Both omega-3 and omega-6 fats are associated with an increased risk of opacification of the lens of the eye, resulting in cataracts.14
Omega-3 and omega-6 oils could benefit people with autoimmune disorders. On the other hand, excessive intake of these fats may actually aggravate these disorders.15 More importantly, we need our immune system functioning at full capacity to fight off infections and cancer. Free oils have been demonstrated to suppress many natural microbe killing mechanisms (with a marked decrease in cytokine, tumour necrosis factor-alpha and interferon-gamma).16
Research on animals suggests the omega-6 variety of oils is very cancer-promoting and the omega-3 variety may be beneficial for cancer prevention.17 However, this may not be the case. In one animal experiment on colon cancer, a fish oil diet and a safflower oil diet induced, respectively, 10- and 4-fold more metastases (number) and over 1000- and 500-fold more metastases (size) than were found in the livers of rats on the low-fat diet.18 Other, animal experiments also have shown essential fats to be cancer promoting.19,20 Most importantly, population studies tell us that, worldwide, the lower the total fat intake, the less the risk of common cancers, such as breast, colon and prostate.21-23
Most likely, the heart benefits of a Mediterranean diet are due to it being a nearly vegetarian diet. The Mediterranean diet is a good diet in spite of the olive oil.13
