SEOUL, SOUTH KOREA — In a small randomized, crossover study, shortly after study subjects drank canned soy milk, researchers detected high urine bisphenol A (BPA) levels, and systolic blood-pressure levels were higher than after they drank the same beverage from glass bottles.
This study builds on previous epidemiologic evidence, as reported by heartwire , showing that that people with high urine concentrations of this chemical, which is found in the plastic lining of canned foods and beverages, had a higher risk of CVD.
The current study of 60 elderly Korean participants, mainly women, was published online December 8, 2014 in Hypertension.
This was an acute effect, and “the associations of repeated or chronic BPA exposure with cardiovascular diseases are still to be evaluated in further longitudinal study,” study authors Drs Sanghyuk Bae and Yun-Chul Hong (Seoul National University, South Korea) caution.
Nevertheless, they conclude that the study presents stronger evidence that BPA “poses a substantial health risk,” and they call for greater efforts to limit this exposure. “Considering that the use of epoxy resin for the inner coating of canned food and bisphenol A exposure from consumption of canned food are almost ubiquitous, the consequent increase of blood pressure poses a substantial public-health risk,” they write. “More stringent measures should be considered to prevent exposure to bisphenol A,” Bae and Hong conclude.
What Is the Real Risk From BPA in Canned Soups or Sodas?
The researchers aimed to examine whether consuming a canned beverage and being exposed to bisphenol A would affect blood pressure and heart-rate variability.
They recruited 56 women and four men age 60 and older (mean age 73) from a community center. The study subjects had a mean blood pressure of 134/80 mm Hg, and 43% were being treated for hypertension.
The participants visited the study site three times, at 1-week intervals, after an overnight fast. They were asked to consume two servings of 195 mL of commercially available soy milk from glass bottles, cans, or both.
Two hours after they drank soy milk from plastic-lined cans, the participants’ mean urine BPA levels were 1600% higher than after they drank soy milk from glass bottles: 16.91 µg/L vs 1.13 µg/L.
Mean systolic blood-pressure levels fell by 7.9 mm Hg after the participants drank from glass bottles, but it dropped by only 2.9 mm Hg after they drank canned beverages (P=0.016), for a 5-mm-Hg difference.
This “increase” in blood pressure might explain the link between urine BPA levels and CVD seen in the epidemiologic studies, Bae and Hong suggest.
“The 5-mm-Hg increase [in systolic blood pressure] observed in the present trial may cause a clinically significant increased risk of cardiovascular disorders, such as heart diseases and peripheral arterial diseases, which were associated with increased BPA concentration in the previous epidemiological studies,” they write.
They note that they chose soy milk as the study beverage, because it does not increase blood pressure. In fact, it has been shown to lower blood pressure in patients with mild to moderate hypertension, as was observed in this study.
The study did not detect any differences in heart-rate variability.
The study was supported by a grant of the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea. The authors report they have no relevant financial relationships.