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8/11/2019 The Zinc, Copper, And Selenium Status of a Selected Sample Od Canadian Elderly Women
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8/11/2019 The Zinc, Copper, And Selenium Status of a Selected Sample Od Canadian Elderly Women
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TRACE ELEMENT STATUS OE ELDERLY WOMEN
297
tes mellitus and marked obesity (defined as weight
for age above the 90th percentile, Health & Welfare
Canada, 1980) were excluded from the study. The
study protocol was approved by the Human Ethics
Committee of the University of Guelph. Consent
was obtained from the participants after the nature
of the study had been fully explained to them.
Prior to retirement, 63% of the women were
employed outside of the home. Of these 65% were
in full time employm ent and 26% w orked part time.
The remainder (37%) described themselves as
homem akers. Of those who had been employed full
time,
40% were employed as university professors
or in health-related jobs (nurses, dietician s, labora-
tory technicians, or nurse's assistants). The others
had been in positions that included administrators,
teachers, secretaries, and sales clerks.
The socioeconomic index (SEI) of the women
was determined from the husband's occupation ac-
cording to the scale of Blishen and McRoberts
(1976). In the case of the unmarried women n =
11),
the SEI was determined from their occupation,
using the same scale. The SEI values ranged from 2
to 7 with a mean index of 5.8; 75% of the women
had a SEI greater than 4.
Sixty percent of the women were taking medica-
tions.
The major groups of medications used were
antiinflammatories, diuretics, antihypertensives,
and hormones. Iron supplements were taken by 7%
of the women, and zinc and selenium by 6% and
1%, respectively.
Procedures. Fasting blood samples were
drawn via peripheral venipuncture from the women
in the recumbent position, using trace-element-free
vacutainers (Becton and Dickinson). The serum
was separated by procedures designed to minimize
risks of contamination and then stored at -20 C in
trace-element-free polypropylene containers
(Sarstedt). Any serum samples showing visible
signs of hemolysis were not analyzed for zinc. Se-
rum zinc and copper analyses were performed via
flame (Fuwa et al., 1964) and flameless (Evenson
& Warren, 1975) atomic absorption procedures,
respectively. Serum albumin concentrations were
also determined using the method of Rodky (1965).
Enzymatic colorimetric methods (Boehringer
Mannheim Kits) were used for serum total choles-
terol (Roschlau et al., 1974) and high density lipo-
protein cholesterol (HDL) (Burstein et al., 1970).
Serum selenium was analyzed by instrumental
neutron activation analysis (INAA). Samples were
irradiated in the McMaster University Nuclear Re-
actor for 7 s at a thermal neutron flux of 5 x 10
i:
neutrons cm
2
sec
1
. After a 5s decay period, the
selenium content of the samples was estimated by
measuring the activity of
75
Seusing a Ge(Li) detec-
tor (relative efficiency 8.5% ; active volume 45 ccs)
coupled to a multichannel analyzer (Can berra). The
area ofthe 156 keV photopeak from
75
Se was calcu-
lated. The accuracy of this INAA method for sele-
nium was checked by analyzing the selenium con-
tent of three replicates of National Bureau of Stand-
ards Oyster (NBS No. 1566). The mean ( SD )
value was 2.1 0.2 /xg/g compared with a cer-
tified value of 2.1 .5 /ag/g.
The hair samples were cut from the occipital
portion of the scalp using teflon-coated scissors.
Only the proximal to 2 cm portions of hair, repre-
senting newly grown hair, were washed by a non-
ionic detergent procedure and analyzed for zinc and
copper by an INAA method, described previously
(Gibson & DeW olfe, 1979). For the hair selenium
analysis, the washed hair samples were irradiated
in acid-washed trace-element-free polypropylene
vials (Sarstedt) and irradiated, together with stand-
ard reference materials and fluxmonitors, for 72
hours in the McMaster N uclear Reactor at a thermal
neutron flux of5 x 10
13
neutrons cm
2
se c
1
. After 6
to 8 weeks, which allowed for the decay of short-
lived isotopes, principally
24
Na, the hair samples
were dissolved in concentrated nitric acid, removed
from the vials, and counted on a Ge(Li) detector
(10%
relative efficiency and 50 cc active volume),
coupled to a microcomputer configured as a multi-
channel analyzer, for 12 to 24 hours, depending on
the size of the sample. Flux monitors were also
counted and flux corrections, as well as half-life
corrections, applied to the net peak areas. Results
were calculated in terms of fJLg/g. The accuracy of
the INNA method for selenium was studied by
analyzing three replicates of Unalloyed Copper- Cu
II (NBS No. 395). The mean ( SD ) value was
0.60 0.02 fxg/g Se compared with the certified
value 0.60 0.05 /Ltg/g.
