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[A1CR]

Ones family members may be pre-disposed to hearing loss at
relatively young ages. Many in Canada having been employed
in the
forest products industry, and males have typically been
exposed to
on-the-job elevated noise levels. A CRONie recalls the
summer in which he was a relief
wood chipper operator. His ears would ring long after the
shifts. Even the
wood waste "hogs" that ground up wood waste for burning were
loud those
evenings working the clean-up on weekends during my high
school years. CR/CRON
may reduce the effects of aging on hearing loss, but how may
the results
identified, after my having been subjected to even the
constant noises of
the plywood factory floor working area? The nearest model
that may be a
control for what males who have not worked in such
industrial settings
should be our nearest evolutionary neighbors, the monkeys.
They may offer
the best experimental system for examining the effects of
aging, with or
without CR, in males and females. Hearing loss is a
substantial hazard of
aging for morbidity and, apparently, may correlate with
mortality.
http://en.wikipedia.org/wiki/Presbycusis is the term used to
characterize
the condition. Maybe, CRONies should take the "Buzzin"
test"? Previously, it
was found, in (1) paper, that our ability to hear may be
improved as we age if we CR/CRON. More recently, a study
(2) documents the
effects of CR from hearing well with aging and CR seems to
confer
significant hearing loss preventive benefits for CRers, but
more for the
lady monkeys.

1. Seidman MD.
Effects of dietary restriction and antioxidants on presbyacusis.
Laryngoscope. 2000 May;110(5 Pt 1):727-38. Review.
PMID: 10807352

Effects of dietary restriction and antioxidants on
presbyacusis. "...
reactive oxygen metabolites (ROM). ROM ... mitochondrial DNA
(mtDNA),
resulting in the production of specific mtDNA deletions ...
RESULTS: Results indicated that the
30%-caloric-restricted group
maintained the most acute auditory sensitivities, the lowest
quantity of
mtDNA deletions, and the least amount of outer hair cell
loss. The
antioxidant-treated subjects had improved auditory
sensitivities, and a
trend for fewer mtDNA deletions was observed compared with
the placebo
subjects. The placebo subjects had the poorest auditory
sensitivity, the
most mtDNA deletions, and the greatest degree of outer hair
cell loss.
CONCLUSIONS: ... Nutritional and pharmacological
strategies may very
well provide rational treatment options that would limit the
age-associated
increase in ROM generation, reduce mtDNA damage, and reduce
the degree of
hearing loss as the organism advances in age.

Now, here is the monkey study:

2. Fowler CG, Torre P 3rd, Kemnitz JW.
Effects of caloric restriction and aging on the auditory
function of rhesus
monkeys (Macaca mulatta): The University of Wisconsin Study.
Hear Res. 2002 Jul;169(1-2):24-35.
PMID: 12121737

... The control group had 35 monkeys allowed to eat
freely and the
caloric-restricted group (CR) had 33 monkeys with a 30%
reduction in caloric
intake. Monaural and binaural auditory brainstem response
(ABR) and middle
latency response (MLR) were obtained from 27 female and 41
male monkeys that
were 11-23 years of age and had been in the study for 102,
42, or 36 months
when tested. Significant findings were the following: (1)
wave I amplitudes
were larger for females and for younger monkeys, and
amplitudes decreased in
aging males but not in aging females; (2) wave IV amplitudes
were larger for
females than males, and amplitudes for CR females were
larger than for
female controls, whereas the amplitudes from control and CR
males were not
different; (3) wave Pa latencies were shorter for females,
and shorter
latencies were maintained for aging females but not for
aging males; (4)
interwave interval IV-Pa was shorter for females, and
intervals lengthened
for aging males but not aging females; (5) binaural wave IV
amplitude
decreased faster with age for control monkeys than for CR
monkeys, and the
L+R Pa amplitude decreased with age. Additional trends were
identified for
longitudinal monitoring as monkeys enter old age.

[...]

3.4. Summary In summary, although not all waves evidenced
the same
significant findings, several consistencies emerged for the
electrophysiological responses. When the effect of sex was
significant, the
latencies were shorter and the amplitudes larger for the
responses of the
females as compared with the responses of the males. When
dietary condition
was significant, the latencies were shorter and the
amplitudes were larger
for the subjects under the CR condition. When age was
significant, the
latencies were shorter and the amplitudes were larger for
the younger
monkeys. The significant findings for each wave were the
following:

