I came across some interesting research the other day concerning the potential role of Bisphenol-A (BPA) in regulating weight.
BPA is a chemical that is found in several plastics and plastic additives. It’s in the water bottles folks carry to gyms and in the baby bottles moms use to feed their infants. And it’s in almost all of our bodies. A CDC study in 2007 found that 92% of 2,500 subjects studies had detectable amounts of BPA in their urine.
A study published in 2002 by Masuno and colleagues demonstrated that relatively small amounts of BPA significantly reduced insulin sensitivity and accelerated the formation of adipocytes (fat cells). In other words, BPA made the mice fat.
Not only did BPA trigger the conversion of pre-adipocytes to adipocytes, it also stimulated the conversion process once triggering had occurred. This “double-whammy” effect caused a 1,300% increase in fat levels, compared with a 150% increase with insulin alone.
The worldwide obesity epidemic has been primarily explained in terms of poor diet, decreases in exercise, and other lifestyle factors. (I am planning a future series on weight loss, so stay tuned!) However, this research raises the possibility that hormone-disrupting contaminants such as BPA may play a role in regulating weight. BPA triggers and then stimulates two of the key biological mechanisms underlying obesity. It increases the number of fat cells, and it enhances their fat storage.
Health authorities in the US make the claim that the levels of BPA found in most humans are not a risk to human health. However, researchers working in the field have a different view. Ample evidence suggests that BPA can harm lab animals at concentrations below those already occurring in most people.
A report (PDF) published in Reproductive Toxicology by 38 scientists evaluated the strength of data from more than 700 BPA studies.
The panel concluded that BPA exposure in the womb permanently alters the genes of animals, impairs the function of organs in ways that persist into adulthood, and triggers brain, behavioral, and reproductive effects, including diminished sperm production. Effects deemed likely included a heightened sensitivity to carcinogens, impaired immunity, and diminished insulin sensitivity.
Although the jury is still out on BPA’s ability to cause weight gain in humans, I think the consequences of obesity and the diseases it’s linked to far outweigh the “convenience” of drinking out of plastic water bottles. Of course there are several other reasons not to use plastic water bottles, including the waste they generate and their harmful effect on oceans and sea life.
So do yourself and the planet a favor: get a stainless steel water bottle, and abstain from drinking bottled water! I like the Klean Kanteen brand, but there are many others.
It has also been shown that polycarbonate baby bottles heated by microwave leach BPA into milk fed to infants. So Moms, please don’t heat those bottles in the microwave!
{ 9 comments… read them below or add one }
What do you make of that report that came out last fall about credit card receipts and BPA? I’ve been wary of receipts since then, but haven’t heard any follow up… Thanks, Dan
I didn’t see that report, Daniel. In general I think it’s wise to minimize BPA exposure to the extent that we can. Some is unavoidable.
The water bottles portrayed in your post are PET (polyethylene terephthalate). PET doesn’t have BPA but the jury is still out as to the safety of PET as this Discovery article points out but many people believe PET is much safer than the hard clear BPA plastics.
Hi Chris, good post, but there seems to be something wrong with the link in the following paragraph (or is it just my browser (Chrome)?):
“A report (PDF) published in Reproductive Toxicology by 38 scientists evaluated the strength of data from more than 700 BPA studies.”
From which study is the picture with the two mice?
Paleofriend,
The mouse picture is from Jenny Ruhl’s book “Blood Sugar 101″, on p.36. I believe it comes originally from an article by Janet Raloff published in Science News on 9/29/07 called Do Common Plastics and Resins Carry Risks?
Thanks for the article, but what’s the source of this,
Not only did BPA trigger the conversion of pre-adipocytes to adipocytes, it also stimulated the conversion process once triggering had occurred. This “double-whammy” effect caused a 1,300% increase in fat levels, compared with a 150% increase with insulin alone.
?
H. Masuno et al, “Bisphenol A in Combination with Insulin Can Accelerate the Conversion of 3T3-L1 Fibroblasts to Adipocytes,” Journal of Lipid Research 43:676-684, May 2002.
This is the abstract of the experiment that found that there is a 1300% increase in fat levels.
Once the BPA has been removed, does the weight gain stop? Is the weight gain permanent? Interestingly enough, my son was (plastic) bottle fed from 4+ months (due to circumstances beyond my control) and my daughter was breast fed (no bottle, ever) until she told me she was ready to wean at 9 months. My son has always had a weight problem and my daughter is as slim as ever. Any suggestions for reversing this effect?
Once the BPA has been removed, does the weight gain stop? Is the weight gain permanent? Interestingly enough, my son was (plastic) bottle fed from 4+ months (due to circumstances beyond my control) and my daughter was breast fed (no bottle, ever) until she told me she was ready to wean at 9 months. My son has always had a weight problem and my daughter is as slim as ever. Any suggestions for reversing this effect?
{ 3 trackbacks }