(Source: SaluGenecists, Inc.)
Omega 3 fatty acids are categorized as polyunsaturated which indicates, from a chemical perspective, that not all of the carbons in their structure are bound to hydrogen atoms. From a more practical perspective, from that of the kitchen, the term polyunsaturated takes on a different meaning. Polyunsaturated fats, unlike saturated fats such as butter and lard or hydrogenated fats like margarine, are liquid at room temperature and when refrigerated or frozen. Monounsaturated fats, like those found in olive oil, are also liquid at room temperature, but solidify when refrigerated. While most each type of fat can contribute to health when eaten in appropriate amounts, the importance of omega 3 fatty acids in health promotion and disease prevention is so vital that it cannot be overstated.
Among the three most nutritionally important omega 3 fatty acids are alpha-linolenic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Alpha-linolenic acid is one of two fatty acids traditionally classified as "essential" with the other fatty acid traditionally viewed as essential being an omega 6 fat called linoleic acid. Their status as essential reflects that the body is unable to manufacture them on its own and that they play a fundamental role in several physiological functions. Therefore, it is of extreme importance that the diet contains sufficient amounts of both alpha-linolenic acid and linoleic acid.
While alpha-linolenic acid can be converted in the body into two important omega 3 fatty acids, eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA), these two fatty acids can also be derived directly from dietary sources, including cold-water fish such as salmon, tuna, herring and halibut. Certain types of algae are also known to contain DHA. EPA is suggested to play an important role in cardiovascular disease prevention while DHA is a necessary nutrient for proper nerve and brain development.
Physiological functions of omega 3 fatty acids
- Reduce inflammation
- Keep blood from clotting excessively
- Maintain cellular membrane fluidity
Physiological events that may signal a need for greater omega 3 fatty acid intake
- Dry, itchy skin
- Brittle hair and nails
- Joint pain
- Inability to concentrate
Functions of omega 3 fatty acids
Promoting healthy cell membranes
Each cell in the body is surrounded by a cell membrane that is composed primarily of fatty acids. The cell membrane plays a very important role in regulating physiological functions since it allows for the entry of nutrients into the cell while also ensuring that waste products are efficiently removed from the cell.
The cell membrane must maintain its fluidity and integrity in order to perform these functions optimally. Without a healthy membrane, cells lose their ability to hold water and vital nutrients as well as their ability to communicate with other cells. Researchers believe that this cell-to-cell communication is so important and that without it physiological events occur that can lead to the growth of cancerous tumors.
Since cell membranes are made up of fatty acids, their fluidity and integrity is determined in large part by the types of fats that we consume in our diets. Remembering that saturated fats and hydrogenated fats are solid at room temperature while omega 3 fatty acids are liquid at room temperature allows us to better understand how they may function differently as components of the cell membrane. Researchers suggest that diets rich in omega 3 fatty acids produce cell membranes have that have a high degree of fluidity and integrity while diets containing large amounts of saturated or hydrogenated fats create cell membranes that are rigid and lack fluidity.
Omega 3 fatty acids play a critical role in the production of prostaglandins, powerful hormone-like substances. Prostaglandins have an extensive array of physiological functions in the body including nerve transmission, blood pressure, blood clotting, inflammatory and allergic responses, promoting proper functioning of the kidneys and gastrointestinal tract, and the production of other hormones.
The involvement of prostaglandins in physiologic functioning is almost ubiquitous. What guides the production of the type of prostaglandin produced, and therefore, what effects they create, is dependent upon the types of fats consumed in the diet. Without the proper balance of fat consumed that lead to the proper balance of prostaglandins produced, an imbalance may be created in the body that can lead to the generation of disease.
EPA and DHA serve as direct precursors for series 3 prostaglandins, those that are referred to as good or beneficial ones because they function to reduce platelet aggregation, reduce inflammation and improve blood flow. Its ability to produce favorable prostaglandins is one of the reasons that EPA and DHA are noted to be involved in the prevention of cardiovascular disease.
