By Viktoriya Zabigaylo & Orest Szczurko
The factors that increase the risk of developing prostate cancer are not necessarily the same ones that increase the risk of its recurrence or progression. Recent studies looking at men diagnosed with prostate cancer to evaluate who does better during and after treatment have found dietary and lifestyle influences on the progression and death from prostate cancer, specifically after its diagnosis. Part 1 of this review summary outlines the harmful factors that worsen this outcome. Part 2 will focus on the diet and lifestyle measures that reduce this risk.
Men with prostate cancer who are advised to follow a healthier diet often eat less red and processed meat, but compensate for the reduced protein intake by eating more eggs and chicken. Studies show that men who ate more eggs or chicken with skin were at double the risk of prostate cancer recurrence compared to men who ate smaller amounts. The science behind this points to the large amounts of heterocyclic amines that are found in chicken skin (especially cooked chicken skin), which are also the reason why eating large amounts of meat is a risk for developing prostate cancer. Eggs are the biggest source of choline, which promotes the growth of prostate cancer cells. According to our other blog post, eggs can be beneficial in heart disease, however they do not seem to have the same helpful effects in prostate cancer.
Other studies concluded that a higher intake of saturated fat after prostate cancer diagnosis may increase risk of death from prostate cancer as well as all-cause mortality, while vegetable fats may lower these risks. High fat dairy products confirmed this association. Men who consumed more milk (greater than 4 servings per week) had a 51% increased risk of recurrence of prostate cancer, double the risk of death from prostate cancer, and triple the risk of recurrence for men with a higher BMI (over 27). The higher the fat content of the milk, the greater the association.
Lifestyle factors such as smoking and gaining weight after diagnosis were also shown to be harmful. Smoking increases the progression and mortality associated with prostate cancer, as well as risk of metastasis and development of hormone-resistant disease. Men who smoked had an 80% higher risk of recurrence compared with those who did not smoke.
A higher BMI score by even 1 unit before diagnosis was associated with a 10% increase in the risk of death due to prostate cancer. Additionally, men who gain more than 2 kg 5 years before and up to 1 year after prostate cancer surgery are at a 94% increased risk of prostate cancer recurrence.
Based on this evidence, limiting consumption of chicken with skin, eggs, whole milk and high fat dairy products can be beneficial in reducing the risk of prostate cancer recurrence. In terms of lifestyle, smoking cessation and weight loss (keeping BMI below 27) are also helpful.