Re: Soy Neurotoxicity, or CALORIC NEUROTOXICITY!!

[Guest guest]

had an interesting take on the soy dementia study as posted on

sci.life-extention:

http://groups.google.com/groups?dq= & hl=en & lr= & ie=UTF-8 & oe=UTF-8 & threadm=a7b55247\

..0308091840.77e08ca8%40posting.google.com & prev=/groups%3Fhl%3Den%26lr%3D%26ie%3D\

UTF-8%26oe%3DUTF-8%26q%3Dsci.life-extension%26sa%3DN%26tab%3Dwg

" Hi Ian,

Your well researched recent additions to this question of soy

consumption add to the slowly growing picture. I look forward to your

future updates. While in vitro and animal studies may suggest caution,

human studies must dominate the question when available. The HAAS

study which you posted has been widely misinterpreted by the popular

press, peer reviewers, and the authors themselves. I'm disappointed at

the lack of competency shown by the authors and their peer reviewers,

but take heart in the many good studies being done at an ever

increasing rate. Here is my critique.

As of late it seems to have fallen my lot to criticize several

large observational and randomized trials. IMO the discrepancies I've

seen in the papers are due to a marked bias on the part of the

investigators against natural dietary supplements. The HAAS study that

Ian posted doesn't seem to follow the pattern, never the less the

rudimentary nature of the mistakes suggests to me some psychological

pressure rather than plain incompetency, perhaps the desire to be

published or to splash louder with the publication is the cause of the

large number of serious mistakes.

I first read the paper with a sense of doubt that the long

standing custom of tofu consumption could display enough negative

power to stand out against such a cacophony of variables. Table 1

first caught my eye because of the small size of the low tofu

consumption group and the astounding fact that the authors had ignored

the second dietary survey, basing the table on the results of only the

first. In the absence of an explanation this surely smacks of

" doctoring " data. At the very bottom of the table they give scores of

the intelligence test. (CASI) It turns out that the failures of the

low consumption group are only 2.0%. This is an impossible number

since the denominator of the calculation is 38, the group size. If

unadjusted it must clearly be zero, or some multiple of 2.6%,

corresponding to failures of 1,2, 3 individuals etc. divided by 38.

The paper says these values were adjusted for age, and education, (why

only these factors among the many available?) but such an adjustment

would leave the values at zero or raise them to some value higher than

2.6%, probably, judging from similar adjustments in the study to about

four or five, which would take away almost all of the impact of tofu

consumption. " Mistakes " like this are almost always indicative of data

doctoring IMO.

The hypothesis of the authors is not that the tofu consumption

in the cohort is associated with lifelong lower intelligence, but with

" accelerated brain aging " . Figure two clearly shows them wrong on both

counts. The median age at testing was 80, putting the first two bar

graphs below the medium, and the last three above. A quick glance

shows that the younger members of the hi-hi tofu group failed at about

four times the rate of the low-low tofu group. As the members get

older this failure rate is gradually reduced to near equality.

Comparisons of the other two groups show the same trend but not as

significantly. ACCORDING TO THIS STUDY TOFU ATTENUATES BRAIN AGING

BETWEEN AGE 71 AND 93. Why were the hi tofu eaters so much less

intelligent at age 71-75 than the low group? They went to grade school

in Japan. People always (groups, not individuals) demonstrate a

relative lack of intelligence when dealing with written or oral tests

in a second language. A most pertinent example of this is the wives of

the cohort. Those who went to grade school in Japan failed the CASI

test at a rate of 2.7 times those who didn't (table 4). THIS HUGE

MULTIVARIENT FACTOR WAS NOT APPLIED TO HUSBANDS. Had it been, it would

have eliminated the difference in the CASI scores of the husbands at

age 71, and would have destroyed the thesis of the paper. A much

milder factor of 1.04 based on childhood years in Japan was applied to

them. Why was such a different factor used? All I know is there would

not have been a story without it. Why were the hi tofu eaters of about

equal intelligence at near age 90? Perhaps, because they ate tofu. No

other reason is apparent to me. This was the dependent variable after

adjusting for all others in the study. The stratification of the group

into two smaller groups (over 80 and under 80) would have reduced the

P values by about half leaving results only of marginal significance,

but still indicating with a probability of about ten to one that tofu

consumption attenuates brain aging from ages 71 to 93.

