Hormones in Soybeans and Beef

About 90% feedlot cattle in the US are administered some type of growth hormone to promote growth.  Use of the hormones convey economic benefits to consumers (lower prices) and a host of environmental benefits (more meat using less land, less water, less C02).  The biggest drawback, from my perspective, is the evidence that use of such hormones reduces the eating quality of steaks, particularly by reducing tenderness.  

While reduced tenderness might be a reason to eschew hormones, food safety isn't.  Some people are worried about the health effects of these hormones, but such concerns do not mesh well with the scientific literature, and the concerns tend to ignore relative risk.  Specifically, there are much higher levels of naturally occurring hormone-like substances in many foods we eat.

As a result, there have been many attempts to communicate this information to the public.  Examples of such discussions appear at BeefMyths.orgUS Meat Export Federation, the NCBA, and extension facts sheets from Michigan State UniversityUniversity of Nebraska,University of Georgia, and many others.  

A common approach is to compare the extra amount of estrogen in a serving of beef from an animal that has received a hormone implant to one that hasn't, and then compare that to estrogen-like substances in other foods like soybean oil (it is a comparison I've made myself in a study on the effectiveness of such communication), cabbage, peas, and potatoes.

After making this comparison in a talk a couple weeks ago, an audience member gently questioned my numbers on soybean oil.  While it is true that soybeans have high levels of isoflavones, which acts like estrogen in humans, it turns out that these compounds are not in soybean oil.  

Here is a publication from the USDA Ag Research Service showing the isoflavone content of a long list of foods.  As you can see, soybeans have quite a bit, but if you'll look down on page 38, you'll find soybean oil listed in a table titled "List of Foods Containing Zero Values for Isoflavones."  This website neatly summarizes the USDA data.

So, where does that leave us.  First, those that have used this comparison should try to correct the record (as I'm doing here).  If we are arguing that the public should make decisions on "the facts," we darn well better get our facts straight.  Second, the relative hormone comparison remains useful (though only marginally persuasive with most consumers), but one needs to drop soybean oil and use other soy products instead.  An Iowa State University Fact's Sheet by Dan Loy helps make the proper comparisons.

Here is a key screenshot