Asia Pacific J Clin
Nutr (1997) 6(1): 56-59
Red
palm oil for combating vitamin A deficiency
R Manorama1, M Sarita and
C Rukmini2
1Center of Advanced Studies,
Department of Foods and Nutrition, Post graduate and Research Center,
Andhra 2Pradesh Agricultural University,
Rajendranagar, Hyderabad, AP, India
Red palm oil (Elaeis guineensis,RPO) is nutritionally
rich and unique in comparison with other edible oils as it has a
high content of b-carotene (400 ppm).It is the
ideal choice for combating vitamin A deficiency in developing countries.
The Modified Relative Dose Response test was conducted to assess
the vitamin A status of school children fed RPO in the form of a
sweet snack supplying the RDA (2400 µg) of b-carotene for two months. A significant
increase was seen in serum retinol levels from 0.86 ± 0.14 to 1.89
± 0.23 µmol/L, comparable with a control group fed oral vitamin
A drops daily whose retinol levels increased from 0.74 ± 0.09 to
1.94 ± 0.21µmol/L. The dehydroretinol/ retinol ratio (DR/R) decreased
from 0.073 ± 0.025 to 0.023 ± 0.003 in a RPO group and from 0.095
± 0.023 to 0.023 ± 0.004 in the vitamin A group, indicating saturation
of liver reserves of retinol, the cut-off point for inadequate status
being > 0.03.
In another study, school children fed RPO snacks
for one month were compared with massive vitamin A dosed groups.
Serum retinol level increased significantly in both groups. Serum
b-carotene increased from 0.06 ± 0.002 to 0.21 ± 0.01 µmol/L in the
RPO group, but remained the same in a control group.
A third study indicated that RPO can afford protection
for as long as six months, similar to massive vitamin A doses. School
children fed RPO snack for one month as per the RDA, maintained
normal levels even after six months of cessation of supplementation.
Children fed 50 % of RDA from RPO snack also maintained normal levels
(>0.7µ mol/L) at the end of six months of supplementation. Hence,
periodic bouts of RPO feeding twice or thrice a year may help in
maintaining adequate vitamin A status throughout the year. Hence
RPO has great promise in maintaining the nutritional well-being
of the population.
Introduction
The prospects for augmenting the cultivation of red
palm oil (RPO) in India1 warrant research into it’s
nutritional and health benefits, and food uses of RPO. RPO is the
unrefined, unbleached, thick, orange coloured oil extracted from the
oil palm fruit with it’s carotenoid content intact2.
Carotenoids are precursors of vitamin A in the human biological system,
b-carotene being the most active. In addition
to vitamin A activity, carotenoids along with tocopherols, are also
powerful anti- oxidants which have been implicated in keeping both,
cancer and cardiovascular disease3 at bay. RPO
contains about 500-700 PPM of carotenoids and 1000 PPM of tocopherols
and tocotrienols. It is easily one of the richest natural sources
of carotenes, and could serve as an excellent vehicle for vitamin
A supplementation which has been reported to have beneficial effects
on child mortality and morbidity4. Vitamin A deficiency,
despite being a preventable nutritional problem, continues to be a
major public health problem in developing nations5. Prevalence
of xerophthalmia in India was reported to be 0.7%. A baseline survey
for a vitamin A supplementation trial in Tamilnadu6, India,
noted high xerophthalmic rates including night blindness (3.7%), Bitot’s
spots (7.2%) and total xerophthalmia rate of 10.95%. Biochemical data
from the same survey indicated that 37.5% had retinol levels <0.7
µmol/L.
The reason for continued prevalence is inadequate
dietary intake. Undernutrition, especially with respect to micronutrients
like vitamin A, iron and iodine, persists in developing countries
despite the rapid leaps and bounds in production of food grains and
food availability7 in countries like India. New and alternate
sources of foods rich in micronutrients could alleviate these lacunae.
At the 1995 world summit for children8,
WHO and UNICEF emphasised the need to improve the intake of foods
rich in micronutrients as a low cost strategy for reducing illness,
blindness and death among children of the developing world. It was
estimated that half a million children were still going blind due
to vitamin A deficiency, and among those, 50 were dying from common
diseases. This tragedy of half a million children was considered to
be the tip of a much larger problem. 500 times that number have lowered
resistance to infections and disease because of milder forms of deficiency,
and are at a higher risk of death from common diseases, which is 20-30%
higher than normal children.
Thus, a detailed investigation was undertaken to evaluate
the efficacy of RPO as a vitamin A supplement, as its distribution
could serve as one of the long term strategies to improve vitamin
A status of vulnerable groups.
