What is the role of dietary fats in the etiology of prostate cancer?

Updated: Oct 11, 2019
  • Author: Mark A Moyad, MD, MPH; Chief Editor: Edward David Kim, MD, FACS  more...
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Per-capita fat consumption is highest in males in North America and Western Europe, and rates of prostate cancer deaths are also highest in these regions. (The typical American male obtains about one third of his daily energy intake from dietary fat.) Conversely, the countries in the Pacific Rim have the lowest fat consumption and the lowest prostate cancer death rates.

Whittemore et al studied the relationship of diet, physical activity, and body size in black, white, and Asian men living in North America and found that the only factor that correlated with prostate cancer was the amount of dietary fat. [22] The same was true in Hawaiian men; the highest prevalence of prostate cancer was in men with the highest intake of saturated fat. [23]

The introduction of Western diets in Japan, where the traditional diet is low in fat, has led to an increased incidence of aggressive prostate cancer. Giovannucci et al reported that men who consumed high levels of fat were more likely not only to develop prostate cancer but also to develop a more aggressive form of the disease. [24]

In an animal study by Wang et al, a low-fat diet decreased the growth of prostate tumor cells. [25] These investigators injected prostate cancer cells from the androgen-sensitive cell line (LNCaP cells) into nude mice. Initially, all of the animals were placed on a diet in which 40% of their caloric intake came from fat. When the tumors were established and measurable, the diet was changed. Tumor growth was markedly inhibited in the animals in which dietary fat contributed no more than 20% of the total caloric intake. There was no significant difference in total ingested calories between the 2 groups.

If higher fat intakes are associated with prostate cancer in older studies, why do more recent and more extensive cohort studies and a meta-analysis [26] show minimal to no correlation at best? Perhaps the reduction in saturated fat and replacement with unsaturated fats has provided protection, as was observed in numerous cardiovascular studies. [27] Perhaps it is the need to adjust for countless variables, such as smoking status, overall caloric intake, age, family history, physical activity levels, alcohol consumption, types of fat (eg, omega-3, omega-6), fruit, vegetable, and fiber consumption, and fat-soluble nutrient intake. Thus, it is possible that in older studies, fat consumption may have been a marker or indicator for unhealthy overall behavior (eg, higher caloric intake, less physical activity, smoking).  

Still, it is intriguing that numerous clinical trials have begun examining the impact of higher fat consumption or a ketogenic diet on prostate cancer progression. It seems plausible that if higher fat intake can lead to heart-healthy parameter changes (eg, reduced blood pressure, cholesterol, blood sugar, weight/waist size, inflammation) then the potential for success should somewhat rival what is observed with other heart-healthy dietary programs.

At the other extreme, many adverse cardiovascular risk factors appear to increase prostate cancer risk and/or aggressiveness.  For example, men with metabolic syndrome have been shown to have a higher incidence of prostate cancer, and potentially more aggressive disease at the time of diagnosis. [28]


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