Saturated and unsaturated dietary fats and risk for aggressive prostate cancer


A newly published article in Prostate Cancer and Prostatic Diseases has (potentially) expanded our understanding of the role of saturated fats in men’s diets and consequent risk for diagnosis with aggressive forms of prostate cancer.

This new paper by Allott et al. is based on data from the North Carolina-Louisiana Prostate Cancer Project, which was funded by the Prostate Cancer Research Program of the Department of Defense’s Congressionally Directed Medical Research Programs. The full text of this paper is available on line, and the paper is also discussed in a commentary on the Medscape web site.

It has long been suspected that diets high in certain types of dietary fat are associated with an increased risk for prostate cancer. A great deal of evidence supports the idea that cholesterol has a role in the development and progression of prostate cancer. And we know that saturated fat content in the diet has an impact on cholesterol levels. However, to date, there is no absolute proof that eating any one particular type of dietary fat is linked to risk for more aggressive forms of prostate cancer.

Allott et al. started from the hypothesis that:

high saturated fat intake would be associated with increased [prostate cancer] aggressiveness, and that statin use would modify this association.

First of all, they looked at the 1,854 cases of men with prostate cancer identified in the course of the North Carolina-Louisiana Prostate Cancer Project and found that

  • 321 cases (17 percent) were classified as highly aggressive (i.e. Gleason score ≥ 8, PSA > 20ng/ml) or Gleason score ≥ 7 and clinical stage T3-4)
  • 1,533 cases (83 percent) were classified as low/intermediate aggressive

Then, using the low/intermediate aggressive case subset as the referent group, they looked to see whether there were any meaningful associations between tertiles of total fat-adjusted saturated fat intake and highly aggressive prostate cancer, both overall and stratified by race and statin use.

Here is what they found:

  • High total fat-adjusted saturated fat intake was associated with
    • An elevated odds ratio (OR) for aggressive prostate cancer overall (ORT3vsT1 = 1.51; P-trend = 0.009)
    • An attenuated association in statin users (ORT3vsT1 = 1.16; P-trend = 0.661) compared with non-users (ORT3vsT1 = 1.71; P-trend = 0.053)
  • High total fat-adjusted cholesterol intake was associated with
    • An elevated OR for aggressive PC in European Americans (ORT3vsT1 = 1.62; P-trend = 0.056)
    • NO elevated OR for African Americans (ORT3vsT1 = 0.92; P-trend = 0.750).
  • High total fat-adjusted polyunsaturated fatty acid intake was inversely associated with prostate cancer aggressiveness (ORT3vsT1 = 0.75) but this was not significant.
  • There were no associations found between total fat-adjusted mono-unsaturated fatty acid or trans-fat intake and prostate cancer aggressiveness.

As a consequence, Allott et al. concluded that:

High total fat-adjusted saturated fat intake was associated with increased [prostate cancer] aggressiveness, with a suggestion of a stronger effect in men not using statins. The association between total fat-adjusted cholesterol intake and [prostate cancer] aggressiveness was most pronounced in European Americans.

But in the commentary on the Medscape web site, Dr. Allott is also quoted as stating that:

Our findings suggest that limiting dietary intake of saturated fat, clearly important for cardiovascular disease prevention, may also have a role in aggressive prostate cancer prevention.

Pao-Hwa Lin, PhD, of Duke University Medical Center, another expert in this field (but one who was not involved in the study) confirmed that

The study supports a role of saturated fat in prostate cancer progression. However, this study is still observational in nature and thus cannot provide [a] definitive conclusion.

Future studies will therefore be needed to confirm that high total fat intake and a dietary fat composition higher in saturated fat really are more strongly associated with prostate cancer aggressiveness in European Americans compared to African Americans, and that cholesterol is associated with higher prostate cancer aggressiveness only in European Americans.

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: