Journal of Anti-Aging Medicine, 2003;6(4):335-6

New Findings May Support

Soy-Dementia in Men

August 9, 2003 - Ian Williams Goddard

In April 2000, Lon White and others reported a dose-dependent positive correlation between tofu consumption and brain atrophy in a large sample of men over several decades. [1] While correlation does not prove causation, study size and duration along with the robust dose-dependent relationship caused me, even as a vegetarian, to avoid tofu and other soy products.

Correlation-based hypotheses should be tested against the availability of possible causal mechanisms. In addition to possible causal mechanisms previously cited by this author, [2] recent findings significantly increase the case for a causal mechanism of soy-induced brain atrophy.

Atrophic Pharmacology Indicated

Brain-derived neurotrophic factor (BDNF) facilitates the survival and genesis of brain cells. [3,4] The neuroprotective effects of caloric restriction are attributed in part to increased BDNF. [5] On the other hand, reduced BDNF is known to cause brain-cell atrophy and is associated with Alzheimer’s disease. [6,7] Now, a study in "Neuroscience Letters" reports that soy significantly reduced BDNF in the hippocampus and cerebral cortex of male rats. [8] Since reduced BDNF can cause neural atrophy, these findings appear to provide compelling evidence for a causal mechanism that might explain the positive correlation between tofu (soy) consumption and brain atrophy reported by White et al. [1]

Bad For Boys, Good For Girls?

While soy appears to reduce BDNF in male rats, it has also been shown to increase BDNF in female rats. [9] In fact, soy appears to affect neurological parameters in a sex-defined fashion wherein females benefit and males suffer. [10-13] There is little doubt among researchers that this is because soy is high in phytoestrogens, which are plant-derived substances that act like the female hormone estrogen.

However, that sex-defined difference fails to explain the findings regarding the wives of male subjects in White et al., who reported: "A similar association of midlife tofu intake with poor late life cognitive test scores was also observed among wives of cohort members, using the husband’s answers to food frequency questions as proxy for the wife’s consumption." [1] White et al. proposed that long-term consumption of weaker soy estrogens may displace the body’s own stronger estrogen along with its benefits.

Evidence Against Soy-Dementia Hypothesis?

A possible signal contrary to a soy-dementia link is the low prevalence of dementia [14] and high consumption of soy in Okinawa, Japan. [15] However, that negative correlation, like any correlation, does not prove causation. For example, perhaps soy does cause dementia but other factors in Okinawa offset the effect.

Also, White et al. explored correlations of a range of foods to neurological parameters, whereas this Okinawa analysis is a sweeping generalization of only tofu to all of Okinawa. In other words, it stands to reason that the study by White et al. finding a positive tofu-dementia correlation has the greater likelihood of providing the more accurate picture. Nevertheless, in my view this Okinawa data warrants further examination as a possible route to falsifying the soy-dementia hypotheses.

In closing, the findings of soy-induced BDNF reduction in male rat brain regions that are central to the onset of dementia, in addition to previous findings, [2] appear to provide compelling evidence of a possible causal mechanism that might explain the soy-dementia correlation reported by White et al. [1] Obviously further research is necessary before a clear picture emerges regarding the effects of long-term soy consumption on the brain. But in the meantime, my inclination is to play it safe and avoid soy.


