Essential fatty acids (EFAs) are a type of polyunsaturated fat that cannot be made by the body. They must be obtained from food sources. Polyunsaturated fats are liquid at room temperature and when chilled. Molecularly speaking, polyunsaturated fats are fatty acids that have more than one double-bonded (unsaturated) carbon in the molecule. To compare, saturated fats have no double bonded carbons and are consequently solid at room temperature.
Polyunsaturated fats can have a beneficial effect on your health when consumed in moderation and when used to replace less heart healthy saturated fats or trans fats. Polyunsaturated fats can help reduce cholesterol levels in your blood and lower your risk of heart disease.
There are only two essential fatty acids in human nutrition: omega-6 and omega-3. Omega-6 and omega-3 play a crucial role in brain function and in the normal growth and development of your body.
Omega-6 fatty acids are also known as linoleic acid (LA). It can break down into arachadonic acid. Omega-6 has inflammatory properties and is the precursor for pro-inflammatory agents called eicosanoids. The eicosanoid family includes prostaglandins, thromboxanes, prostacyclins and leukotrienes. Your body can easily metabolize and use these compounds when eaten in moderation. Omega-6 fatty acids help with skin and renal function, but if you ingest too much, detrimental effects may result. Studies have shown that asthma, arthritis, and lupus may have a connection to the inflammatory response.
Dietary sources include nuts, cereals, whole grain breads, most vegetable oils (corn, safflower, sunflower, palm, and peanut), eggs and poultry.
Omega-3 fatty acids are also known as alpha-linolenic acid (ALA). It can be broken down into Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA). Omega-3 has anti-inflammatory properties and may lower the risk for heart disease and certain cancers.
Eicosanoids can also be made from omega-3 fats, but often have opposing functions to those made from omega-6 fats (anti-inflammatory rather than inflammatory). If both omega-3 and omega-6 are present in the body, they will compete to be used, so the ratio of omega-3:omega-6 directly affects the type of eicosanoids that are produced. The best thing to do would be to consume more omega-3 and fewer omega-6 fatty acids.
Dietary sources include flaxseed, walnuts, cold water oily fish (wild salmon, herring, mackerel, anchovies, sardines), eggs and meat from grass-fed animals. Grass fed animals tend to have higher levels of omega-3 fatty acids than grain fed animals.
Flax is a good source of omega-3 fatty acids, especially ALA. Flaxseed contains approximately three times as much omega-3 as omega-6 fatty acids which is a good ratio.
In North America, we use the term flax when it is eaten by humans and the term linseed when it is used for industrial purposes. Linseed oil is flax’s vegetable oil. It is okay for human consumption if it is fresh, refrigerated and unprocessed.
There are two types of flaxseed: yellow and brown. Brown has been found to be higher in omega-3 fatty acids. Yellow flax can be broken down into solin and a new product developed for the food industry called ‘Omega’. The ‘Omega’ flax is as high in omega-3’s as brown, while solin is very low in omega-3 fatty acids.
In general, both brown and yellow flaxseed (except for solin) provide the same nutritional benefits. Flaxseeds contain vitamins C, E, thiamine, riboflavin and carotene. The seeds also contain iron, zinc, and trace amounts of potassium, magnesium, phosphorus and calcium. Its other benefits include phytochemicals, lignans, fiber and protein.
Lignans are plant compounds that act as antioxidants. Lignans aid in ridding the body of excess estrogen which in turn may lower the risk for estrogen related diseases like breast cancer.
Flaxseeds are more nutritious than their oil, yet, most consumers prefer simply using the oil for its omega-3 fatty acids and not having to bother with grinding the seeds.