Table 2 gives the heart of the papers results, the OR for the

failure rate in the CASI test of 1.0 (reference), 1.42, 1.74, and 1.62

for the low-low, the low, the hi, and the hi-hi groups respectively.

The difference for these rates is miniscule and totally insignificant

for all groups except the low-low one. The difference for the failure

rate between the low-low group and the low group is significant, but

the difference in tofu consumption is little more than answering once

last week instead of zero times last week in the second dietary survey

ALONE. That one serving per week of tofu can increase your failure

rate in a test by 42% is just not believable especially in the face of

such a small dose response and the many errors made by the authors.

Speaking of which they have more of the wives going to school in Japan

than were born there. (table 3), and they put the OR for going to

grade school in Japan at an unbelievably low 1.04, they may have meant

to add per year. These mistakes led to the apparent failure to adjust

properly for the all important lack of schooling in English. The data

are especially unconvincing since we are asked to believe that tofu

consumption until age 71 accelerates brain aging and then begins to

attenuate it after that age.

Apart from the fatal mathematical and procedural mistakes listed

above. The authors made two fundamental mistakes in logic. First they

did not use the average CASI score, but rather the percentage of

failures. This would have been the appropriate dependent variable only

if their hypothesis were " tofu accelerates brain aging of those who

are of low mentality, but not those of normal or hi mentality. " And

second their assumption that they had listed all the reasons for a

lower apparent intelligence of the hi tofu groups at age 71 was based

only on the logic that since that's all we can think of, there are no

more. I can easily think of several quite probable ones.

Contrary to the CASI data the relationship with brain size was

most pronounced in the hi-hi group, being totally insignificant

between the other three groups. I would guess that this was caused by

lower growth due to the fact that soy protein is lacking in

methionine, a deficiency of which is known to slow growth rates, but

only at hi levels of deficiency. The high-high group, which show

lowered growth would have been deficient to at least some extent in

this amino acid, the restriction of which is also shown to extend

lifespan.

Buried in the small print is the important datum that tofu was

related to a lifespan extension of the autopsied members of about a

year and a half.

In summary the data of the experiment, in contradiction to the

author's claims indicate that tofu consumption in men extends life

span and protects the aging brain from dementia, and further that the

vaunted peer reviewing of world class medical journals has room for

improvement.

"

>From: " C.B. Rinaldo " <jcrina0@...>

>Reply-

>< >

>Subject: [ ] Soy Neurotoxicity, or CALORIC NEUROTOXICITY!!

>Date: Sun, 10 Aug 2003 13:25:44 -0400

>

> I apologize in advance for perseverating on the issue of soy

>neurotoxicity. I've now (finally) read the article a couple times, and I

>just had a " duh " experience unexpectedly.

> Given that we're all posting to the " CALORIC RESTRICTION " support

>group, I feel dumb that I hadn't thought about calorie intake in the study!

>(hence, the self-directed " Duh " ).

> It stands to reason that those who ate more servings of tofu, were

>also

>those who at more servings of food generally, and who took in more total

>calories. I don't see any indication in the study (reading the " dietary

>assessments " section very carefully) of measures of calorie intake being

>reported. Furthermore, when they list covariates that they controlled the

>effects of, they never mentioned caloric intake as a covariate.

> My first concern, that the " tofu effect " was too small to worry about

>was substantiated: there was a very small effect size uniquely associated

>with greater tofu intake (.8 of one percent of the variability in dementia

>(pg. 251)). Furthermore, and more importantly to us, CR science would

>anticipate greater overall intake of food to be the cause of the effect

>seen

>in the study. Actually, I would have expected a larger effect if greater

>tofu intake was associated with greater caloric intake.

> Please let me know if I missed something in the study that you picked

>up on. More eyes and memories are certainly an improvement over mine

>alone.

>

> R.

>

>

_________________________________________________________________

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[Guest guest]

Hi ,

As a layperson who doesn't fully grasp all the stastical intracacies

of the soy studies, could you sum it up for me? Is soy, in moderation,

still safe to eat or should I stop all tofu consumption?

-

[Guest guest]

My opinion about the study comes from these aspects of the study (I don't

think I was very clear in the last email):

1. the authors asked people to mark how many times they'd eaten a serving

of various foods.

2. the authors did not control for the total amount of food (calories)

eaten

3. the people who said they ate more, really did.

They probably ate more of everything, not just tofu.

