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:

Where Vitamin D Supplements Fail

As I discuss in my video Do Vitamin Supplements Help with Diabetes, Weight Loss, and Blood Pressure?, review articles continue to be published touting vitamin D as a veritable cure-all. The vitamin D receptor is found in most tissues in the body, including the brain, and upwards of 2,000 genes may be regulated by vitamin D. Within 24 hours of vitamin D exposure, we can change the expression of hundreds of genes.

The term vitamin is a misnomer, though, because vitamins by definition cannot be synthesized within our body, but we can make all the D we need with sufficient sun exposure. So, rather than a vitamin, D is actually a hormone that’s produced by our skin in response to sunlight exposure. D is not just a hormone of calcium regulation and bone health; it’s also a hormone of fertility, immunity, and brain function. But is it a panacea or a false prophet?

Remember when vitamin E was the vitamin du jour, touted as a “curative for many clinical disorders”? Supplement sales of vitamin E, the “radical protector,” created a billion-dollar business that capitalized on the public’s fears. After all, those with low levels of vitamin E in their blood had a 50 percent higher cancer risk. Similar attention was directed towards vitamin A or beta-carotene. People who eat lots of greens, sweet potatoes, and other beta-carotene-rich foods have lower risk of cancer, so maybe we should give people beta-carotene pills? When they were put to the test, however, beta-carotene pills actually increased cancer rates. In fact, beta-carotene, vitamin A, and vitamin E supplements all may increase mortality, so when we buy these supplements, we’re potentially paying to shorten our lifespans. As such, I imagine you can understand the skepticism in the medical community regarding claims about vitamin D, which is now enjoying its moment in the sun.

Having a half-billion-dollar vitamin D supplement industry doesn’t help matters in terms of getting at the truth. And there’s also a highly lucrative vitamin D testing industry that loves to talk about the studies suggesting that having higher vitamin D levels may reduce the risk of heart disease, cancer, diabetes, autoimmune diseases, and infections. Most of this research, however, stems from observational studies, meaning studies that correlate higher D levels in the blood with lower disease risk, but that doesn’t mean vitamin D is the cause. It’s like the early beta-carotene data: Higher levels in the blood may have just been a marker of healthy eating. Who has high beta-carotene levels? Those who eat lots of greens and sweet potatoes. Similarly, higher levels of vitamin D may just be a marker of healthy behaviors. Who has high vitamin D levels? Those who run around outside, and those who run around outside, run around outside. Indeed, higher vitamin D levels may just be a sign of higher physical activity.

So, for instance, when you see studies showing significantly lower diabetes rates among those with higher vitamin D levels, it doesn’t mean giving people vitamin D will necessarily help. You have to put it to the test.  And, when you do, vitamin D supplements fall flat on their face, showing no benefit for preventing or treating type 2 diabetes.

So, when supplement companies wave around studies suggesting vitamin D deficiency plays a role in obesity, because most population studies show that obese individuals have lower vitamin D levels in their blood, is that simply because they’re exercising less or because it’s a fat-soluble vitamin so it’s just lodged in all that fat? We might expect obese sunbathers to make more vitamin D, since they have more skin surface area, but the same exposure level for them leads to less than half the D bioavailability, because it gets socked away in the fat. This is why obese people may require a dose of vitamin D that’s two to three times higher than normal weight individuals, although they may get it back if they lose weight and release it back into their circulation. This would explain the population data. Indeed, when you put vitamin D to the test as a treatment for obesity, it doesn’t work at all.

It’s a similar story with artery health. Those with low vitamin D levels have worse coronary blood flow, more atherosclerosis, and worse artery function, but if you actually put it to the test in randomized controlled trials, the results are disappointing. Vitamin D is also ineffective in bringing down blood pressures.

This all adds to the growing body of science “casting doubt on the ability of vitamin D supplementation to influence health outcomes beyond falls, fractures, and possibly respiratory tract infection and all-cause mortality.” Wait. What? Vitamin D supplements may make you live longer? That’s kind of important, don’t you think? I talk about that in my video Will You Live Longer If You Take Vitamin D Supplements?.


