April 2011 Issue

Fatty Acid Flip-Flop — Address Dietary Imbalance by Boosting Omega-3s, Decreasing Omega-6s
By Melinda Hemmelgarn, MS, RD, LD
Today’s Dietitian
Vol. 13 No. 4 P. 48

Just when you thought food labels might have too much information for most consumers to digest, I’m suggesting the addition of two more critical items to the Nutrition Facts panel. Specifically, we need to know the quantity of both omega-3 and omega-6 fatty acids.

Scientific evidence strongly supports increasing dietary omega-3 fatty acids and decreasing omega-6 fatty acids to reduce risk of chronic disease and support optimal development throughout the life cycle. Simply knowing the amounts of saturated, monounsaturated, and polyunsaturated fats in a serving of food is not enough to correct dietary imbalances of essential fatty acids prevalent in U.S. society.

Artemis Simopoulos, MD, president of the Center for Genetics, Nutrition, and Health and world-renowned fatty acid researcher, explains that since Paleolithic times, there has been little change in human genetic composition. But our nutritional environment has been transformed “enormously,” especially in the last 100 years, with the advent of the agricultural revolution and the industrialization of our food supply.1,2

According to Simopoulos, humans evolved on a diet with an omega-6 to omega-3 fatty acid ratio of approximately 1:1. Today, that ratio is about 16:1, with corresponding public health consequences. For example, an abundance of omega-6 fatty acids and deficiency of omega-3 fatty acids increases the risk of developing cardiovascular disease, cancer, osteoporosis, arthritis, mental health disturbances, obesity, diabetes, and inflammation.1-4

Blaming high-fat diets for chronic diseases doesn’t fully or correctly account for risk. We may be wiser to focus on fatty acid imbalance.

What Went Wrong?
Simopoulos attributes our fatty acid imbalance largely to modern agribusiness production methods and technology. For example, when humans were hunter-gatherers, diets consisted mostly of wild plants, fruits, leafy green vegetables, fish, and meat from grazing animals. The eventual switch in domestic animal feed from grass and hay to omega-6–rich grains changed the fatty acid composition of the animals’ meat and dairy products accordingly.2,5

In addition, the Industrial Revolution gave us the ability to produce large amounts of grains and “vegetable” oils from grains and seeds, which are typically high in omega-6 fatty acids and low in omega-3s. Simopoulos cites corn oil, for example, as having an omega-6 to omega-3 ratio of 66:1; for sunflower oil, the ratio is 77:1. She advises a dietary ratio not to exceed 4:1. Furthermore, to extend the shelf life of processed foods, manufacturers prefer using oils that are lower in omega-3 fatty acids.2

Then there’s misguided dietary advice based in part on the misinterpretation of research. For example, Evelyn Tribole, MS, RD, author of The Ultimate Omega-3 Diet, is concerned about the general perception and promotion of vegetable oils as being universally “heart healthy,” even though many are high in omega-6 fatty acids. Based on international recommendations, she advises limiting omega-6 fatty acids to no more than 6.7 g per day.

To put Tribole’s advice into perspective, 1 T of corn oil contains 7.3 g of omega-6 fat, 1 T of cottonseed oil contains 7 g, and 1 T of soybean oil contains 6.9 g. If consumers believe the fish sandwich at their favorite fast-food restaurant is the heart-healthy choice, they may be surprised to learn it contains more than 6 g of omega-6 fat.

Putting Balance Into Practice
While omega-6 fatty acids are essential in our diet, Tribole explains that just two slices of whole wheat bread with nothing on top will provide all we need. As for omega-3 fatty acids, she recommends consuming 650 mg per day, specifically from the long-chain omega-3 fatty acids DHA and EPA.

To increase omega-3 and at the same time decrease omega-6 fats, we can eat more fish, take DHA/EPA supplements, follow a Mediterranean diet, and choose a mix of olive and canola oils for everyday cooking.

It’s also important to request and choose grass-fed meat and dairy products. For example, Tribole does not condemn butter and cheese because according to her, the trouble is not dietary cholesterol; rather, it’s the inflammation arising from fatty acid imbalance. She cites the famous “French paradox,” which can be explained in part by the nutritional superiority of omega-3–rich high-fat foods. When meat, milk, butter, and cheese come from grazing animals, these formerly demonized foods actually contribute healthful omega-3 fats to the diet, she explains.

While personal diet change is advantageous, broader national food, farm, and health policies are necessary to make more meaningful improvements in public health.6 For example, when national farm policies support corn and soy production, we can expect an abundance of inexpensive corn and soy oils in the food supply. If we reward livestock farmers for grazing instead of grain feeding, we will likewise see improvements in fatty acid composition of meats and dairy.

When asked why food labels don’t contain critical information on essential fatty acids, Tribole explains, “No organization is lobbying or championing the cause.” We need scientific consensus plus clamor from health professionals and consumers.6

“Education of the public is essential to demand changes in the food supply,” says Simopoulos.6

Armed with science, dietitians can exert powerful influence in improving public health.

— Melinda Hemmelgarn, MS, RD, LD, is a freelance writer, speaker, and radio host based in Columbia, Mo. She is a former Food and Society Policy Fellow.

 

Fatty Acid Refresher
• Two families of polyunsaturated fatty acids, omega-6 and omega-3 are considered essential because the human body cannot make them; therefore, we must consume them in our diets.

• The terms “omega-3” and “omega-6” identify the location of a double bond that links two carbon atoms together in the chain. Omega-6 fatty acids are found in commonly consumed oils made from grains and seeds, such as corn, soy, sunflower, safflower, and cottonseed oils, as well as the highly processed foods made with them, such as fast foods, margarines, mayonnaise, and salad dressings.

• Omega-3 fatty acids include the following: Alpha-linolenic acid (ALA), with sources such as flaxseed, walnuts, and meat and milk products from animals raised on pasture; and eicosapentanoic acid (EPA) and docosahexanoic acid (DHA), with sources such as fatty fish, fish oil supplements, algae, and fortified products.

 

Learn More and Stay Informed
• Essential Fats in Foods: http://efaeducation.nih.gov/sig/esstable1.html

• Fats of Life, a science-based website about the health effects of polyunsaturated fatty acids: www.fatsoflife.com

• National Institutes of Health Essential Fatty Acid Education: http://efaeducation.nih.gov

• Omega-6 fat news and commentary: http://omega-6-omega-3-balance.omegaoptimize.com

• Sustainable, safe fish and seafood: www.montereybayaquarium.org/cr/cr_seafoodwatch/sfw_resources.aspx

 

References
1. Simopoulos AP. The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Exp Biol Med. 2008; 233:674-688.

2. Simopoulous AP. Omega-3: Food, health agriculture [transcript]. Food Sleuth Radio. September 9, 2010. Available at: http://kopn.org/aasp?u=http://kopn.org/a/showrss4.php?n=http://kopn.org/dc/dircaster2.php?p=fs

3. Tribole E, Hibbeln JR. Food for thought: Omega-3s and the brain [transcript]. American University Radio. July 28, 2010. Available at: http://thekojonnamdishow.org/audio-player?nid=17429

4. National Institutes of Health. Essential fats in foods. Available at: http://efaeducation.nih.gov/sig/esstable1.html

5. Union of Concerned Scientists. Greener pastures: How grass-fed beef and milk contribute to healthy eating. 2006. Available at: http://www.ucsusa.org/food_and_agriculture/solutions/smart_pasture_operations/greener-pastures.html

6. Simopoulos AP. n-3 fatty acids and human health: Defining strategies for public policy. Lipids. 2001;36 Suppl:S83-S89.