Curcumin, a compound found in the cooking spice turmeric, can cause a modest but measurable increase in levels of a protein that’s known to be important in the “innate” immune system, helping to prevent infection in humans and other animals. This cathelicidin antimicrobial peptide, or CAMP, is part of what helps the immune system fight off various bacteria, viruses or fungi.
The CAMP peptide is the only known antimicrobial peptide of its type in humans. It appears to have the ability to kill a broad range of bacteria, including those that cause tuberculosis and protect against the development of sepsis.
The newest findings were made by researchers in the Linus Pauling Institute at OSU and published in the Journal of Nutritional Biochemistry, in collaboration with scientists from the University of Copenhagen in Denmark. The work was supported by the National Institutes of Health.
In this study, the potential was looked at of both curcumin and omega-3 fatty acids to increase expression of the CAMP gene. They found no particular value with the omega-3 fatty acids for this purpose, but curcumin did have a clear effect. It caused levels of CAMP to almost triple.
Curcumin has also been studied for its anti-inflammatory and antioxidant properties. “Curcumin, as part of turmeric, is generally consumed in the diet at fairly low levels,” said Adrian Gombart, an associate professor of biochemistry and biophysics in the Linus Pauling Institute “However, it’s possible that sustained consumption over time may be healthy and help protect against infection, especially in the stomach and intestinal tract.”
Curcumin, the principal curcuminoid found in the spice turmeric, is generally considered its most active constituent. In addition to its use as a spice and pigment, turmeric has been used in India for medicinal purposes for centuries. More recently, evidence that curcumin may have anti-inflammatory and anticancer activities has renewed scientific interest in its potential to prevent and treat disease.
The results of phase I clinical trials in colorectal cancer patients suggest that biologically active levels of curcumin can be achieved in the gastrointestinal tract through oral curcumin supplementation. There is some evidence that orally administered curcumin accumulates in gastrointestinal tissues.
Curcumin is an effective scavenger of reactive oxygen species and reactive nitrogen species in the test tube (in vitro). The finding that oral curcumin supplementation for seven days decreased the number of oxidative DNA adducts in malignant colorectal tissue suggests that curcumin taken orally may reach sufficient concentrations in the gastrointestinal tract to inhibit oxidative DNA damage. In addition to direct antioxidant activity, curcumin may function indirectly as an antioxidant by inhibiting the activity of inflammatory enzymes or by enhancing the synthesis of glutathione, an important intracellular antioxidant.
Curcumin has been found to induce cell-cycle arrest and apoptosis (cell death) in a
variety of cancer cell lines grown in culture. Only a few types of induced cancer cells have tested with successful results. The ability of curcumin to induce apoptosis in cultured cancer cells by several different mechanisms has generated scientific interest in the potential for curcumin to prevent some types of cancer.
Cancerous cells invade normal tissue with the aide of enzymes. Curcumin has been found to inhibit the activity in cell culture studies. To fuel their rapid growth, invasive tumors must also develop new blood vessels by a process known as angiogenesis. Curcumin has been found to inhibit angiogenesis in cultured vascular endothelial cells and in an animal model.
Many of the biological activities discussed above were observed in cells cultured in the presence of curcumin at higher concentrations than are likely to be achieved in cells of humans consuming curcumin orally. As a result of the promising findings in animal studies, several controlled clinical trials in humans designed to evaluate the effect of oral curcumin supplementation on precancerous colorectal lesions, such as adenomas, are under way.
To date, most of the controlled clinical trials of curcumin supplementation in cancer patients have been Phase I trials. Phase I trials are clinical trials in small groups of people, which are aimed at determining bioavailability, safety, and early evidence of the efficacy of a new therapy. Findings thus far suggest that oral curcumin is more likely to be effective as a therapeutic agent in cancers of the gastrointestinal tract than other tissues.
The anti-inflammatory activity of curcumin has been demonstrated in cell culture and animal studies a preliminary intervention trial that compared curcumin with a nonsteroidal anti-inflammatory drug (NSAID) in 18 rheumatoid arthritis patients found that improvements in morning stiffness, walking time, and joint swelling after two weeks of curcumin supplementation were comparable to those experienced after two weeks of a (NSAID) therapy.
In Alzheimer’s disease, a peptide called amyloid beta forms aggregates (oligomers), which accumulate in the brain and form deposits known as amyloid plaques. Inflammation and oxidative damage are also associated with the progression of Alzheimer’s disease. Curcumin has been found to inhibit amyloid beta oligomer formation in vitro. In animal models of Alzheimer’s disease, dietary curcumin has decreased biomarkers of inflammation and oxidative damage, amyloid plaque burden in the brain, and amyloid beta-induced memory deficits. It is not known whether curcumin taken orally can cross the blood brain barrier or inhibit the progression of Alzheimer’s disease in humans. As a result of the promising findings in animal models, clinical trials of oral curcumin supplementation in patients with early Alzheimer’s disease are under way. The results of a 6-month trial in 27 patients with Alzheimer’s disease found that oral supplementation with up to 4 g/day of curcumin was safe.
Curcumin extracts are available as dietary supplements without a prescription in the U.S. Some curcumin preparations also contain piperine from black pepper, which may increase the bioavailability of curcumin by inhibiting its metabolism. Piperine is a chemical that interferes with the mechanism in cancer cells that allows tumors to progress in size. When combined with curcumin this effect is intensified greatly.
Because of its ability to eliminate the bacteria in the stomach, black pepper is also thought of as an antibacterial agent. Black pepper, rich in antioxidants, effectively controls blood pressure and heart rate with its high level of potassium. Pepper is also high in iron which is essential in the production of healthy blood cells. Peperine contain vitamin A and vitamin C and are also rich in other antioxidants such as carotenes which work to help the body fight cancers and other diseases.
Central Food Technological Research Institute in India suggests that black pepper may help the body regulate cholesterol. It may also help digestion by stimulating the taste buds, signaling to the stomach to produce hydrochloric acid. Without sufficient hydrochloric acid heartburn may develop. According to a 2010 study at Michigan State University, black pepper exhibits anticancer, antioxidant and anti-inflammatory properties.
In the United States, both turmeric (curcumin) and black pepper (and its derivatives) are generally recognized as safe (GRAS) by the FDA as a food additive by the FDA. Serious adverse effects have not been reported in humans taking high doses of curcumin. Curcumin has been found to inhibit platelet aggregation in vitro, suggesting a potential for curcumin supplementation to increase the risk of bleeding in people taking anticoagulant or antiplatelet medications.
Black pepper may lower blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Piperine found in piper nigrum may also increase the bioavailability and slow the elimination of a number of drugs.