[Antioxidants for prophylaxis of eye
diseases]
Kaluzny J
Klin Oczna (Poland) Feb 1996, 98 (2) p141-3
The contemporary literature has widely
described the role of free oxygen radicals and
their antioxidants in pathogenesis of some eye
diseases, mainly cataract, age-related macular
degeneration, retinopathy of prematurity and
cystic macular oedema. This paper presents
publications which stress the importance of
antioxidants use in prophylaxis of cataract and
age-related macular degeneration. Positive
antioxidants role was proved both in experimental
research and in clinical observations. (29
Refs.)
Antioxidants and angiogenetic factor
associated with age-related macular degeneration
(exudative type)
Ishihara N, Yuzawa M, Tamakoshi A
Department of Ophthalmology, Nihon University
School of Medicine, Tokyo, Japan.
Nippon Ganka Gakkai Zasshi 1997
Mar;101(3):248-51
To confirm the hypothesis that antioxidants and
angiogenetic factors may be associated with the
development of age-related macular degeneration
(exudative type), we compared serum levels of
vitamins A, C, and E and carotinoid, zinc,
selenium and b-FGF (basic-fibroblast growth
factor) in 35 patients with age-related macular
degeneration (exudative type) with the levels in
66 controls. The average serum zinc level was
significantly lower in the patient group than in
the control group. Serum vitamin E-alpha levels
also tended to be lower. Most serum b-FGF levels
were below the standard value in each group. Based
on the above results, we conclude that subnormal
levels of zinc and vitamin E may be associated
with the development of age- related macular
degeneration.
Retinal
tubulin binds macular carotenoids.
Bernstein PS, Balashov NA, Tsong ED, Rando
RR
John A. Moran Eye Center, University of Utah
School of Medicine, Salt Lake City 84132, USA.
Invest Ophthalmol Vis Sci (United States) Jan
1997, 38 (1) p167-75
PURPOSE: To investigate the biochemical
mechanisms responsible for the specific uptake,
concentration, and stabilization of the
carotenoids lutein and zeaxanthin in the
macula.
METHODS: Soluble extracts of bovine retina
mixed with radioactive carotenoids were purified
by hydrophobic interaction, ion exchange, and gel
filtration chromatography. Carotenoid-associated
proteins in these purified preparations were
identified through photoaffinity labeling and
protein microsequencing. Similar purifications on
human macular tissue without the addition of
exogenous carotenoids also were performed.
RESULTS: Experiments on bovine retinal tissue
demonstrated that tubulin is the major soluble
carotenoid-binding protein. When soluble extracts
of human macular protein were examined, the
endogenous carotenoids lutein and
zeaxanthin were found to copurify with
tubulin.
CONCLUSIONS: Tubulin is found in abundance in
the receptor axon layer of the fovea, where it can
serve as a locus for the deposition of the high
concentrations of macular carotenoids found there.
The binding interaction of carotenoids and tubulin
in the Henle's fiber layer could play an important
role in the photoprotective effects of the macular
carotenoids against the progression of age-related
macular degeneration. The association of
carotenoids with tubulin, a protein that can form
highly ordered linear arrays, may provide an
explanation for the dichroic phenomenon of
Haidinger's brushes.
Cigarette
smoking and retinal carotenoids: implications for
age-related macular degeneration.
Hammond BR Jr, Wooten BR, Snodderly DM
Schepens Eye Research Institute, Department of
Ophthalmology, Harvard Medical School, Boston MA
02114, USA.
