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Omega-3s From Fish Over Flax for Cancer Prevention, Study Finds
University of Guelph
Omega-3s from fish pack a stronger
punch than flaxseed and other oils when it comes to cancer prevention,
according to a first-ever University of Guelph study.
Prof. David Ma has discovered that
marine-based omega-3s are eight times more effective at inhibiting tumour
development and growth.
The study was reported on in
the Daily Mail, one of the largest newspapers in the United Kingdom.
It also appeared in a CBS Boston story.
“This study is the first to compare the cancer-fighting potency of plant- versus marine-derived omega-3s on breast tumour development,” said the professor in the Department of Human Health and Nutritional Sciences.
“There is evidence that both omega-3s from plants and marine sources are protective against cancer, and we wanted to determine which form is more effective.”
There are three types of omega-3
fatty acids: a-linolenic acid (ALA), eicosapentaenoic acid (EPA) and
docosahexaenoic acid (DHA). ALA is plant-based and found in such edible seeds
as flaxseed and in oils, such as soy, canola and hemp oil. EPA and DHA are
found in marine life, such as fish, algae and phytoplankton.
Published in the Journal of
Nutritional Biochemistry, the study involved feeding the different types of
omega-3s to mice with a highly aggressive form of human breast cancer called
HER-2. HER-2 affects 25 per cent of women and has a poor prognosis.
Ma exposed the mice to either the
plant-based or the marine-based omega-3s, beginning in utero.
“The mice were exposed to the
different omega-3s even before tumours developed, which allowed us to compare
how effective the fatty acids are at prevention,” said Ma. “It’s known that EPA
and DHA can inhibit breast tumour growth, but no one has looked directly at how
effective these omega-3s are compared to ALA.”
Ma found overall exposure to
marine-based omega-3s reduced the size of the tumours by 60 to 70 per cent and
the number of tumours by 30 per cent.
However, higher doses of the
plant-based fatty acid were required to deliver the same impact as the
marine-based omega-3s.
Omega-3s prevent and fight cancer by
turning on genes associated with the immune system and blocking tumour growth
pathways, said Ma.
“It seems EPA and DHA are more
effective at this. In North America, we don’t get enough omega-3s from seafood,
so there lies an opportunity to improve our diet and help prevent the risk of
breast cancer.”
Based on the doses given in the
study, Ma said, humans should consume two to three servings of fish a week to
have the same effect.
Besides certain foods containing EPA
and DHA, supplements and functional foods, such as omega-3 eggs or DHA milk,
can offer similar cancer prevention effects, he added.
The next step is to investigate the
effects of omega-3s on other forms of breast cancer.
“Seeing the significant benefits
omega-3s can have in combating a highly aggressive form of breast cancer means
omega-3s will likely be beneficial for other types of cancer.”
