Eating apples and grapes may help stave off prostate cancer onset, the most common cancer among American men. As reported by Nature.com, a study published on Precision Oncology revealed that a combination of nutritional compounds can inhibit cancer cell growth.

As part of the study, a team of researchers at the University of Texas at Austin looked at 142 natural compounds and tested them on mouse and human cell lines to determine which ones may inhibit prostate cancer cell growth when used either alone or in combination with other compounds. According to the experts, the ursolic acid in apple peels and resveratrol in grapes were among the most effective compounds that starve prostate cancer cells and halt their proliferation. The researchers also noted that a combination of ursolic acid and resveratrol prevented prostate cancer cells from consuming glutamine, a compound that the malignant cells need in order to grow.

“After screening a natural compound library, we developed an unbiased look at combinations of nutrients that have a better effect on prostate cancer than existing drugs. The beauty of this study is that we were able to inhibit tumor growth in mice without toxicity [emphasis added]. These nutrients have potential anti-cancer properties and are readily available. We only need to increase concentration beyond levels found in a healthy diet for an effect on prostate cancer cells,” corresponding author Stefano Tiziani explained in the paper.

Previous studies show apples, grapes keep prostate cancer at bay

Much research has long established that compounds found in apples and grapes may reduce the odds of prostate cancer onset. In fact, a study carried out by researchers at the University of Wisconsin revealed that antioxidants found in apple peels may impede cancer cell growth. As part of that research, the scientists observed what happened to cancer cells when exposed to Gala apple extracts. According to the research team, prostate cancer cells grew more slowly and had shorter survival time as a result of the exposure. The researchers also noted a marked increase in marpin levels. Marpin is an essential protein that is known to suppress tumor growth.

Another study conducted by researchers at the University of Missouri found that resveratrol, a compound commonly found in grapes and red wine, may boost the effects of radiation therapy in prostate cancer patients. It was widely known that prostate tumor cells contain very low levels of cancer-killing proteins called perforin and granzyme B. The proteins need to be “highly expressed” in order to the cancer-killing properties. The researchers found that exposing prostate tumor cells to resveratrol effectively increased the levels of the essential proteins. The scientists also found that using resveratrol as an add-on to radiation treatment eliminated up to 97 percent of prostate tumor cells. The combination therapy resulted in cancer cell deaths at a much higher rate compared with radiation treatment alone.

“We found that when exposed to the compound, the tumor cells were more susceptible to radiation treatment, but that the effect was greater than just treating with both compounds separately…It is critical that both proteins, perforin, and granzyme B, are present in order to kill the tumor cells, and we found that the resveratrol helped to increase their activity in prostate tumor cells. Following the resveratrol-radiation treatment, we realized that we were able to kill many more tumor cells when compared with treating the tumor with radiation alone. It’s important to note that this killed all types of prostate tumor cells, including aggressive tumor cells,” said researcher Michael Nicholl.

Prostate cancer by the numbers

The recent findings may have positive implication in prostate cancer management. According to Cancer.org, prostate cancer is the second most common form of cancer in American men after skin cancer. The organization estimated that about 161,360 new cases of prostate cancer may be diagnosed in 2017, while about 26,730 deaths may occur in the same year.

The American Cancer Society also noted that one in seven men will be diagnosed with prostate cancer during his lifetime. The condition is also more prevalent in older men, with an average diagnosis age of 66 years old.