McGill: A commonly used plasticizer known as DINCH, which is found in products that come into close contact with humans, such as medical devices, children's toys and food packaging, might not be as safe as initially thought. According to a new study from the Research Institute of the McGill University Health Centre (RI-MUHC) in Montreal, DINCH exerts biological effects on metabolic processes in mammals. The findings, published in the journal Environmental Research, may have important implications since DINCH has been promoted by industry has as a safe alternative to phthalate plasticizers, despite there being no publicly available peer-reviewed data on its toxicology.
"This is the first study to show a biological disruptive effect of
the plasticizer DINCH and its metabolites on the metabolism in mammals,"
states study lead author, Dr. Vassilios Papadopoulos, who is a
researcher in the Experimental Therapeutics and Metabolism Program of
the RI-MUHC and a professor of Medicine at McGill University. "These
findings show that DINCH might not be as safe as it has been promoted
and there is a real need for more research on the safety and the use of
this widely used product.''
Health concerns about plasticizers have been the subject of
considerable scientific, legal and media debate in recent years. Some
phthalates - which are among the best-known plasticizers - have been
restricted or banned in children's products across North America and in
many countries in Europe, during the last 10 years, because of their
effects on reproductive health. DINCH (1,2-cyclohexanedicarboxylic acid,
diisononyl ester) has been used as an alternative and is approved and
certified by many authorities and institutions worldwide; however, until
now there have been no peer-reviewed research publications on its
safety and potential metabolic and endocrine-disrupting properties.
The research team at the RI-MUHC, which has been working on
phthalates for years, decided to evaluate the effects of DINCH and two
of its major metabolites (CHDA and MINCH) with in-vitro experiments on
the adipose tissue of rats. In fact, the researchers initially used
DINCH as a control, since it was believed to be safe, but found that it
was working in the same way as the phthalates. The action of DINCH was
found to be particularly similar to a type of phthalate known as DEHP, a
group of chemicals whose use in Canada and the US was restricted to
small amounts in all children's products 2011, at the same time as the
EU began phasing out their use.
The study shows that DINCH's metabolite (MINCH) acts as a metabolic
disrupter by affecting adipose tissue differentiation, in other words
how fat is made in the body. They also found that, similar to
phthalates, the effect of MINCH was mediated by a receptor involved in
both the metabolic and endocrine systems, which allowed the researchers
to infer that MINCH could interfere with the endocrine system in
"We were surprised by these findings since DINCH was supposed to be a
trusted plasticizer devoid of phthalate effects," says Dr.
Papadopoulos. "The fact that MINCH can affect metabolism, which is a
major regulator system of our body, is concerning."
"It is currently difficult to assess whether DINCH exposure
represents a risk to human health, but specific populations such as
occupational workers could be at risk if the level of DINCH reaches
environmental levels as high as the banned phthalate DEHP, " adds Dr.
According to the researchers, considering the continuous exposure of
humans to plastics throughout life and the fact that there are periods
in life when humans are more sensitive to exposures (such has early
development), the effects of this plasticizer should be evaluated more