Madrid: Re-heating cooking medium such as sunflower oil could release
toxic compounds, which could be linked with brain diseases and some types
Researchers from the University of the Basque Country
(the region comprising three provinces of northern Spain on the Bay of
Biscay bordering france in the north-east) have been the first to discover
the presence of certain aldehydes in food, which may be linked with
neurodegenerative diseases and some cancers.
"It was known that
at frying temperature, oil releases aldehydes that pollute the atmosphere
and can be inhaled, so we decided to research into whether these remain in
the oil after they are heated, and they do," said study co-author Maria
Dolores Guillen, the journal Food Chemistry reports.
these substances had only been seen in bio-medical studies, where their
presence in organisms is linked to different types of cancer and
neurodegenerative diseases such as Alzheimer's and Parkinson's, according
to a statement.
The toxic aldehydes are a result of degradation
of the fatty acids in oil, and although some are volatile, others remain
after frying. That is why they can be found in cooked food. As they are
very reactive compounds they can react with proteins, hormones and enzymes
in the organism and impede its correct functioning.
involved heating three types of oil (olive, sunflower and flax seeds) in
an industrial deep fryer at 190 ºC. This was carried out for 40 hours,
eight hours a day in the first two, and 20 hours for the linseed oil. The
latter is not normally used for cooking in the west, but it has been
chosen due to its high content in omega 3 groups.