I was recently asked whether organic beef would be a good choice to avoid exposure to toxic chemicals.  It was an excellent question because our consumption of products from animals high on the food chain is one of the key ways we are exposed to fat-soluble contaminants such as dioxins, organochlorine (OC) pesticides, and polychlorinated biphenyls (PCBs).  And because it takes decades to clear these chemicals from our bodies, the best approach is to avoid them in the first place.  So wouldn’t consuming organic rather than conventionally raised beef reduce your exposure to toxic chemicals? The answer to this question is – not entirely.

There are several good reasons for switching to grass-fed organic beef products from those of conventionally raised animals.  For example, beef from grass-fed cattle contains a healthier ratio of omega 3 to omega 6 fats.  And, conventionally raised cattle may be exposed to pesticides in their feed.

However, switching to organic beef will not reduce your exposure to the contaminants listed above because these chemicals are present in air pollution worldwide and are deposited on both grasses and grains that provide food for cattle.  As cattle consume large quantities of these crops over their life span, they accumulate fat-soluble toxic chemicals into their fatty tissues, a process called bioaccumulation.

Not all cattle are equally contaminated.  Although air pollution is transported to all corners of the earth, some areas are more contaminated than others and cattle’s toxic body burdens tend to reflect contamination in their local environment.  For example, butter collected from 23 countries across 5 continents was most contaminated in areas where these chemicals were in current use, such as India and Mexico, and less so in the U.S. and parts of Europe, where their use has been discontinued but where the environment was still contaminated from past use (ref 1).

Just as it is the fat in beef and butter that introduces these fat-soluble chemicals into your diet, don’t forget about other products that get their fat from cattle, such as cheese, milk, and yogurt.  If you love beef or dairy products, one way to reduce your exposure to these contaminants is to choose products with the lowest fat content for regular consumption and save the higher fat delicacies (e.g. butter and brie) for the occasional treat.  Also, discarding the fats released when you cook meat reduces the amount of these contaminants that you consume (ref 2).

So, how do you shop for a cleaner source of meat and dairy products?  The research on butter contamination discussed above demonstrated that the most highly contaminated butter was collected in areas located near urban and industrial sources.  In the U.S., which has a legacy of environmental contamination, east coast butter samples were found to be more contaminated than those purchased along the west coast, which receives air that has traveled thousands of miles across the Pacific Ocean and had time to be cleared of many contaminants.

Bottom line: choosing lower fat organic beef and dairy products from cattle reared in cleaner environments, such as rural areas along the west coast of the U.S., is the best option for reducing your exposure to fat-soluble toxic chemicals.


1Kalantzi, O. I., R. E. Alcock, P. A. Johnston, D. Santillo, R. L. Stringer, G. O. Thomas, and K. C. Jones (2001). The global distribution of PCBs and organochlorine pesticides in butter.  Environ. Sci. Technol. 35:1013-1018.

2Petroske, E., R. G. Zaylskie, and V. J. Feil (1998).  Reduction in polychlorinated dibenzodioxin and dibenzofuran residues in hamburger meat during cooking. J. Agric. Food Chem. 46:3280-3284.