Diet, Fats & Prostate Health: Trying to Unravel the Puzzle

Fats & the Prostate: Trying to Unravel the Puzzle

The research on dietary fats and prostate health has produced conflicting results and left many men wondering whether they should be avoiding some kinds of fats while eating more of others.

When it comes to intake of omega-3 fatty acids from fish, some studies have found no effect on prostate cancer while others suggest that consuming more might be protective. A study published in 2012 even raised the question of whether higher intake of DHA could be detrimental for men with high-grade prostate cancer. (This same study, however, reported that trans-fatty acids – the “bad” fats – were also linked to a lower risk of high-grade prostate cancer – a finding that contrasts with the available evidence and heightens doubts about the study’s findings overall).

All of these confusing results could mean that the relationship between fat and the risk of prostate cancer is complex.

Omega-3s and Prostate Cancer Research

Enter Dr. William Aronson and his colleagues from UCLA. These researchers are trying to shed some light on the effects of low fat diets and omega-3 fats, at least in men who already have prostate cancer.

Their latest study (1) (an analysis of an earlier study they conducted in men who underwent prostate removal), found that men assigned to eat a low fat diet and fish oil had lower levels of pro-inflammatory substances and lower cell cycle progression (CCP) scores than those eating a typical American high-fat diet.

The level of pro-inflammatory compounds is relevant because inflammation is thought to be a factor in prostate cancer development.  CCP score is a measure used to predict cancer recurrence, and lowering scores may help prevent this cancer from becoming more aggressive.

Based on the results of their research, Aronson’s team will begin a randomized trial at UCLA this year. It will study men who have elected to join the active surveillance program – a program that monitors slow-growing prostate cancer with imaging and biopsy instead of treatment. Men will be randomly assigned to the low-fat fish oil diet or to their usual diet.  Stay tuned for results ... 

Heart-Healthy Diet May be Prostate-Healthy

A heart-healthy diet that reduces intake of carbs, animal fats and saturated fats, and replaces those calories with unsaturated oils (e.g. olive and canola) and nuts might benefit men with prostate cancer according to a team of Harvard and UC San Francisco investigators.

In their analysis of a large-scale observational study (2), this pattern of eating was associated with lower risk of death in men with prostate cancer that hasn’t spread beyond the prostate (non-metastatic).

These researchers also report that a Mediterranean style of eating was associated with decreased overall mortality in men diagnosed with non-metastatic prostate cancer (3). The Med-style diet is lower in animal fat and has more fats from olive oil, nuts and fish. (It’s also rich in tomatoes and tomato products – a source of the carotenoid lycopene, which has also been linked in some studies to prostate health). 

It’s known that heart disease and prostate cancer share causative factors such as inflammation, obesity and high blood cholesterol. So until more is known, perhaps a heart-friendly diet like the Med-style diet is a reasonable choice, as well as avoiding excessive fat intake and losing weight if you’re overweight. Remember, too, that anyone who has been diagnosed with prostate cancer should seek individual dietary advice from his or her own physician.

References

1. Galet C, et al. Effect of a low-fat fish oil diet on pro-inflammatory eicosanoids and cell cycle progression score in men undergoing radical prostatectomy. Cancer Prev Res 7:97-104, 2014.
2. Richman EL, et al. Fat intake after diagnosis and risk of lethal prostate cancer and all-cause mortality. JAMA Intern Med173:1318-326, 2013.
3. Kenfield SA, et al.  Mediterranean diet and prostate cancer risk and mortality in the health professionals follow-up study. Eur Urol [Epub ahead of print], Aug, 2013.