Soya-bean crisis
Scientists
versus the soya industry
Jane
Phillimore addresses some of the concerns raised by new research
Jane
Phillimore
Observer
Sunday August 27, 2000, Sunday Mail of the Brisbane Courier
Mail Sunday September 19 2000
Twelve
years ago, I visited an alternative health practitioner with some
non-specific health symptoms. I'd hardly sat down before he told me
that my diet needed radical attention - I had to cut out all dairy,
wheat, alcohol and caffeine, and substitute protein in the form of soya
milk and tofu instead. Nowadays this kind of advice is routine, but at
the time, it seemed glamorously radical: I had to trek to Clapham's one
health-food shop to stock up on soya milk because Sainsbury's certainly
didn't have their own brand (as they do now) and veggie/soya sausages
were just a glint in Linda McCartney's eye.
In the
event, I lost a stack of weight and felt immensely rejuvenated. So much
so that, four months later, I started eating normally again. Just as
well, because it has now been found that soya - far from having the
magical, health-giving properties that the alternative medicine brigade
endlessly bangs on about - can actually be bad for you. Its reputation
as an anti-cancer, cholesterol-lowering, osteoporosis-fighting, low-fat
all round good egg of a product is based on bad science and superlative
marketing by the powerful soya industry.
Worldwide,
the evidence is starting to stack up against soya. In this country,
MAFF is so worried about the possible health problems of phytoestrogens
in soya that they are funding a rolling programme of 19 separate
research projects, due to end in 2002. Preliminary findings by
Professor John Ashby of AstraZeneca Central Toxicology Laboratory in
Macclesfield, for example, confirm that soya infant formula (currently
the sole food of 6,500 British babies) has an oestrogenic effect on
rats. According to public health minister Yvette Cooper, no new advice
will be given on soya until the independent COT (Committee on Toxicity
of Chemicals in Food, Consumer Products and the Environment) has
reviewed the programme's findings.
This could
take several years. Meanwhile, if you've been seduced by the message
that soya is the healthy 21st-century superfood, read on...
Is soya bad for you?
It contains
high quantities of various toxic chemicals, which cannot be fully
destroyed even by the long cooking process. These are: phytates, which
block the body's uptake of minerals; enzyme inhibitors, which hinder
protein digestion; and haemaggluttin, which causes red blood cells to
clump together and inhibits oxygen take-up and growth. Most
controversially of all, soya contains high levels of the phytoestrogens
(also known as isoflavones) genistein and daidzein, which mimic and
sometimes block the hormone oestrogen.
Surely, the Japanese eat huge quantities of soya, and as a
result have low rates of breast, uterus, colon and prostate
cancers?
That's the
big myth on which the idea of 'healthy' soya is built. In fact, the
Japanese don't eat that much soya: a 1998 study showed that a Japanese
man typically eats about 8g (2 tsp) a day, nothing like the 220g (8oz)
that a Westerner could put away by eating a big chunk of tofu and two
glasses of soya milk. Secondly, although Japanese people may have lower
rates of reproductive cancers, this is thought to be due to other
dietary and lifestyle factors: they eat less fatty meat, more fish and
vegetables and fewer tinned or processed foods than in a typical
Western diet. Thirdly, Asians have much higher rates of thyroid and
digestive cancers, including cancer of the stomach, pancreas, liver and
oesophagus.
I'm vegetarian and eat loads of tofu and soya milk. Should I
stop?
Soya has
become vegetarians' meat and milk, the major source of protein in their
diet. But eating soya actually puts vegetarians at severe risk of
mineral deficiencies, including calcium, copper, iron, magnesium and
especially zinc. According to Dr Mike Fitzpatrick, a New Zealand
biochemist who runs a soya information website (see below), this is
because soya contains high levels of phytic acid, which blocks the
absorption of essential minerals in the digestive tract. To reduce the
effects of a high-phytate diet, you need to eat, as the Japanese do,
lots of meat or fish with tiny bits of soya.
I'm
intolerant to cow's milk, so should I drink soya milk
instead?
Soya has
become the fashionable option for people 'intolerant' to dairy
products. It's little known that soya is the second most common
allergen. Only 1 per cent of the population is truly allergic to cows'
milk and, of those, two-thirds will also be intolerant to soya milk. In
addition, soya milk is high in aluminium. That's because the soya
protein isolate it's made from is acid-washed in aluminium tanks. No
wonder it tastes bad.
Can
soya affect your thyroid?
