By Allison Helms D.O. and Sooji Rugh, M.D.
What are Omega-3 Fatty Acids?
Omega-3 and omega-6 are types of essential fatty acids, which means our bodies cannot make them on our own and we have to obtain them from our diet. Both are types of polyunsaturated fatty acids (PUFA) that differ from each other in their chemical structure.
Where Omega-3 is Found in Our Diet
There are few sources of omega-3 fatty acids, mainly the fat of cold water fish such as salmon, sardines, herring, mackerel, black cod and bluefish. There are two critical omega-3 fatty acids (eicosapentaenoic acid, called EPA and docosahexaenoic or DHA) that the body needs. Vegetarian sources, such as walnuts and flaxseeds, contain a precursor omega-3 (alpha-linolenic acid called ALA) that the body must convert to EPA and DHA.
Omega-6 fatty acids are found in refined vegetable oils such as soy oil used in most snack foods, cookies, crackers and sweets, as well as in fast foods.
Why Western Diets Need Omega-3
Humans evolved on a diet with the ratio of omega-3 fatty acids and omega-6 fatty acids being 1/1, whereas today this ratio is 10/1 to 20-25/1 with excessive omega-6. Western diets are deficient in omega-3 fatty acids and have excessive amounts of omega-6 fatty acids. The typical ratio seen in a western diet promotes the development of many diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune diseases. Conversely, if there is an increase in omega-3, thus reducing the ratio of omega-6/omega-3, there is reduction and suppression seen in many chronic diseases.
For example, in the secondary prevention of cardiovascular disease, a ratio of 4/1 was associated with a 70% decrease in total mortality. A ratio of 2.5/1 reduced rectal cell growth in patients with colorectal cancer, whereas a ratio of 4/1 with the same amount of omega-3 PUFA had no effect. The lower omega-6/omega-3 ratio in women with breast cancer was associated with decreased risk. A ratio of 2-3/1 suppressed inflammation in patients with rheumatoid arthritis, and a ratio of 5/1 had a beneficial effect on patients with asthma, whereas a ratio of 10/1 had adverse consequences.
How Omega-3 Helps Weight Loss
In addition to the impact of omega-3 PUFA on cardiovascular mortality, EPA and DHA have been shown to impact obesity by improving insulin sensitivity, reducing body fat and increasing satiety. Omega-3 supplementation in animal studies has shown positive effects related to the prevention of obesity, as well as increasing and maintaining weight loss. Smaller human studies of shorter duration have also shown evidence that supplementation helps to reduce body fat formation during development, and to reduce fat cells once an individual is already obese.
How Much Omega-3?
The American Heart Association recommends consumption of 2 servings of oily fish per week (about 400-500mg EPA and DHA) for patients without cardiovascular disease. They recommend approximately 1 gram of EPA and DHA, ideally from oily fish (or supplementation after consult with your doctor), for those with diagnosed cardiovascular disease. For those with high triglycerides, 2-4 grams of EPA and DHA prescribed by a physician are recommended.
Most commercial fish oil capsules generally have 180 mg of EPA and 120 mg of DHA, therefore 3 capsules per day provides the recommended dosage of 0.9 grams per day. Another alternative would be to select pharmaceutical grade fish oil products which may provide more highly concentrated dosages of EPA and DHA.
Choosing Safe Omega-3s
Consumers of oily fish should be aware of the potential presence of heavy metals and fat-soluble pollutants like PCBs and dioxin which may accumulate up the food chain. Fish oil capsules may offer a safer alternative. There are companies, such as consumerlabs.com, an independent testing company, that have tested over 42 brands of fish oil supplements that have passed their criteria for safe levels of mercury and PCBs, with some also tested for dioxins.
For more information about omega-3 and how it can be incorporated into a healthy diet, speak with your Greenlite Medicine Physician or Health Educator.
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