Monday, August 19, 2013

Trans Fats

In the last several blogs I have mentioned the danger of processed “trans fats” in our diet.  Let's explore them a little more.

“Trans fatty acids”, otherwise labeled as “partially hydrogenated fatty acids” (or hydrogenated vegetable oils) are now widely used in many products to lengthen shelf life and improve the texture of foods.  Fatty acids are based on carbon chains that have hydrogens attached.  Saturated fatty acids have hydrogens attached at every available bond (they are saturated with hydrogens), whereas unsaturated fatty acids have one (monounsaturated fat) or more (polyunsaturated fat) places on the carbon chain that do not have a hydrogen attached (an "empty bond").  Normally, when oxygen attaches to the site on the carbon chain of the fatty acid where there is an empty (available) bond the product goes rancid faster.  Partially hydrogenated oils undergo a chemical process which adds hydrogens to unsaturated fat to make it more saturated, making less available bonds for oxygen to attach so the product stays fresher longer.  The purpose of “partially hydrogenating” a fat is to increase the product’s shelf life, not your life. 

In addition to making a perfectly healthy unsaturated fat more “saturated” (with hydrogens), hydrogenation causes the structure of the fatty acid to be altered.  During the process the structure of a natural unsaturated fat (where the "cis" configuration of the fatty acid hydrogens are attached on the same side of the carbon chain) may be changed to a "trans" configuration (where the hydrogen atoms occur on both sides).  Thus the name “trans” fatty acids.

Trans fatty acids are harmful!

Trans fatty acids have been implicated in a host of degenerative diseases including cardiovascular disease (which does not just happen because there is too much cholesterol—there is an initial insult to the inside of the arteries), cancer, arthritis, and even premature aging!  Trans fatty acids are at least as bad as, if not worse than, saturated fats as they have an equally negative effect on increasing the LDL (“bad”) cholesterol.  An increasing number of researchers and nutrition experts agree that trans fats are actually worse (and some say much worse) than saturated fats because they not only increase LDL cholesterol like saturated fats do but also significantly reduce HDL (“good”) cholesterol, delivering a “double whammy”.  Additionally, trans fatty acids increase Lp(a) lipoprotein levels (a particularly harmful type of LDL cholesterol associated with an increased risk of coronary heart disease) and triglycerides.  Many studies have confirmed the adverse effects of trans fatty acids, prompting the FDA to require labeling of trans fatty acid content of foods on product labels starting January 2006.

In June 2006 the American Heart Association issued updated dietary recommendations which set a goal for trans fatty acids of less than 1% of total calories.  The typical American diet contributes 10 grams of trans fatty acids for every 3,000 calories (equivalent to 3%).  The largest single source of trans fatty acids is margarine.  Watch out for peanut butter too!  Steer clear of the big brand name peanut butters which advertise “low cholesterol”, “low sugar” and/or “low fat” on the front of the label and check the label for “partially hydrogenated” oil.  Choose the brand that lists only “peanuts and salt” on the ingredients label.  While there are a lot of “natural” brands of peanut butter without partially hydrogenated fat, there is usually an inexpensive store brand with just “peanuts and salt” too.   

The 2005 Dietary Guidelines Advisory Committee reports that processed foods (cakes, cookies, crackers, pies, etc.) provide 40% of the total trans fats consumed, animal products provide 21%, and margarine 17%, while the 2010 Dietary Guidelines Committee reports that trans fatty acid levels in the U.S. food supply have decreased since 2006 when the declaration of the amount of trans fatty acids on the Nutrition Facts label became mandatory.  Trans fatty acids are also produced by grazing animals, and small quantities of “natural” or “ruminant”  trans fatty acids are found in meat and milk products.  There is limited evidence to conclude whether synthetic and natural trans fatty acids differ in their metabolic effects and health outcomes.

Also, while labeled products initially rushed to reformulate and banish trans fats from their products, the fast food chains and restaurants will probably be slower to change, making it likely that trans fats will lurk at a higher level where you eat out.  Skip the fried foods when eating out (a large order of french fries typically contains 6 grams of trans fat).

·  Avoid peanut butter which has been “partially hydrogenated”. 

·  Buy more unprocessed foods and read labels on processed foods. 

·  Avoid fried foods while eating out.

·  Avoid margarine.  Margarine is the largest single contributor of trans fatty acids to the American diet.  The harder the margarine, the more trans fats (stick margarine has more than tub, which has more than oil because when hydrogens are added to a fat it gets harder).  The new plant sterol margarines (Benecol and Take Control) purportedly contain no trans fatty acids, however, Tu T. Nguyen, M.D., the Mayo Clinic endocrinologist and lipid expert leading a team researching the plant sterol margarine admits that the mechanism by which plant sterols lower LDL cholesterol is not entirely known.  Furthermore, only preliminary results from beginning studies are available.  Use these products with some confidence, and caution, while awaiting further data.  Smart Balance margarine is formulated with the “right balance of natural fats [which] can improve cholesterol ratio”, and also boasts a favorable ratio of omega-6 to omega-3 fatty acids.  If you want to use Smart Balance as another alternative to margarine keep in mind that the ingredients include palm and canola oils.  I much prefer people use my Better Butter recipe:

                              Better Butter  (copyright 2011 N.E.W. LIFEÒ)

                                    1/2 cup (1 stick)      Softened Butter
                                    1/2 cup                     Olive Oil (or Safflower Oil, etc.)*
                 (optional) 1/2 cup                     Water (for low-cal better butter)*
                 (optional) < 1 Tbsp.                  Honey**

Blend all ingredients in a blender for several minutes, until smooth and creamy.

*If the recipe comes out too watery, use a scant less than 1/2 cup water and/or oil.

**Using too much honey yields a grainy mixture.

N.E.W. LIFE program participants really like Better Butter.  You can cook with it, just like butter.

Enjoy the good fats in your diet,
Diane Preves, M.S., R.D.

Thank you for sharing this post with others who might benefit from the information shared herein.  Please contact me if you are interested in hosting a 10-week  N.E.W. LIFE program on Long Island.

N.E.W. LIFE (Nutrition, Exercise, Wellness for LIFE)Ò copyright 2012

1 comment:

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