How quickly a person’s body can process the caffeine in coffee may affect prostate cancer survival, but more research is needed to better solidify the coffee-survival link, according to an expert.

“In a broad group (of patients with prostate cancer), coffee didn’t seem to be harmful … maybe survival was a little better in terms of prostate cancer-specific death (for higher coffee intake), but none of it was statistically significant, meaning that we’d hang our hat on it,” Dr. Justin R. Gregg, an assistant professor in the Department of Urology at The University of Texas MD Anderson Cancer Center in Houston, said in an interview with CURE®.

Fast Metabolizers Versus Slow Metabolizers

Gregg explained that when data were broken down by genotype — meaning the genetic makeup of individuals — findings showed that there was a statistically significant improvement in prostate cancer-specific survival in patients who were “fast metabolizers” of caffeine, compared to those who were slow or intermediate metabolizers.

Fast metabolizers of caffeine are individuals whose body processes caffeine quickly. As such, they may feel more energized for only a few hours immediately after drinking a caffeinated drink, such as coffee. On the contrary, slow caffeine metabolizers tend to be more sensitive to caffeine and can be jittery for up to 12 hours after having coffee.

READ MORE: Coffee and Tea Consumption Are Not Associated With Harmful Quality of Life, Survival Outcomes Among Breast Cancer Survivors

Put simply, if someone can drink a cup of coffee in the afternoon or evening and go to sleep without issue, they’re likely to be fast metabolizers, whereas those who experience difficulty sleeping after consuming a cup of coffee late in the day may be slow metabolizers, according to Gregg.

“Our hypothesis is that coffee has certain compounds that are protective … you can think of them as anti-cancer: they’re anti-inflammatory and the type of plant-based compounds that we can think of as positive,” Gregg said. “But then on the flip side, there’s some evidence that caffeine itself may be detrimental because caffeine — at least in some laboratory models — can do some things that actually help prostate cancer.”

With that in mind, Gregg and his team theorized that fast metabolizers get the protective benefits from coffee but get rid of the caffeine more quickly.

Should Men Change Their Coffee Habits?

Gregg emphasized that patients with prostate cancer should not rush to gain more insight to their metabolism or change their coffee habits just yet. In fact, in an earlier study, Gregg and colleagues found that in men undergoing active surveillance for prostate cancer, coffee did not show and increased risk of death, regardless of patient genotypes.

“Men should not drop everything and go change their coffee intake, but they should be reassured that I don’t think that they’re harming themselves by continuing to drink coffee, even if they have prostate cancer,” Gregg said.

Gregg also mentioned that he plans on conducting more research that analyzes different coffee metabolites (substances created when the body breaks down coffee) to see if they are associated with the risk of prostate cancer worsening.

“Ideally, if we can continue to expand on this, I’d love in the future to look at the effect of actually changing coffee intake in people, especially if we find something where the goal of all these different studies is to find a marker where it’s related to prostate cancer worsening,” Gregg said. “Then we can do something to change that marker …. We’re not at the point of doing those human studies yet, but with further funding and expansion of the research, I think that’s a possibility.”

For more news on cancer updates, research and education, don’t forget to subscribe to CURE®’s newsletters here.