Low-Fat Diet

Eating a low-fat diet has many benefits. Here are some points to keep in mind.

• The increased cancer risk observed in developed countries may be, in part, due to the fact that a high-fat diet stimulates increased testosterone levels, which is known to be associated with prostate cancer growth.
• A comprehensive review reported that 24 of 32 studies found positive, although not all statistically significant, associations between dietary fat intake and prostate cancer risk.
• Prospective studies to date, however, have failed to find a consistent association between prostate cancer and overall fat intake.

What to Do: Most researchers agree to aim for 20 percent of your total calories from fat, with less than 10 percent of total calories from saturated fat.

Ethan's comment: The above comment is controversial. Other experts claim that more calories should be obtained from fat because calories obtained from carbs increase insulin-like growth factor. The IGF pathway is known not only to be integral in the progression of prostate cancer but also well known to be highly controlled through dietary intake (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959866/). Many similar articles have been published on the benefits of a ketogenic diet and high intensity exercise (which also affects IGF-1). See references at bottom of this article for partial list.

The type of fat is significant.

Saturated Fat

Several studies indicate a positive association between saturated fat intake from meat and dairy products and prostate cancer. Intakes of red meat and dairy products appear also to be related to increased risk of metastatic prostate cancer. Therefore, it is wise to reduce or eliminate consumption of red meat, milk and other dairy products.

What to Do: Reduce or eliminate consumption of red meat, milk and other dairy products. Limit use of butter, mayonnaise, baked goods and regular salad dressing due to their high saturated fat and total fat content. Consider rice vinegar, balsamic vinegar, lemon juice or salsa as alternative salad dressings. Limit cheese consumption. Cheese is typically between 60 to 80 percent fat, much of which is saturated fat.

Trans Fat

Trans fatty acids are known to be atherogenic, or heart disease causing. They also may cause an imbalance in hormonal systems that regulate healing, lead to the construction of defective membranes and encourage the development of cancer.

What to Do: Limit use of hydrogenated fats found in products such as margarine, fried foods and processed foods, which are high in harmful trans fatty acids. When you read that a product contains "hydrogenated" or "partially-hydrogenated" oils, you may want to consider putting it back on the shelf. Trans fatty acid labeling went into effect in 2006, so nutritional labels should spell out the amount of trans fatty acids in the product.

Omega-6 Fatty Acids

Omega-6 fatty acids, which is linoleic acid that can be converted to arachidonic acid, may stimulate growth of prostate cancer cells. These fatty acids are found in corn oil, safflower oil, sunflower oil, cottonseed oil, soybean oil and other polyunsaturated oils.

What to Do: Substitute olive oil for your current cooking oil, but remember to use in moderation. These oils are rich in monounsaturated fats, which have not been shown to increase cancer risk.

Omega-3 Fatty Acids

Omega-3 fatty acids may reduce your risks for prostate cancer and cancer progression. They induce apoptosis (cell death), suppress cancer cell initiation and compete with arachidonic acid, which limits harm from arachidonic acid. One study indicated that men who consumed cold-water fish three to four times per week had a reduced risk of prostate cancer. A more recent study found similar results. Men who consumed fish three or more times per week also had a lower risk of prostate cancer, especially for metastatic prostate cancer where the effect was even greater.

Researchers in New Zealand reported that men with high levels of EPA and DHA, the omega-3 fats found in fish, had a 40 percent lower risk of prostate cancer than those with low blood levels. A 30-year follow-up study found that men who ate no fish had a two to three times higher frequency of prostate cancer than those who ate moderate or high amounts of fish. The mechanism of cancer reduction may occur through the inhibition of arachidonic acid-derived eicosanoid biosynthesis.

Dietary sources of omega-3 fatty acids include cold-water fish — such as salmon, trout, herring and sardines — flaxseeds, walnuts, soybeans and canola oil.

What to Do: It may be wise to consume fish at least twice weekly to obtain an adequate amount of omega-3 fatty acids.

Fish and plant-based foods contain different types of omega-3 fatty acids. Fish contains EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), two specific fatty acids that have shown promising results in research. The plant-based omega-3 fatty acid sources, such as flaxseed and others listed above, contain ALA (alpha-linolenic acid). In an ideal environment, ALA is converted to EPA and DHA, however, in 10 percent to 20 percent of the population, this conversion process is dysfunctional. On the positive side, the conversion process is enhanced by following a diet that is low in saturated fats and low in omega-6 fatty acids.