Line 4Line 4 Copyic/close/grey600play_circle_outline - material
Answers

Question

Have there been any studies of mineral and vitamin levels in livestock that have been fed roundup ready forages and grain to determine whether roundup acts as a chelating agent?

Submitted by: Jerry G


Answer

Expert response from Community Manager

Friday, 15/05/2015 17:03

As I looked at your question, there are two sub-questions that can be answered to understand your bigger question.  First, does glyphosate chelate minerals in such a way as to alter mineral content of feeds?  Second, does glyphosate affect the bioavailability of minerals?  I’ll answer both and also base my answer on only minerals.  You suggested vitamins, but there is no reason to even suspect glyphosate binds any vitamin and there is no homogeneity in the structure of vitamins that would result in binding of this class of nutrients. 

 

Mineral Content. The chemistry of glyphosate is such that it will bind certain minerals.  Binding does not mean irreversible (see previous answer from this site).  Binding is just part of the full story and chelators actually can facilitate movement of minerals into plants.  Other chelators are present in plants and soil and strong chelators, such as EDTA, when added to soil can promote uptake of minerals; however, relatively weak chelators, like glyphosate, do not affect uptake. Composition studies indicate that nutritional content, including minerals, is not affected by spraying glyphosate on corn.   

 

Bioavailability.  Another issue is bioavailability.  In other words, are the minerals in the diet available to be digested, absorbed and available for metabolism.  The experiment you suggest has not been conducted because the issue of bioavailability is answered by growth studies.  Animals that lack necessary nutrition, including minerals and vitamins, will not grow as expected.  In toxicology studies, feeding large amounts of glyphosate has not restricted growth.

 

Another way to approach this question is to do some simple calculations.  We know from chemistry that a single molecule of glyphosate will bind to one divalent cation (such as Fe++).  Chickens are fed diets that typically contain just a few feedstuffs (corn grain, soybean meal and minerals), but their diets are developed to maximize gain with minimal cost.  This type of diet can have 100% of the non-mineral feedstuffs coming from GM (i.e. Roundup Ready®).  If making the highly-conservative assumptions that all feeds contained the maximum residues of glyphosate (see link to explain MRL) and if all of these molecules irreversibly bound a divalent cation, there would be 0.02% of the recommended dietary amounts of dietary divalent cations bound to glyphosate.  If looking only at manganese, about which some claims have focused, it would represent 5 percent of the recommended intake.  Even with these conservative assumptions you can see that this is a small portion of the total dietary intake for divalent cations.

 

We can conclude by study data and understanding the biology that glyphosate would not impact minerals, vitamins, or other nutrients in animal products when glyphosate is used according to the label.