Eat healthy live healthy


Is Soy safe?

Q: Is Soy Dangerous?answers where soy and breast cancer are
Q: I've been reading quite a bit aboutconcerned. However, the evidence is
the dangers of consuming too much soy,sufficient to say that soy consumption
but to date I have not figured out whatdoes not increase risk of breast cancer
those dangers are other than too muchand may reduce risk in some people,
estrogen production with itsespecially if soy is consumed from an
consequences for higher cancer risk. Aearly age. For those who have
friend told me that a woman with aestrogen-positive breast cancer, it also
Vegetarian Nutrition course to herappears safe to use soy in moderation.
credit told her that she would recommendSoy and Thyroid
rice beverage over soy. Why? Would youClaim : Soy contains natural chemicals
kindly clarify this matter for me.known as goitrogens that interfere with
Thanks,thyroid function. These can cause an
Joyce Ward, Winnipegenlargement of the thyroid gland (a
A: Dear Joyce,“goiter”) and symptoms of
Thank you for the opportunity to providehypothyroidism, such as lethargy,
some clarity about this issue. As youdullness, coldness, and depression.
may be aware, soy has enjoyedIt is true that soy contains goitrogens,
considerable favourable press over theas do many other foods such as
past decade. We have seen reports of soycruciferous vegetables (cabbage,
reducing risk of heart disease, cancer,cauliflower, broccoli, and brussel
osteoporosis, and reducing symptoms ofsprouts), sweet potatoes, lima beans,
menopause. Just when soy seemed to be onand millet. However, these foods have
top of the world, articles and websitesbeen found only to cause problems when
began to appear claiming that thisiodine intake is low , because
new-found health hero was really agoitrogens do their damage by
villain in disguise. Soy bashers saidinterfering with the thyroid gland's
all the hype about soy was really justability to utilize iodine. Between 1951
propaganda, and that in truth, soy wasand 1961, several cases of goiter were
not a health food, but rather adiagnosed in infants who had been fed
dangerous substance that should beinfant formula made from soy flour.
carefully avoided by humans. In fact,These cases are frequently cited by the
anti-soy advocates claim that eating soyanti-soy lobbyists to prove soy damages
raises risk of cancer, osteoporosis,thyroid function (especially in
thyroid problems, birth defects,infants). But not a single case of
reproductive problems, nutritionalgoiter in infants has been caused by soy
deficiencies and Alzheimer's disease.formula since the 1960s. At that time
This has left consumer wondering if soythe soy formula base was changed from
is really a saint or a sinner.soy flour to soy protein isolates, which
First, it is important to understandare low in goitrogens, and manufacturers
that soy is not something new. Thebegan fortifying soy formula with
soybean has been used for food foriodine.
centuries, particularly in the Orient.Soy does not cause thyroid problems in
Traditional forms of soy foods includedhealthy, well-nourished people who are
fresh or frozen beans from the soy podnot deficient in iodine. However, people
(called edamame ), soy milk, tofu, andwho do not have a reliable source of
fermented foods, such as tempeh, misoiodine could increase their risk of
and soy sauce. More recently soy hasthyroid problems if they eat a lot of
become a huge hit in North America, withsoy and/or other foods rich in
all of the traditional forms of soygoitrogens. Iodized salt, dairy
widely available in addition to numerousproducts, and fish are the main dietary
others, such as soy nuts, soy-based meatsources of iodine, and most multivitamin
analogues, soy-based protein beverages,mineral supplements provide the
soy chips, soy ice cream, soy yogurt,recommended daily allowance. So the
and the list goes on. These productsanswer is not to avoid soy or
have become staples for many vegetarianscruciferous vegetables, but to get
and vegans. So, the question of theenough iodine.
safety of soy is one that certainlyConclusion : There is no evidence that
deserves serious consideration.eating soy foods regularly causes
Let's briefly address a few of the majorthyroid problems in healthy people who
claims against soy. For more detailedinclude sufficient iodine in the diet.
information about each of these issues,Soy and Cognitive Function
the following websites are most helpful:Claim: Soyfoods, especially tofu, can
cause mental deterioration and
www.llu.edu//llu/vegetarian/soy2.htmlaccelerate aging.
www.foodrevolution.orgOne study done in Hawaii (the Honolulu
what_about_soy.htmHeart Study) found that
www.soybean.com/drsuz.htmJapanese-American men who ate the most
Soy and Breast Cancertofu in middle age had the greatest
Claim : Soy increases risk of breastmental deterioration and dementia as
cancer.seniors. This study is widely cited as
Among the very first health claims madeevidence that tofu may cause a reduction
for soy is that it may reduce incidencein cognitive function. Interestingly,
of breast cancer. It seemed so obviousthere have been at least three other
when one compared the very low rates ofstudies that have suggested that soy
breast cancer in Asian countries usingprovides significant beneficial effects
large amounts of soy with rates in Northon cognitive function. In addition
American countries that usedpopulations with relatively high soy
comparatively small amounts of soy. Theintake (about a serving a day),
risk reduction was thought to be due toincluding people in Asia and Seventh-day
the isoflavones (mainly genestein andAdventists, experience lower rates of
daidzen) in soy. Isoflavones are a typedementia than those populations who eat
of phytoestrogen (plant estrogen) thatlittle if any soy. While this does not
has been thought to interfere with theprove that soy is beneficial, it does
ability of the potent human form ofsuggest that moderate soy consumption is
estrogen to increase cell proliferationlikely not detrimental.
and, therefore, cancer risk. However,Conclusion. The weight of the evidence
studies have been mixed. While some dosuggests that soy may offer some
indeed show soy acting as anbenefits to cognitive function, although
anti-estrogen, others suggest soy maymore research is needed before firm
act as a weak estrogen itself,conclusions can be made on this issue.
increasing cancer risk. Interestingly,What about soy versus rice milk? It all
some studies have shown that while smalldepends. If you are sensitive to soy or
amounts of genestein increase celluse a lot of soy products, you may wish
growth, large amounts inhibit it.to use fortified rice milk. However, my
Finally, there is some evidence thatpreference is for soy – especially for
women eating soy from an early agechildren. Soy is a much richer source of
(especially during puberty) do reducehigh quality protein, vitamins and
their breast cancer risk, while thereminerals. It also contains isoflavones,
seems to be less protection for thosewhich are protective for heart health
who begin to eat soy later in life.and against osteoporosis. I think it
Conclusion: We still do not know all thetastes better too.



1 A B C 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97