The omega 6 fatty acids serve as precursors for series 1 and series 2 prostaglandins. Similar to the series 3 prostaglandins produced from omega 3 fats, series 1 prostaglandins are believed to be beneficial. Yet, the series 2 prostaglandins are usually considered to be "bad" or "unhealthy" since they are capable of promoting an inflammatory response and increasing platelet aggregation. Therefore, as stated above, it is important to ensure proper balance of types of fats, including the ratio of omega 3 and omega 6 fats, in the diet.
Insufficient dietary intake of direct sources of EPA and DHA, such as cold-water fish, are a contributing factor for omega 3 fatty acid deficiency. In addition, it is now well known that the enzymes critical for conversion of alpha-linolenic acid to EPA and DHA, delta-6 desaturase and delta-5 desaturase, do not function optimally in most people. Therefore, only a small amount of the alpha-linolenic acid that is consumed in the diet is actually converted to EPA and DHA, contributing to deficiency states.
A variety of nutrients including vitamin B6, vitamin B3, vitamin C, magnesium and zinc can increase the activity of desaturase enzymes. Saturated fat and partially hydrogenated fat limit the activity of delta-6 desaturase.
Although recent research indicates that nearly 99% of people in the United States do not consume adequate amounts of omega 3 fatty acids, few people realize that they may be deficient in this important nutrient. Part of the reason for this is that the symptoms of omega 3 fatty acid deficiency can oftentimes be attributed to other nutrient deficiencies or health conditions. These symptoms include joint pain, lack of physical endurance, fatigue, dry and/or itchy skin, brittle hair and nails, depression, poor concentration and frequent colds.
There are no known adverse effects from excessive consumption of omega 3 fatty acids.
Cooking, Storage and Processing
Similar to other polyunsaturated oils, the omega 3 fatty acids are extremely susceptible to damage from heat, light, and oxygen. Exposure to these elements over an extended period oxidizes the fatty acids causing them to become rancid. In addition to changing the flavor and smell, rancidity decreases the nutritional value of oil and fatty acids. It produces free radicals, oxidative molecules believed to play an instrumental role in the development of chronic diseases such as cancer and osteoarthritis.
In general, rancidity becomes a problem only when the oils and fatty acids are removed from their natural food packaging. Flaxseeds are an example of a food whose packaging, its hard shell, protects the oil inside the seed from elements such as heat, light and oxygen, and which naturally contains antioxidant compounds such as vitamin E that further protect against oxidation. Yet, when the seed is pressed in the manufacturing of flaxseed oil, the oil can become susceptible to the negative effects of the elements and rancidity can ensue. Therefore, omega 3 fatty acids should be stored in dark glass, tightly sealed containers in the refrigerator or freezer and should never be heated on the stove.
Drug & Nutrient Interactions
Omega 3 fatty acid-rich fish oil supplements have been found to reduce high blood pressure in individuals taking cyclosporine, an immunosuppressive drug that is used to prevent rejection of transplanted organs.
People taking prescription blood pressure medications and/or anticoagulants should consult with their healthcare practitioner before taking fish oil supplements since a high dietary intake of omega 3 fats, especially from fish, may decrease blood pressure and thin the blood.
Vitamin E protects omega 3 fats from oxidation, a chemical process that produces free radicals.
Health conditions that require special emphasis on omega 3 fatty acids
Individuals who have the following health conditions should pay special attention to their omega 3 fatty acids status:
- Attention deficit hyperactivity disorder (ADHD)
- Bipolar disorder
- Cardiovascular disease
- High blood pressure
- Migraine headaches
- Multiple sclerosis
- Rheumatoid arthritis
Forms in Dietary Supplements
Omega 3 fatty acids are available in supplemental form in either softgel or bottled liquid form. Cod liver oil and salmon oil, rich sources of EPA and DHA, and flaxseed oil, a rich source of alpha-linolenic acid, are among the popular omega 3 fatty acid supplements.
Since omega 3 fatty acids are highly sensitive to damage from elements such as heat, light and oxygen, choose a certified organic, refrigerated product that is packaged in a dark brown or green glass container. Always store the product in your refrigerator or freezer. Additionally, if possible, choose a supplement that contains vitamin E since it will help prevent the fatty acids from becoming rancid.
Flaxseeds are an excellent source of omega 3 fatty acids. Very good sources include salmon and walnuts while good sources of these fats include Brussel sprouts, collar greens, halibut, kale, scallops, shrimp and soybeans.