Although it is wise to reduce the overall amount of total fat in our diet, some fat is absolutely essential. I am referring here to the essential fatty acids, linolenic and linoleic acid, otherwise known as omega 3 and omega 6. Oily fish, flax seeds and walnuts are excellent omega 3 food sources, whereas omega 6 is found in the oils of seeds and nuts.
The body converts omega 3 into the long-chain omega 3 fats, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fats can be derived directly from cold-water fish, including salmon, tuna, halibut, and herring, and from marine algae. EPA is believed to play a role in the prevention of cardiovascular disease, while DHA is necessary for proper brain and nerve development.
A common misconception, especially amongst vegetarians and vegans, is that our need for EPA and DHA can be met by consuming flax oil and other plant sources of omega 3. Although it is possible for the body to synthesise EPA and DHA from the short-chain alpha-linolenic acid (ALA) found in plant foods such as flax, hemp and pumpkin seeds, and walnuts, research clearly indicates that the this conversion is extremely limited. Less than 5% of ALA is converted to EPA, and less than 0.5% of ALA is converted to DHA.
The good news for vegetarians and vegans is that Purslane contains more omega-3 fatty acids than any other leafy vegetable. It also also contains EPA, which is not found in flax seed, and which can usually only be found in oily fish. So, unless vegetarians and vegans are eating Purslane, or supplementing with an algae-derived source of DHA, it is likely that most vegetarians and vegans are omega deficient.
Human beings evolved on a diet with a ratio of omega 3 to omega 6 of approximately 1:1, whereas in Western diets, today, the ratio is closer to 1:16. Western diets are deficient in omega 3 and have excessive amounts of omega 6, compared to the diets of our ancestors, on which our genetic patterns were established. This excess of omega 6, and the low ratio of omega 3 to omega 6, is contributing to the prevalence of cardiovascular disease, cancer and inflammatory and autoimmune diseases, whereas increased levels of omega 3 are protective, and a better ratio of omega 3 to omega 6 can reduce the risk of many of these chronic diseases.
The ideal ratio of omega 3 to omega 6 is 1:3 or less. This has been shown to have beneficial effects by reducing inflammation in the body.