It's been
known for years that phytoestrogens in soya depress thyroid function.
In Japan, 1991 research showed that 30g of soya a day results in a huge
increase in thyroid-stimulating hormone. This can cause goitre,
hypothyroidism, and auto-immune thyroid disease.
I'm
pregnant. Should I avoid soya?
Probably,
and especially if you're vegetarian. A new study of babies born to
vegetarian mothers showed that baby boys had a five-fold risk of
hypospadias, a birth defect of the penis. The researchers suggest this
was due to greater exposure to phytoestrogen rich-foods, especially
soya. Inappropriate hormone levels such as that caused by a high intake
of soya during the first 12 weeks of pregnancy can also cause damage to
the foetus's developing brain.
But
surely I can feed my baby soya formula? It must be safe: it's available
in every supermarket and chemist.
Soya-fed
babies are taking part in 'a large, uncontrolled and basically
unmonitored human infant experiment', said Daniel Sheehan, director of
the FDA's National Center for Toxicological Research, in 1998. A
newborn baby's sole food is the milk it drinks: a soya-fed baby
receives the equivalent of five birth control pills' worth of oestrogen
every day, according to Mike Fitzpatrick. These babies' isoflavone
levels were found to be from 13,000 to 22,000 times higher than in
non-soya fed infants.
As a result
of this phytoestrogen overload, soya-fed babies have a two-fold risk of
developing thyroid abnormalities including goitre and auto-immune
thyroiditis. Boys risk retarded physical maturation, while girls risk
early puberty (1 per cent of girls now show signs of puberty, such as
breast development or pubic hair, before the age of three) and
fertility. Researchers have also suggested that diabetes, changes in
the central nervous system, extreme emotional behaviour, asthma, immune
system problems, pituitary insufficiency and IBS may be caused by high
phytoestrogen intake in early life. Last year, compounds in soya were
also implicated in the development of infantile leukaemia. Current
government advice is that breast is best and that soya formula should
not be given to infants unless on the advice of a health
professional.
Can
soya help with prostate cancer?
Ex-junk
bond trader Michael Milken certainly thinks so. He consumes 40g of soya
protein every day with that hope in mind. The science is less
conclusive - a recent study on Japanese-Americans living in Hawaii
showed that men who had eaten two or more servings of tofu a week
during mid-life not only had 'accelerated brain ageing', and more than
twice the incidence of Alzheimer's and dementia, but also looked five
years older than those men who didn't.
My mother
died of breast cancer and I've been advised by both mainstream and
complementary medical sources that increasing my soya intake may offer
me protection against the disease. Is this true?
The
evidence is highly inconclusive. In The Breast Cancer Protection Diet ,
published last year, Dr Bob Arnot states that eating between 35g and
60g of soya protein daily protects against breast cancer by raising
intake of the oestrogen-blocker genistein. But this ignores contrary
evidence. In 1996, research showed that women eating soya had an
increased incidence of epithelial hyperplasia, a condition that
presages malignancy. In 1997, genistein in the diet was also found to
stimulate human breast cells to enter the cell cycle. As a result, the
researchers advised women not to eat soya products to prevent breast
cancer.
But
surely soya prevents osteoporosis, the bone thinning that particularly
affects post-menopausal women?
No. In
fact, soya blocks calcium and causes a deficiency of vitamin D, both of
which are needed for strong bones, say American nutritionists and soya
debunkers Sally Fallon and Mary G Enig.
Is
there any kind of soya product I can safely eat?
Yes.
Fermented soya products, such as soy sauce, tempeh and miso. The long
fermentation process counteracts the effects of natural toxins in
soya.
Can
I avoid soya?
It's hard.
You can stop eating the obvious candidates such as soya milk and tofu,
but soya is also to be found in breakfast cereals, ice cream,
convenience food such as hamburgers, fish fingers and lasagne, and all
manner of baked goods from cakes and biscuits to tortillas and bread.
If that's your mission in life, read labels carefully, and eat organic
processed foods wherever possible.
Finally,
the pro-soya lobby always says that, in the US, a quarter of the
population has been fed infant soya formula for 30 to 40 years, with no
adverse health problems. So why should I worry?
Scientists
are only just beginning to research and understand the harmful
long-term effects that eating large quantities of soya can have on the
human body. As Fallon and Enig write: 'The industry has know for years
that soya contains many toxins. At first they told the public that the
toxins were removed by processing. Then they claimed that these
substances were beneficial.' Sounds like there's a big battle ahead.
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