  1. White et al.: "In this population, higher midlife tofu consumption was independently associated with indicators of cognitive impairment and brain atrophy in late life."
  2. Goddard (scroll to): "Is There Reason to Believe Tofu May Cause Brain Atrophy?"
  3. Korte M: "Neurotrophic factors have long been known to promote neuronal survival and differentiation."
  4. J Neurochem (Sep 2002): "These findings suggest that BDNF plays an important role in the regulation of the basal level of neurogenesis in dentate gyrus of adult mice [...]."
  5. Endocrinology (Jun 2003): "Recent studies have shown that DR [dietary restriction] stimulates the production of brain-derived neurotrophic factor (BDNF) in brain cells, which may mediate neuroprotective and neurogenic actions of DR."
  6. Arch Gen Psychiatry (Jul 1997): "stress can decrease the expression of brain-derived neurotrophic factor and lead to atrophy of these same populations of stress-vulnerable hippocampal neurons."
  7. Brain Res Mol Brain Res (Oct 3, 1997): "a reduction in BDNF mRNA expression has been observed in human post-mortem Alzheimer’s disease hippocampi. [...] These results support and extend previous findings that BDNF mRNA is reduced in the human Alzheimer’s disease hippocampus and temporal cortex, and suggest that loss of BDNF may contribute to the progressive atrophy of neurons in Alzheimer’s disease."
  8. Neurosci Lett (Feb 27, 2003): "significant reductions were found in brain-derived neurotrophic factor (BDNF) mRNA expression in the CA3 and CA4 region of the hippocampus and in the cerebral cortex in the [male] rats fed the diet containing phytoestrogens, compared with those on the soya-free diet."
  9. Neurosci Lett (Feb 1999): "soy phytoestrogens significantly increased the mRNA levels of BDNF [] female rats."
  10. Neurotoxicol Teratol (Jan-Feb 2002): "when learning and memory parameters were examined in a radial arm maze testing visual-spatial memory (VSM), the diet treatments significantly changed the typical sexually dimorphic pattern of VSM. Specifically, adult Phyto-rich fed females outperformed Phyto-free fed females, while in males on the same diets, the opposite pattern of maze performance was observed."
  11. BMC Neurosci (2001 2(1):20): "Female rats receiving lifelong exposure to a high-phytoestrogen containing diet (Phyto-600) acquired the maze faster than females fed a phytoestrogen-free diet (Phyto-free); in males the opposite diet effect was identified. [...] These findings suggest that dietary soy derived phytoestrogens can influence learning and memory and alter the expression of proteins involved in neural protection and inflammation in rats."
  12. BMC Neurosis (2001 2(1):21): "When a diet change was initiated in adulthood, control phytoestrogen-rich fed females outperformed control females switched to a phytoestrogen-free diet. Whereas, in control males the opposite diet effect was identified."
  13. Neurosci Lett (May 15, 2003): "This study is the first to show that lifelong consumption of dietary phytoestrogens alters the HPA stress response in male rats."
  14. Dementia Rates in Okinawa vs Japan & US.
  15. Soy Phytochemical Intake in Okinawa.


Previous Soy Reports & Information


 (c) 1999 Ian Williams Goddard

 The recent study suggesting a link between tofu and brain
 atrophy [1] calls to attention animal research showing that 
 the soy-phytochemical genistein reduces DNA synthesis in the
 brain and inhibits the proliferation of brain cells. [2][3][4] 
 That research tends to support the tofu study, for, since cell 
 replication requires DNA synthesis, genistein-induced synthesis 
 reduction leading to fewer new cells could manifest as atrophy. 

 The only counter I've seen is that cell-proliferation physiology 
 does not apply to adult brain cells, since they don't replicate. 
 That claim, however, has been invalidated, for it has been shown 
 that neurogenesis--the replication of new brain cells--appears 
 to occur in the brain throughout life. As Dr. David Amaral told 
 The Washington Post (11/21/99): "A decade ago, we still had the 
 notion that you acquired all the neurons you would ever have by 
 the sixth month of pregnancy... It turns out that nothing could 
 be further from the truth." The Washington Post continued:

  "Last month, biologists at Princeton University demonstrated 
   that monkey brains constantly produce thousands of new 
   neurons which travel to the cerebral cortex, the center 
   of higher intellectual functions. Earlier studies had 
   documented other examples of neurogensis... The same 
   process occurs in humans. ...researchers at the Salk 
   Institute for Biological Studies in La Jolla, Calif., 
   found evidence of recent cell division in a part of the 
   brain called the hippocampus in every person studied." [5]

