Of cow’s milk, doughnuts, fried chicken, and other important food groups

Two recent articles have linked certain dietary habits to risk for development of prostate cancer. The degree to which one feels that these dietary habits may be “proven” to increase risk for prostate cancer is probably going to be debatable; the existence of a potential link is certainly clear.

In their article just published on line in The Prostate, Stott-Miller et al. have reported that regular consumption of deep-fried foods (fried chicken, French fries, doughnuts, etc.) appears to be associated with an increased risk for  diagnosis of prostate cancer. Their actual article is supported by information in a media release from the Fred Hutchinson Cancer Research Center.

Stott-Miller et al. estimates the odds ratios (ORs) and the confidence intervals (CIs) for any association between diagnosis of prostate cancer and tertiles of intake of deep-fried foods from a food frequency questionnaire. Their core data are as follows:

  • The study population included 1,549 men who had a diagnosis of prostate cancer (“cases”) and 1,492 othet men who did not have such a diagnosis (“controls”).
  • Compared to those men who ate specific fried foods (see below) less than once a week, they were able to show
    • A higher risk for prostate cancer among men eating French fries ≥ once a week (OR = 1.37; 95% CI, 1.11–1.69)
    • A higher risk for prostate cancer among men eating fried chicken ≥ once a week (OR = 1.30; 95% CI, 1.04–1.62)
    • A higher risk for prostate cancer among men eating fried fish ≥ once a week (OR = 1.32; 95% CI, 1.05–1.66)
    • A higher risk for prostate cancer among men eating doughnuts ≥ once a week (OR = 1.35; 95% CI, 1.11–1.66)
    • No increase in risk for prostate cancer among men eating snack chips ≥ once a week (OR = 1.08; 95% CI, 0.89–1.32)
  • In general, estimates were slightly stronger for more aggressive disease (OR = 1.41; 95% CI, 1.04–1.92 for fried fish).

The authors are careful to note that we do not know whether this risk is specific to deep-fried foods, or whether it represents risk associated with regular intake of foods exposed to high heat and/or other aspects of the Western lifestyle (e.g., excessive consumption of “fast foods”).

On what is perhaps a potentially more worrisome level, however, an article by Melnick et al. on the Medscape web site (reprinted from Nutrition and Metabolism) suggests that exposure to high levels of cow’s milk and its derivatives (cheese, yoghurt, etc.) “predominantly during critical growth phases of prostate development and differentiation may exert long-term adverse effects on prostate health.” In other words, consumption of high levels of cow’s milk and its dairy derivatives by male infants, children, and teenagers may predispose them to higher risk for prostate cancer later in life.

Melnick et al. explain their hypothesis by reference to the fact that the nutrient-sensitive kinase mTORC1 (common in cow’s milk and other non-human, mammalian milks) is upregulated in nearly 100 percent of advanced, human cases of prostate cancer. They note that, historically, consumption of cow’s milk has been associated with reduced infant mortality, improved fertility, increased body mass index among children, earlier onset of menarche, and increased linear growth during adolescence. Later in life, however (and most especially among Western populations with high life expectancies), such early “beneficial” effects may become adverse effects.

We are all well aware that the clinical manifestation of prostate cancer is most evident among older males. What Melnick et al. propose is that the initiation phase of prostate cancer may occur even as early as the fetal growth and development stage. Given the well-known, extended time frame for the development of prostate cancer in men, The “New” Prostate Cancer InfoLink has long felt that dietary factors in very young males might have some relationship to later risk for this disease (although your Sitemaster would note that he had a long history of high milk consumption in childhood, but no sign of any risk for prostate cancer as yet).

The associations between specific diets and risk for prostate cancer are easy to demonstrate hypothetically but hard to prove with any degree of certainty. We don’t — as yet — see any clarity on the horizon as to whether specific dietary factors over a lifetime are at the core of risk for clinically significant prostate cancer as we age.

One Response

  1. OTOH, maybe we should just stick to skim milk and cheese. Check out this new study.

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