Curcumin, the pigment that makes the curry spice turmeric a bright orange-yellow, is one of the best-researched potential preventatives for a number of kinds of cancer.
On a molecular level, curcumin interacts with an extraordinary range of cellular processes involved in cancer. Curcumin:
- Stops the activation of some"transcription factors" that lay down the DNA for a new cancer cell,
- Acts in the same as other anti-inflammatory agents in stopping the expression of growth factors in existing cancer cells,
- And (in almost all kinds of cancer) activates a "watchdog" gene, p53, that deactivates cells that have become cancerous.
Curcumin is non-toxic even if it is taken in doses 30-40 times more than needed for it to work, up to 12 grams (12,000 mg) a day. The body uses curcumin in various antioxidant processes that it does not build up in the bloodstream in most people even when taken in doses of 10,000 to 12,000 mg a day.
And there's no reason to try to build up a bloodstream concentration of curcumin if you get just a little more than once a day. The liver clears curcumin out of circulation in 8 to 12 hours.
What is the evidence that curcumin might prevent cancer? Well, aside from the over-100 studies of curcumin in the laboratory, curcumin has been used in clinical trials.
In a study of 62 patients who had various skin cancers and pre-cancers (actinic keratosis, basal cell carcinoma that had not infiltrated below the skin, and external genital warts), researchers found that a curcumin ointment applied to the skin brought lasting relief from the itching, burning, and ache associated with the cancer and stopped cancer growth.
Curcumin stopped skin itching in all the patients, "dried up" oozing lesions in 70 per cent of cases, and actually reduced the size of the cancer in 10 per cent of patients. Only one patient had any adverse reaction to curcumin, an allergy. The ointment consisted of 1 per cent curcumin in a cream base.
Curcumin has also been treated in other pre-cancerous conditions, including:
- Bladder cancer,
- Bowen's disease of the skin (squamous cell carcinoma),
- Leukoplakia (white patches inside the mouth found in smokers),
- Intestinal metaplasia of the stomach (a kind of pre-cancer of the stomach caused by Helicobacter pylori infection and associated with peptic ulcer disease).
In 10 out of 12 cases in this very small trial, pre-cancer patients who used up to 12,000 mg of curcumin a day did not go on to develop cancer. Moreover, in one patient with bladder cancer, two with leukoplakia, one with a cervical tumor, and two with squamous cell carcinoma, the pre-cancerous lesions actually shrank.
Curcumin (in a dosage of 3,600 mg per day) may be beneficial to people who have advanced drug-resistant colorectal cancer. Scientists at least know that curcumin concentrates in the cancer tissues of the colon and that some markers of cancer activity drop significantly after the patient takes curcumin for four months.Curcumin for colon cancer increases the effectiveness of traditional radiation and chemotherapy treatments.
Finally, in otherwise untreatable advanced pancreatic cancer, a daily dose of 8,000 mg of curcumin has been tried for up to two months. Two months, as you may know, is a very long time to be treating advanced pancreatic cancer.
That's what science knows about curcumin and cancer in humans. Dozens of other studies are in the works, however, for treatment of esophageal cancers, stomach cancers, liver cancer, lung cancers, lymphoma, and breast cancer. And doctors are following up on an intriguing observation that women who live in countries where turmeric-based (and curcumin-loaded) curries are part of the daily diet have very low rates of breast cancer.
Curcumin does not interfere with any other therapy you should continue if you have or if your doctor believes you may develop cancer. Its side effects are very rare, and it's cheap. There's no way to prove that curcumin could prevent cancer for you, but it should rank very high on your list of natural preventive measures that may help keep you healthy, along with prostate cancer and breast cancer early detection.
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Goel A, Kunnumakkara AB, Aggarwal BB. Curcumin as "Curecumin": From kitchen to clinic Biochem Pharmacol. 2008 Feb 15;75(4):787-809. Epub 2007 Aug 19.
Sharma RA, Euden SA, Platton SL, Cooke DN, Shafayat A, Hewitt HR, Marczylo TH, Morgan B, Hemingway D, Plummer SM, Pirmohamed M, Gescher AJ, Steward WP. Phase I clinical trial of oral curcumin: biomarkers of systemic activity and compliance.1: Clin Cancer Res. 2004 Oct 15;10(20):6847-54.