 Research in animals shows neurogenesis occurs in several areas 
 of the adult brain. [6][7][8] Research also shows that reduced
 DNA synthesis decreases the number of new brain cells produced. 
 [9] Based on the available data, I would dare to posit that IF 
 in fact genistein inhibits DNA synthesis in the adult human 
 brain as it has been shown to in developing rat brains [2]
 (and based on human/animal/soy studies, I see no reason to 
 believe the rat/soy-to-human/soy extrapolation is unfounded), 
 it stands to reason that soy products would reduce neurogensis
 and/or initiate apoptosis (programmed cell death) in the human 
 brain, which could manifest itself as brain atrophy. In short, 
 there's reason to believe the tofu study [1] may be accurate.

 Of course I hope the tofu study is not true, and that 
 soy products ARE the healthy panacea I've always assumed! 
 I've been a vegetarian since I was 13-years old because I 
 believe we need to advance beyond the systematic mass murder 
 sentient beings simply for pleasurable taste sensations. With 
 my refrigerator full of soy stuff, I wish I could be sure now,
 but until the soy picture gets clearer, the evidence is enough
 for me to be inclined to err on the side of caution. However, 
 it should be noted that the research indicating an anticancer 
 potential for soy is consistent, and research shows that the 
 cytotoxic properties of soy products are strongly specific, 
 but apparently not entirely exclusive, to cancer cells. If 
 I had terminal cancer, I would consider using soy products!

[1] Honolulu Star-Bulletin: Too much tofu induces ‘brain aging,’
study shows. By Helen Altonn, November 19, 1999 
[2] Experimental Neurology, 1999 Sep;159(1):164-76. 
Early effects of protein kinase modulators on DNA synthesis 
in rat cerebral cortex.
[3] Brain Research, 1998 Jan 19;781(1-2):159-66. 
Transmural compression-induced proliferation and DNA 
synthesis through activation of a tyrosine kinase 
pathway in rat astrocytoma RCR-1 cells.
[4] About glial cells: NeuroNews: Modulation of 
neuronal activity by glial cells. June 15, 1998 
[5] The Washington Post: The Brain's Power to Heal. 
D. Hales and R. Hales, Parade section, 11/21/99, page 10.

[6] Science, 1999 Oct 15;286(5439):548-52.
Neurogenesis in the neocortex of adult primates.
[7] Proceedings of the National Academy of Science, 
1999 Sep 28;96(20):11619-24. Regeneration of a germinal layer 
in the adult mammalian brain.
[8] Journal of Comparative Neurology, 1999 
Aug 30;411(3):495-502. Neurogenesis in the adult rat 
dentate gyrus is enhanced by vitamin E deficiency. 
[9] Brain Research. Developmental Brain Research, 1998 
Jun 15;108(1-2):39-45. Developmental neurotoxicity of chlorpyrifos: 
delayed targeting of DNA synthesis after repeated administration.


Follow-up soy posts

Date: Thu, 09 Dec 1999 02:33:39 -0500
From: Ian Goddard 
Subject: Tofu Study Update

 The following contains much information about the "tofu study"

 I contacted Lon White, lead researcher in the tofu study 
 to ask some questions. I asked him about the statistical 
 significance of the findings in the study. He informed 
 me that there were four major endpoints in the study:

 1. cognitive impairment of men (number of men=3734)
 2. cognitive impairment of sample of wives (n=502)
 3. brain atrophy by weight of men who died (n=290)
 4. brain atrophy by volume measured via MRI (n=574)

 The probability (p) value was less than .05 (significant) 
 for a correlation between each endpoint and tofu intake 
 (there was no significant correlation for other foods).
 In some cases the p value is less than .001 (if the p 
 value is more than .05, it's not significant, if it's 
 .05 or less, it's significant). Here's what this means:

 IF  p = .05  there's 95% chance the correlation is true
 IF  p = .01  there's 99% chance the correlation is true
 IF  p = .001 there's 99.9% chance the correlation is true

 So the correlation between the four endpoints listed above
 and tofu consumption had an over 95% probably of being true,
 with a probability of truth as high as 99.9%. Of course this
 cannot be read as proof that tofu causes those problems, but 
 at the least it signals the need for further investigation.
 What is perhaps most significant is that Dr White informed
 me that there is a dose-dependent relationship between 
 tofu consumption and the endpoints, ie, the more tofu was 
 eaten, the more impairment and/or atrophy is found. The 
 odds that such findings would be chance are extremely low!

