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Sitting alongside these is an increasing body of evidence indicating more subtle harm from glyphosate and long-term problems and unexpected environmental interactions with 'Roundup'* [1,2].
*Roundup formula contains glyphosate as the active herbicidal ingredient plus a variety of other ingredients which help glyphosate kill plants more efficiently.
Such evidence of harm is unsystematic and fragmented. It comes largely from underfunded, independent researchers, and appears to yield inconsistent results. This isn't really surprising given the vast scope for varying the materials and conditions in any experiments on glyphosate or Roundup effects.
- glyphosate exists in several chemical formats
- Roundup can consist of a plethora of different (sometime secret) ingredients
- the test material can be anything from individual cells from any tissue of any animal to whole animals of any species (except human, because experiments on us aren't allowed)
The scope of tests possible is limited only by the scientific imagination. There's endless room for inconsistency, and inconsistency leaves endless room for 'doubt'.
There's therefore endless room for the biotech industry and regulators to generate 'doubt' so as to refute perfectly good science whose findings don't suit them. The evidence of harm can easily be binned, leaving nothing but that swathe of data showing no adverse effects.
Two recently published papers with apparently contradictory findings illustrate the situation very well.
Both studies probed what was going on inside the cell when exposed to glyphosate or Roundup. In particular, they looked at calcium and membranes.
“Calcium plays a pivotal part of the regulation of many key cellular activities including cell development, proliferation, secretion, gene activation, and natural cell death. While glyphosate as a pure chemical is known to bind to metal ions, any effects inside the cell, where calcium is bound to proteins and may be associated with membranes, are too complex to predict.” 
Cells have an outer membrane enclosing them, while inside, they are compartmented by numerous membranes, and contain huge numbers of bodies which consist of folded membranes besides outer membranes. These ubiquitous membranes are transport routes within the cell, and provide essential anchorage sites for the active proteins which carry out the life-processes. Add into this picture, Roundup formulae which includes ingredients which penetrate the fatty- material of cell membranes.
In mouse skin cells, glyphosate was found to induce calcium depletion, suppressing the actions of vital calcium-dependent enzymes, and inducing stress responses which can lead to cancer (Mesnage).
On the other hand, in rat testicular cells, Roundup was found to induce calcium-overload, inducing stress responses and death (Cavalli).
The evidence is building that glyphosate and Roundup interfere with calcium-dependent processes in the cell: the herbicides deplete cellular anti-oxidant defenses, and stimulate oxidant accumulation with a host of harmful outcomes.
And that's not all. Glyphosate and Roundup have also been identified as endocrine disruptors. This means that toxic effects may vary at different concentrations of exposure, or for different exposure times, or at different life-stages, or with gender, or with different cell-types ...
The bottom line is that it's ever so much easier to prove that glyphosate or Roundup is safe than it is to prove harm.
This is because changing one single factor in an experiment on these herbicides is likely to reveal a different harm from all other experiments. Rather than looking for a consistent outcome indicative of one consistent toxic effect, Scientists will have to focus on the underlying multi-factorial mechanism of glyphosate/Roundup interference at sub-cellular level.
On a purely practical level, the inadequate safety testing of glyphosate and especially Roundup has left us with population monitoring as a sole means to reveal harm. This won't work: there are likely to be just too many different problems arising.
Labelling GM foods won't help much in linking symptoms to diet either, but it might help identify a comparator sector of a population who haven't had much exposure to GM food.
It is urgent that the sub-cellular effects of very low, chronic intake of glyphosate and Roundup are scientifically tested.
 IS GLYPHOSATE WRECKING AQUATIC LIFE? - September 2013
 ROUNDUP IS NOT SAFE TO EAT - March 2013
 HOW GLYPHOSATE COULD BE LINKED TO CANCER - January 2014
- R. Mesnage, et al., 2012, Ethoxylated adjuvants of glyphosate-based herbicides are active principles of human cell toxicity, Toxicology
- V. LdeL. O. Cavalli, et al., 2013, Roundup disrupts male reproductive functions by triggering calcium-mediated cell death in rat testis and Sertoli cells, Free Radical Biology and Medicine 65