How to Avoid BPA

The purported link between obesity and hormone-disrupting plastics chemicals like bisphenol A (BPA) was initially based in part on observations that the rise in chemical exposure seemed to coincide with the rise of the obesity epidemic, but that may only be a coincidence. Many other changes over the last half century, like an increase in fast-food consumption and watching TV, would seem to be simpler explanations. But why are our pets getting fatter, too? Fido isn’t drinking more fries or drinking more soda. Of course, the more we watch Seinfeld reruns, the less we may walk the dog, but what about our cats? They’re also getting fatter. Are we giving both them and our kids a few too many treats? That would seem to be an easier explanation than some pervasive obesity-causing chemical in the environment building up in the pet and person food chains.

How then do we explain the results of a study of more than 20,000 animals from 24 populations, showing they are all getting fatter? The odds that this could happen just by chance is about 1 in 10 million. The study’s “findings reveal that large and sustained population increases in body weight” are occurring across the board, even in those without access to vending machines or getting less physical education in schools. Perhaps some environmental pollutant is involved. I discuss this in my video How to Avoid the Obesity-Related Plastic Chemical BPA.

We’re exposed to a whole cocktail of new chemicals besides BPA, but the reason researchers have zeroed in on it is because of experiments showing that BPA can accelerate the production of new fat cells, at least in a petri dish. This was at more than a thousand times the concentration found in most people’s bloodstream, though. We didn’t know if the same thing happened at typical levels…until now. Most people have between 1 and 20 nanomoles of BPA in their blood, but even 1 nanomole may significantly boost human fat cell production. So, even low levels may be a problem, but that’s in a petri dish. What about in people?

Why not just measure the body weights of a population exposed to the chemical compared to a population not exposed to the chemical? There is virtually no unexposed population: BPA is everywhere. In that case, how about those with higher levels compared to those with lower levels? This is what researchers at New York University did, and the amount of BPA flowing through the bodies of children and adolescents “was significantly associated with obesity.” However, since it was a cross-sectional study, a snapshot in time, we don’t know which came first. Maybe instead of the high BPA levels leading to obesity, the obesity led to high BPA levels, since the chemical is stored in fat. Or, perhaps BPA is a marker for the same kinds of processed foods that can make you fat. What we need are prospective studies that measure exposure and then follow people over time. We never had anything like that…until now! And indeed, researchers found that higher levels of BPA and some other plastics chemicals were significantly associated with faster weight gain over the subsequent decade. So, how can we stay away from the stuff?

Though we inhale some from dust and get some through our skin touching BPA-laden receipts, 90 percent of exposure is from our diet. How can we tell? When we have people fast and drink water only out of glass bottles for a few days, their BPA levels drop as much as tenfold.

Fasting isn’t very sustainable, though.

What happens with a three-day fresh foods intervention, where families switch away from canned and packaged foods for a few days? A significant drop in BPA exposure. If we do the experiment the other way, adding a serving of canned soup to people’s daily diet, we see a thousand percent rise in BPA levels in their urine compared to a serving of soup prepared with fresh ingredients. That study used a ready-to-serve canned soup, which, in the largest survey of North American canned foods, was found to have about 85 percent less BPA than condensed soups, but the worst was canned tuna.

I previously touched upon bisphenol A in BPA Plastic and Male Sexual Dysfunction. Some companies make canned foods without BPA, for example, Eden Foods. (See Do Eden Beans Have Too Much Iodine? for more information.) You can also buy aseptic packaged beans or boil your own. Personally, I like pressure-cooking them.

For more on BPA, see:

Phthalates are another concerning class of plastics chemicals. I covered those in Avoiding Adult Exposure to Phthalates and What Diet Best Lowers Phthalate Exposure?.

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 Lower Phthalate Exposure Through Diet

Phthalates are hormone-disrupting plastics chemicals linked to a number of adverse health effects, such as disturbing infant and child development, and, in adults, may affect reproductive health in men and endometriosis in women, and is associated with increased abdominal fat in both. “Given the increasing scientific evidence base linking phthalate exposure with harmful health outcomes, it is important to understand major sources of exposure,” which I discuss in my video What Diet Best Lowers Phthalate Exposure?.

What is the most major exposure source? Diet. If you have people stop eating for a few days, you get a significant drop in the amount of phthalates spilling out in their urine. One can only fast for so long, though. Thankfully, we can see similar drops just from eating a plant-based diet for a few days, which gives us a clue as to where most phthalates are found.

The highest levels are found in meats, fats, and dairy. Poultry consistently comes out as being the most contaminated across the board with some of the highest levels ever reported, though there are geographic exceptions. In the United Kingdom, for example, fish came out worse than poultry, and, in Belgium, nothing appears to beat out reindeer meat in terms of contamination. In the United States, though, it is poultry, and the finding that egg consumption is also significantly associated with phthalate levels “suggests that chickens themselves may be contaminated” and not just arise from the plastic they’re wrapped in at the store.

The same might not be true with dairy, however. Realizing that these chemicals may be harmful, researchers in Seattle took ten families and randomized them into a five-day complete dietary replacement with fresh organic foods without any packaging. Nothing touched plastic. Organic milk was delivered in glass, and even the crates used to carry the food were wooden instead of plastic. This was like a fasting study to see what role eliminating processed foods would have on lowering phthalate levels because not everyone wants to switch to a plant-based diet—or stop eating completely. In my video, I show a chart depicting where the families started at baseline before changing their diet and where they were a week after the experiment, once again back on their baseline diet. What happened in the middle? When eating fresh and organic food, their phthalate levels went up, “a dramatic and unexpected increase in one of the most toxic phthalates—and not just by a little: It was like a 2000 percent increase. So the researchers tested all the foods. One of the spices was off the chart, and so was the dairy. Most of the phthalates apparently don’t come from the cow, however; they come from the tubing. If you milk cows by hand (which even the Amish don’t do anymore) the levels of phthalates in the milk are low, but if the same cows are milked by machine, the milk picks up phthalates from the tubing. As such, the final levels may depend more on the tubing than on what the cows are fed.

