Hoping to find a way to provide relief from shear-stress, researchers at UCLA used a two-part trial. In the first part they tested the effects of high shear-stress on human cells in a culture dish. After establishing that this type of continuous stress created inflammatory compounds, they coated the cells with antioxidants (a combination of vitamins C and E), and L-arginine (also known as, simply, “arginine”) – an amino acid known to promote dilation of blood vessels.
When this method was shown to reduce the inflammatory compounds, the researchers conducted the second part of their trial with mice, specially bred to have high levels of cholesterol. Like the human cells in the first part of the test, the blood vessels of the mice showed a marked reduction in inflammation. Dr. Louis J. Ignarro of UCLA, reporting in the Proceedings of the National Academy of Sciences, acknowledged that while the findings are preliminary, the results demonstrate that the adverse effects created by turbulent shear-stress, “can be prevented by co-treatment with antioxidants and L-arginine.”
- Facilitates muscle metabolism by reducing body fat while increasing muscle mass
- Helps regulate the activity of the thymus gland, giving assistance to the immune system
- Increases insulin in the pancreas
- Helps repair skin and connective tissue and plays a part in the formation of bone and tendons
- Neutralizes ammonia in the liver
- Helps create nitric oxide, an essential compound that helps blood circulation and is important to sexual function for both women and men
L-arginine’s dietary sources include dairy products, meat, poultry and fish, as well as nuts, rice, whole-wheat, soy and raisins. It can also be taken in supplement form (available in most health food stores), but in an e-Alert I sent you last fall (“A Measure of Comfort” 10/29/02), HSI Panelist Allan Spreen, M.D., offered some important advice, pointing out that any amino acid supplement should not be taken with protein foods because the protein receptor cites are flooded and absorption of the supplement is minimized.
Clearly, this new research shows us that citrulline and L-arginine are important to heart health and may be helpful supplements for those at risk of cardiovascular disease or immune system disorders. I should add just one word of caution: While L-arginine has been shown to stimulate the immune system in cancer patients, at least one study has concluded that an extremely high intake of L-arginine (30 grams per day) may actually promote cancer cell growth. This is a troubling contradiction that we will continue to research. In the meantime, it’s important that anyone fighting cancer should consult his doctor before supplementing with either L-arginine or citrulline.
To Your Good Health,
Health Sciences Institute