Eating tomatoes reduces the risk of prostate cancer, particularly in Asians and Pacific Islanders, a study suggests.

The research, “Tomato consumption and prostate cancer risk: a systematic review and meta-analysis,” was based of a review of 24 studies. It was published in Scientific Reports.

Although many studies have been done on tomato consumption and prostate cancer, the results have been conflicting and sometimes controversial.

While some research suggested that tomatoes lowered the incidence of prostate cancer, other studies found no association. One even concluded that the higher the tomato intake, the more incidence of prostate cancer.

Researchers reviewed 24 cohort and case-control studies covering 15,099 individuals that were published between 1989 and 2016. Seven studies were cohort and 17 case-control.

Because cohort and case-control approaches are different, the team broke out the results by study design. In addition, they examined results by region — Europe, Asia, North America, and the Pacific Islands.

Cohort studies compare disease incidence in a population exposed to a certain factor with one that has not been exposed to it. Case-control studies start with a group with the disease and a group without out it who match the disease population in age, location, and other factors. The case-control team then determines the percentage of the two groups exposed to the factor.

The team concluded that tomato consumption cut the risk of prostate cancer by 14%.

When the researchers broke out the data by study design, they found that only case-control studies showed a significant association between tomato intake and prostate cancer. The risk of prostate cancer was 24 percent less in those studies, they said.

The research showed major geographic differences in tomato consumption and prostate cancer. Asians who ate tomatoes had a 57% lower risk of the cancer, and Pacific Islanders a 19% lower risk. No association between tomato intake and prostate cancer was seen in Europe and North America.