By Hal Amsbaugh MD Member-Owner of Oneota Community Co-op
Susan Allport has written an excellent history of the discovery of the essential fatty acids in our diet, outlining their importance for our health and chronicling their disappearance from much of the food sold to us.
First of all some organic chemistry must be introduced. Fatty acids are designated Omega-3 and Omega-6, based on the position of the first double bond from the non-carboxyl end of the molecule. Omega-3 fatty acids have their first double bond between the 3rd and 4th carbon atoms from the non-carboxyl end of the molecule; Omega-6 fatty acids have their first double bond between the 6th and the 7th carbon atoms from the non-carboxyl end of the molecule.
Omega-3 fatty acids act in a number of ways that are beneficial for good health. First of all, they tend to decrease the tendency of blood to clot, thus leading to a lower incidence of heart attacks and strokes. Second, the Omega-3 fatty acids are essential for brain development in infancy. Lastly, the Omega-3 fatty acids act to stabilize heart rhythm and prevent the development of abnormal heart rhythms, that are a major cause of heart attacks.
The principal Omega-3 fatty acids are:
1.Alpha linolenic acid or ALA
2.Eicosapentanoic acid or EPA
3.Docahexaenoic acid or DHA
ALA is present in green leafy plants as well as flaxseed. ALA is found in the chloroplasts of plants, the small organelles that are involved in photosynthesis. While humans can convert ALA to EPA and DHA, this conversion can be inefficient. The efficiency in the conversion depends on the ratio of Omega-6 to Omega-3 fatty acids in our diet. As we consume a higher ratio of Omega-6 to Omega-3 fatty acids, we become less efficient at this conversion. The optimum ratio for this conversion is 2.3 to 1, or 2.3 times more Omega-6 fatty acids than Omega-3 fatty acids. The typical American diet is is the range of 15 to 1.
EPA and DHA sources include a variety of green leafy plants, as well as the meat of animals that have been allowed to forage for their food on grasslands rather than having been grain-fed. Fish caught from the ocean rather than farm-raised fish are another important source of EPA and DHA.
The principal Omega-6 fatty acids are linoleic acid and arachidonic acid. Omega-6 fatty acids act to promote the tendency of blood to clot, thus predisposing us to heart attacks and strokes. Omega-6 fatty acids also act to increase the inflammatory response, and inflammation is now implicated as a major contributing factor to heart disease. The principal sources of Omega-6 fatty acids are the seeds of plants such as wheat, soybeans and corn.
Omega-6 fatty acids are more stable than Omega-3 fatty acids and for this reason food manufacturers have steadily increased the ratio of Omega-6 to Omega-3 fatty acids in their products in order to extend their shelf life.
Allport’s book gives detailed information regarding the ratios of Omega-6 to Omega-3 fatty acids in various foods and oils. This is a summary of her information as regards to cooking oils.
Canola Oil 2:1
Soybean Oil 7:1
Olive Oil 12:1
Corn Oil 46:1
Safflower Oil No Omega-3 fatty acids.
Lastly Allport gives a number of common sense suggestions as to how to increase the ratio of Omega-3 fatty acids in our diet.
1. No surprise, eat lots of leafy green vegetables and fruit.
2. Consume oils that have a healthy balance between Omega-6 and Omega-3 fatty acids.
3. Try to include a source of Omega-3 fatty acids in every meal.
4. Avoid hydrogenated and partially hydrogenated oils.
5. Try to eat meat and chicken where the animals have foraged on grassland.
6. Cut down on saturated fats.