 Here are two papers Dr. White, et al., have had published:

 White, L., Petrovitch, H., Ross, G.W., & Masaki K.H. (1996) 
 Association of mid-life consumption of tofu with late life 
 cognitive impairment and dementia: The Honolulu-Asia Aging 
 Study. The Neurobiology of Aging, 17 (suppl 4), S121.

 White, L.,  Petrovich, H., Ross, G. W., Masaki, K. H., 
 Abbot RD, et al. (1996) Prevalence of dementia in older 
 Japanese-American men in Hawaii. JAMA, 276, 955-960.


 Here's a brief review of those two papers found in a letter 
 to the FDA from Daniel Sheehan, PhD, Director of the Estrogen 
 Base Program Division of Genetic and Reproductive Toxicology, 
 and Daniel Doerge, PhD, Division of Biochemical Toxicology:

On 02/18/99, Dr. Sheehan & Dr. Doerge comment on White's work
Finally, initial data from a robust (7,000 men) long-term 
(30+ years) prospective epidemiological study in Hawaii showed 
that Alzheimer's disease prevalence in Hawaiian men was similar 
to European-ancestry Americans and to Japanese (White, et al, 
1996a).  In contrast, vascular dementia prevalence is similar 
in Hawaii and Japan and both are higher than in European-
ancestry Americans. This suggests that common ancestry or 
environmental factors in Japan and Hawaii are responsible for 
the higher prevalence of vascular dementia in these locations.  
Subsequently, this same group showed a significant dose-dependent 
risk (up to 2.4 fold) for development of vascular dementia and 
brain atrophy from consumption of tofu, a soy product rich in 
isoflavones (White, et al, 1996b).  This finding is consistent 
with the environmental causation suggested from the earlier 
analysis, and provides evidence that soy (tofu) phytoestrogens 
causes vascular dementia.    Given that estrogens are important 
for maintenance of brain function in women; that the male brain 
contains aromatase, the enzyme that converts testosterone to 
estradiol; and that isoflavones inhibit this enzymatic activity 
(Irvine, 1998), there is a mechanistic basis for the human findings. 
Full Letter: 

 The following is the abstract to the recent study, which 
 should be published by April. Below that is a memorandum 
 sent out by Doctor White after the newspaper publications:

Association of high midlife tofu consumption with accelerated  
brain aging .   Lon White,  MD, MPH   (From the Pacific Health 
Research Institute, Honolulu, HI.)  

This investigation utilized the resources of the Honolulu 
Heart Program, a longitudinal study of Japanese-American men 
established in 1965 for research on heart disease and stroke.   
Questions regarding frequency of consumption of tofu and 26 
other foods were asked at interviews in 1965-67 and again 
in 1971-74.  Cognitive testing was done (n=3734) and cases 
of dementia identified (n=225) at the 1991-93 examination, 
when participants were aged 71-93 years.  Atrophy was assessed 
by neuroimaging (n=574) or autopsy (n=290).  Cognitive test 
data were also analyzed for wives of a sample of study 
participants (n=502) who had been living with the participants 
when their dietary interviews were done.  Poor cognitive test 
performance in late life was associated with higher midlife 
tofu consumption.  An independent association of similar 
magnitude and direction was apparent among wives of cohort 
members, using the husband's answers as proxy for the wife's 
consumption.  Midlife tofu consumption was independently 
associated with low brain weight and with ventricular 
enlargement.  Independent associations of more frequent 
midlife tofu consumption with clinically diagnosed Alzheimer's 
disease and with poor cognitive functioning among non-demented 
subjects were demonstrated.  Associations generally followed 
a dose-response pattern, were statistically significant after 
controlling for all relevant and potentially confounding 
factors, and remained apparent after stratifying for age or 
obesity.  These data suggest that regular consumption of tofu 
over many years in middle life may have an adverse influence 
on brain aging manifest as accelerated atrophy, cognitive 
decline, and a lowering of the threshold for the clinical 
manifestations of Alzheimer's disease.  We speculate that 
these may reflect chronic sub-optimal neuronal plasticity 
caused by isoflavone inhibition of tyrosine kinase activity 
and/or by interference with estrogen-related mechanisms.


