Adequate Levels of Folic Acid and Arginine
Q In a recent issue of Life Extension News, Durk & Sandy wrote that there has been considerable research on nitric oxide synthase because of the importance of nitric oxide in functions such as vasodilation. They go on to report that an inadequate supply of arginine or too little of the cofactor tetrahydrobiopterin, which can be mimicked by folic acid, can uncouple nitric oxide synthase from the production of nitric oxide, producing a bunch of free radicals. Does this mean we should be careful about how much folic acid we take?
They also report that an increase in the arginase pathway can inhibit arginine production of nitric oxide. Among the causes of this increase in arginase rerouting are reperfusion injury, asthma, psoriasis, arthritis, and breast cancer (and possibly prostate cancer). The increased arginase decreases arginine availability to be converted to nitric oxide, as well as increasing ornithine, which can be converted to polyamines and procellular proliferation factors. In the arthritis paper they referenced, it was reported that arginase II could be induced by inflammatory factors such as PGE2 and LPS and that ornithine, produced by arginase, is necessary for the production of collagen, which occurs in rheumatoid arthritis. Does this mean we should be careful about supplementing with ornithine?
Shelly, Allen, TX
A As Durk & Sandy point out in their interview in this issue (see
“Maintain Your Brain the Durk Pearson & Sandy Shaw Way” on page 4), it’s important to get enough folic acid for a number of reasons, including the prevention of peroxynitrite, a free radical that can cause damage to your brain and other tissues throughout your body.
Regarding ornithine, the referenced paper suggests that “agents that induce arginase II in synovial cells could downregulate the levels of NO and divert L-arginine metabolism toward cell proliferation and/or tissue regeneration.” Does the exogenous use of ornithine induce arginase production? As far as we know, there is no indication of this. However, because arginine provides so many additional benefits compared to ornithine, we recommend the use of arginine.