Tuesday, December 3, 2013

GMO Update: Seralini Paper Retracted!

          The infamous Seralini paper, which as explained in my GMO post stated that roundup-resistant maize causes organ damage and even cancer in rats, is now being retracted by the editor of the journal in which it was published.

The authors claim no fraud, but as explained here, they admit that the publication was rushed through peer review and "should never have been published in the first place."

While this will surely be a blow to the anti-GMO advocates, Seralini and other authors are protesting the retraction, commenting that "a short Monsanto study was published in the same journal to prove the safety of their product contains errors or frauds, and is not the subject of a controversy".

Overall, while this clearly damages the evidence supporting a safety concern from ingesting genetically modified crops, it is likely to only continue fueling the debate, with legitimate concerns about conflict of interest on both sides among the editors of the journal.

Sunday, September 29, 2013

Vitameatavegamin: Potential Risks of Using Vitamin Supplements

          Vitamins are nutrients required for proper metabolic function that cannot be sufficiently synthesized by the body and therefore must be obtained from external sources such as diet or resident symbiotic microbes.  Vitamins may have both widespread and organ-specific functions, during development and throughout adult life.  The letter descriptor for vitamins (Vitamin A, etc) typically refers to a group of inactive provitamin forms or “vitamers” that are metabolized into active form within the body.  There are 13 accepted vitamins in human metabolism, each with distinct sources and functions. Vitamins are either water soluble or fat soluble.  Water soluble vitamins are easily excreted and therefore must be replenished more often. Fat-soluble vitamins are stored in tissues and do not require daily intake, while sustained increased intake can lead to hypervitaminosis as concentrations increase to toxic levels.
Bioavailability of Vitamins
It is unclear exactly what percentage of vitamins ingested in supplement form are available for absorption and metabolic action.  One obvious factor is the fat solubility of many vitamins, which are often ingested as a pill with water, but in reality determining the “bioavailability” of vitamins ingested from supplements is very complex.  The two major factors affecting bioavailability of dietary supplements are: the ease of molecule release into solution and the presence of interfering inactive ingredients.  Additionally, a multitude of physiological factors (affected by age, sex and other variables) also have a large effect on the relative bioavailability of ingested vitamins.  For example, inherent homeostatic (equilibrium) regulation of existing nutrients may prevent utilization of further ingested nutrients while shorter digestive time correlates with improved nutrient absorption. The bioavailability of certain nutrients may also be affected by the size of the overall “load” of food or supplements ingested, and nutrients are much better absorbed when intake levels are spread out over a long period of time.
Variation also often exists in the actual amount of vitamin present within commercially sold supplements.  Manufacturers are required by US regulations to include greater amounts of listed vitamins within supplements than is listed on the label, in order to account for degradation and potential disparities among batches.  While most vitamins are sold at 30-100% in excess of the listed amount, examples have been reported showing actual values as low as 20% below listed amount and as high as 2.5 times the listed amount.
Vitamin Deficiency
The risk of vitamin deficiency varies for each vitamin depending on the individual metabolic requirements and how they are stored in the body.  Vitamins A, D and B12 are stored in large amounts by the liver, preventing deficiency conditions for several months up to a few years.  At the other extreme, niacin is very poorly stored and reserves may only last a few weeks.  Common vitamin deficiency diseases in humans include beriberi for thiamine, scurvy for Vitamin C, pellagra for niacin and rickets for Vitamin D, however deficiency diseases are rare in developed nations both due to the abundance of sufficient amounts of food and additional nutrient fortification of the food supply. 

Wednesday, June 5, 2013

The [Real] Facts About Genetically Modified Organisms

    The European Food Safety Authority (EFSA) defines a "Genetically Modified Organism", or GMO, as "an organism in which the genetic material has been altered in a way that does not occur naturally through fertilisation and/or natural recombination. GMOs may be plants, animals or micro-organisms, such as bacteria, parasites and fungi." 'Genetically engineered' (GE) is an alternative term used to refer to the manipulation of these species to produce or promote particular traits.  It is difficult to determine the origin of the term "Genetically Modified Organism", or GMO, but it is known that people have been attempting to exploit and select for desirable traits in agriculture for hundreds and perhaps thousands of years.

History of GMOs
While the ability to manipulate DNA is a relatively recent technology, farmers since prehistoric times have used selective breeding and hybridization to increase the frequency of desirable traits within the crop population.  The study of genetic inheritance by Mendel further increased recognition of the benefits of selective breeding around the onset of the 20th century.  Many of the "normal" crops which exist today are a result of extreme selective breeding and would never have existed on their own; early farmers isolated the genetic outliers of a crop population that exhibited the most advantageous traits in order to improve future yields, selecting on the basis of size, fruit production and other desirable characteristics.  

     The first published reports of genetic engineering date back to 1972 when Paul Berg successfully spliced foreign genes into a circular viral DNA molecule, followed by the first bacterial transformation utilizing genetically engineered DNA in 1973.  This 1980s saw the first industrial and medical applications of this technology, with the creation of oil-eating bacteria by Exxon and the production of human insulin in bacteria by Genentech. Genetic engineering is now an integral tool for laboratory research, industrial technologies and many medical applications.  While little controversy exists concerning most applications of genetic engineering, the use of genetically modified crops in the agricultural industry has received much public backlash over the past few years.

     Agricultural biotechnology has been experimenting with genetic manipulation of plant varieties since the late 1920s, originally through the use of ionizing radiation, which induces mutations randomly within the genome.  Today’s practice of selectively genetically engineering plants is much more precise and efficient than randomly mutated plants, because scientists are able to select the specific traits they wish to be included in the target organism. The first GMO tested in the environment was the "ice-minus" P. syringae bacterium in 1987, which prevented frost formation when sprayed on the surface of plants.  The first commercially available GM crop was the FlavrSavr tomato, released in 1994, which exhibited an extended shelf life.  Other common agricultural GMOs that followed include insect-resistant Bt (B. thuringiensis) plants and the commonly used glycophosphate herbicide-resistant (Roundup Ready) crops.

Agricultural Benefits
     The advent of GM crops has had significant economic benefits on the agricultural industry worldwide, especially in developing nations, although accounting for all variables when determining the true economic effects of GMOs is difficult.  The increased abundance of insect and herbicide-resistant GM crops has also been shown to reduce pesticide use and associated greenhouse gas emissions, although recent outbreaks of herbicide-resistant weeds may have counteracted this effect and the true environmental impact of GMOs is yet to be fully determined. By eliminating crop loss and allowing more efficient cultivation, a major outcome of increased GMO use has significantly improved crop yield compared with non-engineered crop fields.  In addition to increasing yield, GM crops can greatly benefit developing nations through enrichment of nutrients typically lacking within the regional population.  

Reasons for GMO Mistrust
     There seem to be many complex reasons why a multitude of nations, organizations and individual citizens have recently made public stands against GMOs. Overall, the aversion of GMOs appears to derive from (i) the lay public's 
unfamiliarity with and often bias against science, (ii) legitimate concerns about potential long-term environmental effects, (iii) a preponderance of bad pseudoscientific anti-GMO studies, and (iv) general distrust against the economic motivations of Monsanto and other corporations involved with GMO production.  Together, all of these factors build on each other, feeding on fear-mongering in the media and creating a mob mentality of revulsion towards GMOs.