Dietary Fats...The Good, Bad and the Ugly
We have all been hearing a lot lately about our Omega-3 fatty acid to Omega-6 ratios and how the typical western diet has "flipped" the ratio backwards. Basically, we eat too many omega-6, not enough omega-3 and too much saturated and trans fat.
Copyright (c) 2008 Ainsley Laing
We have all been hearing a lot lately about our Omega-3 fatty acid to Omega-6 ratios and how the typical western diet has "flipped" the ratio backwards. Basically, we eat too many omega-6, not enough omega-3 and too much saturated and trans fat. Omega-3 fatty acids are sorely lacking in the typical western diet having been replaced by oils with a high proportion of omega-6 oils such as corn oil.
So what does all this mean?
The fats in foods are a combination of saturated, monounsaturated and polyunsaturated. Omega-3 and 6 fats are polyunsaturated. All oils and fats contain combination of the above. But, some fats have a higher proportion of saturates (butter) or monounsaturates (olive oil) or polyunsaturates (nut oils, corn oil, etc.).
Trans fats are produced when an oil is "hydrogenated". More simply, the oils are processed to make them more stable and less likely to go rancid quickly. Trans fats are used in most processed foods and are not good for the body. Vegetable shortening is hydrogenated oil - lots of trans fats!
With the exception of trans fats, the body requires all of the above fatty acids in different combinations. Yes - even saturated fats. These fatty acids are used to help the body absorb vitamins such as Vitamin A as well as a host of processes like cellular metabolism and the manufacture of hormone like substances. Alpha-linolenic acid is one of two fatty acids traditionally classified as "essential." The other fatty acid traditionally known as "essential" is an omega 6 fat called linoleic acid. "Essential" means that the body is unable to manufacture them on its own and must come from the diet.
The body converts alpha-linolenic acid into two important omega 3 fats, eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA). EPA plays a role in the prevention of cardiovascular disease, while DHA is the necessary for proper brain and nerve development.
Omega 3 fats also play a role in the production of hormone-like substances called prostaglandins. Prostaglandins help regulate many functions like blood pressure, blood clotting, nerve transmission, inflammation, allergic responses, kidney function, gastrointestinal function and the production of other hormones.
Depending on the type of fat in the diet, certain types of prostaglandins may be produced in large quantities, while others may not be produced at all. This can lead to an imbalance in the body and ....disease.
From omega-3 fats are manufactured series 3 prostaglandins, which act to reduce platelet aggregation, reduce inflammation and improve blood flow. From omega 6 fats are manufactured series 1 and series 2 prostaglandins. Like series 3 prostaglandins, series 1 prostaglandins are beneficial. On the other hand, series 2 prostaglandins promote inflammation and increase platelet aggregation.
This is why it is important to balance the amounts of omega 3 and omega 6 fats in the diet- aiming for a higher proportion of omega-3 fats.
Polyunsaturated oils are extremely susceptible to damage from heat, light, and oxygen. When exposed to these elements for too long, the fatty acids in the oil become oxidized. The oil becomes rancid which means it tastes and smells different. Oxidation also means free radicals. Free radicals are not a good thing - contributing to the development of degenerative diseases and cancer. Hence, polyunsaturated oils should be stored in dark glass, tightly closed containers in a cool place. Also, cooking with oils high in polyunsaturates produces free radicals. A better choice for cooking are oils rich in monounsaturates (such as olive oil) which do not change in composition as much when heated. Saturated fats (like butter) also do not oxidize much when cooking, but only should be used in limited amounts.
If you want to increase your omega-3 intake, the foods providing the best omega-3 profiles are flaxseeds, walnuts and salmon. There are many other foods rich in omega-3 fats as well as the oils derived from these foods. A simple web search for "foods rich in omega-3 fats" will give you all kinds of information on this topic.
To your health!
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ABOUT THE AUTHOR
About the Author: Ainsley Laing, MSc. has been a Fitness Trainer for 27 years and writes exclusively Body for Mind eZine. She holds certifications in Group Exercise, Sports Nutrition and Personal Fitness Training. She is also a professional engineer and mom. To see more articles by Ainsley visit http://www.bodyformind.com or the blog at http://www.bodyformind.blogspot.com