<body><h1><strong>Turmeric (curcuma longa)</strong></h1><p> </p><h2><strong>Description:</strong></h2><p>Curcumin is a yellow pigment found primarily in turmeric, a flowering plant of the ginger family best known as a spice used in curry. It’s a polyphenol with anti-inflammatory properties and the ability to increase the amount of antioxidants that the body produces. Curcumin and the curcuminoids found in turmeric can be extracted to produce supplements that have a much higher potency than turmeric. However, curcumin is absorbed poorly during digestion, so a myriad of different formulations have been created to improve its bioavailability.</p><p>You probably recognize turmeric, or curcuma longa, from your spice rack. Also known by its active compound, curcumin, it’s widely known for its bright yellow color. It is made from the root of the turmeric plant, which is native to India and Southeast Asia. It’s one of the components of curry, but is also included on its own in many Southeast Asian dishes. Beyond its use in the kitchen, this spice has been used in traditional medicine for hundreds of years, most prominently in the Ayurvedic tradition. Partially due to this popularity, curcumin has been extensively researched for decades. Recently, it has been earning notoriety as a “super spice” of sorts, with a wide range of potential benefits. It’s becoming popular both as a encapsulated supplement, and as an ingredient in lotions and face creams.</p><p>Although the bioavailability of the curcumin in turmeric is still being studied, clinical trials have found it has potential to be a powerful antioxidant. It also has been found to help combat exercise-related pain and inflammation.</p><p><strong> </strong></p><h2><strong>Benefits:</strong></h2><h2><strong>Turmeric as an Antioxidant:</strong></h2><p>Our bodies get subjected to oxidative stress through many mechanisms, including exercise, unhealthy body composition, the environment we live in, and certain foods we eat. This type of stress can cause cell damage through the creation of free radicals, as well as speeding up the aging process. Turmeric’s antioxidant properties help fight damage caused by oxidative stress. Studies have shown it to have many potential benefits, including improving blood flow and adding resilience to skin.</p><p>Supplementation of curcumin reliably reduces markers of inflammation and increases the levels of endogenous antioxidants in the body. More research is needed for many areas of health, but what research there is supports a small to moderate improvement in the symptoms of depression and anxiety, and pain and function in osteoarthritis. A reduction in LDL-cholesterol, blood glucose and blood pressure is possible, but the research is less consistent and more is needed.</p><p> </p><p><strong> </strong></p><h2><strong>Effect on Muscles:</strong></h2><h2><strong>Acute Protective Effects</strong></h2><p>Through its anti-oxidant effects, curcumin can ameliorate oxidative damage to skeletal muscle via Ischemia/Reperfusion when preloaded at 100mg/kg (I.P injection) to rats, with a potency greater than vitamin E. Curcumin also ameliorates the increase in inflammatory cytokines associated with Ischemia/Reperfusion injury.</p><p>As for the mechanisms of the above, curcumin (5-10uM) appears to increase Glucose-Regulated Protein 94 (Grp94) expression, which regulates calcium homeostasis; this regulation of calcium homeostasis appears to precede the standard inhibition of NF-kB activation and reduce the state of oxidation when an oxidative insult is produced. Interestingly, curcumin can also inhibit upregulation and damage from lead via preventing Grp94 upregulation, and general protection against cadmium as well.</p><p> </p><p><strong>Catabolism/Anabolism</strong></p><p>Curcumin (via injection) is also implicated in increasing the recovery of skeletal muscle capacity associated with deloading, although it was not able to preserve skeletal muscle mass during deloading. These results differ from earlier ones showing a 100mg/kg oral dose of curcumin in rats was able to reduce muscular atrophy while a higher dose of 250mg/kg actually improved skeletal muscle weight.