Soy Neurotoxicity?

Ian Goddard igoddard at erols.mon
Wed Aug 13 19:05:46 EST 2003


tcarter2 at elp.rr.com (Thomas Carter) wrote:

>Hi Ian,
>       Foremost allow me to apologize if I upset you. I know how
>easily we humans can be irritated by opposing opinions, and I try to
>avoid it. But I guess I'll have to try harder. I'd like to continue
>our discussion in a dispassionate, scientific manner. If you can't,
>feel free to cuss away. I have a thick skin, and a short memory for
>such things. :>) 


 IAN: Tom, it's important to accurately represent another's response.
 You represent my response as "cussing away." "Cuss" means to curse,
 and curse means "a profane word or phrase." A review of my reply 
 to you will not find the profanity that you imply exists therein:

http://www.google.com/groups?selm=fdpfjvs4ss628n4oqojjqbpjneelodk7rp%404ax.com

 As I said there: "you could broach your comments as hypotheses and
 questions, rather than, as you have, accusations of 'data doctoring'
 and firm conclusions of 'fatal mistakes' and such by the authors that
 you use to caste sweeping aspersion on peer-review per se." Yet once
 again in this response you're back declaring that your quick-glance 
 conclusions are inherently accurate prior to consultation with the 
 authors regarding what are really questions, not clear conclusions. 



>>   IAN: It says, "CASI score adjusted for age (single year) and 
>>   years of schooling completed." As such, it need NOT be 2.6%.
>>   So you base the charge of "data doctoring" on your assumption 
>>   that the figure "probably" should have adjusted to some number 
>>   other than 2%.
>
>No, I did not say improbable, I said impossible. This is matter that
>can be resolved by simple math and need not be disputed among
>intelligent people. 1/38=2.6%. The low cohort of 38 was younger, and
>had more education, so the stated adjustments could only have raised
>the 2.6%, as I stated.


  IAN: That the unajusted figure must at least be 2.6% is obvious,
  which is why I said the adjusted figure need not be 2.6%. Your 
  point is it MUST be higher. I don't know what it should be so
  I sent an email to Lon White asking him why the figure is 2%.



>>   IAN: That's a cross-sectional, not longitudinal, analysis,
>>   so you can't really say, "As the members get older this 
>>   failure rate is gradually reduced," since each stratified
>>   group represents a different set of people. The important 
>>   point is the sixth grouping showing the overall relation:
>> 
>>   http://www.jacn.org/cgi/content/full/19/2/242/F2
>
>     Are you quibbling about my syntax? I will restate it for you more
>formally, but the conclusion is the same. The low-low group members
>who died just after age 71 failed at one fourth the rate of the hi-hi
>group members who died just after age 71. BUT the low-low group
>members who died just after age 90 failed at nearly the same rate as
>the hi-hi members who died just after age 90. The obvious presumption
>is that at age 71 the low-low group members were more intelligent, but
>those low-low members who survived to age 90 were only of equal
>intelligence with the hi-hi group members. Thus between the ages of 71
>and 90 the intelligence of the longer lived low-low members declined
>relative to the intelligence of the hi-hi members.
>This suggests that tofu attenuated brain aging. 


  IAN: Well, I still think my reply above holds--some subgroups 
  could easily stand outside the overall trend, but that does not
  refute the overall trend. I raised your argument an email to White. 



>> >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. 
>> 
>> 
>>   IAN: But the study states: "The CASI has been validated as 
>>   a screening instrument for dementia in the United States 
>>   and Japan, in both English and Japanese languages. [...] 
>>   participants selected either Japanese or English for testing, 
>>   depending on the language with which they were most comfortable."
>> 
>>   So your conclusion that scores were biased by native education
>>   stands in direct opposition to information provided in the study.
>> 
>No, people who switch from one language to another are less
>comfortable in either language, 


  IAN: Well, that's not what you said before. The study seems to 
  have delt any language problem as effectively as possible, and...


>The relevant point is that table 4 shows
>that the wives who went to grade school in Japan failed at a rate of
>270% higher than those who didn't. The fact that they had their choice
>of languages for the test can not negate (and in fact doesn't even
>relate to) this OVERWHELMINGLY  large factor which was not applied to
>the men.
[...]
>No, Ian, the relevance is that if the wives failed at a rate of 270%
>because of their schooling, we should expect the husbands who went to
>grade school in Japan to also fail at somewhere near the same
>percentage because of their own schooling.
[...]
>About 20% more of the hi-hi group compared to the low-low group went
>to grade school in Japan. If these men failed at just 200% the rate,
>this would have tripled one fifth of the failings due to schooling in
>Japan which would have added 60% to the total number of failings and
>all but wiped out the 62% advantage of the low-low group in table 2
>relative to the hi-hi group.


  IAN: The study (http://www.jacn.org/cgi/content/full/19/2/242) says:

"To investigate alternative explanations for the association of high 
mid-life tofu intake with poorer cognition in late life, analyses were
conducted to identify possible confounding factors [...] Thirty-one 
factors were examined [...] birth in Japan, years of childhood lived 
in Japan [...] When the 933 subjects who had lived one or more years 
of their childhood in Japan were excluded from the analysis, the 
corresponding values were beta=-1.69, p=0.01 for 1965–67 tofu intake; 
beta=-0.65, p=0.01 for 1971–74 tofu intake, and beta=-0.72, p=0.015 
for the composite tofu intake index." 

  So even when the subgroup you claim biased the results was excluded,
  a statistically significant relationship to tofu intake remained. 



>>   Frankly, I just don't have time to respond point-by-point. 
>>   Given that you're asking us to believe your personal analysis 
>>   and thereby doubt eight expert epidemiologists and their peer-
>>   reviewers, it's fair to ask: exactly what are your credentials?
>>   I don't care for appeals to authority, but regarding complex
>>   statistical data analyses, expertise really means something.
>
>No, I'm asking you and others to read, and follow my math and logic. I
>don't think it's too complex for many of the group with a bit of
>effort.
> 
>>   One last comment:
>> 
>> 
>> >      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.
>> 
>> 
>>   IAN: So there IS a relation to smaller brain size and tofu 
>>   (which was the primary focus of my post), but alas you've 
>>   determined that it is a result of methionine deficiency. 
>
>But not brain atrophy, nor accelerated brain aging. At least not shown
>by this paper. Some of the animal and in vitro data is quite
>suggestive.
> 
>>   http://www.jacn.org/cgi/content/full/19/2/242/F3  You know,
>>   you could broach your comments as hypotheses and questions,
>>   rather than, as you have, accusations of "data doctoring" and 
>>   firm conclusions of "fatal mistakes" and such by the authors
>>   that you use to caste sweeping aspersion on peer-review per se.
>>   Moreover, you should locate and ask the authors directly before
>>   posting public accusations against their expertise and honor. 
>
>Actually I've always emailed a copy to any author who has a currently
>valid address in their Pubmed listing. Most don't, and none have
>replied. All humans, including myself, have a difficult time accepting
>and dealing logically with unsettling facts. We can all profit by
>recognizing and dealing with this "design flaw" to the best of our
>ability.
>
>Thomas



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