4. the authors concluded erroneously that eating more TOFU was the cause of

cognitive decline, when as we know well, eating more food is a very

important factor.

5. I'm concluding that the study accidentally measured how much total food

was eaten by each

subject, through the proxy variable of how much tofu they ate. In other

words, the study

should be retitled: " Brain Aging and Midlife Total Consumption " rather

than

" Brain Aging and Midlife Tofu Consumption " .

6. Because of this, the study adds to the literature on the health benefits

of CR, not of tofu restriction.

In my opinion... well, I've got a bowl of soy-protein based oatmeal in

front of me as I type.

-----Original Message-----

From: paultheo2000 [mailto:paultheo2000@...]

Sent: Sunday, August 10, 2003 1:59 PM

Subject: [ ] Re: Soy Neurotoxicity, or CALORIC

NEUROTOXICITY!!

Hi ,

As a layperson who doesn't fully grasp all the stastical intracacies

of the soy studies, could you sum it up for me? Is soy, in moderation,

still safe to eat or should I stop all tofu consumption?

-

[Guest guest]

: thank for straightening this out. As I write this, I'm fishing a

quart of soy milk 3/4 full (that I got free via a coupon) out of the

garbage, that I had just thrown away. It takes a great mind to admit his

mistake and I thank you for helping us clear up the matter. I have a couple

of pounds of soy burgers in the freezer (my husband loves 'em) that I was

about to pitch and now can be saved from extermination.

on 8/10/2003 2:23 PM, C.B. Rinaldo at jcrina0@... wrote:

> My opinion about the study comes from these aspects of the study (I don't

> think I was very clear in the last email):

>

> 1. the authors asked people to mark how many times they'd eaten a serving

> of various foods.

> 2. the authors did not control for the total amount of food (calories)

> eaten

> 3. the people who said they ate more, really did.

> They probably ate more of everything, not just tofu.

> 4. the authors concluded erroneously that eating more TOFU was the cause of

> cognitive decline, when as we know well, eating more food is a very

> important factor.

> 5. I'm concluding that the study accidentally measured how much total food

> was eaten by each

> subject, through the proxy variable of how much tofu they ate. In other

> words, the study

> should be retitled: " Brain Aging and Midlife Total Consumption " rather

> than

> " Brain Aging and Midlife Tofu Consumption " .

> 6. Because of this, the study adds to the literature on the health benefits

> of CR, not of tofu restriction.

>

> In my opinion... well, I've got a bowl of soy-protein based oatmeal in

> front of me as I type.

>

>

>

[Guest guest]

" C.B. Rinaldo " <jcrina0@u...> wrote:

> I apologize in advance for perseverating on the issue of soy

> neurotoxicity. I've now (finally) read the article a couple

times, and I

> just had a " duh " experience unexpectedly.

> Given that we're all posting to the " CALORIC RESTRICTION "

support

> group, I feel dumb that I hadn't thought about calorie intake in

the study!

> (hence, the self-directed " Duh " ).

> It stands to reason that those who ate more servings of tofu,

were also

> those who at more servings of food generally, and who took in more

total

> calories.

IAN: That actually does not follow. If tofu intake was higher

(and correlated to dementia for being higher, as was the case)

because overall intake was higher, then other food-types would

ALSO be consumed at a higher rate and therefore should produce

a similar dementia correlation for the same reason. But that

was not the case. So I don't see your conclusion, and...

I don't see any indication in the study (reading the " dietary

> assessments " section very carefully) of measures of calorie intake

being

> reported.

IAN: Reread the " Results " section:

http://www.jacn.org/cgi/content/full/19/2/242

Furthermore, when they list covariates that they controlled the

> effects of, they never mentioned caloric intake as a covariate.

IAN: Again, please reread the " Results " section.

> My first concern, that the " tofu effect " was too small to

worry about

> was substantiated: there was a very small effect size uniquely

associated

> with greater tofu intake (.8 of one percent of the variability in

dementia

> (pg. 251)).

IAN: With all due respect to your background in statistics,

I'm going to weigh in with the eight expert epidemiologists

who conducted the study who believe otherwise, along with

those who conducted the peer-review for acceptance.

Furthermore, and more importantly to us, CR science would

> anticipate greater overall intake of food to be the cause of the

effect seen

> in the study. Actually, I would have expected a larger effect if

greater

> tofu intake was associated with greater caloric intake.