(1) For wave I, amplitudes were larger for the females
and for the
younger monkeys, and additionally the amplitudes were
decreased with age for
males but not for females.
(2) For wave IV, amplitudes were larger for the
females, and
additionally the amplitudes for the females were larger
under the caloric
restriction as compared to the control condition, whereas
the amplitudes of
the males were not different in these two conditions.
(3) For wae Pa, latencies were shorter for the
females, and the
latencies lengthened with aging for the males but not for
the females.
(4) For interwave interval IV-Pa, the intervals were
shorter for
females, and the latencies lengthened with aging for the
males but not for
the females.
(5) In the binaural conditions, the binaural wave IV
amplitude
decreased with age faster for control monkeys than for CR
monkeys, and the
L+R Pa amplitude simply decreased with age.
In addition, the following effects bordered on
significance and will be
monitored for longitudinal developments in future studies:
(1) For interwave interval I-IV, the interval tended
to be shorter for
the younger monkeys.
(2) For interwave interval IV-Pa, the interval tended
to be shorter for
the female monkeys than for the males.
(3) For the binaural conditions, the L+R Pa tended to
decline faster
for older monkeys than for younger monkeys.
(4) For threshold, although the females tended to have
better
thresholds overall, the effect of caloric restriction
improved the
thresholds of the males but not the females.

... males are older than the females, with 29 males
aged between 18 and
23 years, and only nine females aged between 18 and 19
years. The males
under caloric restriction had better thresholds than the
males under the
control condition, but these better thresholds were in line
with the
thresholds of the female group at large. The older males are
entering the
ages at which presbycusis begins to be evident with the ABR
measures, and
where the effect of caloric restriction on auditory function
is most likely
to have an effect. The females, being younger than the
males, may not have
begun to show evidence of presbycusis in their thresholds in
either dietary
condition. A further possibility may be the duration of
caloric restriction;
25 males had been in the study for 102 months at the time of
testing,
whereas the longest participation of the female monkeys was
only 42 months.

... In humans, sex differences in auditory function are
often attributed to
lifestyle factors, including exposure to noise ... monkeys
participating in
the present study did not experience variations in lifestyle
or diet ...
other endogenous effects controlled the better hearing in
the female
monkeys. ... older men may have an abnormality of binaural
processing at
high brainstem or cortical levels ... minimal effects of
caloric restriction
on the ABR and MLR of the monkeys in the present study. The
amplitude of
wave IV was enlarged only for the females on caloric
restriction ... The
amplitude of the binaural IV decreased with age more so in
the control group
than in the CR group. The amplitude of the L+R Pa also
decreased with age,
and showed a tendency to decrease more in the control group
than in the CR
group. The effects on amplitude and not on latency are not
unexpected given
that the amplitude measures generally are affected by
pathology before the
latency measures are. The subtlety of these findings is
underscored because
only a few waves showed significant effects, presumably
because of the high
degree of variability in amplitude measures. Further, the
thresholds of the
male monkeys on caloric restriction tended to be improved
over the
thresholds of the control monkeys. Thresholds are
intricately associated
with the amplitudes of the potentials, and so provide
further support for
the subtle effects of caloric restriction on the amplitudes
of the
potentials. That the threshold effect of caloric restriction
is seen only in
the males may be related to their status as older
participants or as longer
participants in the caloric restriction. While these effects
are
intertwined, the fact that the older control monkeys had the
highest
(poorest) thresholds suggests that the caloric restriction
may, in fact, be
operating on the development of presbycusis. Any difference
in the rate of
development of presbycusis between the sexes will become
evident with future
studies as the monkeys continue to age. Although background
noise level may
have interfered somewhat with the lowest thresholds, it
should not have been
a factor for the elevated thresholds in the older monkeys. ...

... People on experimental diets with reduced fat had
a drop in
cholesterol levels, fewer new onsets of coronary artery
disease, and
significantly better auditory thresholds as compared to
people on standard
high-fat diets ( http://tinyurl.com/z644v ). People with
cardiovascular
disease have been reported to have significantly poorer
auditory thresholds
than healthy people (Rubinstein et al., 1977). ...
Histopathologic changes
in temporal bones of people with hearing loss commonly
included a narrowing
of the internal auditory leading to a reduction of blood
supply to the
cochlea and spiral ganglion atrophy (Makishima, 1978). ...
Male and female
monkeys may have different physiological responses to
caloric restriction
that may eventually have a bearing on auditory sensitivity.
... caloric
restriction lowers the plasma lipoprotein a in CR males to
the level in
females. Because the current female monkeys are
premenopausal, sex hormones
may play a role. These findings suggest that the physiologic
response of the
females to caloric restriction may change as they go through
menopause
(Edwards et al., 2001), which typically occurs between 25
and 27 years of
age (Kemnitz et al., 1998). .. effects of caloric
restriction on hearing
loss also may change as the monkeys go through menopause in
the coming
years.