These two coffee compounds may inhibit drug-resistant prostate cancer

Past research has found evidence that coffee drinkers may have a lower risk of developing prostate cancer, and a new study may have figured out what's behind that beneficial effect. The project, which has been presented at the European Association of Urology, found that two particular coffee compounds inhibited drug-resistant prostate cancer cells in cell cultures and lab mice.READ: California coffee cancer warning: another advisory you'll ignore

The study comes out of Kanazawa University in Japan, where researchers looked at half a dozen compounds that are naturally found in coffee. These six compounds were tested on human prostate cancer cells in cell cultures, meaning cells in a petri dish.

During the work, researchers found that two compounds in particular — cafestol and kahweol acetate — slowed the growth of these prostate cancer cells compared to control substances. Moving on from the petri dishes, the scientists then tested these two compounds with 16 lab mice, four of which were control specimens.

The remaining mice were split into three groups: four were given cafestol, four were given kahweol acetate, and four were given a combination of both compounds. The researchers discovered that both compounds individually inhibited prostate cancer cell growth in mice, but that the two combined had the best effect.

The result in the mice group that received both compounds was 'significantly slower tumor growth than in untreated mice,' according to study lead Dr. Hiroaki Iwanmoto. It's important to note that additional research needs to be performed on humans to determine whether these effects translate from cell cultures and animal models to human patients, however.

Iwanmoto explained:

We also found the growth reduction in transplanted tumor cells, rather than in native tumor cells. What it does show is that these compounds appear to have an effect on drug resistant prostate cancer cells in the right circumstances, and that they too need further investigation. We are currently considering how we might test these findings in a larger sample, and then in humans.

The study follows research published in early 2017 out of Italy that found men who consumed at least three cups of coffee per day had a prostate cancer risk 53-percent lower than men who drink less coffee. The effects were noted in men who drink Italian-style coffee, meaning the beverage brewed at high temperatures and pressures; the preparation method may have influenced the bio-active compounds that contributed to the health benefit.