Rhammond@vision.eri.harvard.edu
Vision Res (England) Sep 1996, 36 (18)
p3003-9
The foveal region of the retina has a yellow
pigmentation composed primarily of the carotenoids
lutein and zeaxanthin. Past studies have shown
that cigarette smoking depresses carotenoid
concentrations in the blood. This is the first
report on the effects of cigarette smoking on
carotenoids in the retina. Macular pigment optical
density (MP) was measured psychophysically by
comparing foveal and parafoveal sensitivities to
light of 460 and 550 nm. General dietary patterns,
smoking frequency (cigaretts/day) and personal
data were collected by questionnaire. Thirty-four
smokers and 34 nonsmokers were compared. Subjects
were matched with respect to age, sex, dietary
patterns and overall pigmentation (i.e., eye, skin
and hair color). The smoking group had a mean MP
of 0.16 (SD = 0.12) compared to a mean MP of 0.34
(SD = 0.15) for nonsmokers (P < 0.0001). MP
density and smoking frequency were inversely
related (r = -0.498 P < 0.001) in a
dose-response relationship. A variety of evidence
suggests that MP protects the macula from actinic
damage both passively (by screening potentially
harmful short-wave light) and actively as an
antioxidant (e.g., by quenching reactive oxygen
species). If smoking causes a reduction in MP
density, then smokers may be at risk.
Epidemiologic data identifying smoking as a risk
factor for the neovascular form of age-related
macular degeneration are consistent with this
hypothesis.
Sex
differences in macular pigment optical density:
relation to plasma carotenoid concentrations and
dietary patterns.
Hammond BR Jr, Curran-Celentano J, Judd S, Fuld
K, Krinsky NI, Wooten BR, Snodderly DM
Schepens Eye Research Institute, Boston, MA
02114, USA.
Vision Res (England) Jul 1996, 36 (13)
p2001-12
Sex differences in macular pigment (MP) optical
density (measured psychophysically) were examined.
Concentrations of lutein and zeaxanthin (L and Z)
(non-separated) and beta-carotene (BC) in the
blood were determined using reverse phase
high-performance liquid chromatography. Dietary
intake of L and Z, BC, fat, and iron were
estimated by questionnaire. Males had 38% higher
MP density than females (P < 0.001) despite
similar plasma carotenoid concentrations and
similar dietary intake (except for fat). Dietary
intake of carotenoids, fat and iron, as well as
plasma concentrations of L and Z were positively
related to MP density in males. Conversely, only
plasma L and Z was related to MP density for
females, and dietary fat was negatively related to
MP density. Sex differences in protection of the
retina by MP and in the relationship between the
retina, blood and diet could be a factor in the
incidence of retinal diseases, especially
age-related macular degeneration.
Retinol
(Vitamin A) supplements in the
elderly
Ward BJ
Centre for the Study of Host Resistance, Montreal
General Hospital, Quebec, Canada
cybj@musica.mcgill.ca
Drugs and Aging (New Zealand), 1996, 9/1
(48-59)
Aging is associated with many changes in
epithelial tissues, immune function and
haematopoiesis-myelopoiesis. There is increasing
evidence that retinoids can significantly
influence some of these changes. Retinoids may
also have anticancer effects and protect against
age-associated conditions such as macular
degeneration. However, retinol (vitamin A) can be
toxic when taken in excess and the elderly may be
at particular risk for hypervitaminosis A.
Evaluation of elderly people ingesting
significantly more or less than the recommended
daily intake of retinol requires an understanding
of the biology of retinoids and consideration of
the relative risks and benefits of
supplementation.
Studies
on the mechanism of early onset macular
degeneration in cynomolgus monkeys. II.
Suppression of metallothionein synthesis in the
retina in oxidative stress
Nicolas MG, Fujiki K, Murayama K, Suzuki MT,
Shindo N, Hotta Y, Iwata F, Fujimura T, Yoshikawa
Y, Cho F, Kanai A
Department of Ophthalmology, Juntendo University
School of Medicine, Tokyo, Japan.
Experimental Eye Research (United Kingdom), 1996,
62/4 (399-408)
Initial investigations done in this laboratory
detected increased albumin and decreased
glyceraldehyde 3-phosphate dehydrogenase
concentrations in the retina of an animal model
manifesting early onset macular degeneration. Both
glyceraldehyde 3-phosphate dehydrogenase and
albumin are markers of oxidative stress in cells.
