Healthy diet reduces prostate cancer risk, study shows
A healthy diet appeared associated with a decreased risk for prostate cancer, according to results of a Canadian population-based, case-control study published in Nutrients.
“A role for diet in the development of prostate cancer has long been suspected,” Karine Trudeau, PhD student at Institut National de la Recherche Scientifique in Canada, and colleagues wrote. “It has been proposed as a potential explanation for the persistent geographic distribution of the incidence of this cancer and by studies of migrant populations. However, the evidence on this issue remains weak and inconsistent.”
For this reason, Trudeau and colleagues sought to describe the association between dietary patterns and prostate cancer risk among 1,919 cases (median age, 64 years) compared with 1,991 controls (median age, 65 years) in Montreal.
They administered a 63-item food frequency questionnaire during in-person interviews between 2005 and 2012 that focused on the 2 years either before a cancer diagnosis or before the interview. Researchers inquired about the frequency and portion size of foods consumed per day, week or month, including the consumption of coffee, black tea, green tea, beer, wine and spirits, as well as the consumption of fat from meat, skin of poultry and cooking methods.
The principal component analysis identified three dietary patterns:
- healthy eating pattern, characterized by high consumption of fruits, vegetables, tofu, soybeans, fish, brown bread, nuts or peanut butter, and yogurt and no consumption of white bread;
- Western sweet and beverages pattern, characterized by high loadings of pasta with tomato sauce, pasta with cheese, pizza, cookies, muffins, donuts, cakes, pastries, pies, oatmeal or cream of wheat, breakfast cereal, chips, corn chips, popcorn, tortillas, chocolate, ice cream, tomato or vegetable juice, milk by the glass or milk in cereal, dark carbonated soft drinks and other carbonated soft drinks; and
- Western salty and alcohol pattern, characterized by high loadings of beef, pork, chicken, veal, lamb, hot dogs or sausages, cold cuts, bacon, breakfast sausage, barbeque cooking, white bread, beef or pork fat, slightly blackened meat, beer, wine and spirits and no consumption of brown bread, tofu or soybeans.
After adjusting for age, ethnicity, education, family history and timing of last prostate cancer screening, researchers used unconditional logistic regression to estimate the association between dietary patterns and prostate cancer.
Results showed an association between the healthy eating pattern and a decreased risk for overall prostate cancer (OR = 0.76; 95% CI, 0.61-0.93), which appeared strongest for high-grade cancers (OR = 0.66; 95% CI, 0.48-0.89).
Conversely, the Western sweet and beverages pattern was associated with a higher overall prostate cancer risk (OR = 1.35; 95% CI, 1.1-1.66).
Researchers did not observe an association between the Western salty and alcohol pattern and prostate cancer risk, suggesting that certain dietary patterns may influence the development of prostate cancer more than others.
“In this study, we observed an inverse association between adherence to the healthy eating pattern and overall, as well as high-grade, prostate cancer, with evidence of an exposure-response pattern,” Trudeau and colleagues wrote. “In contrast, adherence to the Western sweet and beverages pattern was associated with a higher prostate cancer risk overall and for high-grade tumors. Increasing adherence to this pattern increased risk. No clear association was found in relation to the Western salty and alcohol pattern.”