Why We Get the Flu in Winter...

James Michael Howard jmhoward at arkansas.net
Thu Mar 18 11:34:13 EST 2004

Why We Get the Flu in Winter, Why We Are Fat, and Other Things
 The Importance
of the Testosterone - DHEA Ratio

Copyright 2004, James Michael Howard, Fayetteville, Arkansas, U.S.A.

It is my hypothesis that mammals evolved because of increases in
dehydroepiandrosterone (DHEA).  The DHEA increased energy production from fat.
Hence, mammals are "warm blooded."  Furthermore, I suggest primates arose from
other mammals because of increases in testosterone.  Humans continued along this
path; we produce the most testosterone.

Humans produce so much testosterone, the ratio of testosterone to DHEA may
produce some benefits and some advantages.  DHEA is the active molecule, DHEAS
(DHEA sulfate) is the large reservoir of DHEA in our blood.  The trouble with
the ratio of testosterone and DHEA is that testosterone may interfere with the
transformation of DHEAS into DHEA.  Testosterone inhibits steroid sulfatase.
Steroid sulfatase makes DHEA from DHEAS.  This may be the real reason for the
evolution of humans from other primates.  Increased testosterone in women would
increase their DHEAS at the expense of their DHEA.  Women would become fat and
testosterone would increase the sex drive of women.  Fat is a good thing when
the climate is cold.  Increased fat and sex drive in females will increase
offspring when the climate is cold, and when the climate is warm.  (Human males
and females produce more testosterone than chimpanzee males and females,
respectively.)  Again, it is that ratio thing.

Now, it is known that testosterone decreases the effectiveness of the immune
system while DHEA increases the effectiveness of the immune system.
Testosterone in people increases in the autumn and winter.  DHEA sulfate is also
higher in the autumn and spring.  I suggest the reason is that increased
testosterone of autumn and winter reduces production of DHEA from DHEA sulfate.
This may be the reason that infections, such as influenza increase in the
winter.  It may also produce more fat in us during the autumn and winter.  It
certainly is not nice to get the flu, but fat is certainly nice if we want to
get pregnant in the autumn and winter and have lots of fat for our babies'
growth when it is needed.  Again, this is human evolution determined by females.

It is part of my work that many mental illnesses result from low DHEA during
growth and development of the brain and these are exacerbated by low DHEA.
Therefore, I would predict that mental disorders should increase in severity and
incidence in winter.  This is the case.  Now, you need to know that, according
to my work, the level of DHEA determines the strength of motivation.  (This is
derived from my explanation of the "fight or flight mechanism" which suggests
that higher DHEA increases motivation.)  Therefore, I have to explain that the
increased ratio of testosterone to DHEA in winter reduces DHEA so this should be
a time when behaviors that we control are reduced.  I suggest the increased
testosterone to DHEA ratio reduces our ability to control our impulses, but it
may also reduce actions based on those impulses.   
unless one is provoked.

In the case of homicides, suicides, voluntary aggression, etc., a number of
studies indicate that, in fact, winter is a time of reduced behaviors of this
sort.  "Referrals" for disciplinary actions in schools actually decline in the
winter.  In winter, we have less DHEA to act on our actions.  However, as in the
case of the mental disorders and infections mentioned above, there are
consequences of the increased testosterone to DHEA ratio of winter.  DHEA is
very low in the elderly and the very young.  I think very low DHEA results in
death.  Winter is a time of increased mortality in young children and the
elderly.  Low DHEA has been linked to depression; this may be the mechanism of
seasonal affective disorder or SAD.  Venous thromboemolism exhibits a higher
incidence in winter.  I suggest cancer may be triggered by low DHEA.  There is a
significant excess of childhood acute lymphocytic leukemia in winter.  A study
in Poland found increased type 1 diabetes mellitus in autumn and winter months.
I think preeclampsia is a disorder of low DHEA and high testosterone; in one
study, August had the lowest risk of preeclampsia while "the risk was highest in
the winter months."  Sudden infant death syndrome, another I attribute to low
DHEA, is higher in the winter and in boys.  This list could be expanded.

Often reports of diseases and season of occurrence are conflicting, often
involving infectious agents.  The testosterone - DHEA ratio should increase
infections primarily in winter.  However, as pointed out above, motivation
increases when DHEA begins to increase as testosterone declines with spring and
summer.  Therefore, many infectious diseases will increase because of increased
activities which increase infections.  This will be difficult to differentiate.
However, a pattern does emerge in many of these with increased rates cited in
the literature for both autumn-winter and spring-summer, that is, two peaks.

Humans may be animals that evolved because of increased testosterone.  This
produces benefits and disadvantages.  Larger brains are one result.  However, I
suggest testosterone levels periodically increase and skew the effects of
testosterone towards the negative aspects.  That is, I suggest people of higher
testosterone reproduce faster than those of lower testosterone.  Therefore, they
will increase in percentage within populations with time.  This is how
"testosterone increases" and is the cause of the "secular trend," the increase
in size of children and earlier puberty that is real and robust in the United
States as well as other countries.  The negative aspects of testosterone are
increasing.  The examples I mentioned above are increasing as well as will
others not mentioned.  We are getting fatter, sexier and infections are

James Michael Howard

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