The latest study by researchers at the Harvard School of Public Health, in the USA, has raised fresh debate over the regulation of Bisphenol A (BpA), a chemical compound often used as protective lining on the inside of cans containing food or beverages.

The Harvard study’s findings were published on 22 November 2011, in the Journal of the American Medical Association. The researchers say their study is one of the first to quantify BpA levels in humans after ingestion of canned foods.

Exposure to BpA has been shown to interfere with reproductive development in animals and has been linked with cardiovascular disease, diabetes, and obesity in humans.

BPA has been considered to be cost effective and durable, which has led to its widespread usage, especially in baby bottles, reusable water bottles, microwave ovenware and food package linings.

In the European Union and Canada, BpA use in baby bottles has previously been banned.

In January 2010, Australia’s food agency Food Standards Australia New Zealand (FSANZ) evaluated the safety of BpA in food. It concluded that levels of intake of BpA do not pose a significant human health risk for any age group. An international panel of experts established by the World Health Organization and the Food and Agricultural Organization of the United Nations also found that BpA is not accumulated in the body and is rapidly eliminated through urine.

However, in June 2010, the Australian Government announced the voluntary phase-out by major Australian retailers of polycarbonate plastic baby bottles containing BpA. The government claimed this was “in response to consumer preference and demand and not an issue about product safety”.

Harvard study focused on migration of BpA in canned soup

In the Harvard study, a group of people consumed canned soup each day for five days. The researchers found that these people had a more than 1,000 per cent increase in urinary Bisphenol A (BpA) concentrations compared with when the same individuals consumed fresh soup daily for five days.

The researchers, led by Dr Jenny Carwile and Dr Karin Michels, associate professor in the Department of Epidemiology, recruited student and staff volunteers from the Harvard School of Public Health. One group consumed a 12-ounce serving of vegetarian canned soup each day for five days; another group consumed 12 ounces of vegetarian fresh soup (prepared without canned ingredients) daily for five days. After a two-day “washout” period, the groups reversed their assignments.

Urine samples of the 75 volunteers taken during the testing showed that consumption of a serving of canned soup daily was associated with a 1,221 per cent increase in BpA compared to levels in urine collected after consumption of fresh soup.

Senior author of the study, Dr Michels said, “The magnitude of the rise in urinary BpA we observed after just one serving of soup was unexpected and may be of concern among individuals who regularly consume foods from cans or drink several canned beverages daily. It may be advisable for manufacturers to consider eliminating BpA from can linings.”

Despite Food Standard Australia New Zealand assuring consumers that BpA is expressed through urine, this assurance does not appear to be dispelling the mounting concerns as to what the BpA may be doing while it is in the human body, especially its effect on the endocrine system.

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