Building Health By Dale Peterson, MD

Genetically modified organisms (GMOs) are plants or animals that have been created using the gene splicing techniques of biotechnology, which is also called genetic engineering or bioengineering.


The techniques merge DNA from different species and create combinations of plant, animal, bacterial, or viral genes that cannot occur in nature.


The first GMOs were introduced in the early 1990s.  Their use has rapidly expanded and today 88 % of corn and over 90 % of all sugar beets, cotton, soybeans, and canola plants grown in the United States come from genetically modified seeds.

It is estimated that over 70 % of all processed food in the United States today contains GMO ingredients such as high fructose corn syrup, corn oil, cottonseed oil, and canola oil.  Some examples of foods likely to contain GMOs are sodas and fruit drinks, soups, condiments, salad dressings, breads, crackers, and corn chips.

Genetically modified foods were introduced without being tested for safety.  This is because the U.S. Food and Drug Administration granted “generally regarded as safe” (GRAS) status to GMOs in 1992.  The first long-term study of animals fed genetically modified corn was finally published in the November 2012 issue of the journal Food and Chemical Toxicology.  The results were shocking and alarming.

The study compared groups of rats fed varying amounts of GMO corn or given herbicide-contaminated drinking water to a control group fed corn that was not genetically modified.  The mortality rate in GMO-fed males was up to five times greater and in GMO-fed females up to six times greater than that of animals fed non-GMO corn.   The first GMO-fed deaths occurred a year earlier than the first deaths in the non-GMO group.  50 to 80 % of females in the treatment groups developed tumors compared to 30 % in the control group.  Males in the treatment groups had four times the number of tumors of males in the control group.

The leading causes of death in treated males were liver and kidney failure.  Severe kidney disease was over twice as common in treated males.  Liver congestion and cell death occurred over five times as often.

The mechanisms that caused tumors, kidney, and liver disease in the rats fed GMO corn or given contaminated drinking water are not completely understood, but it is known that the activity of aromatase, an enzyme that governs the production of estrogen and other hormones, was altered.  It is believed that other changes triggered by the modified gene led to liver and kidney disease.   Since aromatase is an important enzyme in the human body it is likely that similar effects are occurring in people eating GMO foods.

Consumers in the U.S. are at a disadvantage because regulatory agencies have steadfastly refused to require food producers to reveal that a food has GMO ingredients.  There are a number of precautions that can be taken to limit the amount of GMO foods in a family’s diet, however.

Growing your own food when possible enables you to control the type of seed used.  Locally grown produce is less likely to be genetically modified than that of large commercial farms.  Stick to whole foods as much as possible, as most whole foods are not genetically modified.  Two exceptions are sweet corn, some of which is genetically altered, and Hawaiian papaya, 80 % of which is genetically modified.   When buying processed or packaged foods look for those labeled “100 % organic", as foods with an “organic” label are allowed to contain up to 30 % GMO ingredients.  Similarly, eat only “100 % grass-fed” beef.  Nearly all cattle are fed grass at some point and can legally be sold as “grass-fed” beef, even if their diet included GMO corn.

Avoid foods that contain corn, cottonseed, or canola oils.  Choose oils that do not come from GMO plants such as olive, coconut, or grape seed.  Be particularly cautious of the “Big Four” of corn (corn flour, meal, oil, starch, gluten, and syrup), soybeans (soy flour, lecithin, protein isolate, and textured vegetable protein), cotton (cottonseed oil), and canola (canola oil).

Look for a “GMO Free” or “Non-GMO” label.  These are becoming more common as producers of non-GMO foods seek to inform consumers of their purity.  Price look up (PLU) codes can also be helpful.  Fresh produce often has a PLU sticker.  A five digit number beginning with “8” indicates that the produce came from a GMO source.  A five digit number beginning in “9” is of organic origin, and a four digit number doesn’t indicate how it was grown.  Unfortunately, since the system is voluntary it cannot be relied upon to be completely accurate.

Although genetically modified food crops have been grown for nearly two decades, we are only beginning to recognize the threats they pose to human health.  Because eating GM corn was found to have deadly consequences in the first long-term animal study, I am seeking ways to keep GMO crops out of my family’s diet and I urge you to do the same.

Dale Petersen MD

By Dale Peterson, MD- Building Health

Dr. Dale Peterson is a graduate of the University of Minnesota College of Medicine. He completed his residency in FamilyMedicine at the University of Oklahoma. He is a past president of the Oklahoma Academy of  Family Physicians. He had a full-time family practice in Edmond, Oklahoma, for over 20 years and was a Chief of Staff of the Edmond Hospital. He was active in teachingfor many years as a Clinical Professor of Family Medicine through the Oklahoma University Health Sciences Center.

Dr. Peterson left his full-time family practice in 1999 to consult with individuals who are seeking ways to restore and maintain their health through improved nutrition and other lifestyle changes. He founded the Wellness Clubs of America to give people access to credible information on supporting and maintaining their health.  His monthly wellness letter, Health by Design, and his Health by Design E-Newsletter provide helpful information to individuals interested in preventing and conquering health challenges.  He is the author of Building Health by Design:  Adding Life to Your Years and Years to Your Life .

Dr. Peterson speaks regularly on subjects related to health and nutrition. He hosted a weekly radio program,Your Health Matters, on KTOK in Oklahoma City for five years. For the past nine years he has addressed questions from across the nation on his Your Health Matters weekly teleconference.He offers a free video LifeXtension course at

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