Monday Aug 8, 2016 (foodconsumer.org) -- Previous studies have shown that intake of dietary fat can be a risk factor for breast cancer and a determinant for the risk for death from breast cancer and other causes.  Thta is, high intake of dietary fat may increase the risk for breast cancer.   

A new study suggests the type of fat ingested also matters when it comes to the risk of breast cancer.   The study based on data from the Melbourne Collaborative Cohort shows that high levels of saturated fatty acids in plasma phospholipids were associated with 64% increased risk of breast cancer.

Saturated fatty acids and palmitic acid were positively associated with risk for ER positive or PR positive breast cancers. Omega 6 polyunsaturated fatty acid and trans fatty acids were positively associated with ER negative/PR negative breast cancer.   The ratio of dietary omega 6 to omega 3 fatty acids was also positively associated with breast cancer risk.   Palmitic acid is found palm oil, which is now commonly used to replace trans fat.   Other studies have  evidence suggesting that palm oil may not be a good replacement for trans fat.

Another study reported early shows that trans fat consumption may increase risk for epithelial ovarian cancer. 

On the other hand, dietary docosapentaenoic acid (DPA), dietary docosahexaenoic (DHA) and eicosapentaenoic acid (EPA) were inversely correlated with risk for breast cancer.  Those who had highest amounts of these fatty acids were 43% less likely to be diagnosed with breast cancer.  An early study has already found that high intake of omega 3 fatty acids can supress the growth and metastasis of breast cancer.  

An inverse association was also found between the risk for ER-/PR- breast cancer and dietary dihomo-γ-linolenic acid (DGLA) in older women.  Dihomo-γ-linolenic acid is a rare omega 6 fatty acid with 20 carbons found in animal products.  This acid has some anti-inflammatory property.

The study indicates that high intake of saturated fat, trans fat, and omega 6 fatty acids, and high ratio of omega 6 to omega 3 fatty acids may increase risk of breast cancer while eating fish or other foods with long chain omega 3 fatty acids may reduce the risk.  Corn oil and soybean oil are found high in omega 6 fatty acids.

It should also be noted that low amounts of plasma phospholipids is a signature sign of cancer.  Dr. Johanna Budwig, a biochemist, found in 1950s that all cancer patients have low levels of phospholipids, which prompted her to propose the flaxseed oil and cottage cheese diet for cancer patients. (David Liu)

Julie K. Bassett , Allison M. Hodge, Dallas R. English, Robert J. MacInnis, Graham G. Giles, Plasma phospholipids fatty acids, dietary fatty acids, and breast cancer risk, Cancer Causes & Control, June 2016, Volume 27, Issue 6, pp 759-773, First online: 04 May 2016