A common coating used in soft drink cans could cause high blood pressure and put heart patients at risk, a new study has warned.
The consumption of BPA, a chemical used as an epoxy lining for cans and plastic bottles, has been associated with high blood pressure and heart rate variability. Previous studies have shown that BPA can leach into foods and drinks.
"A 5 mm Hg increase in systolic blood pressure by drinking two canned beverages may cause clinically significant problems, particularly in patients with heart disease or hypertension," said Yun-Chul Hong, study author and chair of the Department of Preventive Medicine and director of the Environmental Health Centre at Seoul National University College of Medicine in South Korea.
"A 20 mm Hg increase in systolic blood pressure doubles the risk of cardiovascular disease," said Hong.
In this study, researchers conducted a randomised crossover trial recruiting 60 adults, mostly Korean women, over the age of 60 from a local community centre. Each trial member visited the study site three times and was randomly provided with soy milk in either glass bottles or cans. Later urine was collected and tested for BPA concentration, blood pressure and heart rate variability two hours after consumption of each beverage. Urinary BPA concentration increased by up to 1,600 per cent after consuming canned beverages compared to after consuming the glass-bottled beverages.
Soy milk was the ideal beverage for the test because it has no known ingredient that elevates blood pressure, researchers said. The study may provide important information for decision-makers, clinicians and the public on the heart risks associated with BPA, researchers said.
"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," Hong said. "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," Hong said.
The research was published in the American Heart Association's journal Hypertension.