We’re not sure where the chickens are getting contaminated with phthalates, though. While that study was done on adults, we learned more recently where our kids may be getting it. Researchers found pretty much the same thing: mostly meat, including poultry and fish. Again, poultry appeared to be the worst, while soy consumption was associated with significantly lower levels. But what kind of exposure are we talking about? Researchers calculated what may be typical exposures for infants, teens, and women. How do these data compare with current guidelines? The U.S. Environmental Protection Agency’s reference dose, which is like the maximum acceptable threshold, is 20 µg/kg-day, based on liver risk. Europe places their maximum daily intake for testicular toxicity at 50 µg/kg-day. So a typical infant diet exceeds the EPA’s safety level, “while a diet high in meat and dairy was over this threshold by approximately four times. For adolescents, a diet high in meat and dairy also exceeded the EPA’s reference dose.” Indeed, diets high in meat and dairy consumption resulted in a two-fold increase in exposure. And “[a]ll diets for all groups exceeded the allowable daily intakes (ADI) derived by the US Consumer Product Safety Commission” for problems with sperm production, while diets high in meat and dairy consumption may exceed the allowable intake for risk of reproductive birth defects as well.

For more information on dietary sources of phthalates, I encourage you to watch both Chicken Consumption and the Feminization of Male Genitalia and Lowering Dietary Antibiotic Intake. Diet isn’t the only way one can be exposed internally, though. See my video Avoiding Adult Exposure to Phthalates, which discusses the risk in both children’s and adult toys.

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 Plastics Can Affect Your Love Life

Most of the attention on phthalates, a group of hormone-disrupting chemicals found in PVC plastics, has been focused on fetal and child health, particularly regarding genital and behavioral development. Recent data have shown, for example, “incomplete virilization in infant boys” and reduced masculine play as they grow up, and for girls, an earlier onset of puberty. What about affecting hormonal function in adults? I explore this in my video Avoiding Adult Exposure to Phthalates.

Men exposed to high levels of phthalate had lower testosterone levels, but that was for workers in a plastics plant. In the general population, the evidence is mixed. A study in Sweden of men in their 20s found no effect on testosterone, whereas a U.S. study on men in their 30s did find an effect, even at levels of exposure much lower than those of factory workers. When there’s conflicting evidence like this, ideally we’d put it to the test, but you can’t ethically expose people to phthalates so scientists have come up with convoluted methods like implanting the testicles from human fetuses into mice to keep them growing. We want to know about the effects on adult, not fetal, testicles, which had been harder to procure… until recently. “[C]onsent was obtained from all donors.” Now, I’ve heard of blood donors, but this is a whole other level. Researchers obtained donated testicles from prostate cancer patients who underwent castration to control their disease and, indeed, were able to get direct evidence that phthalates can inhibit testosterone production at the kinds of levels one sees in general population studies.

What about breast cancer, the number-one cancer killer of young women? Women working in automotive plastics and food canning are at five times the odds of breast cancer, suggesting a link. In a petri dish, however, phthalates didn’t seem to accelerate breast cancer growth at the levels of exposure expected in the general population. More recently, though, phthalate exposure was found to boost breast cancer cell growth in vitro at the levels found circulating in the bodies of many women. Therefore, the maximum tolerable dose set by governments should be re-evaluated.

How do you avoid the stuff? Well, when you think of plastic chemicals, you may think of water bottles, but they appear to play only a minor role. Most phthalates come from food. How do we know this? If you take people and have them stop eating for a few days, you get a significant drop in the amount of phthalates spilling into their urine. Fasting isn’t exactly sustainable, though. Thankfully, we can see similar drops from simply eating a plant-based diet for a few days, which gives us a clue as to where most phthalates are found. There were a few cases of spikes within the fasting period after showers, however, suggesting contamination in personal care products.

We can counsel patients to reduce phthalate exposures by avoiding the use of scented personal care products, soaps, and cosmetics, since phthalates are used as a fragrance carrier. Phthalates can also be found in children’s toys, as well as adult toys. “On behalf of the Danish [Environmental Protection Agency] EPA, [the Danish Technological Institute] DTI has made inquiries about the consumption pattern in connection with the use of sex toys made of rubber or plastics” to see what kind of exposure one might get “based on worst case scenarios.” Those working behind the counters at sex shops “proved to possess very little knowledge of the materials,” so the researchers had to do their own testing. It turns out that “jelly” is plasticized PVC—up to two-thirds phthalates by weight. Though the use of water-based lubricants may reduce the health risks 100-fold, phthalate exposure through lubricants may still have the opposite of the intended effect. Women with the highest levels of phthalates flowing through their bodies “had over 2.5 times the odds of reporting a lack of interest in sexual activity,” and these weren’t women in a canning factory, rather they were at typical exposure levels in America.

To find out how to lower your exposure to phthalates, see What Diet Best Lowers Phthalate Exposure?

More on hormone-disrupting chemicals in our food supply in:

Interested in learning more about improving sexual health? 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: