Hello and welcome to Nutrition Facts. I'm your host, Dr. Michael Greger. Today we're going to explore smart nutrition choices based naturally on facts.

Have a history of high blood pressure in your family? How about heart disease, diabetes? There are foods we can eat that may not only help prevent many of these chronic diseases, but even stop them in their tracks.

Today we take a close look at BPA, the compound that has been used in industrial chemicals to make certain plastics and resins since the 1960s.

Research suggests that BPA is linked to billions of dollars worth of medical problems a year, so why is it still allowed in the food supply? Here are some answers.

The number of new chemicals is increasing exponentially. We're talking 12,000 new substances a day. Yet data aren't available on the hazards of even some of the high volume chemicals.

BPA is one of the highest volume chemicals with billions of pounds produced each year. And studies have raised concerns about its possible implication and the cause of certain chronic diseases, such as diabetes, obesity, reproductive disorders, cardiovascular disease.

The cardiovascular disease is birth defects, chronic respiratory and kidney diseases and breast cancer.

A new study in health implications of BPA comes out nearly every week. BPA was first developed over 100 years ago as a synthetic estrogen.

But it wasn't until the 50s that industry realized it could be used to make polycarbonate plastic and rapidly became one of the most used chemicals worldwide, even though it was recognized to have hormonal effects.

About a billion pounds are also used to line food and beverage cans, especially, it seems, in tuna and condensed soups.

And now we basically all have BPA in our bodies and our children's bodies. But not to worry the government says up to 50 a day is safe, 50 micrograms per kilogram.

And even those working in Chinese BPA factories don't get exposed to more than like 70 times lower than that safety limit.

Okay, then why did exposures seem to affect the male worker sperm counts?

In the US, the general population only gets less than like a thousand times lower than the safety limit, yet still we seem to be seeing adverse effects on thyroid function, weight control, blood sugar control, cardiovascular disease, liver function, and immune function even at those incredibly low doses.

So the fact that there are significant adverse effects in populations exposed to BPA at concentrations, thousands of times lower than the official tolerable daily limit indicates that the same thing is happening.

It indicates that the safe exposure to BPA may be much lower than previously thought in humans, yet the limit hasn't been changed.

It's been banned from baby bottles and sippy cups, but nearly unlimited doses are still apparently okay for everyone else.

What's the disconnect here?

It has to do with the fascinating world of low dose effects of hormone disrupting chemicals for decades.

These chemicals have challenged traditional concepts in toxicology, particularly the old adage that it's the dose that makes the poison.

The concept that lower exposures to a hazardous compound will therefore always generate lower risks.

That's the core assumption underlying our system of chemical safety testing.

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