Every 10 g carrot reduces chance of prostate cancer by 5 percent
Every 10 g of carrots that men eat each day reduces their chance of developing prostate cancer by 5 percent. Chinese epidemiologists at the University of Zhejiang have published their calculations in the European Journal of Nutrition. If the Chinese are correct, men who munch their way through a large carrot each day can halve their risk of developing prostate cancer.

The Chinese publication is a meta-study: the researchers used 10 previously published epidemiological studies for it. They found no indications of bias, which means that it was not only positive or only negative studies that had been published.Results
When the researchers amassed the data from the studies and re-analysed them, they discovered that eating carrots protected men against prostate cancer. The more often the men ate carrots each week, or the greater the amount of carrots the men ate daily, the less likely they were to develop prostate cancer.

Carrots are a good source of carotenoids such as alpha-carotene and beta-carotene. Beta-carotene can also be converted into vitamin A.
The researchers believe that all of these substances inhibit the growth of prostate cancer cells.

Eur J Nutr. 2014 Dec;53(8):1615-23.