Explore the other videos in my series on vitamin D, including:

And check out these other videos on vitamin D’s potential benefits:

For additional videos on supplements, 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:

Turmeric Curcumin Put to the Test for Inflammatory Bowel Disease

My video Striking with the Root: Turmeric Curcumin and Ulcerative Colitis tells the story how this amazing discovery was made, and how curcumin stacks up against pharmacological interventions.

Despite evidence going back 40 years that the turmeric spice component curcumin possesses significant anti-inflammatory activity, it wasn’t until 2005 that it was first tested on inflammatory bowel disease. Why did it take so long? Well, who’s going to fund such a study? Big Curry? Even without corporate backing, individual physicians from New York decided to ask the next five patients with ulcerative colitis who walked through their office doors to start curcumin supplements.

“Ulcerative colitis (UC) is a debilitating, chronic, relapsing-remitting [i.e., it comes and goes] IBD [inflammatory bowel disease] that afflicts millions of individuals throughout the world and produces symptoms that impair quality of life and ability to function.” As with most diseases, we have a bunch of drugs to treat people, but sometimes these medications can add to disease complications, most commonly nausea, vomiting, headaches, rash, fever, and inflammation of the liver, pancreas, and kidneys, as well as potentially wiping out our immune system and causing infertility. Most ulcerative colitis patients need to be on drugs every day for the rest of their lives, so we need something safe to keep the disease under control.

So how did those five patients do on the spice extract? Overall, all five subjects improved by the end of the study, and four of the five were able to decrease or eliminate their medications. They had “more formed stools, less frequent bowel movements, and less abdominal pain and cramping. One subject reported decreased muscle soreness, commonly felt after his exercise routine.” This, however, was what’s called an open-label study, meaning the patients knew they were taking something so some of the improvement may have just been the placebo effect. In 2013, another small open-label pilot study found encouraging results in a pediatric population, but what was needed was a larger scale, double-blind, placebo-controlled trial.

And, researchers obliged. They took a bunch of people with quiescent ulcerative colitis and gave them either turmeric curcumin along with their typical anti-inflammatory drugs, or a placebo and their drugs. In the placebo group, 8 out of 39 patients relapsed, meaning their disease flared back up. In the curcumin group, however, only 2 out of 43 relapsed, significantly fewer. And, relapse or not, clinically, the placebo group got worse, while the curcumin group got better. Endoscopically, which is objectively visualizing the inside of their colons, doctors saw the same thing: trends towards worse or better.

The results were stunning: a 5 percent relapse rate in the curcumin group compared with a 20 percent relapse rate in the conventional care group. It was such a dramatic difference that the researchers wondered if it was some kind of fluke. Even though patients were randomized to each group, perhaps the curcumin group just ended up being much healthier through some chance coincidence, so maybe it was some freak occurrence rather than curcumin that accounted for the results? So, the researchers extended the study for another six months but put everyone on the placebo to ensure the initial findings were not some aberration. The curcumin was stopped to see if that group would then start relapsing, too—and that’s exactly what happened. Suddenly, they became just as bad as the original placebo group.

The researchers concluded: “Curcumin seems to be a promising and safe medication for maintaining remission in patients with quiescent ulcerative colitis.” Indeed, no side effects were reported at all. So, “Curry for the cure?” asked an accompanying editorial in the journal of the Crohn’s and Colitis Foundation of America. “Can curcumin be added to our list of options with respect to maintaining remission in ulcerative colitis? What is noteworthy about this trial is the fact that not only did the authors demonstrate a statistically significant decrease in relapse at 6 months, but a statistically significant improvement in the endoscopic index as well. Equally telling is the fact that upon withdrawal of curcumin the relapse rate quickly paralleled that of patients treated initially with placebo, implying that curcumin was, in fact, exerting some important biologic effect.”

Similarly, a Cochrane review concluded in 2013 that curcumin may be a safe and effective adjunct therapy. Cochrane reviews take all the best studies meeting strict quality criteria and compile all the best science together, which is normally a gargantuan undertaking. Not so in this case, however, as there is really just that one good study.


Turmeric is one of the most popular trending topics, and I encourage you to check out the most popular turmeric videos, including:

For more on ulcerative colitis and inflammatory bowel disease, 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: