-Microbial and Wound Healing: Curcumin has been shown to have antimicrobial properties and is being investigated as a topical treatment to protect and aid in wound healing. It has been shown to improve wound healing by acting on various stages of the wound healing process. Curcumin with hydrogel silver nanoparticles has been shown to improve the function of the silver in wound dressings. Topical preparations of curcumin combined with a myristic acid emulsion was found to inhibit staphylococcus epidermidis bacteria by 50 percent. Curcumin may inhibit several strains of bacteria, including strains of vibrio, staph, listeria, e. coli, and salmonella. Some studies have shown to have antibacterial activity against various forms of Helicobacter pylori. A combination of curcumin and several antibiotics, including ciprofloxacin, have illustrated a synergistic effect against methicillin-resistant Staph. aureus (MRSA) infections. In vitro experiments have found curcumin to have anti-influenza activity against several strains of influenza virus, showing more than a 90 percent reduction in virus yield and no resistance was developed to curcumin developed. Curcumin may also have an inhibitory effect against two strains of human papilloma viruses (HPV-16 and HPV-18) linked with increased cancer risk by disrupting the expression of viral oncoproteins. As an anti-fungal, curcumin may be a potent anti-candida treatment, found to be effective against 38 strains of candida, including some fluconazole-resistant strains.
- Eye health: Curcumin may have beneficial effects on eye health and may offer benefit on many ocular diseases, including diabetic retinopathy, glaucoma, chronic anterior uveitis, age-related macular degeneration, and dry eye syndrome
Chronic inflammation and oxidative damage are well-known drivers of a multitude of diseases, including chronic disease states. Curcumin and curcuminoids are potent phytonutrient antioxidants that boost the body’s antioxidant capacity to reduce inflammation. With its wide range of mechanisms to protect the body, curcumin represents an important option for many natural medicine interventions.
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