Dietary zinc, copper, and selenium intakes were
assessed by chemical analysis of 24-hour duplicate
diet composites, collected by the women following
procedures described previously (Gibson &
Scythes, 1982, 1984). In addition, the women
completed dietary records for 3 consecutive week-
days,
recording all foods and beverages consumed
(including drinking water) in household measures.
One of the record days included the diet composite
day. Participants also provided recipes for all pre-
pared food items. Mean energy, protein, and total
dietary fiber, copper, and zinc intakes were calcu-
lated from the 3-day records using food composi-
8/11/2019 The Zinc, Copper, And Selenium Status of a Selected Sample Od Canadian Elderly Women
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298
GIBSON MARTINEZ, AND MACDONALD
tion tables and literature values, as reported earlier
(Gibson & Scythes, 1982).
Hair trace element concentrations are not usually
normally distributed; thus nonparametric statistics
employing ranks w ere used, the m edian being used
to indicate central tendency. Spearman's rank-
order correlation coefficients were calculated to as-
sess the relationship of hair, serum, and trace ele-
ment intake levels. Analyzed dietary zinc and
copper intakes were compared with those calcu-
lated from the corresponding record day and with
the mean intakes calculated from the 3-day records
using Spearman rank-order correlation coef-
ficients.
RESULTS
Table 1 presents the mean serum zinc, m ean
analyzed zinc intake, and median hair zinc concen-
trations for the study group.
Only 5% of the women had hair zinc values
below 100 /u,g/g, and of these 4% were below 70
/u,g/g, the level suggestive of suboptima l zinc status
(Hambidge et al., 1972). None of the women had
low serum zinc levels (i.e., below 70 yitg/dl) (Ham-
bidge et al., 1976). Serum albumin concentrations
M = 4.2 0.4 g/dl) were all above 3.2 g/dl.
Figure 1 gives the frequency distributio n of the
zinc intakes determined by analysis of the 1-day
duplicate diets. The mean analyzed zinc intake (7.6
mg/d) was very close to the Canadian Recom-
mended Nutrient Intake (RNI) (Health & Welfare
Canada, 1983) for zinc (8mg) but below the U.S.
Recommended Dietary Allowance (RDA) for zinc
of 15 mg (National Research Council, 1980). As
determined by analysis of the 1-day duplicate diets,
20%
of the women had zinc intakes below two-
thirds of the Canadian RNI; 78% had zinc intakes
below two-thirds the U.S. RDA.
Table 2 presents the average daily energy, total
dietary fiber, protein, zinc, and copper intakes cal-
Table 1. Zinc, Selenium, and Copper Concentrations of
Hair, Serum and Duplicate Diets from 90 Elderly
Canadian Women
Trace
element
Zinc
Selenium
Copper
Hair (Mg/g)
(median)
155
(131-183)
0.63
(0.71-0.50)
12.8
(10.8-16.0)
Serum
(Mg/ml)
m SD)
1.09 0.13
0.115 0.03
1.22 0.29
Diet (mg/day)
M SD)
7.6 3.3
.078 .045
1.2 0.6
culated from the 3-day dietary record data using
food composition data (Gibson& Scythes, 1982).
The mean calculated daily zinc intake was above
the Canadian RNI. The mean calculated zinc in-
takes showed 5% of
the
women below two-thirds of
the Canadian RNI; 50% were below two-thirds of
the U.S. R DA.
Selenium status. The data for the selenium
status of the women are also given in Table 1.
40
35
30
in
s
u
b
j
e
c
t
r
o
O
20
O *
u
z
15
10
5
n
-
-
-
-
x = 7.6
SD = 3.3
Median = 7.2
l l
3 6 9 12 15 18 21
Zinc intake mg/day)
Figure 1. Distribution of zinc intakes analyzed from 24-hour
duplicate diets from 90 elderly Canadian women.
Table 2. Mean Daily Energy, Protein, Zinc, Copper
and Total Dietary Fiber Intakes Calculated from 3-Day
Records
Intake
SD
25 to 75th quartiles
Energy (Kcal)
Energy (Kj)
Protein (g)
Zinc (mg)
Copper (mg)
Dietary fiber (g)
1596
6651
67 2
1 1
1 6
21 4
446
1859
19
3 5
7
7 9
8/11/2019 The Zinc, Copper, And Selenium Status of a Selected Sample Od Canadian Elderly Women
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TRACE ELEMENT STATUS OF ELDERLY WOMEN
299
Serum selenium concentrations ranged from 0.05
to 0.18 /ig/ml; 26% of the women had serum sele-
nium levels below 0.10 /Ag/ml.
