Broccoli
of andere koolsoorten voor het voorkomen van kanker?*
Broccoli
is de belangrijkste bron van de bioactieve stof glucosinolaat die in het lichaam
omgezet wordt in isothiocyanaat. Van isothiocyanaat is bekend dat dit een van de
krachtigste kankerbestrijders in de voeding is. De helft van alle mensen heeft
wel een uitdaging want zij missen een glutathion gen en wel GSTM1 waardoor
slechts een deel de glucosinolaten in het lichaam opgenomen wordt en er dus ook
minder isothiocyanaat gemaakt wordt. Zij zouden meer broccoli moeten eten of
super-broccoli (een speciaal gekweekte soort die ruim 3x zoveel glucosinolaten
bevat). Ook zouden zij meer andere koolsoorten en chinese kool kunnen eten. Een
algemeen advies voor iedereen is dan eet behalve broccoli ook zoveel mogelijk
andere kruisbloemige groenten.
Broccoli,
Cancer Protection - Depending On Your Genes, You May Need To Eat More Than Other
People, Or Consume 'super Broccoli'
People who gain less protection from cancer by eating
broccoli may be able to compensate for the difference in their genetic make-up
by eating ‘super broccoli', a variety with higher levels of the active plant
chemical sulforaphane, or by eating larger portions.
Lead scientist on the new research, Professor Richard Mithen of the Institute of
Food Research (IFR), said: “Eating a few portions of broccoli each week may
help to reduce the risk of cancer. Some individuals, who lack a gene called
GSTM1, appear to get less cancer protection from broccoli than those who have
the gene.
“Our studies suggest that this may be because if you lack the gene you cannot
retain any sulforaphane inside your body, it is all excreted within a few hours.
However, if you consume larger portions of broccoli, or broccoli with higher
levels of sulforaphane, such as the ‘super broccoli', you may be able to
retain as much sulforaphane in your body as those who have the gene. Eating
larger portions may have additional benefits since broccoli is also a rich
source of other vitamins and minerals”.
Broccoli is the main source of natural compound sulforaphane. It belongs to the
crucifer family of plants which includes the brassica vegetables cabbage,
cauliflower and Brussels sprouts, and the closely related Chinese cabbage and
turnips. Other crucifers include watercress and salad rocket. The most
distinctive characteristic of crucifers is that their tissues contain high
levels of glucosinolates. When they are eaten, glucosinolates are broken down to
release isothiocyanates. There is a well established body of evidence to show
that isothiocyanates are among the most potent dietary anticarcinogens known.
Sulforaphane is the main isothiocyanate derived from broccoli. ‘Super
broccoli' contains 3.4 times more sulforaphane than standard varieties. It has
been developed by traditional plant breeding methods.
Fifty per cent of the population lack the GSTM1 gene. While these people may
gain less cancer protection from consuming broccoli, it is likely that they gain
more cancer protection from eating other types of crucifers, such as cabbages
and Chinese cabbage. So the best advice is to eat a mixture of crucifers.
This research was funded by IFR's Core Strategic Grant from the Biotechnology
and Biological Sciences Research Council and by the University of Nottingham and
Seminis Inc. It is part of ongoing research at IFR to identify the optimal
levels of a range of food compounds for human health.
The mission of the Institute of Food Research (www.ifr.ac.uk) is to undertake
international quality scientific research relevant to food and human health and
to work in partnership with others to provide underpinning science for consumers,
policy makers, the food industry and academia. It is a company limited by
guarantee, with charitable status, grant aided by the Biotechnology and
Biological Sciences Research Council (http://www.bbsrc.ac.uk).
The University of Nottingham is one of the UK's leading universities and is
consistently ranked in the top ten. With recently opened campuses in both China
and Malaysia, it has more than 31,000 students in total, including 6,000
international students from more than 100 nations. The University has 33
top-rated teaching subjects and research awards for 2004-5 topped £100m - a
testament to its reputation for world-class research. The Sunday Times
University Guide 2005 said: "At the cutting edge both academically and in
terms of revenue raising, Nottingham is one of the finest institutions in the
country."
Seminis Inc. (http://www.seminis.com) is the world's leading developer,
producer and marketer of vegetable seeds. Its products are designed to increase
crop yields, reduce dependence on agricultural chemicals, limit spoilage, offer
longer shelf life, and produce vegetables and fruits with better taste and
nutritional content. Seminis has established a worldwide presence and global
distribution network that spans 150 countries. It is developing commercial
varieties of broccoli with enhanced levels of glucosinolates for consumers.
(December
2005)