</p><p><strong>Glucose metabolism</strong></p><p>Skeletal muscle, via glucose uptake and oxidation, is a tissue regulator of glucose metabolism. Some fatty acids, such as palmitic acid, can activate (phosphorylize) IRS-1 which causes negative feedback to the insulin receptor and desensitizes muscle cells to insulin-stimulated glucose uptake; curcumin appears to prevent this from occurring. This effect is shared by green tea catechins. Improvements in this mechanism of insulin resistance have been seen in vivo with dose-dependent oral doses of curcumin at 50, 150, and 250mg/kg bodyweight. AMPK activation appears to be a key intermediate in these effects. Beyond acting upon IRS, curcumin may also increase glucose uptake into skeletal muscles by acting on muscarinic acetylcholine receptors and then through PLC and PI3K. Curcumin has been implicated in reversing some aberrations in skeletal muscle associated with type II diabetes, such as upregulation of beta-adrenergic receptors and Akt, the downregulation of NRF2 and Heme Oxygenase-1, and downregulation of AMPK and CPT-1. At least one study has suggested that the state of diabetes may be a prerequisite, and although it didn’t measure all above parameters it did note no effects of curcumin in non-diabetic mice.</p><p> </p><h1><strong>Effect on Hormones:</strong></h1><h2><strong>Testosterone:</strong></h2><p>Curcumin, at 100mg/kg bodyweight in rats, has been shown to preserve testosterone levels when coadministered with a drug (Metronidazole) that causes testosterone reductions and worsens parameters of sperm. Protective effects on the testes have also been noted with curcumin in regards to alcohol, where curcumin (80mg/kg bodyweight) was able to preserve testicle structure and testosterone levels despite alcohol consumption, most likely though preventing the oxidation of ethanol to acetylaldehyde. Other compounds that damage the testicles and reduce testosterone, but are protected against by curcumin, include excessive chromium levels and cadmium. When looking at the 17beta-HSD3, the final step in testicular testosterone synthesis, curcumin was found to be a noncompetitive inhibitor with an IC50 of 2.3uM, and brought Luteinizing-Hormone stimulated testosterone levels down to 34% of control at a concentration of 10uM. This effect was not dose-dependent, and concentrations of 1uM were not significantly different from 0.1uM and control cells. Curcumin may also possess inhibitory actions against 5-alpha reductase, the enzyme that converts testosterone into the more potent androgen DHT. Given the above two mechanisms (17beta-HSD3 and 5AR inhibition) are anti-androgenic in nature, it would be prudent to observe in vivo effects of curcumin. The only current study on the matter used injections of PEG-curcumin at 0.5mg (giving a Cmax of 7ug/mL to then decline to 1ug/mL) noted a decrease in circulating testosterone levels and function of seminal vesicles, although testicle weight did not decline. In regards to aromatase, the enzyme that converts testosterone to estrogen (and thus higher activity would mean a more anti-androgenic profile), curcumin does not directly inhibit aromatase in vitro but appears to reduce the catalytic activity of aromatase (also known as CYP1A) in mice. Clinical relevance of these effects is not known. Curcumin appears to have protective effects on testicular functions, but possesses anti-androgenic activity. The concentration required for inhibition is high, but it appears to occur in vivo when it is met; it is uncertain what oral dose is needed for these effects, but it might occur with superloading and increasing bioavailability. Low doses of curcumin may have no adverse effect whatsoever.</p><h2><strong>Estrogen</strong></h2><p>In regards to possible anti-estrogen effects, the lack of inhibition on aromatase but potential to reduce catalytic activity of aromatase suggests some interactions may exist at this stage. One study comparing normal rats versus a Menopausal model (ovariectomized) noted that 10mg/kg oral ingestion in the normal mice was able to reduce circulating estrogen levels. 100nM of Curcumin is able to act as an agonist at estrogen receptors in MCF7 breast cancer cells, but has low activation of target genes relative to estradiol, although more potent than quercetin and Enterolactone. It is possible that Curcumin may act as a Selective Estrogen Receptor Modulator (SERM) and compete for the more potent estradiol, as it has been noted to reduce estrogen-induced cell proliferation elsewhere (was not tied directly to the estrogen receptor in this study). In regards to anti-estrogenic activity, limited but theoretical potential of Curcumin to be antiestrogenic via either reducing the effects of aromatase or via acting as a SERM (not yet wholly established).</p><h2><strong>Side Effects:</strong></h2><p>Doses of up to 8 grams of curcuminoids aren’t associated with serious adverse effects in humans. However, long-term studies that are more comprehensive in their assessments are needed. High doses of curcumin may produce nausea and gastrointestinal complaints. Use of curcumin with piperine may cause adverse drug reactions, as piperine greatly increases intenstinal permeability. The different formulations of curcumin have not all been tested for safety to the same degree.</p></body>
