Omega 6 oils and Breast cancer

Q: I have read in some magazines that omega 6 oils should not be consumed when you have breast cancer while other magazines say it is beneficial. Can you clear up this confusion?

A: Omega 6 oils should be broken down into two types: Omega 6 oils that contain Gamma Linolenic Acid (GLA) and those that do not. Those that have GLA, including black current seed, evening primrose, and borage, have been shown in clinical studies to be breast protective. Those that do not contain GLA, including corn, safflower, canola and soy, have been found to be disease promoting.

The reports that linked omega 6 oils to breast cancer are misleading because the studies they are based on did not consider the type of omega 6 oils that the participants were using. Nor did they expose whether the oils consumed were refined, genetically modified or organic. Studies that did consider the type of omega 6 oil found that evening primrose oil and borage oil reduce the risk of breast cancer, eliminate breast pain (a risk factor for breast cancer), and improve fibrocystic breast disease. For example, an important British study published in 2000 found women with breast cancer who received GLA along with Tamoxifen demonstrated faster clinical response than those on Tamoxifen alone.

The reported studies also did not consider the total amount of fat from all sources. This is important because consuming too many of the "bad" omega 6 oils (highly refined safflower, sunflower, soybean and canola), too many saturated fats from red meat and dairy, and not enough of the good omega 3 oils (e.g., flaxseed, fish) disrupts our fatty acid balance, setting the stage for disease.


  1. Effect of gamma-linolenic acid on the transcriptional activity of the Her-2/neu (erbB-2) oncogene.
  2. Inhibition of fatty acid synthase-dependent neoplastic lipogenesis as the mechanism of gamma-linolenic acid-induced toxicity to tumor cells: an extension to Nwankwo's hypothesis.
  3. Omega-6 polyunsaturated fatty acid gamma-linolenic acid (18:3n-6) enhances docetaxel (Taxotere) cytotoxicity in human breast carcinoma cells: Relationship to lipid peroxidation and HER-2/neu expression.
  4. Synergistic interaction between vinorelbine and gamma-linolenic acid in breast cancer cells.
  5. Effect of dietary GLA+/-tamoxifen on the growth, ER expression and fatty acid profile of ER positive human breast cancer xenografts.
  6. Gamma linolenic acid with tamoxifen as primary therapy in breast cancer.