The Omega-6 and Omega-3 Essential Fatty acids in Food
(Updated August 2010)
Each fat molecules contains three fatty acids.
Fatty acids are made of a spine of carbon atoms, bearing hydrogen atoms all along and with two oxygen atoms at one extremity of the carbon spine. The two oxygens give the molecule an acid value and the hydrogen atoms repelling water gtive ther molecule its “fatty” quality. More about the chemistry of fatty acids
Fatty acids come in a large variety of lengths and structures.
Humans make all kinds of fatty acids from carbohydrates except for two types we can not synthesize and have to find in food. Hence, their name Essential Fatty Acids (EFAs). There are two types of EFAs: the omega-6 (n-6) EFAs and the omega-3 (n-3) EFAs. How the two types differ from each other is extensively explained at the Longevity Institute Website. The importance of the EFAs derives from their exclusive involvement in the activity of our cells and from their obligatory supply in food.
Among other things, we use EFAs to make hormones named prostaglandins. There are two classes of prostaglandins. One class is made from n-6 EFAs, the other class from n-3 EFAs. The two classes have opposed properties. Prostaglandins derived from n-6 EFAs stimulate the functions of cells, while prostaglandins derived from n-3 EFAs reduce cell's activity. This applies particularly to the cells of the immune system and to the cells responsible for coagulation. Prostaglandins derived from n-6 EFAs stimulate the immune system and help form blood clots. Prostaglandins derived from n-3 EFAs down regulate an immune response, and maintain blood fluidity.
It is of particular interest that the American diet contains much more n-6 EFAs than n-3 EFAs. In the American diet, the n-6 EFAs to n-3 EFAs ratio is around 20 to 1. Which is to say there is about 20 times more n-6 EFAs in the diet than n-3 EFAs. In Australia the ratio is 25 to 1.
A good diet should contain only twice as much -6 EFAs than n-3 EFAs. That proportion of 2 to 1 is the ideal ratio recommended by the Cloister Workshop .
The actual n-6 EFAs to n-3 EFAs imbalance in the American diet contribute to many health deteriorations. The n-6 EFAs to n-3 EFAs imbalance exaggerates immune response and blood coagulation. Hence, the ample use in our n-6 inundated and n-3 EFAs deprived society of pharmaceutical products opposing (1) an overactive immune system (anti-allergy products, cortisone and NSAIDs) and (2) undue coagulation (anticoagulants).
From the above, one can see it makes goods sense to supply the diet with food and supplements containing n-3 EFAs..
It makes equally good sense to reduce the consumption of N-6 EFAs rich food.
Sorting Foods By Its N-6 EFAs Content
Table 1 lists some foods sorted by their decreasing n-6 EFAs content in grams per 100 grams edible portion. The table also indicates the n-3 EFAs contents and the n-6 EFAs to n-3 EFAs ratios.
Some of the foods listed contain n-6 EFAs only. Sunflower oil, safflower margarine, apricot kernel oil, avocado oil, and almond oil belong to that group. Other of the foods listed do not do much better. The content of n-3 EFAs is negligible in corn oil, sesame oil, safflower seeds, brazil nuts, corn margarine, soybean margarine, pumpkin seeds, squash seeds, peanuts, peanuts butter, pistachio nuts, palm oil, and crackers.
Some other foods listed in table one have their relative high n-6 EFAs content balanced by their n-3 EFAs content. Examples are borage oil and canola oil, with their respectively n-6 EFAs content of 38 grams, and 20 grams per hundred grams, and their 25 and 9.3 grams of n-3 EFAs. Borage oil and canola oil have the favorable n-6 EFAs to n-3 EFAs ratios of 1.5 and 2.18. However if consuming borage oil and canola oil does not increase the n-6 to n-3 ratio of your diet, it shall also not contribute to restore the overall n-6 EFAs to n-3 EFAs imbalance of the diet. Only the consumption of foods and of supplements with a very low n-6 EFAs to n-3 EFAs ratio can help restore the overall n-6 EFAs to n-3 EFAs imbalanced ratio of the diet. It appears that from all the foods listed in table 1, flax seed oil with its content of 59 grams of n-3 EFAs per hundred grams and the resulting n-6 EFAs to n-3 EFAs ratio of 0.24 is one of the best candidates on the list to do the job.
Table 1 - List of some foods sorted by their decreasing omega-6 EFA content in grams per 100 grams edible portion.
The table also indicates the omega-3 EFA content in grams per 100 grams edible portion and the omega-6 to omega-3 ratio.