> Please let me know if I missed something in the study that

you picked

> up on. More eyes and memories are certainly an improvement over

mine alone.

>

> R.

[Guest guest]

Francesca WROTE:

As I write this, I'm fishing a quart of soy milk 3/4 full (that I got free via a coupon) out of the garbage, that I had just thrown away. It takes a great mind to admit his mistake and I thank you for helping us clear up the matter. I have a couple of pounds of soy burgers in the freezer (my husband loves 'em) that I was about to pitch and now can be saved from extermination.

Now Francesca, where is your sense of moderation theme? This seems rash to have trashed. :-)

The study we have begun to discuss, even its authors admit, no one can draw serious scientific conclusions about whether or not it is "brain safe" to eat or not eat soy products! This is prospective research, and is JUST an indicator that MAYBE soy could be a problem. Until a double blind placebo type study is done no one really knows. The studies authors admit that! This study is an indicator that a serious research study needs to be done to obtain possible "real" answers.

Soy will no doubt be of more benefit to some people & less to others. If you drop soy & replace it with another UNKNOWN researched protein or food, then you MIGHT put yourself at greater risk eating another less researched food item!!! Nutrition science is very limited in its knowledge about optimizing the best diet for any one person.

Now, if I had been a big time eater of soy, every other day or so, then I might dig into this (potential) soy problem and do some serious research on the body of research studies regarding soy & the brain (etc.) before continuing on such a diet. But I would not stop soy entirely.

Because I had some dairy allergies, I switched to using soy milk more than a year ago. I also enjoy eating my sea vegetables (more accurate than saying seaweed), onions, broccoli, sometimes tofu, in Miso Soup which is also soy based. My new brownie recipe I'm developing also uses soy milk.

What am I to do? IMO, the answer is always more variety & moderation & less reliance on any one type of food. There is Barley based Miso, so I will use that often too. There is good old chicken or vegetable broth too. My brownies with soy milk will now often be made with non-fat milk or some other milk-soy substitute.

As of my understanding today, I do not buy into the Hawaiian soy study as an all or nothing proposition! There is a heck of a lot of research out there on soy compared to many other foods, so we know more about soy than these other foods. So when Clint says: Well, boy, do you feel lucky or don't you? Just remember the foods you may substitute may cause more harm or less. Better check the research & if there isn't much out there... Well...

Do you feel lucky? Or don't you?

Well, we're all gonna die sometime. ;>)

..

[Guest guest]

Folks: I just took a good look at this study and the date which is the year

2000. Isn't this the same Hawaiian study that Walford touches on and that

has been discussed in the past??? IOW, there is nothing new here. I was

confused and thought this was ANOTHER study pointing to a dementia/soy link,

and had convinced myself that there was really something to this but it

looks like it's the same old study (not that that means it's not relevant -

just that it's the ONLY study being discussed all over again). I'm a bit

confused now. So Ian or , aren't we rehashing old news???

> Now Francesca, where is your sense of moderation theme?

> This seems rash to have trashed. :-)

[Guest guest]

How important are the potential risks anyway? If soy products are

otherwise healthy, I'll take my chances with a 2-3% increased change

of getting dementia. I guess it all depends on how strong the risk

factors really are.

-

[Guest guest]

It seems to me the data supporting soy far exceeds the data against it. By now there should have been a lot more studies against it. I think cancer is a more important issue than dementia, eg.

Regards.

----- Original Message -----

From: paultheo2000

Sent: Monday, August 11, 2003 7:53 AM

Subject: [ ] Re: Soy Neurotoxicity, or CALORIC NEUROTOXICITY!!

How important are the potential risks anyway? If soy products areotherwise healthy, I'll take my chances with a 2-3% increased changeof getting dementia. I guess it all depends on how strong the riskfactors really are. -

[Guest guest]

There's also the issue of "what does the word soy mean". We eat soy in many diff forms.

soy nuts

tofu

fried tofu,

soy "milk"

textured veg protein

soy protein isolate

Regards.

----- Original Message -----

From: numicucamonga

Sent: Monday, August 11, 2003 6:37 AM

Subject: [ ] Re: Soy Neurotoxicity, or CALORIC NEUROTOXICITY!!

