What was his position with the National Institutes of Health and when?
 Also, is there any listing of WHY --on in what context-- he made the
famous statement, (quote) "The amount of Antioxidants that you
maintain in your body is directly related to how long you will live"

I believe that the man who have in mind is Richard G. Cutler.  The
best I can do with your question is give you the following link to a
page that includes his CV, in which he says that he was "Research
Chemist, Gerontology Research Center, National lnstitute on Aging.
National lnstitutes of Health" from 1976-1995,

http://www.pref.shizuoka.jp/kikaku/ki-03/health/pre/cutler.html


Here is another link to self-written biographical information:

http://64.233.161.104/search?q=cache:bthBnMS-FNQJ:www.o2sa.org/O2SAHomepage/CutlerCV.htm+%22Richard+g+cutler%22+nih&hl=en


There are lots of online references by "anti-aging" devotees to the
quote you have cited, but, other than the biographical information
cited above, I have found little other information about the man and
nothing about the primary source of the quote.

Maybe another researcher will have better luck.

The aging expert you are inquiring about is indeed Richard G. Cutler
who was at the NIH's National lnstitute on Aging from 1976-1995.

The quote refers to Dr. Cutler's vast research regarding antioxidants and aging.

His pioneering works include the hypothesis that antioxidants reduce
oxidative stress which in turn can prevent the cumulative destruction
of cellular function.

In layman's terms, aging would be defined as a loss of cellular
function.  Oxidative stress is the process in which highly reactive
molecules (such as free radicals, reactive oxygen species (ROS))
impair particular cellular functions.  Antioxidants reduce the
destructive behavior of ROS by reacting with the ROS directly.  This
reaction inactivates the ROS, which can no longer react with (and
therefore inactivate) critical components of the cell.

Regarding your quote, "The amount of Antioxidants that you
maintain in your body is directly related to how long you will live". 
 This statement comes from a number of studies by Dr. Cutler which
demonstrated that the extent of detoxification of ROS (and as a
consequence, longevity) correlates with the amount of antioxidants
available.

This observation is demonstrated in his 1997 research article
"Preferential use of less toxic detoxification pathways by long-lived
species." Arch Gerontol Geriatr. 1997 Jan-Feb;24(1):87-102.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15374139


Here is another quote in Dr. Cutler's own words from his 1991 review
of the subject.

Exerpt from "Recent progress in testing the longevity determinant and
dysdifferentiation hypotheses of aging", Archives of Gerontology and
Geriatrics Volume 12, Issues 2-3 , March-June 1991, Pages 75-98.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15374441

"There is now some evidence that antioxidants may be longevity determinants.
Many of the antioxidants may be involved in a compensatory homeostatic-like
regulatory system designed to maintain the concentration of reactive
oxygen species in the cell to a species' characteristic level over a
wide range of life styles. It is this mean tissue level of oxidative
stress which is probably unique for each differentiated cell type and
which is proposed to govern the rate of dysdifferentiation of the cell
and thus the aging rate of the organism."

Here are some additional references from Dr. Cutler's research:

Cutler, R.G. (1972): Transcription of reiterated DNA sequence classes
throughout the lifespan of the mouse. In: Advances in Gerontological
Research, Vol. 4, pp. 219-321. Editor: B.L. Strehler. Academic Press,
New York.

Cutler, R.G. (1975): Evolution of human longevity and the genetic
complexity governing aging rate. Proc. Natl. Acad. Sci. U.S.A., 72,
4664-4668.

Cutler, R.G. (1982a): Longevity is determined by specific genes:
testing the hypothesis. In: Testing the Theories of Aging, pp. 25-114.
Editors: R. Adelman and G. Roth. CRC Press, Boca Raton, FL.

Cutler, R.G. (1982b): The dysdifferentiative hypothesis of mammalian
aging and longevity. In: The Aging Brain. Cellular and Molecular
Mechanisms of Aging in the Nervous System, pp. 1-19. Editors: E.
Giacobini, G. Filogamo, and A. Vernadakis. Raven Press, New York.

Cutler, R.G. (1984a): Evolutionary biology of aging and longevity. In:
Aging and Cell Structure, Vol. 2, pp. 371-428. Editor: J.E. Johnson.
Plenum, New York.

