Bisphenol A May Promote Obesity By Interfering with Leptin Early in Life

MedicalResearch.com Interview with:
Alfonso Abizaid PhD

Department of Neuroscience
Carleton University

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Bisphenol A (BPA) is a compound considered to be a potential environmental hazard and an endocrine disruptor. We have found an association between exposure to BPA at levels that are considered safe by Health Canada and the EPA early in life, and the development of obesity. In addition, we found that this propensity to develop obesity is due to under development of the hypothalamic projection field of POMC neurons, a set of neurons that regulate satiety and stimulate metabolic rate.

In this paper we replicate those findings and also show that this abnormal development is due to BPA altering the secretion of the hormone leptin at critical times where this hormone is important for the post-natal development of these POMC neurons.

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Don’t Heat Food in Plastic Containers, Even If Microwave or Dishwasher Safe

MedicalResearch.com Interview with:

Dr. Nancy Wayne, PhD Member, Brain Research Institute Molecular, Cellular & Integrative Physiology GPB Home Area Neuroscience GPB Home Area David Geffen School of Medicine UCLA

Dr. Nancy Wayne

Dr. Nancy Wayne, PhD
Member, Brain Research Institute
Molecular, Cellular & Integrative Physiology
GPB Home Area
Neuroscience GPB Home Area
David Geffen School of Medicine UCLA

Medical Research: What is the background for this study? What are the main findings?

Dr. Wayne: I started this work because of my concern about our continuous exposure to BPA and other endocrine disrupting chemicals. Our first study published in 2008 showed that low doses of BPA accelerated embryonic development and birth within 24 hours of exposure. We extended this work more recently by investigating the impact of BPA and BPS (a common BPA-substitute) on the timing of birth and development of the reproductive system in embryos.

Our research showed that low levels of BPS had a similar impact on the embryo as BPA. In the presence of either BPA or BPS, embryonic development was accelerated leading to abnormal stimulation of the reproductive system. Additionally, BPA caused premature birth. This is cause for concern with human health consequences to long-term exposure to low levels of potentially dozens of endocrine disrupting chemicals that are in our environment.

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BPA in Canned Soda Linked to Increased Blood Pressure

MedicalResearch.com Interview with:
Yun-Chul Hong MD, PhD
Chair, Department of Preventive Medicine
Director, Institute of Environmental Medicine
College of Medicine Seoul National University

MedicalResearch: What is the background for this study? What are the main findings?

Dr. Yun-Chul Hong: Because there are some reports showing Bisphenol-A exposure increase when we eat or drink canned food or beverage and at the same time it has been known that Bisphenol-A exposure is associated with blood pressure increase, we conducted this study to examine whether consuming canned beverage and consequent increase of Bisphenol-A exposure actually increase blood pressure. We found that drinking 2 canned beverages increase in 5 mmHg of systolic blood pressure.
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Sales Receipts May Lead to High Levels of BPA Absorption

Julia A. Taylor, Ph.D. Assistant Research Professor Division of Biological Sciences University of Missouri Columbia, MO 65211MedicalResarch.com Interview with:
Julia A. Taylor, Ph.D.
Assistant Research Professor

Division of Biological Sciences
University of Missouri Columbia, MO 65211


Medical Research: What is the background for this study? What are the main findings?

Dr. Taylor: Bisphenol A (BPA) is an industrial chemical present in a large number of consumer products, including polycarbonate plastics, food can linings, resins and thermal paper. A 2008 study of BPA levels in human urine concluded that over 90% of the U.S. population is exposed to BPA. BPA is an endocrine disrupter; its estrogenic properties were first described long before its commercial use, but today it is known that it not only acts like an estrogen but also interferes with thyroid hormone, androgen and insulin action. In population-based studies, higher urinary levels of BPA have been linked to a number of human health issues. For example, higher BPA concentrations have been associated with obesity and aggressive and hyperactive behaviors in children, and with cardiovascular disease and diabetes, altered liver and kidney function, and immune and reproductive disorders in adults.

It was at one time thought that almost all human exposure occurs via food and drink, but calculations of exposure from these sources do not adequately account for the sometimes high amounts measured in urine, and the fact that BPA concentrations in population-based studies are not lower with increasing fasting time suggests that some other form of ongoing exposure. Our interest here was in thermal paper. BPA has been used as a color developer in thermal paper for many years and can be present in milligram amounts in the paper coating. Because thermal printing is widely used for items such as sales and ATM receipts, airline tickets and luggage labels, thermal paper may represent an important high-concentration source of exposure.

We screened thermal paper receipts from 50 in-state vendors and found that 44% used BPA as the color developer, but 52% used another chemical called BPS (bisphenol S) which was present in similar quantities to BPA. Two receipts contained neither BPA nor BPS, and so presumably used an alternative (unidentified) chemical.

In preliminary work we measured the transfer of BPA from thermal paper to the hands, and found much higher transfer to hands that were pre-wet using hand sanitizer. We also determined that BPA transferred to hands could then be transferred to food. In our study we asked men and women to first wet their hands with sanitizer before holding the receipts for a few minutes, and then with the same hands pick up french fries and hold them briefly before eating them. We then cleaned one hand but allowed the other to remain “contaminated”. We took blood samples over the next 90 minutes, either from the arm linked to the clean hand or the arm linked to the dirty hand, and collected a urine sample at the end.

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BPA Exposure During Pregnancy Linked With Childhood Wheezing

Adam Spanier, MD, PhD, MPH, FAAP Associate Professor of Pediatrics Division Head, General Pediatrics & Developmental and Behavioral Pediatrics Medical Director, Pediatrics at Midtown Department of Pediatrics University of Maryland Midtown Campus Baltimore, MD 21201MedicalResearch.com Interview with:
Adam Spanier, MD, PhD, MPH, FAAP
Associate Professor of Pediatrics
Division Head, General Pediatrics & Developmental and Behavioral Pediatrics
Medical Director, Pediatrics at Midtown Department of Pediatrics
University of Maryland Midtown Campus Baltimore, MD 21201

Medical Research: What are the main findings of the study?

Dr. Spanier: Bisphenol A (BPA) is a chemical that is present in many consumer products (lining of canned foods, some plastics, some receipt paper, etc).

We found that higher maternal Bisphenol A levels during pregnancy were associated with increased odds of persistent wheezing in children and a decrease in lung function at age four. Child BPA levels were not associated with these poor lung health outcomes.
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