The mean analyzed selenium intake fell within
the U.S. National Research Council, (1980) ade-
quate and safe range for selenium (50 to 200 fig/
day) (Figure 2). There is no Canadian RNI for
selenium. Based on analysis of 1-day duplicate di-
ets, 21% of the women had analyzed dietary sele-
nium intakes below the lower limit of the RDA safe
and adequate range (50fig)and 2% above the upper
limit of 200
xg
per day. At the present time it is not
possible to reliably calculate selenium dietary in-
takes for Canadians from food composition data;
thus the average dietary selenium intake and major
food sources of selenium could not be assessed
from the 3-day dietary records. Instead, differences
in the macronutrient, vitamin, and mineral content,
as well as differences in the major food consump-
tion patterns of women with high and low selenium
density diets, were assessed using the Wilcoxon
two-sample rank sum test, by a method adapted
from Welsh et al. (1981). Women with high sele-
35
30
25
A
.* 20
n
o 15
o
10
5
n
X =
SD =
Median =
77.6
44.5
69.6
40 80 120 160 200 240 280
Selenium intake
nium density diets had higher p
8/11/2019 The Zinc, Copper, And Selenium Status of a Selected Sample Od Canadian Elderly Women
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8/11/2019 The Zinc, Copper, And Selenium Status of a Selected Sample Od Canadian Elderly Women
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TRACE ELEMENT STATUS OF ELDERLY WOMEN
3 1
tention to the possible importance of zinc nutriture
per se in relation to cardiovascular health in
humans.
Coronary heart disease has been postulated to be
predominantly a disease of metabolic imbalance in
zinc and copper metabolism, characterized by a
high zinc to copper ratio (Klevay, 1980). In the
study reported here, serum total cholesterol levels
were not related to zinc or copper levels in either
serum, hair, or diet. Likewise Fischer et al. (1980)
did not find that serum cholesterol levels were af-
fected when rats were fed dietary zinc and copper
ratios over the range found in the diets of
this
study.
Both the serum, hair, and dietary copper levels
were within the range noted by others for elderly
adults (Gibson et al., 1983; Health & Welfare Can-
ada, 1981).
The elderly women in this study appeared to
have adequate selenium status as indicated by se-
rum and hair selenium levels. This is not surprising
because, in general, the analyzed selenium intakes
fell within the U.S. National Research Council
(1980) adequate and safe range.
The serum selenium values were comparable to
the plasma levels reported by Lane et al. (1983) for
their U.S. free-living elderly adults. Serum sele-
nium, a measure of short-term selenium status, did
not correlate with dietary or hair selenium levels.
This is a finding noted by other investigators (Lane
et al. , 1983; Thimaya & Ganapathy , 1982). The
hair selenium values also fell within the range noted
by others for healthy U.S. adults of comparable
ages (Thimaya & Ganapathy, 1982). A significant
relationship between hair and serum selenium con-
tent has been demonstrated only in residents of
China from both affected and unaffected Keshan
disease areas (Chen et al., 1980).
The range of analyzed selenium intakes (Figure
2) was very comparable to those reported earlier for
(a) a group of Canadian premenopausal women
from the same university community (Gibson &
Scythes, 1984), (b) analyzed values for
U.S.
Mary-
land diets (Welsh et al., 1981), and (c) U.S . adults
60 years and older (Thimaya & Ganapathy , 1982).
In contrast, the free-living elderly adults studied by
Lane et al. (1983) had a higher mean selenium
intake (94 43 /u-g/day).
The relationships between selenium and energy
and fat intakes, noted in the high and low selenium
density diets, are consistent with the findings of
others (Gibson & Scythes, 1984; Lane et al.,
1983). On the other hand, cereal and potato con-
sumption did not show the same trend here as noted
in the earlier study (Gibson & Scythes, 1984). In-
stead, intakes of fish and beef were significantly
higher in those individuals with high selenium den-
sity diets.
In summary, the zinc, copper and selenium sta-
tus of the elderly women in this study, as indicated
by dietary and biochemical data, appeared ade-
quate. These trends were related to the relatively
high socioeconom ic status of the participants of this
study and is consistent with the findings of several
national nutrition surveys (Health & Welfare Can-
ada 1975) that suggest that nutritional adequacy of
the diet is highly related to socioeconomic status.
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