Updated: Sep 20, 2020
Q. I have a question about Omega 3's. I heard that the type of "omega 3" in walnuts and flax seeds are different that the type of Omega 3's that are in fish and that the ones in walnuts and flax seeds aren’t the right kind of Omega 3’s and because of that, I should eat fish or take fish oil supplements, especially if I choose not to eat any animal products. Can you help me understand why he might feel the omega 3’s in walnuts aren’t the right kind?
Essential fatty acids are a type of polyunsaturated fat (PUFA) that can only be derived from our diets, and this is why they are called "essential". There are two of these essential fatty acids: an omega-6 fatty acid called linoleic acid (LA) a omega-3 fatty acid called alpha-linolenic acid (ALA). These are considered "short chain" essential fatty acids (more on this later). Unlike saturated fat, hydrogenated fat, and trans fats, these fats have several beneficial roles in our body.
- They protect against heart disease by reducing blood clotting,
- They lower triglycerides and cause vasodilation;
- They reduce inflammation;
- They enhance immune function
- The may play a protective role against certain cancers;
- They are necessary for the formation of healthy cell membranes and the proper development
of the brain & nervous system.
The omega-6 fatty acid (LA) is abundant in our food supply and is found in fruits, vegetables, legumes, whole grains, and vegetable oils.
The omega-3 fatty acid (ALA) is not as abundant in our food supply but can be found in fruits, vegetables, legumes, whole grains. Richer sources include flax seeds and walnuts.
As most of us get an abundance of the omega-6 fatty acid (LA) in our diets, (and for many, too much), the main problem right now seems to be in getting in enough of the omega-3's fatty acid (ALA). The Institute of Medicine (IOM) has set an Adequate Intake (AI) of 1.6 gm/day for men and 1.1 gm/day for women. You can find the definition of an AI here.
Not only is getting in enough of each essential fat important to our health, so is the ratio of one to the other, Omega 6 (LA):Omega 3 (ALA,) also important. While there is no consensus on what the ideal ratio of LA:ALA is, expert recommend to keep the ratio no higher then 4:1. It has been estimated that the early human diet had a ratio of ~1:1. Currently, in the US, the ratio is around 14:1 to 20:1, which is even way above the high end estimates.
Many plant foods contain the essential omega-3 fatty acid (ALA), and so a well planned unrefined, unprocessed whole-food plant-based (or plant-exclusive) diet should easily be able to provide us with the AI
However, there is another concern.
As I mentioned, ALA is a "short chain" omega-3 fatty acid. There are two "longer chain" Omega-3 fatty acids called EPA (eicosapentaenoic acid) and DHA (docosahexanoic acid). These fatty acids appear to have significant beneficial cardiovascular effects including the reduction of triglycerides and antiarrhythmic (reduce irregular heart rhythms)and antithrombotic (reduce blood clotting) actions.
There are two sources of EPA and DHA. One source is fish. Fish contain both ALA and EPA and DHA. The other source is that we can synthesize both EPA and DHA ourselves from the "short chain" omega-3 fatty acid ALA if we get in enough on the short chain omega-3 fatty acid, ALA. (Since we can make them ourselves, these "longer chain" omega 3 fatty acids are not considered to be "essential"). However, the concern is that this conversion is not very efficient.
Several things also interfere with this conversion. These include a high intake of saturated fat, trans fat, hydrogenated fat, cholesterol, and alcohol. Vegetable oils like cottonseed, corn, soy, safflower, and sunflower, that are high in the omega-6 (LA) polyunsaturated fatty acid can also interfere with this conversion. These fats and oils all compete with and depress the enzymes necessary to make the conversion from ALA to EPA and DHA. Also, people with certain metabolic diseases like diabetes may also have problems converting ALA to EPA and DHA.
If someone was to dramatically reduce and/or eliminate their intake of saturated fat, hydrogenated fat, trans fat, and vegetable oils high in LA, and also consume a whole food unprocessed, unrefined plant based diet, with a little flax seed or walnuts, then they should be able to meet their ALA requirements, correct their elevated LA:ALA ratio and be able to convert enough ALA to EPA and DHA to meet all their needs this way.
Based on all of the above, my recommendations are:
Dramatically reduce and/or eliminate:
- all vegetable oils high in LA (Corn, Safflower, Sunflower, and Cottonseed Oil);
- all hydrogenated fats (margarine, shortening, and many packaged and processed foods);
- all saturated fats (meat, chicken, dairy, eggs, some packaged products, butter, chocolate,
coconut, palm oil, palm kernel oil and other animal fat);
- Consume a minimally processed, lower fat, predominately plant based (or plant exclusive) diet
- If desired, include 1 tbsp of fresh ground flax seed or 1/2 oz of walnuts per day.
While vegans have no "direct" source of EPA and DHA from their food, if they were to follow the above recommendations, then they should be able to meet both their ALA needs and their EPA and DHA needs..
Remember, Your "Health" Is Your Greatest Wealth!