Why Hasn’t Bisphenol A (BPA) Been Banned Completely?

“The number of new chemicals is increasing exponentially, with approximately 12,000 new substances added daily…”—yet data aren’t available on the hazards of even some of the high-volume chemicals. Bisphenol A (BPA) is one of the highest volume chemicals, with billions of pounds produced each year. Studies have raised concerns about its possible implication in the cause of certain chronic diseases, such as diabetes, obesity, reproductive disorders, cardiovascular diseases, birth defects, chronic respiratory diseases, kidney diseases, and breast cancer. Given this, BPA is the topic of my video Why BPA Hasn’t Been Banned.

A new study on the health implications of BPA comes out nearly every week. BPA was first developed over a hundred years ago as a synthetic estrogen, but it wasn’t until the 1950s that industry realized it could be used to make polycarbonate plastic, and “BPA rapidly became one of the most produced and used chemicals worldwide, even though it was a recognized synthetic estrogen” with hormonal effects. About a billion pounds are also used to line food and beverage cans, especially for tuna and condensed soups.

Today, nearly all of us, including our children, have BPA in our bodies, but not to worry: The government says up to 50 µg/kg per day is safe. Even those working in Chinese BPA factories don’t get exposed to more than 70 times lower than that so-called safety limit. Why then did exposure seem to affect male workers’ sperm counts? In the United States, the general population gets less than a thousand times lower than the safety limit, yet, even at those incredibly low doses, we still seem to be seeing adverse effects on thyroid function, weight control, blood sugar control, cardiovascular disease, liver function, and immune function. Indeed, “[t]he fact that there are significant adverse effects in populations exposed to BPA at concentrations [thousands of] times lower than the TDI [tolerable daily limit]…indicates that the safe exposure to BPA may be much lower than previously thought in humans.” Despite this, the limit hasn’t been changed. BPA has been banned from “baby bottles and sippy cups,” but nearly unlimited doses are still apparently okay for everyone else. What’s the disconnect?

It has to do with the fascinating world of low-dose effects of hormone-disrupting chemicals. “For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of ‘the dose makes the poison’”—that is, the concept “that lower exposures to a hazardous compound will therefore always generate lower risks.” Indeed, that is the core assumption underlying our system of chemical safety testing. Researchers start giving animals in laboratories a super-high dose and then keep lowering the dosage until whatever adverse effects that had occurred disappear. Then, they add a safety buffer and assume everything below that dose should be okay, assuming a straight line showing the higher the dose, the higher the effect. However, hormone-disrupting chemicals can have all sorts of curious curves. How is it possible that something could have more of an effect at a lower dose?

A study was done to see whether BPA suppressed an obesity-protective hormone in fat samples taken from breast reduction and tummy tuck patients. At 100 nanomoles of BPA, hormone levels were no lower than they were at 0nM of BPA. And, since most people have levels between 1 and 20, BPA was considered to be safe. But, although there was no suppression at 0 and no suppression at 100, at the levels actually found in people’s bodies, BPA appeared to cut hormone release nearly in half.

As the world’s oldest, largest, and most active organization devoted to research on hormones concluded, “even infinitesimally low levels of exposure—indeed, any level of exposure at all—may cause [problems].” In fact, it may come to nearly $3 billion in problems every year, counting the estimated effects of BPA on childhood obesity and heart disease alone. There are alternatives the industry can use. The problem, though, is that they may cost companies two cents more.


Related videos about BPA include BPA on Receipts: Getting Under Our Skin and Are the BPA-Free Alternatives Safe?

 BPA isn’t the only problem with canned tuna. Check out:

What can we do to avoid endocrine-disrupting chemicals? See, for example, Avoiding Adult Exposure to Phthalates and How to Avoid the Obesity-Related Plastic Chemical BPA.

Alkylphenols are another group of endocrine-disrupting chemicals. To learn more about them, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

How to Increase Gut Bacterial Richness

We live in an “obesogenic environment,” with cheap junk food everywhere, thanks in part to subsidies going to the “‘food industrial complex,’ which manufactures obesogenic foods that foster addiction…The root causes…[may] make obesity difficult to escape,” but a lot of people do. If it were simply the external environment, why isn’t everyone obese?

