How Does L-Arginine Impact Prostate Cancer?

Prostate cancer is a major concern for many men and their loved ones. The American Cancer Society says it's the second most common cancer among men in the U.S. L-arginine is an amino acid supplement that has drawn some interest in the treatment of prostate cancer. But, is there a link?

One supplement that has drawn interest as a potential cancer treatment, says the Memorial Sloan Kettering Cancer Center, is arginine. Arginine, also known as L-arginine, is an amino acid that is naturally produced by the body. It's available as an oral supplement, and in that form, it's been studied as a treatment for medical conditions such as migraines, erectile dysfunction, high blood pressure and heart conditions, due to its ability to relax and expand blood vessels.

Within the body, the Mayo Clinic notes that the primary role of L-arginine is to help the body build protein. It naturally acts as a vasodilator, which means it opens up blood vessels. This is why L-arginine has shown promise for treating conditions such as erectile dysfunction, angina and high blood pressure. While it's available in supplements, L-arginine is also naturally found in foods such as red meat, poultry, fish, beans, soy, dairy products and more.

​Read more:​ Foods High in L-Arginine

L-arginine supplements clearly show a lot of promise as a medical treatment in some areas; however when it comes to the treatment or prevention of prostate cancer, there is not enough evidence to indicate that L-arginine is a viable treatment.

In fact, Memorial Sloan Kettering Cancer Center cautions that cancer patients should not take this supplement, citing some evidence that it may increase markers of inflammation in the body Patients are urged to discuss any use of the supplement with their treating physician.

"While there are ongoing investigations of L-arginine's effect on apoptosis-programmed cell death, there is no evidence that L-arginine supplementation plays any role in changing the clinical course of prostate cancer," says Damon Davis, MD, a board-certified urologist with the Urology Specialists of Maryland at Mercy Medical Center in Baltimore.

It's studies like the March 2016 review in the ​Journal of Cancer Prevention​ that aim to better tease out the relationship, if any, between high levels of nitric oxide, a molecule increased by L-arginine, and its effect on apoptosis (self-destruction process) in cancer cells. But for now, L-arginine's benefits to prostate cancer is unproven, and more research is necessary.

Memorial Sloan Kettering Cancer Center does note that a few studies of nutritional formulas containing arginine have shown some benefits for cancer patients. For example, they may improve wound healing for patients that need cancer surgery, as well as improve immune system function and reduce the length of the patient's hospital stay. But the cancer center adds that more studies are needed to determine whether taking arginine supplements could be safe and effective.

The Prostate Cancer Research Institute also says that L-arginine may improve sexual health in patients with prostate cancer.

Aside from these secondary effects, though, L-arginine doesn't appear to play a direct role in the prevention or treatment of prostate cancer. The Mayo Clinic notes that the supplement is generally safe to use in the proper doses, but it does have a number of side effects and potential interactions with other medications. For these reasons, it's best to discuss L-arginine with your doctor before taking it on your own.

The risk of prostate cancer among men is significant. The American Cancer Society projects that in 2020, more than 33,000 men will die from prostate cancer, and close to 200,000 new cases will be diagnosed. One in 9 men will receive a prostate cancer diagnosis during his lifetime.

According to the Urology Care Foundation, the prostate is a walnut-shaped gland that produces the fluid that mixes with semen and lubricates it upon ejaculation. It's located in the pelvis.

When prostate cancer occurs, it often causes no signs or symptoms in its early stages, Mayo Clinic says. As the cancer becomes more advanced, it gradually progresses to symptoms such as erectile dysfunction, trouble urinating, bone pain, pelvic discomfort and more. If it's allowed to continue, the cancer can ultimately spread to nearby organs such as the bladder and others.

If there's any good news about prostate cancer, it's that there are a number of treatment options, according to Mayo Clinic. Many cases of prostate cancer progress very slowly and only require active surveillance. When prostate cancer does require treatment — options include surgery, radiation therapy, hormone therapy and chemotherapy, among others.

​Read more:​ 6 Science-Backed Tips to Help Prevent Prostate Cancer