The data is from the United States Department of Agriculture USDA
The significance of the n-6 EFAs content of the foods listed in table 1 greatly depends on their importance in the diet.
It appears that sunflower and corn oil are worse than Canola oil. Canola oil contains 20 grams of n-6 EFAs and 9.3 grams of n-3 EFAs per 100 grams, while sunflower oil , corn oil, and soybean oil contain 66, 58, and 51 grams of n-6 EFAs, and zero, 0.7, and 6,8 grams of n-3 EFAs per 100 grams respectively. Canola oil has an n-6 EFAs to n-3 EFAs ratio of 2.18. The ratio is 8 for soybean, and 83 for corn.
Peanuts and sunflower have little or no n-3 EFAs, and accordingly a very high n-6 EFAs to n-3 EFAs ratio.
Peanuts contain a relatively lower quantity of n-6 EFAs per 100 grams than many of the foods listed in table one. Peanuts, howeve,r are largely used in the food industry, becoming one of the major contributor of the n-6 EFAs to n-3 EFAs imbalance in the American diet. Furthermore, peanuts contain several allergens (substances that can trigger an immune response). The association of allergens and n-6 EFAs turns peanuts into one of the worst food for people with allergies or auto-immune conditions.
Sorting Foods By Its Omega-3 Content
Table two lists foods sorted by their decreasing n-3 EFAs content. The table also indicates the n-6 EFAs contents in grams per 100 grams edible portion and the n-6 EFAs to n-3 EFAs ratios.
From table 2 it comes into view that flax seed oil and cold ocean fish (salmon, sardine, herring, chinook), and shrimp have the best n-6 EFAs to n-3 EFAs ratios, with the exception of the latter containing the highest n-3 EFAs content.
Table 2 - List of some foods sorted by their decreasing omega-3 EFA content in grams per 100 grams edible portion.
The table also indicates the omega-6 EFA content in grams per 100 grams edible portion and the omega-6 to omega-3 ratios.
The data is from the United States Department of Agriculture USDA.
You may want to dig further in the topic of fats and essential fatty acids in our food.
See a collection of charts of the omega-3 and other fatty acid contents of vegetable oils as compared to animal fat, human fat and butter.
Sorting Foods By Its n-6 To n-3 Ratio
Table 3 lists foods sorted by their increasing n-6 EFAs to n-3 EFAs ratio. The table also indicates the n-6 EFAs and the n-3 EFAs content in grams per 100 grams edible portion.
Although the variety of food with an n-6 EFAs to n-3 EFAs favorable ratio appears large, only a few have a sufficiently high n-3 EFAs content to correct the overall imbalance of the n-6 EFAs to n-3 EFAs ratio of the American diet.
Table 3 - List of some foods sorted by their increasing omega-6 to omega-3 ratio.
The table also indicates the omega-6 EFA and the omega-3 content in grams per 100 grams edible portion.
The data is from the United States Department of Agriculture USDA.
See charts of the fatty acid content of vegetable oils as compared to animal fat, human fat and butter
Cold ocean fish and fish oils have a great advantage over flax seed and flax seed oil. Cold ocean fish and cold ocean fish oil contain long chain omega-3 EFAs. Among them Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA), while the only omega-3 fatty acid in flax seed and in flax seed oil is the short chain Alpha Linolenic acid (ALA).
ALA itself has little or no function in human biochemistry except for its contribution to improve cells membrane fluidity. ALA, however, is the raw material cell use to make long chain n-3 EFAs with potent functions, like the n-3 EFAs EPA and DHA.
In good health and in optimal conditions we can make some EPA and DHA from ALA. However, that capacity is blocked by the high n-6 EFAs content of the American diet, because omega-6 and omega-3 EFAs compete for the same enzymes.
People on the American diet can no longer make EPA and DHA form ALA, and adding to their diet more ALA rich food or ALA supplements does not improve their capacity to use it. They need a direct EPA and DHA supplementation with EPA and DHA rich food or with EPA and DHA containing supplements.
Copyright 2003-2010: Edmond Devroey
"A workshop on the Essentiality of and Recommended Dietary Intakes (RDIs) for Omega-6 and Omega-3 Fatty Acids was held at The Cloister, National Institute of Health (NIH) in Bethesda, Maryland, USA, 7-9 April 1999. The workshop was sponsored by the National Institute on Alcohol Abuse and Alcoholism-NIH, the Office of Dietary Supplements-NIH, The Center for Genetice, Nutrition and Health, and the International Society for the Study of Fatty Acids and Lipids: and co-sponsored by several Industry groups."