Bescherming tegen kanker begint tijdens zwangerschap.*
Uit een Amerikaanse studie van het beroemde Linus Pauling instituut blijkt dat gezonde voeding, waaronder veel kruisbloemige groenten voor vrouwen in verwachting en tijdens de borstvoeding belangrijk is ter voorkoming van het ontstaan van kanker bij hun kind. Deze bescherming geldt voor dat kind niet alleen tijdens zijn jeugd maar ook later in zijn leven. De studie werd uitgevoerd met muizen. De bioactieve stoffen van kruisbloemige groenten gaven een zeer hoge bescherming tegen leukemie en lymfeklierkanker bij jonge nakomelingen en beschermden ook tegen longkanker op middelbare leeftijd. Uit eerdere studies is al gebleken dat giftige stoffen in het milieu, waaronder PAK’s en dioxines de oorzaak kunnen zijn van kanker bij kinderen. Bij langere blootstelling aan deze giftige stoffen worden deze ook doorgegeven aan de foetus. In de studie werden zwangere muizen blootgesteld aan de giftige stof benzopyreen. 80% van de babymuizen stierf aan een agressieve vorm van lymfeklierkanker. De resterende 20% overleed op middelbare leeftijd aan longkanker. Als nu behalve dit gif ook een supplement van extracten van indolen (belangrijke bioactieve stoffen in vooral kruisbloemige groenten) gegeven werden daalde het aantal sterfgevallen aan lymfeklierkanker wel met 50% terwijl het aantal doden door longkanker op latere leeftijd ook drastisch afnam. Alleen moedermuizen kregen tijdens de zwangerschap en het zogen het supplement. De babymuizen kregen geen enkel supplement, ook niet later in het leven. De wetenschappers benadrukken nog dat het voor zwangere vrouwen niet verstandig is om ook supplementen te nemen doch gewoon voldoende kruisbloemige groenten. Supplementen kunnen wellicht een te hoge dosering geven hetgeen weer nadelig voor de baby kan zijn.
Protection
Against Cancer May Begin During Pregnancy
There
may be another reason for pregnant and nursing women to eat a nutritious diet
that includes generous amounts of cruciferous vegetables like broccoli and
cabbage - it could help protect their children from cancer, both as infants and
later in life.
A new study by scientists from the Linus Pauling Institute at Oregon State
University, done with laboratory mice, found that supplements of a key
phytochemical found in certain vegetables provided a very high level of
protection against leukemia and lymphoma in young animals, and also
significantly protected against lung cancer during the rodent's equivalent of
middle age.
The research, published in the journal Carcinogenesis, is one of the first of
its type to demonstrate that diet may play a protective role in a fight against
cancer that may begin - and could be won or lost - well before a person is ever
born. And some of the protective benefits may last into adulthood.
"Research of this type is still in its infancy, but it's pretty exciting,"
said David Williams, an LPI researcher and director of the Marine and Freshwater
Biomedical Sciences Center at OSU.
"There's strong epidemiologic evidence that infant cancers can be caused by
exposure of the fetus to carcinogens, either during pregnancy or by nursing,"
Williams said. "Among all childhood deaths in the U.S., cancer is second
only to accidents as the leading cause, and the fetus and neonate are sensitive
targets for toxic carcinogens. It would be important if we could affect this
through maternal diet."
There are particular concerns about common environmental pollutants called
polycyclic aromatic hydrocarbons, or PAHs, which can be produced by cigarette
smoking or the combustion of organic materials such as wood, coal, cooking oil
or diesel fuel. Exposure of a fetus to PAHs has been shown to cause DNA damage
in newborns and is also associated with increased levels of childhood leukemia.
It has also been shown that a significant portion of the total lifetime exposure
to PAHs and other toxins, including PCBs and dioxins, is transmitted to the
fetus across the placental barrier and during nursing.
In laboratory studies, researchers exposed pregnant mice to a single high dose
of one PAH called dibenzopyrene, a potent carcinogen, and about 80 percent of
their 100 offspring died early in life from an aggressive T-cell lymphoma. Of
those that survived to the mouse-equivalent of middle age, 100 percent had lung
tumors.
By comparison, in a group of pregnant mice given the same carcinogen but who
also received the chemoprotective supplement Indole-3-carbinol, or I3C, deaths
from lymphoma were cut in half, and the number of lung tumors later in life was
significantly reduced.
"It's clear that in mice this supplement provided significant protection
against lymphoma and, later on, lung cancer," Williams said. "It's
also worth noting that none of the infant mice received the protective
supplement later in their life, at any stage beyond breast feeding. The
protective effect of the compound came solely from maternal intake during
pregnancy and nursing, but lasted into the animal's middle age. This is somewhat
remarkable."
Although lung cancer is the leading cause of cancer death in both men and women,
it's also true that only about one smoker in 10 gets lung cancer. It's possible,
researchers say, that dietary and other factors in addition to smoking may
predispose some smokers to get cancer while others don't. That this process may
begin with carcinogens crossing the placental boundary - and might be affected
by diet - is an area that has not been adequately studied, Williams said. In
this study, both the exposure to carcinogens and the levels of Indole-3-carbinol
given to pregnant mice through supplements were higher than those that would
ordinarily be found in the environment or a normal diet, researchers said.
The scientists do not recommend that pregnant women take supplements of this
compound, which is available in health food stores, because there have been
questions about its possible role in causing birth defects when ingested at high
levels in the first trimester of pregnancy. That topic needs further study, they
said.
However, the amounts of this and other valuable phytochemicals that could be
obtained in any normal diet rich in cruciferous vegetables should be safe and
useful, they said. These vegetables include broccoli, cabbage, cauliflower,
kale, radishes, turnips and other types of greens and cabbages.
Indole-3-carbinol is also being studied by scientists in other U.S. research
programs for chemoprotection of women against breast cancer.
Cancer chemoprotection is one of the main research areas at the Linus Pauling
Institute, a world leader in the study of vitamins, phytochemicals and other
nutrients that may help prevent disease or provide optimum health.
###
This
research was funded by the National Institutes of Health. (Jan. 2007) (Opm.
Kruisbloemige groeten zijn o.a. broccoli, diversen koolsoorten, radijs
en knolraap)