In this study, we used the same animal model to
study further biochemical and physiological
processes which may be involved in the
pathogenesis of early onset macular degeneration
in monkeys. We detected 60% lower catalase and
glutathione peroxidase activities in the affected
retinas suggesting lower antioxidant activities
and oxidative stress. One of the consequences of
oxidative stress is the production of
metallothionein, a low molecular weight protein
also induced by high concentrations of heavy
metals such as zinc. Metallothionein was detected
by RT-PCR in these monkey retinas. However initial
quantitative PCR studies on this protein showed
that the synthesis of metallothionein in affected
retinas appears to be less than in normal
controls. The affected retinas also showed a
fourfold lower zinc concentration compared with
the normal controls. No significant difference,
however, could be detected in the zinc
concentrations in plasma samples. Since induction
of metallothionein synthesis is mediated by
transcription factors which require heavy metals
such as zinc for binding to specific sites in the
DNA, the lowered zinc concentration may, thus,
correlate with the lowered metallothionein
expression. And since metallothionein is suggested
to function as a free radical scavenger, the
lowered metallothionein synthesis may consequently
contribute to increased peroxidation reactions in
the affected retinas. It appears therefore, that
oxidative stress and the decreased metallothionein
synthesis may be involved in the pathogenesis of
early onset macular degeneration in this animal
model.
Association of zinc and antioxidant
nutrients with age-related
maculopathy.
Mares-Perlman JA, Klein R, Klein BE, Greger JL,
Brady WE, Palta M, Ritter LL
Department of Ophthalmology, University of
Wisconsin, Madison, USA.
Arch Ophthalmol (United States) Aug 1996, 114 (8)
p991-7
OBJECTIVE: To quantify relationships between
dietary intake of zinc and antioxidant nutrients
and early and late age-related maculopathy
(ARM).
DESIGN: A retrospective longitudinal cohort
design using data pertaining to diets in the past
(1978-1980), which were assessed retrospectively
using a food frequency questionnaire.
SETTING: Beaver Dam, Wis.
PATIENTS: A 50% random sample of free-living
Beaver Dam Eye Study participants, 43 to 86 years
of age (N = 1968).
MAIN OUTCOME MEASURE: The presence of early and
late ARM determined from fundus photography.
RESULTS: People in the highest vs lowest
quintiles for intake of zinc from foods had lower
risk for early ARM (odds ratio = 0.6, 95%
confidence interval, 0.4-1.0, P for trend <
.05). This relationship appeared to be stronger
for some types of early ARM (increased retinal
pigment) than for others. Zinc intake was
unrelated to late ARM. However, small numbers (n =
30) of people with this condition limit the
ability to draw conclusions about this later
stage. Levels of carotenoids were unrelated to
early or late ARM.Odds for early ARM were lower
in people in the highest vs lowest quintiles for
the intake of vitamins C or E. However, these
associations were not statistically
significant.
CONCLUSIONS: The data are weakly supportive of
a protective effect of zinc on the development of
some forms of early ARM. Prospective studies are
needed to further evaluate the potential influence
of these and other nutritional factors on
different types and stages of age-related macular
degeneration.
Oral zinc
and the second eye in age-related macular
degeneration.
Stur M, Tittl M, Reitner A, Meisinger V
Klinik fur Augenheilkunde, Abteilung A,
Allgemeines Krankenhaus der Stadt Wien,
Austria.
Invest Ophthalmol Vis Sci (United States) Jun
1996, 37 (7) p1225-35
PURPOSE. To investigate the short-term effect
of oral zinc substitution on the development of
age-related macular degeneration in the second eye
of patients with an exudative form of the disease
in the first eye.