The study we have begun to discuss, even its authors admit, no one can draw serious scientific conclusions about whether or not it is "brain safe" to eat or not eat soy products! This is prospective research, and is JUST an indicator that MAYBE soy could be a problem. Until a double blind placebo type study is done no one really knows. The studies authors admit that! This study is an indicator that a serious research study needs to be done to obtain possible "real" answers.

What am I to do? IMO, the answer is always more variety & moderation & less reliance on any one type of food. There is Barley based Miso, so I will use that often too. There is good old chicken or vegetable broth too. My brownies with soy milk will now often be made with non-fat milk or some other milk-soy substitute.

As of my understanding today, I do not buy into the Hawaiian soy study as an all or nothing proposition! There is a heck of a lot of research out there on soy compared to many other foods, so we know more about soy than these other foods. So when Clint says: Well, boy, do you feel lucky or don't you? Just remember the foods you may substitute may cause more harm or less. Better check the research & if there isn't much out there... Well...

[Guest guest]

Dear Ian,

Thanks for the redirection toward the results section. I think that your

redirection makes me somewhat more cautious about my hypothesis linking soy

to dementia through the mediating variable of caloric intake.

The list of eight foods that the researchers considered along with tofu

included coffee, green tea, black tea, milk, and miso soup, which aren't

particularly relevant to average caloric intake. However, meat and rice

were surveyed as well. I wish I knew more about the Hawaiian-Japanese diet,

so that I would have a better sense of how relevant meats were to the diet.

From what I understand, tofu and meat are substitute dietary items, rather

than complementary (so more tofu eaten may not mean more meat is eaten).

Rice is another matter, and I would definitely expect it to be as related to

average caloric intake as tofu. Unfortunately, the relationship between

caloric intake and tofu was not reported, so I'm left to making a reasoned

conjecture, one to which the 'rice' variable stands as a contrary piece of

evidence.

Next, the authors did not measure the caloric intake of the participants.

They did attempt to estimate it from a single-day self-report of foods eaten

by participants. In my opinion, this is a poor substitute for actual

measurement of such a crucial variable. In behavioral measurement the

observation of single behavioral events (a day's food intake) has a near

zero correlation to behavioral trends (average calorie intake). Estimating

average calories based on a day's intake is analogous to " estimating " how

well a batter will perform over his career based on a single 'at bat', or

even a single game. So, I'm sticking to it, caloric intake was an

unmeasured variable. Evidence to support my doubts about their measurement

method is that their estimate of caloric intake was NOT found to be related

to brain aging (they reported this). We know from CR research that if

caloric intake were measured well, this relationship should have been found.

Lastly, I acknowledge that numerous experts considered the study worthy

of publication. I would have recommended it for publication too, because it

is clearly scientifically relevant. There is a sharp and important

distinction to be made between " statistically significant " findings and

" clinically relevant " findings. Journal editors and researchers are

concerned exclusively with statistical significance, because they're trying

to " discover the truth " about how things are really related, regardless of

the magnitude of those relationships. Statistical significance is necessary

but insufficient for clinical relevance, because clinical relevance must

also involve an effect that is large enough to be worth acting upon. Some

examples to illustrate this difference include the finding that the

radiation that makes clock hands glow is carcinogenic. It's true, and it

was demonstrated experimentally. However, the effect is so small that we

are not practically at risk, so there are no clock-hand regulations needed.

An effect size of .008, as was found in the study of interest, is among this

magnitude of clinically insignificant effect sizes. The authors of this

study admit this tacitly at in their discussion (e.g. " After controlling

for these three most important factors, midlife tofu consumption remained

statistically significant even though it then explained only an additional

0.8% of the variance in test scores. Thus the influence of midlife tofu

intake on late life cognitive functioning appeared to be far less than age,

education and history of stroke in this population " (p. 251)). That takes

away nothing from the fact that, as researchers they have found a very

important relationship that should be duly reported to other scientists!

-----Original Message-----

From: Ian Goddard [mailto:iamgoddard@...]

Sent: Sunday, August 10, 2003 9:06 PM

Subject: [ ] Re: Soy Neurotoxicity, or CALORIC

NEUROTOXICITY!!

" C.B. Rinaldo " <jcrina0@u...> wrote:

I apologize in advance for perseverating on the issue of soy

neurotoxicity. I've now (finally) read the article a couple

times, and I just had a " duh " experience unexpectedly. Given

that we're all posting to the " CALORIC RESTRICTION " support

group, I feel dumb that I hadn't thought about calorie intake in

the study! (hence, the self-directed " Duh " ).