Cutler, R.G. (1984b): Antioxidants and longevity. In: Free Radicals in
Molecular Biology Aging and Disease, pp. 235-266. Editors: A.
Armstrong, R.S. Sohal, R.G. Cutler and T.F. Slater. Raven Press, New
York.

Cutler, R.G. (1984c): Antioxidants, aging and longevity. In: Free
Radicals in Biology, Vol. VI, pp. 371-428. Editor: W. Pryor. Academic
Press, New York.

Cutler, R.G. (1985a): Antioxidants and longevity of mammalian species.
In: Molecular Biology of Aging, pp. 15-74. Editor: A.D. Woodhead, A.D.
Blackett, and A. Hollaender, Plenum, New York.

Cutler, R.G. (1985b): Dysdifferentiation and aging. In: Molecular
Biology of Aging: Gene Stability and Gene Expression, pp. 307-340.
Editors: R.S. Sohal, L. Birnbaum and R.G. Cutler, Raven Press, New
York.

Cutler, R.G. (1985c): Peroxide-producing potential of tissues:
correlation with the longevity of mammalian species. Proc. Natl. Acad.
Sci. U.S.A., 82, 4798-4802.

Cutler, R.G. (1991): Human longevity and aging: Possible role of
reactive oxygen species. Ann. N.Y. Acad. Sci. 621:1-28.

Cutler, R.G. and Semsei, I. (1989): Development, cancer and aging:
possible common mechanisms of action and regulation. J. Gerontol., 44,
25-34.

Hope this helps.  -SG

Here is an update on the whereabouts of Dr. Cutler.

Dr. Richard G Cutler is an internationally known Molecular
Gerontologist. He is best recognized for his Longevity Determinant
Gene and Dysdifferentiated Hypothesis of Aging. He is now
internationally recognized as an expert in the field of oxidative
stress profiling and in the development of genetic and pharmaceutical
means of controlling aging rate and age-dependent diseases related to
oxidative stress. Dr Cutler joined the Gerontology Research Center at
the National Institute on Aging, National Institutes of Health as a
principle investigator. He remained there as a productive research
scientist for 18 years.

Dr Cutler founded the Genox Corporation and developed the procedure of
Oxidative Stress Profiling. He then joined The Kronos Group as the
President and Scientific Director. Here he designed the laboratory and
set up the analytical instruments and assays with an emphasis on
preventive medicine and oxidative stress profiling. Dr Cutler served
briefly as the director of the Kronos Foundation and with The Aurora
Foundation as a consultant. He is now a Senior Scientist with the
Kronos Longevity Research Institute.
http://www.worldscibooks.com/medsci/4714_edi01.html



From his homepage at the Kronos Longevity Research Institute:

Dr. Richard G. Cutler is the Senior Scientist at KLRI. He serves as a
consultant and principle investigator on a broad range of subjects
dealing with gerontology issues in general and specifically with
oxidative stress assay and intervention evaluation studies. Dr Cutler
received an electrical EE degree and a BS degree in physics from
California State College in 1960. In 1966 he obtained MS and Ph.D.
degrees in Biophysics from the University of Houston. Dr. Cutler then
received a NIH postdoctoral fellowship to study the molecular biology
of aging under the direction of Dr. Howard Curtis at the Brookhaven
National Laboratory. In 1969 he joined the Institute for Molecular
Biology at the University of Texas at Dallas as an assistant professor
and in 1976 accepted a position as a NIH principle investigator with
the Intramural Program of the National Institute on Aging. In 1995 Dr.
Cutler established the Genox Corporation, and in 1999 he was recruited
by the Kronos Group to establish the Kronos Science Laboratory. In
2001 he became the Senior Scientist at KLRI. Dr. Cutler is an
internationally recognized expert in molecular gerontology with 128
original research papers and a recipient of the 17th Karl August
Foster Award from the German Academy of Science. He is best known for
proposing and testing the Longevity Determinant Gene Hypothesis and
the Dysdifferentiation Hypothesis of Aging, for his studies of
oxidative stress as a primary mechanism of aging, and in development
of the oxidative stress profiling technique to minimize oxidative
stress in human patients.
http://www.kronosinstitute.org/Biographies/biography-cutler.html


Hope this helps.  -SG