Pancreatic Cancer and L-Arginine Supplementation

Nutritional supplementation with the amino acid arginine is commonly recommended by natural healers, but for some people arginine can be harmful, rather than helpful.

Arginine is an "essential" amino acid in infants, in the elderly, and in people undergoing stress. The human body can convert arginine into nitric oxide, which "opens up" circulation, or into L-ornithine, which is used in creating new tissues. In cancer treatment, arginine supplementation is part of a strategy of giving cancer cells the amino acids they "don't want" while depriving them of amino acids they need to proliferate. The important consideration, however, is that different kinds of cancer cells have different metabolic requirements.

Specialists in the surgical treatment of cancer have been studying the use of supplemental arginine in cancer treatment since the early 1990's. In 1992, these scientists reported that the only time they observed recovery of the immune system from surgery for cancer in the upper digestive tract was when patients received a combination of arginine, RNA, and omega-3 fatty acids.

And in another study of cancers in the lower digestive tract, specifically colorectal cancer, researchers found that giving cancer patients 30 grams (that's 30,000 mg) of arginine for 3 days caused cancer cells to grow more receptor sites where white blood cells could identify and destroy them. So is taking supplemental arginine a good idea in pancreatic cancer?

The answer is no.

In other digestive cancers, the cancer cell uses arginine to make ornithine, which creates new structures in the cell. Among those structures are the receptor sites on the surface of the cell that may make it more susceptible either to chemotherapy or to the action of the immune system.

In pancreatic cancer, the cancer cell ordinarily repairs its structures very slowly, so it is more likely to use arginine to make nitric oxide. This chemical opens the microscopic blood vessels surrounding the cancer cell, then the cancerous tumor, allowing it greater nourishment and an avenue to spread throughout the pancreas and out into other parts of the body. In at least one strain of pancreatic cancer cells, arginine demonstrably increases growth, and application of an enzyme to stop cells' use of arginine slows cancer growth.

While it is not a good idea for people with pancreatic cancer to take supplemental arginine, it is not necessary to avoid foods that are relatively high in arginine (such as sesame seeds, spirulina, pumpkin seeds, soy, gelatin, fried pork skins, cod, almonds, and, to a lesser extent, most meats); at least it is not necessary to avoid them because of their amino acid content.

That's because the amount of supplements needed to make a difference in cancer treatment provides 4 to 15 times the amount of arginine you can get from food. Only supplemental arginine needs to be avoided in pancreatic cancer.

You may also be interested in:

Vitamin D and the Risk of Pancreatic Cancer
Folic Acid and Pancreatic Cancer
Alternative Pancreatic Cancer Therapies
Does a Red-Meat Diet Increase Risk of Pancreatic Cancer?

References:

Heys SD, et al. 1997. Dietary suppplementation with L-arginine: modulation of tumour-infiltrating lymphocytes in patients with colorectal cancer. Br J Surg 84:238-41.

Swaffar DS, et al. 1994. Inhibition of the growth of human pancreatic cancer cells by the arginine antimetabolite L-canavanine [see comments]. Cancer Res 54:6045-48.