In the Newsletter published by the American Gasttoenterology Association there is an interesting article by Kunnumakkara and Aggarwal ( AGA perspectives vol 3 issue 6 pp8-10 )
The write of the belief that sporadic cancers are preventable especially gastrointestinal cancers. To support this belief
Gastrointestinal cancers are more common in developed countries than in developing countries. The incidence of colorectal cancer in India is less than a tenth that in the U.S.
Grilled meal and fried foods, environmental pollutants, and certain viruses and bacteria have been linked to tumoro-genesis of the GI tract in rodent models.
Dietary components derived from fruits and vegetables have been shown to suppress carcinogenesis in animals.
Epidemiological studies and limited clinical trials in humans suggest a role for fruits and vegetables in the prevention of GI cancers.
The foods and the active agents that have been so far linked with prevention of GI cancers include resveratrol from grapes, peanuts and berries; catechins from tea; genistein from soybean; caffeic acid from mustard seeds, olive oil from olives; curcumin from turmeric; quercetin from onions; ellagic acid from pomegranate; diallyl disulfide from garlic; sulforaphane from broccoli; lycopene from tomato; and indoIe-3-carbinol from cruciferous vegetables .
These agents may have protective effects against GI cancers by targeting multiple molecular targets.
Curcumin gives curry powder (turmeric) its yellow colour, and is the dietary agent which the authors know most with respect to GI cancers. Its active ingredient is diferuloylmethane. Curcumin has been shown to protect animals from a wide variety of carcinogens that cause GI cancers .
A protective effects of curcumin have also been reported in patients with Crohn’s disease, ulcerative colitis, irritable bowel disease (IBS) and tropical pancreatitis).
The mechanisms mediating the inhibitory effects of curcumin have been extensively investigated. Their group showed that curcumin down-regulates the activation of NF-kB, leading to down-regulation of anti-apoptoric, cell proliferative, invasive and angiogenic gene products.
Curcumin also suppresses the activation of STAT3 HIF-1 and PPAR-y. Curcumin down-regulates the activity and expression of both COX2 and 5-LOX , down-regulates the expression of TNF,ILl.-l and IL-6; and inhibits EGF receptor signalling. In spite of interfering with all these targets, curcumin has been found to be pharmacologically safe at very high doses, with no dose-limiting toxicity.
I have always been sceptical of comparisons of disease incidence between developed and developing countries. Many diseases so studied occur in an age group older than generally experienced in the developing world. It would also be possible to say that intestinal parasites, malaria and under nutrition may also protect.
Having said that this is serious and interesting work and offers great interest. Remember aspirin and its wide therapeutic value.
- Martin Eastwood