METHODS. A 2-year, double-masked, randomized,
placebo-controlled study including 112 white
patients with age-related macular degeneration and
exudative lesions (choroidal neovascularization,
pigment epithelial detachment, or both) in one eye
and a visual acuity of better than 20/40 and
macular degeneration without any exudative lesion
in the second eye was performed. Patients received
either 200 mg of oral zinc sulfate or placebo once
daily for 24 months. The main outcome parameters
were visual acuity, contrast sensitivity, color
discrimination, and retinal grating acuity, as
well as serum levels of zinc and copper, red blood
cell count, hemoglobin, and morphologic changes
detected by grading of monochrome fundus
photographs and fluorescein angiograms.
RESULTS. In the treatment group, the mean zinc
serum level increased significantly (P <
0.0001) from 79 +/- 10 micrograms/dl to 108 +/- 26
micrograms/dl compared to no change (82 +/- 16
micrograms/dl to 85 +/- 10 micrograms/dl) in the
placebo group. Serum levels of copper, hemoglobin,
and red blood cell count did not change
significantly in either group. A choroidal
neovascular membrane (CNV) was detected in 14
patients during the treatment period (nine in the
treatment group, five in the placebo group). Seven
additional patients (three in the treatment group,
four in the placebo group) experienced visual loss
caused by CNV, and in two patients (one in each
group), serous pigment epithelial detachment
developed without angiographic evidence of CNV
after the end of treatment, during a mean
additional follow-up time of 20.8 +/- 8.2 months.
In eyes in which exudative lesions did not
develop, there was no significant change in any of
the functional parameters during the 24-month
treatment period, but there was a significant
increase in the nonexudative alterations (drusen
size, drusen confluence, hyperpigmentation, and
focal degeneration of the retinal pigment
epithelium) in both groups.
CONCLUSIONS. Oral zinc substitution has no
short-term effect on the course of age-related
macular degeneration in patients who have an
exudative form of the disease in one eye.
Dietary
carotenoids, vitamins A, C, and E, and advanced
age-related macular degeneration. Eye Disease
Case-Control Study Group
Seddon JM; Ajani UA; Sperduto RD; Hiller R;
Blair N; Burton TC; Farber MD; Gragoudas ES;
Haller J; Miller DT; et al
JAMA 1994 Nov 9;272(18):1413-20
Published erratum appears in JAMA 1995 Feb
22;273(8):622
OBJECTIVE--To evaluate the relationships
between dietary intake of carotenoids and vitamins
A, C, and E and the risk of neovascular
age-related macular degeneration (AMD), the
leading cause of irreversible blindness among
adults.
DESIGN--The multicenter Eye Disease
Case-Control Study.
SETTING--Five ophthalmology centers in the
United States.
PATIENTS--A total of 356 case subjects who were
diagnosed with the advanced stage of AMD within 1
year prior to their enrollment, aged 55 to 80
years, and residing near a participating clinical
center. The 520 control subjects were from the
same geographic areas as case subjects, had other
ocular diseases, and were frequency-matched to
cases according to age and sex.
MAIN OUTCOME MEASURES--The relative risk for
AMD was estimated according to dietary indicators
of antioxidant status, controlling for smoking and
other risk factors, by using multiple
logistic-regression analyses.
RESULTS--A higher dietary intake of carotenoids
was associated with a lower risk for AMD.
Adjusting for other risk factors for AMD, we found
that those in the highest quintile of carotenoid
intake had a 43% lower risk for AMD compared with
those in the lowest quintile (odds ratio, 0.57;
95% confidence interval, 0.35 to 0.92; P for trend
= .02). Among the specific carotenoids, lutein and
zeaxanthin, which are primarily obtained from dark
green, leafy vegetables, were most strongly
associated with a reduced risk for AMD (P for
trend = .001). Several food items rich in
carotenoids were inversely associated with AMD. In
particular, a higher frequency of intake of
spinach or collard greens was associated with a
substantially lower risk for AMD (P for trend <
.001). The intake of preformed vitamin A (retinol)
was not appreciably related to AMD. Neither
vitamin E nor total vitamin C consumption was
associated with a statistically significant
reduced risk for AMD, although a possibly lower
risk for AMD was suggested among those with higher
intake of Vitamin-C, particularly from foods.
