Recently, a lot of hype has been circulating about the colorectal cancer-fighting effects of curcumin, a substance found in curry and common flavoring agent in the spice turmeric, but how accurate are these potentially life-saving claims?

As residents of the United States, we are all affected by the threat of colon cancer. “Colorectal carcinoma is the second leading cause of cancer mortality in the United States with 55,000 deaths in 2006” (1). (FYI: Colon cancer is cancer of the large intestine (colon), the lower part of your digestive system. Rectal cancer is cancer of the last 6 inches of the colon. Together, they're often referred to as colorectal cancers.[i]) “About 112,000 people are diagnosed with colon cancer annually, and about 41,000 new cases of rectal cancer are diagnosed each year,” according to the American Cancer Society.[ii] More often than not, conventional therapies, including surgical rejection, chemotherapy, and radiation, have been inadequate at treating the disease, making the need for new treatment options critical.

Here’s the good news: epidemiologic studies suggest that “diet plays a major role in the prevention of many cancers and curcumin may be a dietary component responsible for lower rates of colorectal cancer in certain part of India. Indian folk medicine has treated various ailments with curcumin and, only recently, have preclinical and clinical studies demonstrated the anticancer and antiangiogenic properties of this unique compound.”[iii] In vivo, or in studies conducted “within the body of animal or organism,” curcumin has shown the ability to inhibit tumorigenesis, or the growth of malignant tumors. “The use of curcumin in antiangiogenesis includes the inhibition of vascular endothelial cell proliferation in vitro and capillary tube formation and growth in vivo,” two processes essential to the growth of cancer cells.[iv] A new recently-published study in 2008 showed that “curcumin inhibits epidermal growth factor (EGF)-mediated signaling and growth of intestinal adenomas in APC^min/+ mice. However, due to the low cancer-killing potency and poor intestinal absorption characteristics of curcumin, bioavailability of the compound has limited its use.”[v]

So what does this all mean?

We must review the study results with a critical eye. Although the research looks scientifically promising, dietary curcumin is poorly absorbed through the intestine and, at low doses, may not have a therapeutic effect. Researchers at Johns Hopkins University found that curcumin can reduce the size and number of polyps, but study participants were asked to take a pill containing 480 mg of curcumin, three times a day; a highly concentrated amount not likely to be accumulated in a day by diet, alone.[vi] Before concentrated curcumin supplements can be advocated, more research is needed, especially involving the potential toxicity of frequent supplementation with high doses over a long period of time.

However, now researchers at the Institute of NanoBioTechnology at Johns Hopkins have created polymer coated nano-curcumin that supposedly absorbs better in the body.[vii] The researchers tested pancreatic cancer cells with the new agent and found it just as effective as free curcumin, with no evidence of toxicity. Further research on the use of nanocurcumin in the fight against cancer and other diseases in which the benefits of curcumin have been suggested, such as Alzheimer and cystic fibrosis, is needed say the researchers.

Bottom line: Don’t always eat into the hype, literally-speaking. The research is interesting, but is not definitive. Curry shows great potential for the anticancer effects of curcumin, but whether or not we can reap the benefits of this special spice without additional supplementation is debatable. Nanocurcumin may offer hope for future developments of supplements, but much more research is clearly needed. Eating curry in moderation may or may not help reduce the risk of colorectal cancer, but as long as you do not ingest toxic doses, there should not be any harm in sprinkling a little extra on meats, salads, or sandwiches. Consult with your doctor before consuming any new dietary component.

If you are concerned about polyp formation, you may want to discuss this research with a medical professional who can provide a balanced view of the potential benefits and risks associated with curcumin supplementation.

[iv] Diphenyl Difluoroketone: A Curcumin Derivative with Potent In vivo Anticancer Activity
Subramaniam et al. Cancer Res.2008; 68: 1962-1969

[v]Diphenyl Difluoroketone: A Curcumin Derivative with Potent In vivo Anticancer Activity
Subramaniam et al. Cancer Res.2008; 68: 1962-1969