ANSWER: Urica dioica rhizome (root) is a well-accepted remedy in Europe for prostatic enlargement. It has even been compared to the drug Proscar and found to be more effective, with less side effects. Lignans ((+)-neoolivil, (-)-secoisolariciresinol, dehydrodiconiferyl alcohol, isolariciresinol, pinoresinol, and 3,4-divanillyltetrahydrofuran) from the roots of Urtica dioica and their metabolites bind to human sex hormone binding globulin (SHBG). The net effect of this anti SHBG activity is a positive influence on testosterone metabolism. Testosterone is also metabolized by enzymes called aromatase and 5-alpha-reductase. Prostate enlargement is characterized by elevated testosterone levels (specifically elevated levels of the enzymes involved in testosterone metabolism), and stinging nettle is thought to lower the activity of one or both of these enzymes. This probably plays a key role in the traditional use of the plant to control prostatic enlargement.

Stinging nettle (both the leaf and root) also appears to prevent the over stimulation of proinflammatory cytokines like tumor necrosis factor-alpha and interleukin-1 beta. Cytokines can be thought of in simple terms as immune system messengers. And while a discussion of these proinflammatory cytokines and immune system balance is beyond the scope of this column, cytokine balance is a growing area of interest in medicine. In fact, virtually all immune disorders (from HIV, to cancer, to autoimmune diseases), allergic conditions (like asthma and allergies) and even obesity/insulin resistance have characteristic imbalances in cytokine levels as part of the functional derangement occurring at a metabolic level.

Urtica dioica has a lectin with many unique characteristics. Urtica dioica agglutinin (UDA), a V beta 8.3-specific superantigen, prevents the development of the systemic lupus erythematosus-like pathology in mice. Stinging nettle lectin is actually a "super lectin" called UDA superantigen (UDA for short). For those interested, UDA appears to be an N-acetylglucosamine specific lectin. Evidence indicates that this super lectin can inhibit a range of viruses including those responsible for HIV, colds, and influenza.

For prostate and immune health, Urtica dioica, the humble nettle plant, is hard to beat.