Eggplant, brinjal or aubergine -- the dark-purple fruit has many guises; but
is it also a colon cancer-fighting superfood as a prominent dietician would
have Nigerians believe? As Africa Check discovered, there is no proof to
support the claim.
A prominent dietician has urged Nigerians to reduce their risk of colon
cancer by eating more eggplant. Yemisi Olowookere's comments were published on
a number of news websites, all of which stated that eggplant is "an
excellent source of dietary fibre which can protect against colon cancer".
Olowookere, a dietician at the Garki Hospital in Abuja, also recommended
having eggplant with every meal to treat hyperlipidemia or excess fat in the
blood, saying studies have suggested the fruit is effective at controlling high
blood cholesterol. She added there is further proof that eggplant can fight
ageing, inflammation and neurological diseases.
According to the IQ4News website, Olowookere - who comments regularly in the
Nigerian press - made the statements during a workshop hosted by the Health of
Mother Earth Foundation.
But can eggplant, or the fibre in it, really prevent colon cancer? Or treat
hyperlipidemia? Or ageing, inflammation and neurological disease? And if it
really is this wonderful, why are more of us not gorging ourselves on brinjals?
Being healthy, in general, could reduce risk of colon cancer The exact cause
of colon cancer is not known. But there is a large body of research that
provides important clues as to the factors affecting the risk of developing
colon cancer.
In a review of the evidence, the US National Cancer Institute notes that
excessive alcohol consumption, cigarette smoking and obesity have all been
linked to colon cancer.
As a result, quitting smoking, drinking less and getting regular exercise
feature prominently in the advice for preventing colon cancer dispensed by
health authorities like the Mayo Clinic and support groups like Beating Bowel
Cancer.
According to the same review, the evidence for making dietary changes is
mixed. While some studies have found that low fat diets, reduced red, fatty
meat consumption and a diet high in fibre may offer a protective benefit,
others have not.
Still, most advice for the prevention of bowel cancer includes following a
healthy, balanced diet of vegetables, fruit, grains and cereals and low fat
protein--good advice regardless, since there are clear links between diet and
general health.
Eggplants are quite high in fibre, but so are many other foods
We could not find published research that specifically investigated the
effect of eggplant on colon cancer risk reduction in humans.
But because the claim makes specific reference to the fibre content of
eggplant, this warrants a closer look. Although it offers clear health benefits
in other ways, the role of fibre in the prevention of colon cancer has been
disputed in the past.
However, a fairly recent analysis provided evidence that cereal fibre and
grains had a positive impact on colon cancer prevention. The study does note
that more research will need to be done on the roles played by different
fibres.
There are two types of fibre--soluble and insoluble. Most plant-based foods
contain varying ratios of both. The Institute of Medicine recommends women
under 50 have 25 grams of fibre a day and men 38 grams.
Could eggplant then be a key source of fibre, helping to prevent colon
cancer? With 2.5 grams of dietary fibre per cup you would, as a woman, have to
eat ten cups of eggplant a day to make up your dietary requirement.
Or you could have less than two cups of lentils, or three cups of green
beans, or four cups of raspberries... But you would probably be far better off
(and less bored) opting for a balanced diet containing some of the above and
many of the other foods that are high in fibre.
What about the other claims? A Brazilian study involving 38 participants
found that eggplant had only a "modest and transitory" effect on
blood cholesterol levels, producing an effect similar to following a healthier
diet.
When consumed as part of a "portfolio diet" along with other
cholesterol-lowering foods, like oat bran, almonds, black beans and broccoli,
research suggests that eggplant can actually play a role in cholesterol
reduction.
While it makes sense to substitute cholesterol-rich foods for virtually
fat-free eggplant, it is unlikely that simply "taking eggplant with each
meal", as per Olowookere's instructions, will have the desired effect.
We found no published studies testing the effect of eggplant on ageing,
inflammation or neurological disease in humans. However, when searching for the
claim as a phrase, we found exactly the same statement as Olowookere's on another
website. The website went further, explaining that the purple skin of the
eggplant contains anthocyanins that have anti-oxidant properties which have
"potential health effects against cancer, ageing, inflammation and
neurological diseases".
While anthocyanins, a kind of flavonoid, have been demonstrated to have
powerful antioxidant properties in a laboratory setting, research shows they
are poorly absorbed by the body.
Flavonoids, a large family of compounds synthesised by plants that have a
common chemical structure, may be beneficial to the human body in other ways,
but far more investigation is needed before any conclusive statements can be
made about the exact benefits of anthocyanins for humans.
Conclusion - Less superfood, more foods that are
super There are certain health benefits to eating eggplant. It is low in fat
and contains a decent amount of dietary fibre. But it is not a magic purple
bullet. If it were, the medical and scientific community would have latched on
to it--as they often do, since many treatments have their origins in nature.
Africa Check has previously written about certain foods being falsely
championed as superfoods. Usually this is done at the expense of a proven and
far simpler message: that a healthy, varied diet is far healthier than any one
particular food.
Health practitioners with a public platform like Olowookere would be doing
readers a far better service by providing advice on the benefits of a balanced
diet, rather than than elevating the status of a single plant and giving
credence to unproven treatments.
Edited by Julian Rademeyer
