The state of reproduction in our country is increasingly becoming a concern as popular news, media, and health sites report on the falling birth rate with each passing year. The United States has been tracking birth rates since 1909 and continues to announce a new record low almost every year since 2007. In fact, the US birth rate has been below the calculated replacement rate of 2.1 children per couple, since 1971. While many factors influence these statistics, infertility is certainly a large one as its prevalence continues to rise each year.
The causes of infertility, contributing to our declining birth rates, can affect both males and females. Comprehensive meta-regression analysis reports average sperm counts have declined 50-60 percent between 1973 and 2011. Ovulatory disorders are the main cause of female infertility; although, tubal dysfunction, endometriosis, and endocrine-metabolic disorders also contribute.
Since the mid-1990s, genetically modified (GM) foods have quickly entered the commercial food supply, raising many questions about their potential impact on rising health trends, including infertility. The potentially detrimental health implications of GM foods have been hotly debated with “research” appearing to validate claims of both safety and harm. But as with all scientific inquiries, reported results must be weighed through the lens of bias, personal interests, and corporate motivations.
So what does the research say about the impact of GM foods on the current state of reproduction in our country?
In 2014, a group of researchers with no apparent conflict of interest, from the Reproductive Medicine Center of First Hospital of Lanzhou University, embarked on a journey to answer this question. According to their findings, GM foods may impact our reproductive potential at several levels, but primarily through “abnormal steroid hormones and their receptors, toxic products or products which increases the risk of endocrine-metabolic processes.” GM foods may transfer new genes to human species, capable of expressing novel proteins implicated in endocrine-metabolic disorders. For example, a previous study linked an increase in insulin-like growth factor-1 (IGF-1) to consumption of milk from genetically modified cows. IGF-1 is associated with the development of endometriosis and endocrine-metabolic disorders such as polycystic ovary syndrome (PCOS).
Not only is the direct consumption of GM foods potentially linked to endometriosis, but the environmental toxicants and xenobiotics associated with genetically modified food, such as pesticides residues and xenoproteins, have also been implicated in the pathophysiology of endometriosis.
Three main commercialized GM maize (NK 603, MON 810 and MON863) were fed to rats and confirmed to generate hepatorenal toxicity in a sex- and dose-dependent manner, which would compromise not only general detoxification capabilities, but also estrogen detoxification leading to estrogen dominance and endocrine dysfunction.
When Monsanto (developer and patent-holder of most genetically modified organisms) released its 90-day feeding study to obtain the commercial release of Roundup-tolerant NK603 genetically modified (GM) maize, some researchers remained skeptical about its results. The study was followed up by a 2-year study in which the same strain rats were used and fed a diet containing 11 percent NK603, cultivated with or without Roundup application and Roundup alone (from 0.1 ppb of the full pesticide containing glyphosate and adjuvants) in drinking water. This later study not only revealed very significant chronic kidney deficiencies and necrosis, but significant tumor growth in mammary tissues and the pituitary as a result of endocrine disruption. Pathways induced by the overexpression of a protein transferred from NK603 GM maize induce the production of estrogenic isoflavones and their glycosides, which may modulate estrogen receptors or the estrogenic pathway in mammalian cells.
When Harvard supported the claim that GM foods do not negatively impact reproductive potential throughout generations, they cited a study in which rats were fed a 5 percent GM potato or non-GM potato for 10 weeks prior to conception. However, confirmative studies indicate that the reproductive effects are clearly dose- and time-dependent, evidenced by the previous study that found significant reproductive disturbance after 24 months.
GM foods have also been implicated in the reproductive capacity of males. In a study investigating the morphological and immunological changes of Sertoli cells, spermatogonia and spermatocytes in rats fed a 14 percent GM soybean diet since birth (and whose mothers were fed the same diet), the GM group showed significant alterations. Sertoli cells contained enlarged vesicles of the smooth endoplasmic reticulum (SER) and nucleoli appeared larger and more reticulated. An increase in perichromatin granules and a decrease in the number of nuclear pores was observed in Sertoli cells and in spermatocytes.
Infertility can be an emotionally devastating situation for couples. Although assisted reproductive technologies have advanced and become widely available, many still choose not to pursue these routes due to financial restriction or ethical/religious reasons. Evaluating and correcting the root causes of reproductive difficulty should include an honest assessment of the presence of GM foods in the diet, educating couples on the importance of an organic, non-GMO diet, and offering natural solutions to detoxification.
By Nicole Spear, MS, CNS