Phthalates: Their Influence on Obesity, Insulin Resistance, Diabetes and Their Connection to Testicular Function

Phthalates were first introduced into the world after World War II as a means of making plastics softer and more malleable. Now they are also found in wood stain, vinyl wall coverings and flooring, popular synthetic perfumes that are designer and look-a-like brands, adhesives, cellophane tapes, nail polish, cosmetics, soaps, recycled paper, the list goes on and on. Phthalates are one of the major contributors to the measure identified by the contemporary scientific term "chemical body burden," sometimes stated as "toxic chemical body burden."

Some sources say that this volatile organic compound (VOC) class chemical is now ubiquitous and every human and living creature carries a body burden of phthalates, including infants who acquire phthalates through foods. This is why some European countries have banned phthalates and many American manufacturers are voluntarily eliminating its use, for example from baby's teething toys and from the latest generation of plastic shopping bags. Others give a more conservative estimate at 75% of people carry a body burden of phthalates.

A new research study states that a connection has been found between the physiological presence of phthalates and the occurrence of male obesity, insulin resistance and diabetes. Previous studies have suggested a connection between phthalates and adverse affects on testicular function in human men following a confirmed connection of synthetic chemicals, including phthalates, on reduced testicular function in animals. This connection is highly significant because one of the plausible causes for the growing incidence of obesity, insulin resistance and diabetes in men is lower testicular function.

The research group, which represented a collaboration between two academic departments at the University of Rochester in New York and the Department of Research and Evaluation at Axios International in Paris, France, devised a study to look for a "connection between phthalate exposure" and obesity, insulin resistance and diabetes in adult men--again, one plausible cause of which is suspected to be phthalate related reduction of testicular function. They proceeded by measuring the level of eliminated phthalate and comparing that to waist circumference and "measures of insulin resistance."

The great concern is that in the last years studies, which have given rise to great controversy, have shown connections and correlations between phthalates and antiandrogenic characteristics in males, both infants and adult males. One study that raised particular controversy showed that infants boys born to women with high elimination measures of phthalate had measurements of genitalia that were adversely abnormal--to some, alarmingly so. The current collaborative study was interested in the role of phthalates in producing "antiandrogenic effects in humans, including decreased testosterone levels." A serious concern for any man or boy.

The term "androgen" means any compound that triggers and maintains the development of primary and secondary male characteristics. When produced in the body naturally, they are necessary hormones. Testosterone is the primary one and it is also the precursor--building block--of the female hormone estrogen. An antiandrogenic effect would be one that reduces, inhibits, blocks, or fails to maintain male characteristics.

For further reading, this story is reported in Environmental Health Perspectives on-line(ehponline.org) by Melissa Lee Phillips and is available at this link: http://www.ehponline.org/docs/2007/115-6/ss.html#phth. The collaborative study is also reported on ehponline.org and can be found in its entirety at this link: http://www.ehponline.org/docs/2007/9882/abstract.html. All articles can be read without cost at ehp.org in either full text HTML or PDF files. One optimistic note in the report is that phthalate, unlike some other VOCs, is flushed from the body quickly, although it is not devoid of effects while on its body burden sojourn.