FROM: Lon White, M.D., M.P.H., Senior Neuroepidemiologist, HAAS and PHRI
DATE: November 30, 1999
RE: Responding to questions about tofu

The articles that recently appeared in the Star Bulletin 
and the Advertiser have caused a great deal of distress 
locally, and have elicited a number or requests for 
information.  While we cannot give advice and no definitive 
statements are possible at this time, the following can be said:  

1.   We observed a consistent pattern of association between 
answers given by men interviewed in 1965 and in 1971 
regarding the number of servings of tofu consumed per week - 
and their scores on a test of cognitive function when examined 
1991-93.  Higher frequencies of tofu consumption were 
associated with poorer test scores.  This observation remained 
strong after controlling for all relevant factors (such as age, 
education, occupation, etc.) and no other foods or drink showed 
such an association.

2.	Separately, we observed an association of high midlife 
tofu intake with low brain weight determined at autopsy, 
again after controlling for all other relevant factors.  

3.	Separately, we observed an association of high midlife 
tofu intake with enlarged ventricles identified by MRI.

4.	Although we did not find an association of high midlife 
tofu intake with the brain lesions that characterize Alzheimer's 
disease in our autopsy study, we did find high midlife tofu 
intake to be a risk factor for the clinical diagnosis of 
Alzheimer's disease.  

Taken together, we interpret these as suggesting that consumption 
of tofu over many years during middle life is linked to a mild 
to moderate acceleration in brain aging, perhaps similar to 
that which might occur in a woman who did not receive hormone 
replacement therapy after menopause.  We cannot be sure that 
the causal factor was really the tofu, but no other alternative 
is apparent at this time.    

We believe that the most reasonable mechanism would be an 
interference with the normal mechanisms in the brain that 
maintain the connections between neurons during aging (i.e., 
brain plasticity mechanisms), caused by the isoflavone 
phytoestrogens that are known to be present in pharmacologically 
significant concentrations in most soy foods.  

Although the findings are very consistent, it is never proper 
to draw definitive conclusions from a single study.  It would 
be premature to advise anyone that they should change their 
diets based on a single research study.  In addition, there 
is evidence that consumption of soy foods may have beneficial 
effects related to improving blood lipid levels, and reducing 
risks for breast cancer.  

Unfortunately it is likely that independent confirmation or 
refutation of our findings will require 1-3 years.  In the 
meantime no definitive statements can be made.  Individuals 
will have to weigh the evidence and make their own decisions 
concerning their consumption of soy foods and their isoflavone 

LR White

================== End Of Forward Material ====================


Date: Sat, 04 Dec 1999 02:50:09 -0500
From: Ian Goddard 
Subject: Soy Update

  A second article in another Hawaiian paper on the tofu 
  study has been located. The papers published follow-ups 
  that sought to allay concerns about tofu, raising points 
  from the need for more research before coming to definitive 
  conclusions (obviously) to harming local tofu businesses.
  Here are the articles I've found on the tofu study: 

  I contacted a researcher in a study I quoted showing that 
  the soy phytochemical genistein killed testicular cells. 
  I asked if those cells were normal or cancerous. He said 
  they were altered, but in other studies he has and/or is 
  working on, genistein is found to kill normal testicular 
  cells, yet increase their proliferation at lower doses.