It stands to reason that those who ate more servings of tofu, were also

those who at more servings of food generally, and who took in more

total calories.

IAN: That actually does not follow. If tofu intake was higher

(and correlated to dementia for being higher, as was the case)

because overall intake was higher, then other food-types would

ALSO be consumed at a higher rate and therefore should produce

a similar dementia correlation for the same reason. But that

was not the case. So I don't see your conclusion, and...

I don't see any indication in the study (reading the " dietary

> assessments " section very carefully) of measures of calorie intake

being

> reported.

IAN: Reread the " Results " section:

http://www.jacn.org/cgi/content/full/19/2/242

Furthermore, when they list covariates that they controlled the

> effects of, they never mentioned caloric intake as a covariate.

IAN: Again, please reread the " Results " section.

> My first concern, that the " tofu effect " was too small to

worry about

> was substantiated: there was a very small effect size uniquely

associated

> with greater tofu intake (.8 of one percent of the variability in

dementia

> (pg. 251)).

IAN: With all due respect to your background in statistics,

I'm going to weigh in with the eight expert epidemiologists

who conducted the study who believe otherwise, along with

those who conducted the peer-review for acceptance.

Furthermore, and more importantly to us, CR science would

> anticipate greater overall intake of food to be the cause of the

effect seen

> in the study. Actually, I would have expected a larger effect if

greater

> tofu intake was associated with greater caloric intake.

> Please let me know if I missed something in the study that

you picked

> up on. More eyes and memories are certainly an improvement over

mine alone.

>

> R.

[Guest guest]

" C.B. Rinaldo " <jcrina0@u...> wrote:

> Dear Ian,

> Thanks for the redirection toward the results section. I think

that your

> redirection makes me somewhat more cautious about my hypothesis

linking soy

> to dementia through the mediating variable of caloric intake.

> The list of eight foods that the researchers considered along

with tofu

> included coffee, green tea, black tea, milk, and miso soup, which

aren't

> particularly relevant to average caloric intake. However, meat

and rice

> were surveyed as well. I wish I knew more about the Hawaiian-

Japanese diet,

> so that I would have a better sense of how relevant meats were to

the diet.

> From what I understand, tofu and meat are substitute dietary

items, rather

> than complementary (so more tofu eaten may not mean more meat is

eaten).

> Rice is another matter, and I would definitely expect it to be as

related to

> average caloric intake as tofu. Unfortunately, the relationship

between

> caloric intake and tofu was not reported, so I'm left to making a

reasoned

> conjecture, one to which the 'rice' variable stands as a contrary

piece of

> evidence.

> Next, the authors did not measure the caloric intake of the

participants.

> They did attempt to estimate it from a single-day self-report of

foods eaten

> by participants. In my opinion, this is a poor substitute for

actual

> measurement of such a crucial variable. In behavioral measurement

the

> observation of single behavioral events (a day's food intake) has

a near

> zero correlation to behavioral trends (average calorie intake).

Estimating

> average calories based on a day's intake is analogous

to " estimating " how

> well a batter will perform over his career based on a single 'at

bat', or

> even a single game.

IAN: Well, the next sentence says they examined " midlife body

mass index (BMI), " which should give and idea of overall intake.

> An effect size of .008, as was found in the study of interest, is

among this

> magnitude of clinically insignificant effect sizes. The authors

of this

> study admit this tacitly at in their discussion (e.g. " After

controlling

> for these three most important factors, midlife tofu consumption

remained

> statistically significant even though it then explained only an

additional

> 0.8% of the variance in test scores. Thus the influence of midlife

tofu

> intake on late life cognitive functioning appeared to be far less

than age,

> education and history of stroke in this population " (p. 251)).

IAN: Or look at it this way, they also note: " Thus 20% to 25%

of the cognitive impairment observed in the HAAS population

appears to have been attributable to tofu consumption, or to

some other undefined factor for which tofu consumption served

as a surrogate. " Assuming it was the tofu, I'd easily trade a

20% reduction in cognitive impairment for not eating tofu(soy)!

It's also worth noting that contemporary levels of soy intake

can far exceed the high levels in this study, especially for

vegetarians such as myself. I used to eat upwards of one pound

of tofu a day on some days. So if two or more servings per week

could increase cognitive aging by 20%, what about two per day?

http://IanGoddard.net