BPS induced human fat cell formation in the new study.
Published In the journal Endocrinology, the study found that bisphenol S (BPS) boosted the formation of human fat cells, suggesting that exposure to the chemical may interfere with the body's endocrine system, just like BPA.
Since the 1960s, BPA has been used in polycarbonate plastics - including some used for food and drink packaging - and epoxy resins, used to coat metal products such as food cans and water supply pipes.
As such, the greatest source of daily human exposure for BPA is through food and drinks.
Numerous studies have shown that BPA is an endocrine-disrupting chemical, meaning it may interfere with the body's naturally occurring hormones to produce a number of adverse effects.
A 2014 study reported by Medical News Today, for example, suggested that exposure to BPA in cans and plastic bottles may increase blood pressure, while another study claimed BPA may be linked to infertility in women.
As a result of such studies and because BPA exposure is so widespread, some manufacturers have started to use BPS and other chemicals as a BPA replacement, with many of these products now labeled BPA-free.
However, concerns have been raised that these substitute chemicals may be just as harmful; one study published last month suggests that BPS speeds up embryonic development and disrupts the reproductive system.
"Since BPS is one of the replacement chemicals used in consumer products that are marketed as BPA-free, it is important to examine whether BPS acts as an endocrine-disrupting chemical," says senior study author Ella Atlas, PhD, of Health Canada - the federal department responsible for helping Canada's residents maintain and improve their health.
Smallest and highest BPA concentrations led to lipid accumulation
For this latest study, Atlas and colleagues set out to assess the effects of BPS on human cells.
The researchers used preadipocytes that they took from the hip, thigh or abdomen of female volunteers. Preadipocytes are undifferentiated cells that have the ability to turn into fat cells, or adipocytes.
Cells were exposed to either BPS or the chemical dexamethasone - known to induce a specific level of fat cell formation and build-up of lipids in blood and tissue - at various concentrations for 14 days.
The researchers found that exposure to BPS at all concentrations encouraged fat cell formation; both the highest and smallest concentrations of BPS led to the largest lipid build-up, while moderate concentrations led to a smaller accumulation.
The team notes that even exposure to small amounts of endocrine-disrupting chemicals can interfere with hormone functioning. This is because modest changes to hormone levels are devised to induce alterations to numerous bodily functions, including metabolism, heart rate and respiration.
The researchers believe their findings indicate that BPS may be an endocrine-disrupting chemical. Atlas says:
"This study shows that BPS and BPA have similar effects on fat cell formation, lipid accumulation and expression of genes important for lipid metabolism."
Earlier this year, a study reported by MNT found that another chemical in food packaging - di-(2-ethylhexyl)-phthalate (DEHP) - led to a hormone imbalance in female mice that triggered weight gain.