Pesticides and PCBs in Blood Stream Correlate with Incidence of DiabetesA study conducted among members of New York State's Mohawk tribe found that the odds of being diagnosed with diabetes in this population was almost 4 times higher in members who had high concentrations of PCBs in their blood serum. It was even higher for those with high concentrations of pesticides in their blood.
Diabetes in Relation to Serum Levels of Polychlorinated Biphenyls and Chlorinated Pesticides in Adult Native Americans Neculai Codru, Maria J. Schymura,Serban Negoita,Robert Rej,and David O. Carpenter.Environ Health Perspect. 2007 October; 115(10): 1442-1447.Published online 2007 July 17. doi: 10.1289/ehp.10315.
It is very important to note that there is no reason to believe this phenomenon is limited to people of Native American heritage. Upstate NY has a well-known and very serious PCB problem--remember Love Canal? And the entire population of the U.S. has been overexposed to powerful pesticides for a generation.
More evidence that obesity may be caused by exposure to toxic pollutants which damage genes comes in a study published January of 2009. This study tracked the exposure of a group of pregnant Belgian woman to several common pollutants: hexachlorobenzene, dichlorodiphenyldichloroethylene (DDE) , dioxin-like compounds, and polychlorinated biphenyls (PCBs). It found a correlation between exposure to PCBs and DDE and obesity by age 3, especially in children of mothers who smoked.
Intrauterine Exposure to Environmental Pollutants and Body Mass Index during the First 3 Years of LifeStijn L. Verhulst et al., Environmental Health Perspectives. Volume 117, Number 1, January 2009
These studies, which garnered no press attention at all, probably have more to tell us about the reason for the so-called "diabetes epidemic" than any other published over the last decade.
Use of Herbicide Atrazine Maps to Obesity, Causes Insulin ResistanceA study published in April of 2009 mentions that "There is an apparent overlap between areas in the USA where the herbicide, atrazine (ATZ), is heavily used and obesity-prevalence maps of people with a BMI over 30."
It found that when rats were given low doses of this pesticide in thier water, "Chronic administration of ATZ decreased basal metabolic rate, and increased body weight, intra-abdominal fat and insulin resistance without changing food intake or physical activity level." In short the animals got fat even without changing their food intake. When the animals were fed a high fat, high carb diet, the weight gain was even greater.
Insulin resistance was increased too, which if it happens in people, means that people who have genetically-caused borderline capacity to secrete insulin are more likely to become diabetic when they are exposed to this chemical via food or their drinking water.
Chronic Exposure to the Herbicide, Atrazine, Causes Mitochondrial Dysfunction and Insulin ResistancePLoS ONE Published 13 Apr 2009
Trace Amounts of Arsenic in Urine Correlate with Dramatic Rise in DiabetesA study published in JAMA in August of 2008 found of 788 adults who had participated in the 2003-2004 National Health and Nutrition Examination Survey (NHANES) found those who had the most arsenic in their urine, were nearly four times more likely to have diabetes than those who had the least amount.
The study is reported here:
Arsenic Exposure and Prevalence of Type 2 Diabetes in US Adults. Ana Navas-Acien et al. JAMA. 2008;300(7):814-822.
The New York Times report about this study (no longer online) added this illuminating bit of information to the story:
Arsenic can get into drinking water naturally when minerals dissolve. It is also an industrial pollutant from coal burning and copper smelting. Utilities use filtration systems to get it out of drinking water.
Seafood also contains nontoxic organic arsenic. The researchers adjusted their analysis for signs of seafood intake and found that people with Type 2 Diabetes had 26 percent higher inorganic arsenic levels than people without Type 2 Diabetes.
How arsenic could contribute to diabetes is unknown, but prior studies have found impaired insulin secretion in pancreas cells treated with an arsenic compound.
Prescription Drugs, Especially SSRI Antidepressants Cause Obesity and Possibly DiabetesAnother important environmental factor is this: Type 2 Diabetes can be caused by some commonly prescribed drugs. Beta blockers and atypical antipsychotics like Zyprexa have been shown to cause diabetes in people who would not otherwise get it. This is discussed here.
There is some research that suggests that SSRI antidepressants may also promote diabetes. It is well known that antidepressants cause weight gain.
Spin doctors in the employ of the drug companies who sell these high-profit antidepressants have long tried to attribute the relationship between depression and obesity to depression, rather than the drugs used to treat the condition.
However, a new study published in June 2009 used data from the Canadian National Population Health Survey (NPHS), a longitudinal study of a representative cohort of household residents in Canada and tracked the incidence of obesity over ten years.
The study found that, "MDE [Major Depressive Episode] does not appear to increase the risk of obesity. ...Pharmacologic treatment with antidepressants may be associated with an increased risk of obesity. [emphasis mine]. The study concludesed,
Unexpectedly, significant effects were seen for serotonin-reuptake-inhibiting antidepressants [Prozac,Celexa, Lovox, Paxil, Zoloft] and venlafaxine [Effexor], but neither for tricyclic antidepressants nor antipsychotic medications.
Scott B. Patten et al. Psychother Psychosom 2009;78:182-186 (DOI: 10.1159/000209349)
Here is an article posted by the Mayo Clinic that includes the statement "weight gain is a reported side effect of nearly all antidepressant medications currently available.
Antidepressants and weight gain - Mayoclinic.com
Here is a report about a paper presented at the 2006 ADA Conference that analyzed the Antidepressant-Diabetes connection in a major Diabetes prevention study:
Medscape: Antidepressant use associated with increased type 2 diabetes risk.