Eat Dirt

Science is discovering that genetic information/instructions can transfer from microbes to us.  For instance Japanese who eat seaweed can extract nutrients because the bacteria from the seaweed transfers the genetic instructions necessary to properly create the enzymes or whatever is needed to digest this food.

Adaptation to local food is transferred from the soil to us via bacterial genes. 
Our digestive system is in symbiosis with the soil.  As scientists have recently discovered, without the helpful bacteria in our gut, we can not extract the proper nutrients from our food.  Those gut microbes may even play a role as the first defense in our immune system.

This also applies to the soil itself

"Far from being scourges to be avoided at all cost, microorganisms are an essential component of life. We now understand that it is the cooperation between these microorganisms, the soil’s biome, and the plants’ roots, called rhizosphere that is ultimately responsible for allowing the plant to absorb nutrients from the soil in which it’s grown.

Insects and weeds also have their place in this circle of life. According to soil scientist Dr. Arden Andersen, insects are nature’s garbage collectors. Thanks to their specialized digestive systems, which differ from ours, they remove that which is not fit for us to eat—things we cannot digest.

And weeds are nature’s way of evolving the soil—it’s an intermediate plant that mobilizes nutrients in order to alter the soil, making it more suitable for the next evolutionary level of plants to grow in it."

http://articles.mercola.com/sites/articles/archive/2013/12/23/soil-quality.aspx?e_cid=20131223Z1_DNL_art_1&utm_source=dnl&utm_medium=email&utm_content=art1&utm_campaign=20131223Z1&et_cid=DM37598&et_rid=376463815

In Hebrew. this concept of linking Man to Soil is present in the words themselves:
ADaM  - A human being
ADaMaH - The Soil

Adam in the biblical narrative is created from the soil.  In a sense this creation is ongoing as genetic patterns, material and instructions are transferred from the earth's micro-biome to us.

Perhaps that is why, in the Biblical Narrative, certain species were not permitted to be joined into Hybrids.  The resultant bacteria might transfer harmful genetic instructions.

Gene Splicing, in foods, is far more likely to lead to unknown interactions between bacteria and us.  The current Roundup resistant plants are just such a case.  What genetic strangeness is the genetically modified corn, soy etc. conveying to humans?  Not to mention the Roundup itself which destroys bacteria in the soil and in our gut.  Besides a depletion of nutrients due to the killing of soil bacteria , what will the Roundup immune bacteria, which will evolve, do to us?  What are they already doing?