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The Microbiome and Bisphenol A (BPA) Exposure

The Microbiome and Bisphenol A (BPA) Exposure

About BPA and Health Impacts

Bisphenol A (BPA) has gained a lot of attention over the past several years as a toxic component of plastics. BPA is an environmental estrogen that modulates endocrine systems by competing with estradiol for binding with estrogen receptors. Estrogenic effects have been suspected since the early 1900s, with adverse effects first reported in the 90s. Some of the suspected potential effects of BPA exposure include genital abnormality in boys, earlier puberty in girls, diabetes, cardiovascular disease, liver enzyme abnormalities, and obesity.

After various studies came out indicating negative health effects, BPA was banned for use in baby bottles. Many people now opt for metal or glass water bottles or seek out BPA-free plastic versions. However, BPA is still commonly used in can linings and other food packaging and may be found in small amounts in drinking water. The best way to prevent BPA exposure (and exposure to other chemicals we might not even know about) is to avoid consuming foods from plastic or cans, and especially heating food in plastic containers. However, sometimes it may not be possible to completely avoid these foods, and BPA exposure can come from other sources as well. Some research indicates that probiotic bacteria may help to reduce negative consequences of BPA exposure, which becomes especially useful for those times when it isn’t possible to avoid canned food or plastic containers.

How Bacteria Can Help

Some early indication of the potential role of bacteria in breaking down BPA came from bacteria in aquatic environments. BPA is acutely toxic to aquatic organisms, and is particularly problematic because runoff from factories often pollutes rivers and other water bodies. In exploring those water bodies, surrounding soil, and wastewater treatment plants, scientists identified bacteria that are able to naturally degrade BPA. They isolated Psuedomonas sp. and Psuedomonas putida strains that showed high BPA biodegradability. These could potentially be useful for aquatic environment decontamination, maybe helping to keep BPA out of our drinking water and thereby minimizing consumption in the first place.

Scientific Research

There is also evidence that bacteria found in foods might help to protect against BPA exposure. Researchers have looked at the effects of Bifidobacterium breve and Lactobacillus casei (commonly found in yogurt and other fermented foods) on rats exposed to BPA. After exposing the rats to large concentrations of BPA, they fed the bacteria to the experimental group, and gave a mock treatment to the control group.

The rats given Bifidobacterium and Lactobacillus had decreased blood concentration of BPA, and a greater amount of BPA excreted in feces. In vitro experiments showed that the bacterial cells stored BPA. This suggests that the cells of these bacteria bound BPA from the intestines and promoted excretion into feces. Bacterial cells also stored other toxins, which is promising given that there could very well be other toxic components of plastic that we don’t yet know about. The researchers concluded that the findings suggest that consuming Bifidobacterium breve and Lactobacillus casei leads to a reduction of the risk of exposure to endocrine disruptors. The experiment doesn’t definitively tell us whether the endocrine disrupting effects of BPA are minimized, but it would make sense that this would be the case.

Other research suggests that lactic acid bacteria Lactococcus strains may attach to BPA and help to remove it from the body. Lactococci is used as a starter bacteria in manufacturing cheese and other fermented dairy. In vitro experiments indicate that BPA attaches to the cell wall of of the bacteria, and is then shuttled out of the body when the bacteria is excreted. Lactococcus strains are also known to bind to other toxins such as aflatoxin, suggesting a positive overall effect of consumption.

Kimchi may also contain probiotics that help with preventing some negative effects of BPA exposure. Researchers isolated Bacillus pumilus from kimchi and found that it efficiently degraded BPA. The bacteria appeared to use BPA as a fuel source and break it down into less harmful components, which may then be excreted from the body.

And these are only the strains that have been tested. Unlike research into BPA-degrading bacterial strains in aquatic environments, research into the ability of human gut bacteria to minimize BPA toxicity is relatively new and not very extensively studied. It is entirely possible that other fermented foods have beneficial effects that we don’t yet know about.

What You Can Do

Given the results from the above-mentioned studies, consuming fermented dairy products and kimchi might be a good way to thwart some of the negative effects of BPA exposure. It can’t hurt to consume other fermented foods in addition to yogurt, cheese, and kimchi. We know that there are so many benefits to probiotic foods, so continuing to consume them is a great option for most people. For those who don’t tolerate fermented foods due to something like histamine intolerance or a yeast sensitivity, it might be a good idea to take a high quality probiotic supplement. I really like this one, which contains Bifidobacterium, Lactobacillus sp., and Lactococci, as well as other probiotic strains.

It is always best to avoid BPA exposure as much as possible in the first place. But for those times when you can’t, or for exposure from sources you might not know about, eating fermented foods and/or taking probiotics can be a great option as a next line of defense against the potential negative effects.

Do you have any thoughts or questions? Please share them in the comments!

 

Resources:

Endo, Y., Kimura, N., Ikeda, I., Fujimoto, K., & Kimoto, H. (2007). Adsorption of bisphenol A by lactic acid bacteria, Lactococcus, strains. Applied Microbiology and Biotechnology, 74(1), 202-207.

Howdeshell, K., Hotchkiss, A., Thayer, A., Vandenbergh, J., & vom Saal, F. (1999). Environmental toxins: Exposure to bisphenol A advances puberty. Nature, 401, 763-764.

Kang, J., Kondo, F., & Katayama, Y. (2006). Human exposure to bisphenol A. Toxicology, 226(2-3), 21.

Lang, I., Galloway, T., Scarlett, A., Henley, W., Depledge, M., Wallace, R., & Melzer, D. (2008). Association of urinary bisphenol A concentration with medical disorders and laboratory abnormalities in adults. Journal of the American Medical Association, 300(11).

Oishi, K., Sato, T., Yokoi, W., Yoshida, Y., Ito, M., & Sawada, H. (2008). Effect of probiotics, Bifidobacterium breve and Lactobacillus casei, on Bisphenol A exposure in rats. Bioscience, Biotechnology, and Biochemistry, 72(6), 1409-1415.

Sakamoto, H., Yokota, H., Kibe, R., Sayama, Y., & Yuasa, A. (2002). Excretion of bisphenol A-glucuronide into the small intestine and deconjugation in the cecum of the rat. Biochimica et Biophysica Acta (BBA) – General Subjects, 1537(2), 171-176.

Yamanaka, H., Moriyoshi, K., Ohmoto, T., Ohe, T., & Sakai, K. (2007). Degradation of Bisphenol A by Bacillus pumilus isolated from kimchi, a traditionally fermented food. Applied Biochemistry and Biotechnology, 136(1), 39-51.



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