Is Soy Healthy? John Robbins Responds
- View SourceJohn Robbins was born into the lap of dairy luxury,
with a silver Tiffany spoon feeding Baskin-Robbins
into his unappreciative mouth. The heir to the famed
ice cream empire abandoned his heritage and provided
inspirational support for thousands of Americans to
adopt a plant-based dairy-free diet. Robbins authored
Diet for a New America, and became a leading guru of
America's food revolution. John was recently asked by
"My wife and I practically live on Soy and Tofu.
We have tofu at least three times a week, and
drink soy milk every day. Lately at least five
friends have said to me that there seems to be
evidence that soy products can contribute to
dementia. Since I have minor memory problems,
and my wife seems to be having them too (though
breastfeeding a two-year-old most of the night can
definitely contribute!) we began to wonder if there
is any truth to these rumors. I am sure you have
looked into them and can give me your opinion, or
tell me where to get to find out more. Would much
John Robbins responded:
"The health benefits of soy products have been well
established. But your friends, and now you, have felt
the reverberations from a surprising study that was
published in April 2000, in the Journal of the American
College of Nutrition.
The study, conducted in Hawaii by Lon White, M.D., and his
associates, was part of the Honolulu Heart Study. Looking at
the diets and the risk of dementia of Japanese men residing
in Hawaii, the study found that men who ate the most tofu
during their mid-40s to mid-60s were more likely to have
dementia and Alzheimer's as they grew older.
The correlation between tofu and cognitive decline was
strong, and could not be explained by confounding factors
like age, education, and obesity. In this study, men who
had eaten two or more servings of tofu per week in midlife
were 2.4 times as likely as men who rarely or never ate
tofu to become senile or forgetful by old age. Even the
wives of men who ate tofu showed more signs of dementia.
White and the other researchers said the brains of the
tofu-eaters seemed to have aged more rapidly. By the time
the men reached their 80s and 90s, the tofu-eater's brains
seemed to be the equivalent of non-tofu eater's brains that
were five years older.
Scary stuff for soy eaters. And if that's all you knew, it
would look pretty bad for people like you (and me) who have
been eating lots of soy for some time.
But that's not all we know. We know, for example, that dementia
rates are lower in Asian countries (where soy intake is high)
than in western countries. We know that the Japanese lifestyle
(with its high soy intake) has long been associated with
longer life span and better cognition in old age. And we
know that Seventh Day Adventists, many of whom consume soyfoods
their whole lives, have less dementia in old age than the general
The Honolulu Heart Study is far indeed from conclusive. It
measured intake of only 27 foods, and there are many lifestyle
factors for which it did not control. Researchers acknowledged
that tofu consumption might be a marker for some other factor
that affects cognitive function. And this would make tofu an
innocent bystander. Results of other studies, say soy
researchers Mark and Virginia Messina, "would suggest this is true."
A number of clinical studies have shown that soy and
isoflavones from soy are actually beneficial for cognition.
In one study, published in the journal Psychopharmacology
in 2001, young adult men and women who ate a high-soy diet
experienced substantial improvements in short-term and long-term
memory and in mental flexibility. Other studies have found that
isoflavone supplements from soy improve cognitive function in
It is important to bear in mind that the Honolulu Heart Study
is the only study that has suggested a link between tofu
consumption and dementia in old age. Having studied the
literature, soy researchers Mark and Virginia Messina conclude
that "there is no reason to believe that eating soyfoods is
harmful to brain aging."
I agree, which is why members of my household happily eat
tofu two or three times a week, soy milk daily, and tempeh
once or twice a week..."
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