Study: Retinol tied to risk of prostate cancer
A new study led by researchers of the United States National Cancer Institute suggests that high intake of meat and dairy products may increase risk of prostate cancer.
The study released on March 9 2011 in the American Journal of Epidemiology found high levels of serum retinol, which is high in meat and dairy foods, were associated with increased risk of prostate cancer.
For the study, Alison M. Mondul measured retinol levels in blood samples from 29,104 men at baseline and from 22,843 after three years.
The researchers found men with their levels of serum retinol at baseline in the highest quintile were 19 percent more likely to develop prostate cancer and aggressive prostate cancer.
Data from both time points showed that the increase in the risk of prostate cancer in those with the highest quintile of retinol was 31 percent higher than that in those with the lowest quintile.
Retinol is a vitamin A found in animal-based foods such as meat and dairy foods. It is unknown whether retinol may play any role in the carcinogenesis of the prostate gland.
But in this study, retinol served at least as a biomarker to indicate the risk of prostate cancer.
Another type of vitamin A is carotenoids which are found in plant-based foods. Numerous studies have suggested that eating lots of fruits and vegetables has been associated with lower risk of prostate cancer.
Eiichi Kotake-Nara of Hokkaido University and colleagues published a study in 2001 in Journal of Nutrition suggesting that eating "leafy green vegetables and edible brown algae rich in neoxanthin and fucoxanthin may help reduce the risk of prostate cancer."