In the news: Med Diet May Lower Prostate Cancer Risk; Med Diet and Men’s Sexual Health?

Med Diet May Lower Prostate Cancer Risk

The Mediterranean (Med) style diet offers a cuisine rich in flavors, colors and aromas. Ever-growing evidence from both controlled trials and observational studies has shown that this kind of eating pattern may help ward off heart attack, stroke, dementia and premature death. Spanish researchers now report that this way of eating may also help lower the risk of aggressive prostate cancer (1).

Investigators garnered dietary information from men with confirmed cases of prostate cancer (754) and 1,277 men without the disease who served as controls. They then analyzed the participants’ diets in terms of how well they adhered to three dietary patterns, and assessed the relationship of each eating style with prostate cancer risk.

The dietary patterns and their main included:
1) Med – rich in fish, olive oil, whole fruits, veggies, legumes (seeds and beans) and low in juices;
2) Prudent – low-fat dairy products, whole grains, fruits and veggies, and juices;
3) Western – dairy products, sodas, sweets, fast foods, sauces, processed meats and refined grains.

Sticking closely to the Med dietary pattern, rich not only in fruits and vegetables but also in fish, legumes and olive oil, lowered the risk of aggressive prostate cancer by about 1/3, and the likelihood of advanced stage cancer by about 1/2.

This association was not observed with the prudent pattern, which combines vegetables and fruits with low fat dairy products, whole grains and juices. These findings suggest that key features of the Med diet such as fish, legumes and olive oil are particularly important, and that eating fruits, veggies and whole grains – while also important – might not be enough.

While the data hinted that following a Western dietary pattern closely might increase the risk of more advanced tumors, the observation did not achieve statistical significance.

How Do Diets Impact Men’s Sexual Health?

To shed some light on this question, researchers reviewed the current literature on diet and dietary patterns and male sexual health. Thirteen studies on diet and erectile dysfunction and 15 studies on diet and testosterone levels were reviewed (observational studies and controlled trials). Studies analyzing the relation between diet and semen parameters also were reviewed – 13 studies, all observational(2).

The Med diet pattern was consistently associated with improvements in erectile function and an increase in testosterone levels. This makes sense as the Med diet emphasizes primarily plant-based foods (fruits, veggies, whole grains, legumes and nuts), and uses herbs and spices instead of salt to flavor dishes.

Many green leafy vegetables (kale, lettuce, spinach, cabbage, arugula and chard), as well as root vegetables (e.g. beets, carrots, potatoes, and ginger) contain high levels of nitrates. Nitrates become a source of nitric oxide, which dilates blood vessels and promotes blood flow. Increasing nitric oxide is how erectile dysfunction (ED) drugs work. Fruits and veggies are also a source of flavonoids, whose intake has been associated with reduced incidence of ED.

The review also found that overweight men who lost weight through low-fat, low-calorie diets seemed to have improved erectile function and testosterone levels. Weight loss in some obese and overweight men can favorably affect the enzyme (aromatase), helping convert estrogen to testosterone.

Several studies have shown that the Mediterranean diet can promote weight loss as well. The Western diet, meanwhile, was linked to lower semen quality.

More research is needed to fully establish the benefit of differing dietary patterns on men’s sexual health, according to the authors. In the meantime, the Med diet is shown to be an overall healthful way of eating.

References

1. Castello A, et al. Mediterranean dietary pattern is associated with low risk of aggressive prostate cancer. J Urology. 199:430-37, 2018.
2. La J, et al. Diet and men's sexual health. Sex Med Rev. 6:54-68, 2018.