CONCLUSION--Increasing the consumption of foods
rich in certain carotenoids, in particular dark
green, leafy vegetables, may decrease the risk of
developing advanced or exudative AMD, the most
visually disabling form of macular degeneration
among older people. These findings support the
need for further studies of this relationship.
Evidence by in vivo and in vitro
studies that binding of pycnogenols to elastin
affects its rate of degradation by
elastases
Tixier J.M.; Godeau G.; Robert A.M.; Hornebeck
W.
Biochem Pharmacol 1984 Dec 15;33(24):3933-9
Procyanidol oligomers and (+) catechin bound to
insoluble elastin markedly affect its rate of
degradation by elastases. Insoluble elastin
pretreated with procyanidol oligomers (PCO) was
resistant to the hydrolysis induced by both
porcine pancreatic and human leukocyte elastases.
The quantitative adsorption of pancreatic elastase
was similar on either untreated or PCO-treated
elastin suggesting that the binding of this
compound to elastin increases the non-productive
catalytic sites of elastase molecules. (+)
Catecholin-insoluble elastin complexes were
partially resistant to the degradation induced by
human leukocyte elastase but were not hydrolysed
at the same rate as untreated samples by a
constant amount of pancreatic elastase. In
addition, the coacervation profile of
kappa-elastin peptides as a function of
temperature is greatly modified in presence of
these flavonoids. We conclusively evidenced that
PCOs bind to skin elastic fibres when injected
intradermally into young rabbits. As a result,
these elastic fibres were found more resistant to
the hydrolytic action of porcine pancreatic
elastase when injected to the same site. These in
vivo studies emphasized the potential effect of
these compounds in preventing elastin degradation
by elastase(s) as occurred in inflammatory
processes.
Antioxidant enzymes of the human
retina: Effect of age on enzyme activity of macula
and periphery
De La Paz M.A.; Zhang J.; Fridovich I.
Duke University Eye Center, DUMC, Box 3802,
Durham, NC 27710 USA
Current Eye Research (United Kingdom), 1996, 15/3
(273-278)
The purpose of this research was to evaluate
the effect of age on protective antioxidant enzyme
activity of normal fresh cadaver human retina of
the macula and periphery. Antioxidant enzymes were
assayed in tissue extracts generated from 5 mm
trephined punches of retina obtained centered over
the macula and the superior midperiphery of normal
fresh human cadaver retina. Cadaver tissue was
obtained from donors of a wide age range (age 7 to
85 years). The assays were performed within 6 h of
enucleation and within 24 h of donor death.
Antioxidant enzymes assayed included superoxide
dismutase, catalase, glutathione peroxidase, and
glutathione reductase. Hexokinase and
glucose-6-phosphate dehydrogenase, enzymes not
directly involved in protection against oxidative
damage, were assayed for comparison. Enzyme
specific activities were calculated for the macula
and periphery using protein concentration of the
extract as the denominator. Using linear
regression analysis, over the age range of 25 to
75 years, superoxide dismutase activity of the
periphery but not the macula tended to decline
with age (p = 0.04, R2 = 0.21). Interindividual
variability was high, and variability increased
with age. The difference between the macular and
peripheral enzyme activities for glutathione
peroxidase tended to decline with increasing donor
age (p = 0.025, R2 = 0.33). There was no effect of
age on the specific activities of catalase,
glucose-6-phosphate dehydrogenase, and glutathione
reductase. The specific activity of hexokinase
from the macula declined with increasing donor age
(p = 0.022, R2 = 0.43). Time from death to
enucleation or beginning of experiment was not a
significant factor. In summary, age does not have
an effect on the activity of major antioxidant
enzymes of the macula in normal human retina.
