Omega-3
vetzuren in vis gaan uitzaaiingen bij prostaatkanker tegen.*
Uit
Engels onderzoek blijkt dat omega-3 vetzuren, die gevonden worden in vette
vis, het uitzaaien van prostaatkankercellen tegengaan. De twee
belangrijkste meervoudig onverzadigde vetzuren zijn omega-3 en omega-6.
Beide zijn belangrijk voor essentiële functies in het lichaam. Doch teveel
omega-6 vetzuren bevorderen de groei en verspreiding van kankercellen,
voldoende omega-3 vetzuren daarentegen blokkeren dit. Een goede verhouding
tussen omega-3 en omega-6 bij kanker is 1:2.
Oily
Fish Diet May Reduce The Spread Of Prostate Cancer
Eating foods such as fish that are
rich in omega 3 fats might help prevent the spread of prostate
cancer to other parts of the body,
according to research published in the British Journal of Cancer* today (Tuesday).
Prostate cancer is the most common male cancer in the UK. Men face a much
more dangerous form of the disease if tumour cells from the prostate gland
migrate and invade other parts of the body such as bone marrow. However,
researchers funded by the Association for International Cancer Research (AICR)
and the Medical Research Council (MRC), and based at the Paterson Institute
at the Christie Hospital in Manchester, have found that an omega 3 fat can
inhibit invasion by prostate cancer cells in laboratory tests, which may
reduce their ability to spread to secondary sites.
Omega 3 fats are found in so-called 'oily' fish such as salmon, mackerel and
fresh tuna. It has previously been claimed that they have protective effects
against cancer. This research, though still at an early stage, suggests that
a diet rich in particular omega 3 fats might protect men with prostate
cancer from developing a more aggressive
form of the disease.
There are two main groups of polyunsaturated fatty acids found in our diet -
omega 3 and omega 6. Both types have essential roles in keeping us healthy
but the Manchester research shows they have very different effects on
prostate cancer cells.
Dr Mick Brown from the Paterson Institute, chief scientist in the research
group, said: "Omega 6 fats, found in vegetable oils, nuts and seeds,
increased the spread of tumour cells into bone marrow. This invasion was
blocked by omega 3 fats - the ones found in oily fish. It is possible to
have a healthy balance of these two types of fat - we only need about half
as much omega 3 as omega 6 - that will still stop cancer cells from
spreading."
Mr Noel Clarke, consultant urologist at the Christie Hospital and principal
investigator of the research group, said: "We think tumours may exploit
the omega 6 fats as a high energy source - giving them the energy they need
to maintain a high growth rate - and to create important signalling
molecules. Omega 3 fats are known to interfere with the various functions of
omega 6 fats, something confirmed by our findings. This effectively removes
the cancer's 'free lunch', a fact that may have clinical importance.
"Some tumours develop slowly in the prostate without producing symptoms
and sometimes when symptoms do develop, it is because the cancer has already
spread. Eating a diet with the right balance of omega 3 and omega 6 fats may
well help to keep prostate cancer within the prostate gland where it may be monitored
safely or more easily treated with surgery or radiotherapy."
The Food Standards Agency recommends men can eat up to four portions** of
oily fish a week.
Derek Napier, chief executive of the AICR, said: "Understanding what
drives prostate cancer cells to invade the bone marrow might enable the
development of ways to interfere with that process. We know that many forms
of the disease, including breast and prostate cancer, seem to invade bone marrow rather than
other parts of the body. If it could be shown that this is influenced by the
proportion of different types of fat, then we might be able to develop drugs
that limit the movement of cancer cells."
Professor John Toy, medical director of Cancer Research UK, which owns the
British Journal of Cancer, said: "Diet is a factor in many types of
cancer, but its potential role is not yet fully clear in prostate cancer.
This research shows an effect in the laboratory. However, we would need
large population studies to provide the needed evidence to say a change in
diet could reduce prostate cancer cells from spreading.
"Cancer Research UK advises people to reduce their risk of cancer by
eating a healthy diet, high in fibre, fruit and vegetables and low in red
and processed meat."
*Brown, M.D., et al. (2006)
British Journal of Cancer 94 (6) - www.nature.com/bjc.
**A portion is 140g. Girls and women who are of childbearing age are advised
to eat less oily fish than men - up to 2 portions a week. The Food Standards
Agency has more information and advice on how much fish we should be eating,
including
a list of oily fish.
The BJC's mission is to encourage communication of the very best cancer
research from laboratories and clinics in all countries. Broad coverage, its
editorial independence and consistent high standards have made BJC one of
the world's premier general cancer journals.
The Association for International Cancer Research (AICR) is a totally
independent charity based in St Andrews in Scotland. It has no commercial
ties, no links with any particular research institutions and no commitment
to follow any particular line of research. It funds what it considers to be
the best researchers and the most valuable studies, wherever they are in the
world. This innovative approach to funding research has enabled AICR to
contribute significantly to furthering man's understanding of cancer. For
more information please call 01334 477910 or visit the AICR's website at www.aicr.org.uk
The Christie Hospital NHS Trust in Manchester is one of the largest cancer
treatment centres in Europe. It covers a population of 3.2 million across
Greater Manchester and Cheshire, but because of its expertise take cancer
patients from across the North West and beyond. It is also one of the
leading centres in the UK for clinical trials. Every year the Christie
registers over 12,000 new patients and treats around 180,000.
-- Cancer Research UK's vision is to conquer cancer through world-class
research.
-- The charity works alone and in partnership with others to carry out
research into the biology and causes of cancer, to develop effective
treatments, improve the quality of life for cancer patients, reduce the
number of people getting cancer and to provide authoritative information on
cancer.
-- Cancer Research UK is the world's leading independent charity dedicated
to research on the causes, treatment and prevention of cancer.
http://www.cancerresearchuk.org
( maart 2006)