BPA is used as an inner coating for beverage cans and can also be found in plastic bottles, food containers, optical discs and dental fillings.
Bisphenol A (BPA) is a common chemical, found in products such as plastic bottles and the inner lining of food cans. According to the authors of the study, BPA exposure has been detected in more than 95% of the US population.
The research, published in Hypertension, follows up on previous work associating BPA with cardiovascular disorders such as high blood pressure and heart rate variability.
There is also evidence that BPA can leach into food and drinks from the lining of containers. An earlier randomized crossover trial demonstrated that eating canned soup for 5 days running increased urinary BPA concentration by more than 1000%, in comparison with eating soup made from fresh ingredients.
"A 5 mmHg increase in systolic blood pressure by drinking two canned beverages may cause clinically significant problems, particularly in patients with heart disease or hypertension," says study author Dr. Yun-Chul Hong of Seoul National University College of Medicine in South Korea. "A 20 mmHg increase in systolic blood pressure doubles the risk of cardiovascular disease."
Drinking from cans led to urinary BPA concentration increase of 1,600%
Dr. Hong and Dr. Sanghyuk Bae conducted a new randomized crossover trial, whereby participants would be given soy milk to drink, provided in either cans or glass bottles.
A total of 60 participants, all aged over 60 years, were recruited from a local community center. The participants visited the study site three times, and each time, they were randomly given soy milk in either two glass bottles, two cans, or one can and one glass bottle.
After 2 hours, the participants' blood pressure, heart rate variability and urinary BPA concentration were measured. Participants were asked not to eat or drink any other food for the 2 hours after drinking the soy milk, and for at least 8 hours before each trial.
The researchers chose soy milk for the participants to drink as it does not contain any ingredients known to elevate blood pressure.
The participant's urinary BPA concentration rose by up to 1,600% following the consumption of canned soy milk, compared with consumption of soy milk from glass bottles.
Systolic blood pressure increased by approximately 4.5 mmHg after the consumption of two canned beverages, compared with after the consumption of two glass-bottled beverages. No statistically significant differences in heart rate variability were observed.
Fresh foods and glass bottle-contained foods recommended
Dr. Hong explains the strength of their study's design:
"Thanks to the crossover intervention trial design, we could control most of the potential confounders, such as population characteristics or past medical history. Time variables, such as daily temperatures, however, could still affect the results."
Although their study demonstrates the acute effect of BPA exposure, the authors note that the associations of repeated or chronic BPA exposure with cardiovascular diseases still require further evaluation in a longitudinal study with a larger sample size.
The authors believe their findings could be informative to clinicians, policy writers and the public with regards to the potential heart risks associated with BPA.
Dr. Hong recommends avoiding exposure to BPA where possible. "I suggest consumers try to eat fresh foods or glass bottle-contained foods rather than canned foods and hopefully, manufacturers will develop and use healthy alternatives to BPA for the inner lining of can containers," he concludes.
Previously, Medical News Today reported on a study suggesting there is an association between prenatal exposure to BPA and diminished lung functioning in children.