There is a tendency for an effect of age on
peripheral superoxide dismutase activity and the
difference between macular and peripheral
glutathione peroxidase activity. High
interindividual variability of antioxidant enzyme
activity exists in humans.
Low
glutathione reductase and peroxidase activity in
age-related macular degeneration
Cohen S.M.; Olin K.L.; Feuer W.J.; Hjelmeland
L.; Keen C.L.; Morse L.S.
Department of Ophthalmology, UC Davis, 1603
Alhambra Boulevard, Sacramento, CA 95816 USA
Br. J. Ophthalmol. (United Kingdom), 1994, 78/10
(791-794)
Age-related macular degeneration (ARMD) may
result from events initiated by reactive oxygen
species. Blood samples from 18 patients with ARMD
and 18 similarly aged controls were analysed for
activities of important antioxidants. Blood
glutathione reductase activity was lower in
patients with ARMD compared with controls (p =
0.035). The activities of glutathione peroxidase
(p = 0.18) and erythrocyte superoxide dismutase (p
= 0.29) were similar between the two groups by a
Student's two sample t test. Logistic regression
was used to determine which enzyme activities were
associated with ARMD after adjusting for possible
confounding variables: smoking history, age,
multivitamin use, and cardiovascular disease.
Glutathione reductase activity (p = 0.05) and
glutathione peroxidase activity (p = 0.065) were
significantly associated with ARMD by this
analysis. The relation of glutathione reductase
and glutathione peroxidase activity to ARMD merits
further study.
Antioxidant enzymes in RBCs as a
biological index of age related macular
degeneration
Prashar S.; Pandav S.S.; Gupta A.; Nath R.
Department of Biochemistry, PGIMER, Chandigarh
160012 India
Acta Ophthalmol. (Denmark), 1993, 71/2
(214-218)
The present study was undertaken to assess the
levels of antioxidant enzymes in red blood cells
of subjects with age-related macular degeneration
and age-matched controls. The results obtained
show a significant decrease in activities of
superoxide dismutase (p < 0.001) and
glutathione peroxidase (p < 0.001) as compared
to the controls. A good correlation (r =O.99) was
also observed between age and decreased activity
of antioxidant enzymes in controls, and also
correlated well with age related macular
degeneration. In conclusion, oxidative stress as
assessed by antioxidant enzymes is more pronounced
in subjects with age-related macular degeneration
as compared to age-matched controls.
Oxidative effects of laser
photocoagulation
Jennings P.E.; MacEwen C.J.; Fallon T.J.; Scott
N.; Haining W.M.; Belch J.J.F.
Department of Medicine, Ninewells Hospital and
Medical School, Dundee, DD19SY United Kingdom
Free Radic. Biol. Med. (USA), 1991, 11/3
(327-330)
Diabetic proliferative retinopathy is a common
and sight-threatening condition. Oxidative stress
is an integral and possibly causative part of the
pathogenesis. Although laser photocoagulation is
usually a beneficial treatment it remains unclear
how it works. The possibility that it induces a
sudden, temporary increase in free radical
activity either by direct thermal damage or by
oxygen reperfusion is explored in this clinical
study by measuring the oxidative status in the
peripheral blood of 13 patients undergoing
panretinal photocoagulation. There were
significant increases at one hour in
malondialdehyde-like material (MDA-LM), 8.1
(6.9-9.6) nmol/mL, to 9.1 (7.6-9.8) nmol/mL, (<
0.005); plasma thiols (PSH), 423 (352-457)
microm/L, to 444 (382-478) microm/L, (p <
0.005) and red cell reduced glutathione (GSH),
1357 (1295-1655) microm/L, to 1480 (1305-1760)
microm/L, (p < 0.01). Diene conjugates rose
over the first hour 0.55 (0.36-0.79) od/mL, to
0.58 (0.34-0.85) od/mL falling to 0.56 (0.36-0.79)
od/mL at 2 h but these changes were not
significant. At 2 h, MDA-LM 8.4 (6.7-9.6) nmol/mL
and PSH 404 (379-462) microm/L had returned to
baseline but GSH remained significantly elevated
1500 (1325-1675) microm/L, (p < 0.005 compared
to baseline). This is a new observation and in
some circumstances such generation of free
radicals could explain the mechanism behind the
complications of photocoagulation by direct or
indirect damage to vascular endothelium leading to
increased vascular permeability manifest as
macular oedema or choroidal effusions.
