Genetically Modified Organisms (GMO)

Characteristics

Fate and Transport in the Environment

Exposure Pathway

Routes of Exposure

Methods for Measuring Exposure

Strategies for Preventing Exposure

Methods for Monitoring in the Environment


Harmful Effects

Dose Response

Absorption, Distribution and Metabolism

Sites of Toxicity

Biomarkers of Disease

Risk Assessment

References

5103/5104 Home

Absorption, Distribution, Metabolism

The current scientific evidence regarding the absorption, distribution, and metabolism of a genetically modified organism is identical to that of its conventional counterpart (Hollingworth, 2002). When someone ingests a genetically modified food product, it goes through the same process of digestion in the body as would a non-modified food product. Therefore, the absorption, distribution, and metabolism of GMO’s can be described by following the pathway for normal human digestion. During and after ingestion, the food is broken down into polymers as it passes through the mouth, esophagus, and stomach. These larger organic molecules are digested into monomers, which are then transported across the wall of the small intestine into the blood and lymph. This transportation of the organic food molecules is the absorption process. Absorption occurs at a rapid rate because of the extensive surface area that exists within the folds of the small intestine.

In terms of distribution, different areas of the small intestine absorb and therefore distribute the different food monomers. For example, the absorption of carbohydrates and lipids occurs in the duodenum and jejunum, however the water and electrolytes are absorbed primarily in the ileum. Finally, metabolism of the broken-down GMO occurs, but varies from person to person. The body’s metabolic rate is influenced by exercise, body temperature, age, sex, and rate of thyroid secretion. In general, however, individual differences in metabolic rate are mainly due to differences in physical activity (Fox, 1996).

In terms of the absorption, distribution, and metabolism of the specific transgenic material that is not naturally occurring in the plant, it is not a new type of material to our digestive systems. Humans consume approximately 0.1 to 1 gram of DNA in their diet each day, so it is present in very small amounts. Research has shown that dietary DNA has no known toxicity itself. And with transgenic DNA, defense mechanisms have evolved so that the hydrolytic breakdown of DNA during digestion and the silencing of foreign gene expression prevent the incorporation or expression of foreign DNA (Hollingworth, 2002).