A Review of Medical Benefits
Ankur Chandra, MD
For several thousands of years, cultures from around the world
have used naturally occurring dietary components which have
been discovered to be biologically active. These plant-derived
chemicals have generated considerable interest recently for
their potential to combat human disease such as cancer, inflammation,
and atherosclerosis. Curcumin is a chemical of the polyphenol
family derived from the rhizome Curcuma longa L. The dried,
ground product of this root is the common spice known as turmeric.
Referred to as haldi in Hindi and ukon in Japanese, this spice
has been used as an aromatic and coloring in food, as well
as having a significant role in both Asian medicine and ancient
Most commercial turmeric preparations consist of ~2-8% active curcumin. The popularity of turmeric has increased in the U.S. with the Food and Agriculture Organization of the United Nations estimating that approximately 2400 metric tons of turmeric are imported annually for consumer use. In concordance with this increase in use, curcumin has stimulated an increase in research with several hundred research studies over the past 10-20 years examining its role in the treatment and prevention of cancer, cardiovascular disease, and inflammation.
The purpose of this review is to provide a brief summary of the current knowledge of the effects of curcumin as reported in basic science publications, clinical trials, and previous reviews. A majority of these studies focus on the salutatory effects of curcumin in three areas: the prevention and treatment of a variety of malignancies, the potent anti-inflammatory properties, and the cardiovascular benefits as an anti-atherogenic agent.
Inhibition and Prevention of Cancer
Human head and neck squamous cell carcinoma (HNSCC): curcumin treatment resulted both in the inhibition in the growth of these tumor cells, as well as an increase in death of these tumor cells
Oral cancer: When applied three times per week to the affected area in the mouth, curcumin inhibited the growth of chemically-induced oral cancers with a noted increase in effect if administered with green tea extract.
Hepatic cancer: Curcumin given orally resulted in decreased growth and increased tumor cell death in animal models.
Mantle cell lymphoma: These tumor cells showed a significant inhibition of cell proliferation when treated with active curcumin
Non-small cell lung cancer: Curcumin has been
shown to increase sensitivity to a specific chemotherapy
(IFN-Gamma) which, without curcumin, was relatively insensitive
to this particular cancer type.
Colon cancer and polyps: The oral administration of curcumin
has been shown in multiple rodent models to inhibit polyp
formation as well as increasing cell death in existing colon
With several recent studies focusing on the beneficial effects of polyphenol-based dietary components such as red wine on vascular health, curcumin has been shown to improve several aspects of cardiovascular health.
High homocysteine levels: Patients with high homocysteine levels have been found to have endothelial cells which do not function properly. Endothelial cells are those cells which line the inside of our blood vessels and, amongst other functions, prevent blood from clotting and plaques from forming. Curcumin has been found to prevent this dysfunction. It was suggested that dietary curcumin play a role in the treatment of patients with high homocysteine levels.
Atherosclerotic lesions: : Curcumin treatment resulted in a significant decrease in early atherosclerotic lesions (fatty streaks) in rabbits fed high fat and cholesterol diets.
Oxidized-LDL levels: Curcumin given at a dose of 1.66mg/kg body weight orally to rabbits fed a high fat and cholesterol diet resulted in a significant decrease in oxidized-LDL levels after 7 weeks of treatment.
C-reactive protein (CRP)-induced vascular damage: CRP is a protein which the body produces as a marker of inflammation and has been shown damage endothelial cells. This results in increased evidence vascular disease and blood clotting. Curcumin treatment was shown to completely inhibit the effect of CRP on these endothelial cells.
COX-2 inhibitor: Recently, commercially available COX-2 inhibitors have fallen under much scrutiny in the treatment of arthritis and other inflammatory conditions. Curcumin has been shown to potently inhibit the COX-2 enzyme in a variety of cell types.
Traumatic shock: After accidents and trauma, large quantities of blood loss can cause the body to fail and organ systems to shut down as a result of a massive inflammatory reaction. Curcumin was found to lower the serum levels of certain inflammatory proteins to normal in these cases.
Rheumatoid arthritis: A trial in humans was conducted to determine the effects of curcumin on the symptoms of rheumatoid arthritis. Eighteen patients were administered 1200mg/d of curcumin for two weeks and it was found that this treatment regimen resulted in a significant improvement in morning stiffness, walking time, and joint swelling.
Safety and Absorption
It has been estimated that the average daily intake of
turmeric in the Indian diet is about 2-2.5g which equates
to about 60-100mg of curcumin daily.
Curcumin at a dose of 1.8g/kg/day was given to rats and
0.9g/kg/day to monkeys with no toxicity or adverse events.
A phase I clinical trial in humans was carried out to determine associated toxicity with high dose curcumin administration. Subjects were fed 8000mg of curcumin per day and experienced no toxic effects.
Several clinical studies have used doses of 1000-2000mg/day of pure curcumin with no reports of toxic effects or adverse outcomes in humans.
Absorption (blood levels) after oral administration was highest 1-2 hours after dosing and decreased to undetectable after 12 hours.
Curcumin, the most active curcuminoid found in turmeric, has been shown to possess a multitude of beneficial effects in the treatment of cancers, cardiovascular disease, and inflammation. With this knowledge in hand, many research groups around the country, involving both private and public funding, are focused on the use of this plant-derived chemical in humans. Given the current body of evidence, curcumin, as it has for thousands of years in ancient Asian culture, may provide us a safe, effective therapy for many disease processes which plague our society.