Antioxidant status and neovascular
age-related macular degeneration
Yannuzzi L.A.; Sorenson J.A.; Sobel R.S.; Daly
J.R.; DeRosa J.T.; Seddon J.M.; Gragoudas E.S.;
Puliafito C.A.; Gelles E.; Gonet R.; Burton T.C.;
Culver J.; Metzger K.; Kalbfleisch N.; Zarling D.;
Farber M.D.; Blair N.; Stelmack T.; Sperduto R.D.;
et al.
Biometry and Epidemiology Program, National Eye
Institute, Bldg 31, 9000 Rockville Pike, Bethesda,
MD 20892 USA
Arch. Ophthalmol. (USA), 1993, 111/1
(104-109)
We evaluated the hypothesis that higher serum
levels of micronutrients with antioxidant
capabilities may be associated with a decreased
risk of neovascular age-related macular
degeneration by comparing serum levels of
carotenoids, vitamins C and E, and selenium in 421
patients with neovascular age-related macular
degeneration and 615 controls. Subjects were
classified by blood level of the micronutrient
(low, medium, and high). Persons with carotenoid
levels in the medium and high groups, compared
with those in the low group, had markedly reduced
risks of neovascular age-related macular
degeneration, with levels of risk reduced to one
half and one third, respectively. Although no
statistically significant protective effect was
found for Vitamin-C or E or selenium individually,
an antioxidant index that combined all four
micronutrient measurements showed statistically
significant reductions of risk with increasing
levels of the index. Although these results
suggest that higher blood levels of micronutrients
with antioxidant potential, in particular,
carotenoids, may be associated with a decreased
risk of the most visually disabling form of
age-related macular degeneration, it would be
premature to translate these findings into
nutritional recommendations.
Nutrition in the elderly
Morley J.E.; Mooradian A.D.; Silver A.J.; Heber
D.; Alfin-Slater R.B. BR> Department of
Medicine, University of California School of
Medicine, Los Angeles, CA 90024 USA
Ann. Intern. Med. (USA), 1988, 109/11
(890-904)
Nutritional modulation is one approach to
successful aging. In animals, dietary restriction
increases life span. Alterations in the
macronutrient and micronutrient constituent of the
diet can modulate gene expression. Anorexia is
common in elderly persons. The results of studies
in animals suggest that aging is associated with a
decrease in the opioid feeding drive and an
increase in the satiating effect of
cholecystokinin. Unrecognized depression is a
common, treatable cause of anorexia and weight
loss in elderly persons. Protein synthesis
decreases in elderly persons; nevertheless,
nitrogen balance can be maintained in patients
with fairly low intakes of protein. Carbohydrate
intolerance is common and may be modulated by
nutritional intervention and physical activity.
The role of cholesterol in the development of
heart disease in very old persons is
controversial. Homebound and institutionalized
elderly persons often do not expose their skin to
sunlight; because the skin of older persons has a
decreased ability to form vitamin D, the vitamin D
status in these persons is precarious and they are
at risk for osteopenia. Vitamins are often abused
by elderly persons. Drug administration alters the
vitamin requirements of persons. Borderline zinc
state has been associated with deteriorating
immune function, especially in persons who have
diabetes mellitus or who abuse alcohol. Zinc
administration appears to protect against the
deteriorating vision associated with age-related
macular degeneration. Selenium deficiency seems to
be associated with an increased prevalence of
cancer.
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