  While healthy folks may not need chemicals increasing 
  or decreasing the number of their cells, that evidence 
  suggests that if there's a toxic level, there may also 
  be a safe and possibly beneficial level of soy. With 
  respect to reducing rates of cancer and other major 
  illness, research suggests that soy works. The FDA 
  recently approved the use of a health claim on soy 
  products.[*] PubMed searches find numerous studies 
  (see: over the 
  years that demonstrate an anti-cancer effect of soy 
  phytochemicals, and their cytotoxic effect appears 
  generally to be highly specific to cancer cells.

  Of course, the possibility of a risk of brain atrophy 
  is not to be taken lightly. Of all organs, the brain 
  is arguably the most valuable and important to preserve.





Initial soy-warning post

Date: Sat, 27 Nov 1999 15:32:51 -0500
From: Ian Goddard 


  As a vegetarian, I present the following with great regret.
  Soy products like tofu have provided the staple alternative
  to eating murdered animals. Unfortunately the study reported
  has found a significant link between eating tofu and brain 
  aging and atrophy! My first reaction was to hope that the 
  study was flawed. Unfortunately, a quick study of published
  research at the National Library of Medicine indicates that 
  there is a STRONG physiological basis for the findings in 
  that study. It seems that a main phytochemical in soybeans,
  genistein, reduces DNA synthesis in the brain, and reduced 
  DNA synthesis promotes apoptosis, which is also known as 
  "programmed cell death." Multiple studies I found indicate
  that drug-induced reduction of DNA synthesis is routinely 
  assoicated with reduced cell proliferation and death. DNA 
  synthesis is a critical part of the life cycle of a cell: 

  It appears that the ability of genistein to reduce DNA
  synthesis may be why it is a promising anti-cancer agent, 
  for research suggests genistein can kill cancer cells and
  other drugs that reduce DNA synthesis kill cancer cells. 
  Unfortunately, genistein's cytotoxic properties appear 
  to be nonspecific, ie, it doesn't only kill cancer cells.
  In the first abstract below, it was found that genistein 
  "induced significant testicular cell death." Ouch! The 
  second study finds that genistein reduced DNA synthesis 
  in the brain. To get the full picture of what I've stated 
  here, I recommend using the National Library of Medicine's 
  search engine:  It is 
  easily the most powerful tool on the Internet, accessing 
  most of the published medical research since around 1965.

    Too much tofu induces ‘brain aging,’ study shows: 

Soy-phytochemical genistein "induced significant testicular cell

Biol Cell 1999 Sep;91(7):515-23 

Cytotoxic potential of the phytochemical genistein 
isoflavone (4',5',7-trihydroxyisoflavone) and certain 
environmental chemical compounds on testicular cells.

Kumi-Diaka J, Nguyen V, Butler A

Florida Atlantic University, Department of Biology, 
College of Liberal Arts & Sciences, Davie 33314, USA. 

[Medline record in process]

The effects of genistein (Gn), sodium azide (naz), and 
dexamethasone (dxm) on testicular cells TM3, TM4 and 
GC-1 spg were studied in vitro. First, a series of 
experiments were performed to assess the response of 
the cells to the exposure of Gn, naz, dxm, a combination 
of Gn with naz and Gn with dxm. Trypan blue exclusion 
assay was used to determine the percentage of viability, 
and LDH-cytotoxicity test was used to assess the degree 
of treatment-induced cytotoxicity on each cell type. A
second series of experiments were performed to study 
cytomorphology and determine the type and percentage of
treatment-induced cell death (apoptosis and necrosis) on 
each cell line, using fluorescent dye technique to detect 
apoptotic and necrotic cells, and tunnel assay to confirm 
apoptosis. The results from the data obtained demonstrated: 
i) that incubation of testis cells with each of the agents 
(Gn, dxm, naz) alone and in two combinations (Gn-dxm, and 
Gn-naz) induced significant testicular cell death; ii) that 
both genistein and dexamethasone mostly and significantly 
induced apoptotic cell death while sodium azide induced 
necrotic cell death; iii) that addition of dexamethasone 
to genistein demonstrated synergism in apoptosis on testis 
cells; and iv) that combination of naz with Gn demonstrated 
synergism in necrosis on testis cells even though Gn alone 
did not induce significant necrosis. It is concluded that 
the synergistic actions of genistein and dxm, and of genistein 
+ sodium azide in induction of apoptosis and/or necrosis may 
be of clinical and pathophysiological research interest 
considering the chemopreventive and chemotherapeutic potential 
of genistein; and the clinico-pharmacological application of 
dexamethasone and sodium azide.

