Diabetes Seeping Into Our Systems

[Guest guest]

Diabetes Seeping Into Our Systems

If you like detective stories, you're going to love this. Bear with me, and

I'll tell you a story that will set the stage for what's to come.

As you know, I'm very passionate about the environment, so a few years ago

when a story came out about how the population of gray tree frogs was being

decimated by the use of a common pesticide (carbaryl), it got my attention. But

here's the thing -- the makers of carbaryl insisted it wasn't harming the frogs.

They had a ton of studies showing that if you take the little creatures and put

them in a lab setting and expose them to the pesticide, nothing happens.

But still, the tree frogs were dying. And the environmentalists were positive

it had something to do with their continued exposure to this pesticide.

Enter Columbo, in the form of Rick Relyea, PhD, an ecologist from the

University of Pittsburgh. Long story short, Dr. Relyea discovered that carbaryl

was less harmful to frogs in the unnaturally tranquil setting of the lab (at

least it was less likely to kill them). But most tree frogs don't live in a lab,

they live in the wild. And in the wild there are constant dangers from

predators. When tree frog tadpoles were exposed to a predator, the predator

emitted a chemical cue that resulted in a stress response in the gray tree frog

-- a stress response just like we get when we're caught in traffic or miss a

deadline. Expose a stressed frog to the pesticide and you've got a dead frog.

The combination of the two -- physiological stress and a low-level pesticide,

neither of which has a significant impact on survival alone -- was lethal for a

majority of the gray tree frog tadpoles.

" In other species such as bullfrog tadpoles, carbaryl became up to 46 times

more deadly with the addition of predator cues. Moreover, this phenomenon has

since been observed with both insecticides and herbicides, suggesting that it

may be a quite common phenomenon, " says Dr. Relyea.

The take home point -- and the reason for this story -- is that elements in

the environment often interact with elements of our own physiology to cause

serious problems. And new research is emerging that suggests we may be seeing

exactly the same phenomenon with diabetes.

AN INTERESTING TRAIL OF BREADCRUMBS

We've long known that obesity is a major risk factor for diabetes. But now it

appears that exposure to pollutants can seriously aggravate the risk, and -- in

combination with obesity -- may be associated with the increased risk of

becoming diabetic. A recent study in the journal Diabetes Care looked at the

connection between six persistent organic pollutants (known as POPs) and

diabetes... and what they found was dramatic.

The prevalence of diabetes increased by 14- to 38-fold as the concentrations

of the sum of the six POPs increased, irrespective of participants' weight, said

lead researcher Duk-Hee Lee, MD, PhD. Her team divided the 2,016 subjects into

groups comparing five levels of pollutants. Group 1 had the lowest levels and

group 5 had the highest levels. Compared with group 1 (which had a .4% incidence

of diabetes), group 2 had a 6.7% incidence of diabetes, while group 5 had an

astonishing 25.6% incidence of the disease (groups 3 and 4 ranged in between).

Dr. Lee told me that while obesity remains a risk factor for type 2 diabetes,

the obese and overweight people with very low concentrations of POPs had a much

lower incidence of diabetes. Could obesity and pollutants interact to cause

diabetes in much the way that the pesticide and stress interacted to cause the

death of frogs?

" It's our hypothesis that obesity might be only weakly associated with

diabetes among people with very low serum concentrations of POPs, " Dr. Lee told

me. She explained that while her research concentrated on only six specific

pollutants out of about 50 POPs identified in the National Health and

Examination Survey, there was a striking connection between the blood

concentrations of these six toxins and the prevalence of diabetes. This is not

the first time that such a connection has been demonstrated. Earlier research

from Sweden also found that exposure to POPs may contribute to the development

of type 2 diabetes. And earlier research also demonstrated that exposure to at

least one toxin -- a dioxin called TCDD -- increases the risk of diabetes and

insulin resistance. It's believed that these toxins may interfere with glucose

metabolism.

POPs ARE EVERYWHERE

Persistent organic pollutants (POPs) include certain chemical byproducts, PCBs

and certain insecticides... they've been linked to cancer, neurobehavioral

impairment, endocrine problems and reproductive disorders. Previous researchers

looked at special populations that are occupationally or accidentally exposed to

high levels of these pollutants, for example, Vietnam veterans. (The US

Department of Veterans Affairs includes type 2 diabetes in its list of

presumptive diseases associated with exposure to the dioxin-containing Agent

Orange.) But Dr. Lee's study is the first to examine the cumulative effect of

most commonly detected POPs among a random low-level exposure in the general

population. The six toxins in the study are found in the environment, and move

through the air and water to accumulate in the environment.

Dr. Lee was careful not to let me believe that pollutants by themselves

necessarily cause diabetes, and expressed the usual researcher's caution about

jumping to strong conclusions based on one or two studies. " Plenty of people

have exposure to these pollutants and don't get diabetes, " she explained. " But

the strong connection between high levels and increased incidence is very hard

to ignore, as is the fact that there are such low levels of diabetes among those

with low levels of exposure, even among the overweight and obese. " Could genes

be a factor? " It's prudent to act as if everyone is at risk, regardless of

genetic makeup, " she told me.

How do we get exposed to these chemicals in the first place? " Exposure to POPs

comes mostly from animal fatty food consumption, " Dr. Lee told me. When I asked

her what protective measures people might take, she answered concisely: " A low

intake of animal food and a higher intake of plant food may be beneficial. And,

aside from trying to avoid POPs, preventing obesity is still very important

because the toxicity of POPs appeared to synergistically increase the risk of

type 2 diabetes among obese persons. "