“Some individuals seem to be more susceptible to the obesogenic environment…than others,” which suggests a genetic component, supported by studies of twins and adopted kids, but the genes that have been identified so far account for only 6 to 11 percent of the genetic variation in body mass index between individuals. Perhaps variation in our “other genome”—that is, all the different microbes that inhabit our body, known as the microbiome—may be playing a role. We have a hundred times more bacterial genes inside us than human genes.

As I discuss in my video Gut Microbiome: Strike It Rich with Whole Grains, a study found that people tend to fall into one of two groups: those who have lots of different types of bacteria in their gut (high “gut bacterial richness”) and those with relatively few types. Those with low bacterial richness had more overall body fat, insulin resistance, which is the cause of type 2 diabetes, high triglycerides, and higher levels of inflammatory markers, like C-reactive protein, compared to those with high bacterial richness. Not only did people with lower bacterial richness start out heavier, but the obese individuals with lower bacterial richness also gained more weight over time.

The question then becomes: Can a dietary intervention have any impact “A number of studies have associated increased microbial richness…with diets higher in fruits, vegetables, and fiber.”

Just giving fiber-type supplements doesn’t seem to boost richness, however, but the “compositional complexity” of a whole food, like whole grains, “could potentially support a wider scope of bacterial taxa,” types of bacteria, “thereby leading to an increase in diversity.” Human studies to investigate the effects of whole grains had been neglected, though…until now.

Subjects were given whole-grain barley, brown rice, or a mixture of both for a month, and all three caused an increase in bacterial community diversity. Therefore, it may take a broad range of substrates to increase bacterial diversity, and this can be achieved by eating whole plant foods.

Moreover, the alterations of gut bacteria in the study coincided with a drop in systemic inflammation in the body. We used to think that the way fiber in whole grains helped us was by gelling in our small intestine right off of our stomach, slowing the rate at which sugars were absorbed and blunting the spike in blood sugars one might get from refined carbs. We now know, however, that fiber is broken down in our colon by our friendly flora, which release all sorts of beneficial substances into our bloodstream that can have anti-inflammatory effects, as well. So, perhaps what’s happening in our large intestine helps explain the protective effects of whole grain foods against type 2 diabetes.

Interestingly, the combination of both barley and brown rice worked better than either grain alone, suggesting a synergistic effect. This may help explain “the discrepancy of the health effects of whole grains obtained in epidemiological [population-based] and interventional studies.”

Observational studies “strongly suggest” that those who consume three or more servings of whole grains a day tend to have a lower body mass index, less belly fat, and less tendency to gain weight, but recent clinical trials, where researchers randomized subjects to eat white bread rolls versus whole-wheat rolls, failed to provide evidence of a beneficial effect on body weight. Of course, whole grains are so superior nutritionally that they should continue to be encouraged. However, the “[i]nterventional trials might have failed to show [weight] benefits because they focused on a limited selection of whole grains, while in epidemiological trials [or the population studies], subjects are likely to consume a diverse set of whole grains which might have synergistic activities.”


Until recently, we knew very little about how powerfully our gut bacteria can affect our health. Catch up on the latest science with these related videos:

When it comes to rice, even white rice can be better than many choices, but brown rice is better and pigmented rice is probably the best. See my videos Kempner Rice Diet: Whipping Us Into Shape and Is It Worth Switching from White Rice to Brown? for more.

But what about the arsenic in rice? Learn more:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

How Not to Die from High Blood Pressure

High blood pressure is the number-one risk factor for death in the world. In the United States, it affects nearly 78 million people, one in three adults. As we age, our blood pressures get higher and higher, such that by age 60, high blood pressure strikes more than half of us.

Given that it affects most of us when we get older, could high blood pressure be less a disease and more just an inevitable consequence of aging? No. We’ve known since the 1920s that high blood pressure need not occur, which I discuss in my video How Not to Die from High Blood Pressure.

Researchers measured the blood pressures of a thousand people in rural Kenya, where their traditional diet included more whole grains, beans, vegetables, fruit, and dark leafy greens. Though our pressures go up as we age, their pressures actually go down.

With blood pressure, the lower, the better. The 140/90 cut-off you may have heard here or there is arbitrary. Even people who start out with blood pressures under 120/80 appear to benefit from blood pressure reduction. Your doctor would likely give you a gold star if you had a blood pressure of 120/80, but research indicates the ideal blood pressure—blood pressure that wouldn’t get benefit from being any lower—may actually be 110/70.