"Genistein decreased the DNA synthesis within less than 30 min."

Exp Neurol 1999 Sep;159(1):164-76 

Early effects of protein kinase modulators on DNA synthesis 
in rat cerebral cortex.

Yakisich JS, Siden A, Vargas VI, Eneroth P, Cruz M

Applied Biochemistry, Clinical Research Center, Karolinska 
Institute, Novum, Huddinge University Hospital, Huddinge,
S-141 86, Sweden. 

By using tissue miniunits, protein kinase modulators, and 
topoisomerase inhibitors in short-term incubation (0-90 min) 
we studied (1) the role of protein phosphorylation in the 
immediate control of DNA replication in the developing rat 
cerebral cortex and (2) the mechanism of action for genistein-
mediated DNA synthesis inhibition. Genistein decreased the DNA
synthesis within less than 30 min. None of the other protein 
kinase inhibitors examined (herbimycin A, staurosporine, 
calphostin-C) or the protein phosphatase inhibitor sodium 
orthovanadate inhibited DNA synthesis and they did not affect 
the genistein-mediated inhibition. The selective topoisomerase 
inhibitors camptothecin and etoposide decreased the DNA synthesis 
to an extent similar to that of genistein and within less than 
30 min. In addition, the effects of these substances on 
topoisomerase I and II were studied. Etoposide and genistein 
but not herbimycin A, staurosporine, or calphostin-C strongly 
inhibited the activity of topoisomerase II. Our results (1) 
strongly suggest that the net rate of DNA replication during 
the S phase of the cell cycle is independent of protein 
phosphorylation and (2) indicate that the early inhibitory 
effect of genistein on DNA synthesis is mediated by 
topoisomerase II inhibition rather than protein tyrosine 
kinase inhibition. Copyright 1999
Academic Press.

Reduce DNA synthesis associated with aging

Acta Neuropathol (Berl) 1999 Jan;97(1):71-81 

Age-related changes of DNA repair and mitochondrial 
DNA synthesis in the mouse brain.

Schmitz C, Axmacher B, Zunker U, Korr H

Department of Anatomy and Cell Biology, RWTH University 
of Aachen, Germany. cschmitz@alpha.imib.rwth-aachen,de 

Using quantitative autoradiography, both nuclear DNA 
repair - measured as nuclear unscheduled DNA synthesis 
(UDS) - and mitochondrial (mt) DNA synthesis were 
evaluated in situ for several types of cells in the 
brains of untreated mice of various age. It was found 
that distinct types of neuronal cells showed a decline 
of both UDS and mtDNA synthesis with age, whereas - 
except for glial cells of the cerebral cortex - no glial 
or endothelial cells showed age-related alterations of 
UDS. Together with various data reported in the literature, 
these patterns of a cell type-specific decrease of UDS and 
mtDNA synthesis with age in the mouse brain lead to an 
improved understanding of the complex interrelationships 
between the molecular events associated with the 
phenomenon of aging as well as to a new idea regarding 
the cause of the specific distribution pattern of those 
cells in the human brain that are affected by the formation 
of paired helical filaments in Alzheimer's disease.

To get the full picture of what I stated above, I
recommend using the National Library of Medicine's 
search engine: 
The key words you choose make all the difference!