Doctors measure prostate-specific antigen levels to check for prostate cancer. Having high PSA levels doesn't always guarantee the presence of prostate cancer. However, it's still a common test for early diagnosis. No food or supplement will completely lower your PSA levels. However, some foods show some evidence of lowering or slowing the rate of PSA. Certain supplements may even trigger false PSA readings.
Pomegranate juice appears to play a role in both lowering PSA levels and slowing the rate of PSA increase in men with rising levels. A 2006 study featured in "Clinical Cancer Research" involved male participants drinking 8 oz. of pomegranate juice every day. All participants already had rising PSA levels. However, levels in men who drank pomegranate juice rose at almost a quarter of the rate as in men who didn't drink the juice. Other studies involving mice test subjects also show that pomegranate juice may inhibit prostate cancer cells and lower PSA levels.
A 2000 study published in "The Journal of Urology" shows that fiber may play a small but significant role in lowering PSA levels. Participants were given a tailored fiber diet for four months. However, not all forms of fiber produced the same results. Soluble fiber appears to have more effect than insoluble fiber. Soluble fiber is digestible by the gut. Good dietary sources of soluble fiber include rye bread, oat bran, brown rice, apples, blackberries, potatoes and carrots.
Phytoestrogens occur naturally in some plants. Foods such as nuts, linseed, soy products, some cereals and breads contain lots of phytoestrogen. In a 2004 study published in the "Urology" journal, researchers found that men eating bread containing soy grits had lower PSA levels than men who ate standard wheat bread. Wheat contains less phytoestrogen than soy-based bread. The study concluded that men should consider eating more phytoestrogen-rich foods to help keep PSA levels down.
Some studies point to vitamin E supplements helping to lower PSA levels, though overall evidence was inconclusive as of December 2009. The American Cancer Society also points out that some herbal supplements, such as the Chinese herbal mixture PC-SPES, may act to mask PSA levels. This means that prostate cancer may go undetected. Before you undergo any checks for prostate cancer always tell your doctor about any and all supplements you're taking.