Is it even possible to get blood pressures as low as 110/70? It’s not just possible—it’s normal for those living healthy enough lives.

Over two years, 1,800 patients were admitted to a rural Kenyan hospital. How many cases of high blood pressure were found? Zero. Wow they must have had low rates of heart disease. No, in fact, they had no rates of heart disease. Not a single case of our number-one killer, arteriosclerosis, was found. Rural China, too. There, people are about 110/70 their entire lives—70-year-olds with the same average blood pressure as 16-year-olds.

Those in Asia and Africa traditionally eat vastly different diets, but they do share a commonality: Both were plant-based day-to-day, with meat eaten only on special occasions. Why do we think it’s the plant-based nature of their diets that was so protective? Because in the Western world, as the American Heart Association has pointed out, the only people getting their blood pressures down that low were those eating strictly plant-based diets, coming in around 110/65.

The largest study to date of people eating plant-based diets studied 89,000 Californians. Non-vegetarians were compared to semi-vegetarians (also called flexitarians, those who eat meat more on a weekly rather than daily basis), pesco-vegetarians (those who eat no meat except fish), lacto-ovo-vegetarians (those who eat no meat at all), and vegans (who eat no meat, eggs, or dairy).

The subjects were Seventh-day Adventists, who all tended to eat lots of fruits and vegetables, exercise, and not smoke, and even the nonvegetarians didn’t eat a lot of meat. So, even compared to a group of relatively healthy meat-eaters, there appeared to be a step-wise drop in hypertension rates as people ate more and more plant-based diets, with vegans having lower rates than lacto-ovo-vegetarians, who had lower rates than pesco-vegetarians, and so on—and the researchers found the same for diabetes and obesity.

So, yes: We can wipe out most of our risk by eating a strictly plant-based diet, but it’s not all-or-nothing. It isn’t black-or-white. Any movement we can make along the spectrum towards healthier eating can accrue significant health benefits.

This can be shown experimentally: Give vegetarians some meat (and pay them enough to eat it), and their blood pressures go up. In another study, meat was removed from people’s diets, and their blood pressures went down—and did so in only seven days. What’s more, this was after the vast majority had reduced or even stopped their blood pressure medications completely. Indeed, the subjects had to stop their medications because once you treat the cause, you can’t be on multiple blood pressure pills with normal blood pressure. Your pressures could fall too low and you could get dizzy, fall, and hurt yourself, so your doctor has to take you off the pills. Lower blood pressures on fewer drugs—that’s the power of plants.

So, does the American Heart Association recommend a no-meat diet? No, it recommends a low-meat diet, known as Dietary Approaches to Stop Hypertension, or the DASH diet. Why wouldn’t the AHA recommend a completely plant-based diet? When the DASH diet was being created, were they just not aware of this landmark research, done by Harvard’s Frank Sacks showing those who eat strictly plant-based average 110/65? No, they were aware. The Chair of the Design Committee that came up with the DASH diet was Frank Sacks.

As he described, the DASH diet was designed explicitly with the number-one goal of capturing “the blood pressure-lowering benefits of a vegetarian diet, yet contain enough animal products to make them palatable” to the general population. They didn’t think the public could handle the truth.

In their defense, just as drugs don’t work unless you actually take them, diets don’t work unless you actually eat them. So, maybe they thought few would eat strictly plant-based, so by soft-peddling the message, by coming up with a kind of compromise diet perhaps on a population scale they felt it would do more good. Fine, but tell that to the thousand American families who lose a loved one every day to high blood pressure.

Maybe it’s time to start telling the American public the truth.


The first time someone visits NutritionFacts.org can be overwhelming. With videos on more than 2,000 health topics, where do you even begin? Imagine stumbling onto the site not knowing what to expect and the new video-of-the-day is about how a particular spice can be effective in treating a particular form of arthritis. It would be easy to miss the forest for the trees, which is precisely why I created a series of overview videos that are essentially taken straight from my live, hour-long 2016 presentation How Not to Die: Preventing, Arresting, and Reversing Our Top 15 Killers.

The other videos in this overview series are:

Inspired to learn more about the role diet may play in preventing and treating high blood pressure? Check out these other popular videos on the topic:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: