Consuming an increased number of beverages from cans and plastic bottles, which use the chemical product bisphenol A, can lead to a noticeable increase in blood pressure and, consequently, may predispose individuals to hypertension and related cardiovascular complications, a study showed.

“We had previously reported that increased urinary BPA [bisphenol A] concentration was associated with higher blood pressure and decreased heart rate variability in a panel study with elderly participants,” wrote Dr. Sanghyuk Bae and Dr. Yun-Chul Hong of Seoul (South Korea) National University, adding that, “previous epidemiological studies have reported the associations between BPA exposure and adverse health effects on the reproductive and endocrine systems. BPA exposure had also been associated with cardiovascular disorders.”

In a randomized, crossover intervention study, the investigators recruited 60 subjects aged at least 60 years because of the predisposition of elderly patients to environmental exposure. Individuals with heart diseases, cancer, liver diseases, and endocrine diseases in their medical histories were excluded from the study population ( Hypertension 2015 [doi:10.1161/HYPERTENSIONAHA.114.04261] ).

Each of these participants visited the study site a total of three times, with at least 1-week intervals in between visits, and were randomly assigned to consume two 195-mg servings of soy milk from two cans (CC), two glass bottles (GG), or one of each (CG); all subjects drank the same soy milk, manufactured by a single Korean company. Urine samples from each subject were then collected 2 hours after consumption of soy milk – during which time subjects were instructed not to eat or drink any other food – and were subsequently analyzed for BPA content within 90 minutes of collection.

The average urinary concentration of BPA was significantly higher in the CC and CG groups than in the GG group. Average urinary BPA was found to be 16.91 mcg/L for CC and 7.93 mcg/L (SD, 6.01) for CG (both P < .0001). For the GG group, however, mean urinary BPA concentration was just 1.13 mcg/L. The authors added that the average concentration of BPA in the canned beverages measured 8.22 mcg/L.

“Unlike previous trials, the present study examined only one time of exposure,” Dr. Bae and Dr. Hong noted. “However, this was sufficient to increase urinary BPA concentration by [more than] 1,600%.”

BPA found in canned beverages also had an effect on systolic blood pressure, which the investigators measured during the study. The results indicated that average systolic blood pressure in the CC group increased by around 4.5 mm Hg more than that of the GG group, with similar results being found when the analysis was adjusted for subjects who had no previous history of hypertension or diabetes mellitus.

“Hypertension is a risk factor of cardiovascular diseases, and the 20–mm Hg increase of systolic BP [blood pressure] doubles the risk of cardiovascular disease,” wrote the investigators. “In light of this, the 5–mm Hg increase observed in the present trial may cause a clinically significant increase of risk of cardiovascular disorders, such as heart diseases and peripheral arterial diseases, which were associated with increased BPA concentration in the previous epidemiological studies. However, the increase of BP followed by BPA exposure does not necessarily lead to chronic elevation of BP. The present study only accounted for the acute effect of BPA exposure.” Further study is needed, the investigators said.

The authors reported no relevant financial disclosures. This study was supported by a grant of the Korean Health Technology R&D Project, Ministry of Health & Welfare.