Plastic products can be seen everywhere in life, mineral water bottles, food bags, cups, lunch boxes … Many plastic products contain a substance called bpa. Conventional exposure to this chemical is generally considered safe for humans. But now, experts may have to re-examine the ingredient and related materials.
A recent study published in The Lancet Diabetes and Endocrinology found that previous measurements used by regulators, including the FDA, were flawed, underestimating the level of human exposure to BPA, and that the actual levels of BPA in the human body could be dozens of times higher than previously thought!
Screenshot Source: The Lancet Diabetes and Endocrinology.com
To understand the significance of this study, first of all, why do you need to pay attention to the amount of human exposure of BPA?
On the one hand, BPA is very common, the world produces about 9 million tons per year, is widely used in plastic products, plastic beverages are very common. Therefore, daily human exposure is difficult to avoid. For example, plastics containing polycarbonate (PC) material sit easily release BPA when heated to about 60 degrees, and are affected by material stability, after long-term use, there will be slow decomposition, release BPA phenomenon.
On the other hand, previous animal studies have shown that BPA interferes with the endocrine system, including a variety of biological pathways mediated by estrogen, androgens, progesterone, and thyroid hormones;
However, there is still debate as to whether BPA exposure in daily life poses a health risk to humans, especially if it has not been confirmed by regulatory guidelines. For example, the FDA, by evaluating data from BPA in human urine, concluded that the daily exposure levels of human exposure to the chemical were negligible.
Photo credit: Pixabay
The new study challenges this. The discovery that impacts our perception stems from a more accurate method of measuring BPA. The human body’s metabolism of BPA is relatively fast, so to accurately assess the exposure of BPA, not only to assess the BPA content in the human body, but also to measure its main metabolites. However, in the past, due to the lack of relevant standards, the content of THE main metabolites of BPA is difficult to be directly accurately measured, and most studies have had to be measured indirectly. The new approach, developed by Professor Roy Gerona of the University of California, San Francisco (UCSF) and his team, formally overcomes this by measuring BPA metabolites directly.
The team compared the old and new measurements with 39 urine samples. Taking into account the potential impact on the fetus and the physiological changes associated with pregnancy that may affect BPA metabolism, the sample was from 29 pregnant women, 5 non-pregnant women and 5 men.
By analyzing samples of pregnant women, the new direct method measured a much higher level of BPA, with an average of 51.99 ng/ml, 19 times the indirect method result (2.77 ng/ml) and 44 times the average of the National Health and Nutrition Survey (NHANES) report! With the increase of BPA exposure, the difference between the measurement results of the two methods is more obvious. That is, the greater the exposure, the more the original method is underestimated. The trends observed in the analysis of the other 10 samples were consistent.
As exposure increases (horizontal coordinates), the new method (right) measures significantly higher levels of human BPA than the old method (left) (picture source: Resources
“Are we being careful enough about the safety of this chemical?” said Professor Patricia Hunt, a BPA expert at Washington State University, the paper’s author. The study is a serious reminder. Regulators’ regulatory oversight of BPA may be based on inaccurate measurements. “
The significance of this discovery is not limited to what we know about BPA. Professor Gerona said: “NHANES uses indirect methods to measure the chemicals that affect the endocrine, not just BPA. If our findings are true for BPA, the human exposure of other chemicals measured in a similar way may also be underestimated. “
Currently, the research team is also using new methods to measure human exposure to other applicable chemicals, such as benzoate, benzene, triclosan, etc., which are found in many cosmetics and soaps, as well as phthalates, a plasticizer commonly found in toys, food packaging and personal care products.
Photo credit: Pexles
Of course, it is difficult to overturn existing regulatory standards in just one study, and there is no answer to what a higher dose of exposure means. We need more research to reproduce and verify this problem. “I hope this study will draw attention to the BPA measurement method, and I hope that more experts and the experimental team will evaluate it more carefully and independently,” says Professor Gerona. “
Until further scientific validation, what we can do is to use plastic products correctly under the existing guidance. The bottom of a typical plastic container has a triangular recyclable logo and numbers back, so keep in mind and keep in mind:
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(1) No. 1 plastic (PET) is commonly used as mineral water bottles, beverage bottle materials, not filled with hot water, not heated, recycling not more than 10 months;
(2) No. 2 plastic (high density polyethylene, HDPE) is commonly used as a medicine bottle, toiletries container materials, not to contain food, not recycled;
(3) No. 3 plastic (PVC) commonly used as raincoats, building materials, non-food containers and other materials, not to contain food, not recycled, heating will produce toxic gases;
(4) No. 4 plastic (low density polyethylene, LDPE) is commonly used as a preservation film, plastic film material, not heated;
(5) No. 5 plastic (PP) is commonly used as a bucket, food container materials, can be heated by microwave oven, can be recycled;
(6) No. 6 plastic (PS) commonly used as building materials, toys, bowls bubble noodle box, fast food box and other materials, not heated microwave oven, not filled with orange juice and other acidic drinks;
(7) No. 7 plastic contains a wide variety, the specific situation needs to be further explained, wherepolycarbonate (PC) is commonly used as a kettle, bottle material, not heated.