Are GMOs really all that harmful?

Activists often cite the alleged potential health risks of genetically modified foods. One recent example of this—"10 Scientific Studies Proving GMOs Can Be Harmful To Human Health", posted on Collective-Evolution.com—outlines many familiar concerns and points in each case to “credible scientific studies that clearly demonstrate why GMOs should not be consumed”.

Are these concerns credible? What do the studies cited actually claim?

1) Multiple Toxins From GMOs Detected In Maternal and Fetal Blood.

The blog post sites a 2010 study that alleges to show this danger. The authors identified the Bt protein Cry1Ab in maternal and fetal blood, a protein found in some GMOs, but also commonly used as a pesticide in organic farming. The paper is flawed. The researchers' measurements were based on an experiment/assay designed to detect Bt’s Cry1Ab in plants, not in humans. As this post in Biofortified.org explains, the pregnant women in the study would have had to eat several kilos of corn in order to get the Bt measurements that were detected in their blood.

Additionally, there’s the "so what" factor. Humans lack the receptors for the protein, so it has no impact on us. Did you know that chocolate is toxic to dogs? Are you concerned that it might be toxic to you? Probably not (if you are concerned, then you've missed out on the greatest source of joy known to human taste buds...). Some chemical compounds behave differently among species, and both Bt's Cry1Ab and chocolate are examples of this.

2) DNA From Genetically Modified Crops Can Be Transferred Into Humans Who Eat Them

That's not what the cited 2013 studyconcluded. The authors found that whole genes from our food can be detected in our plasma. That does not mean that they’ve integrated into our DNA; it means that they’ve been found floating in the space between cells. And that's any food, not just GMOs. DNA from GMOs behave no differently than DNA from organic or conventional foods

If you aren't concerned about the DNA from blueberries "transferring" into you, then you should not be concerned about DNA from GMOs either. The paper’s deepest flaw is that a negative control was not included in the sequencing experiments. Several recent papers (see here and here) have outlined the importance of including a negative control in experiments where there is very little DNA to account for possible contaminants from the environment and reagents. (For a lay introduction to the concept of contaminants in sequencing, see here).

Links-

http://m.huffpost.com/us/entry/us_55a40dd0e4b0ecec71bca6a5