A series of experiments were conducted to study the
effect of RPO supplementation on vitamin A status.
Methods
Study
1
Twenty four children of 7-9 years of age comprising
of twelve boys and twelve girls belonging to the low socio-economic
group and residing in government aided homes in Hyderabad city, were
selected and assigned to two age and sex matched groups.
The first group was fed "suji halwa"
( a sweet snack made of semolina, sugar and RPO in the ratio of 1:1:1)
providing 2400 µg (RDA) of b-carotene.
The second group was administered 600 µg of vitaminA
in addition to a piece of "suji halwa" placebo made
with GNO.
The snack was distributed in the evening over and
above their normal diet which was vitamin A deficient. The Modified
Relative Dose Response (MRDR)9 test was conducted to assess
the vitamin A status of children before and after supplementation.
The test was conducted by oral administration of 3,4-didehydroretinol
acetate (DRA) after an overnight fast at the rate of 100 µg / kg of
body weight. A blood sample was drawn five hours after the oral dose,
and retinol (R) and dehydroretinol (DR) were estimated by High Performance
Liquid Chromatography (HPLC) according to the method of Beiri et
al10. The DR/R ratio was calculated and used to measure
vitamin A status as it was reported to be a valid indicator of vitamin
A nutriture9.
Study
2
Thirty-six school children of 7-12 years having mild
to severe clinical signs of vitamin A deficiency, studying in Government
schools in urban Hyderabad, were randomly distributed to two groups.
The first group were supplemented with "suji
halwa" made with RPO and providing 2400 µg of b-carotene.
The second group was administered 100,000 I.U. of
synthetic Vitamin A as a single massive dose. Blood samples were drawn
before and after supplementation/dose and serum was analysed for retinol
and b-carotene by HPLC10,11.
Study
3
100 children (7-9 years) belonging to
an interior village called "Nakhaur" in Puri, Bhubaneshwar,
Orissa, India, were screened for clinical signs of vitamin A deficiency
and 36 of these were selected for the study. They were assigned to
three age and sex matched groups.
Group 1 (control) was administered 100,000
I.U. of vitamin A palmitate drops as a single massive dose.
Group 2 was given 4 g RPO for 30 days
providing 50,000 IU of vitamin A in the form of "Besan laddu"
(a sweet snack made of chick pea flour, sugar and fat in the form
of balls).
Group 3 received 8 g RPO providing 100,000
IU of vitamin A from "Besan laddu". Group 2 provided
only 50 % of the vitamin A supplied by groups 1 & 3. Blood samples
were drawn in three phases:
- Initial, before supplementation;
- Intermediate, after one month of supplementation;
- Final, six months after cessation of supplementation.
Serum was analysed for retinol by HPLC10.
Statistical
analysis
One way analysis of variance was done to compare results
of different groups as well as different time points of study.
Clinical
and anthropometric measurements
Clinical signs of deficiency and anthropometric measurements
were recorded for all children before and after supplementation in
all studies.
Results
Study
1
Results of the MRDR study are presented in Table 1
and Figures 1 and 2. Serum retinol levels increased from basal 0.86
± 0.13 to 1.89 ± 0.023 µmol/L in the RPO group. These values are comparable
to control group whose retinol levels increased from 0.74 ± 0.09 to
I.94 ± 0.021 µmol/L. DR/R ratio decreased from 0.073 ± 0.025 to 0.025
± 0.003 in the RPO group, and from 0.095 ± 0.023 to 0.023 ± 0.004
in the control group, indicating liver saturation with vitamin A in
both groups.
Table 1. Serum retinol and DR/R ratio of children
fed RPO and vitamin A.
| |
Retinol(µMol/L)
|
DR/R
|
| Groups |
Initial
(12)
|
Final
(12)
|
Initial
(12)
|
Final
(12)
|
| Vitamin A |
0.74 b + 0.09
|
1.94 a+ 0.021
|
0.095 + 0.023
|
0.023* +0.004
|
| Red Palm Oil |
0.86b +0.13
|
1.89 a+ 0.023
|
0.073 + 0.025
|
0.025* + 0.003
|
Values are Mean + SEM; Alphabets in superscript
indicate significant differences (P<0.05) between columns (retinol)
* denotes significant differences (P<0.05) between columns (DR/R).
Figures in parenthesis indicate no. of subjects.
Figure 1. Mean serum retinol levels (mmol/L) of children fed RPO and vitamin
A.
Figure 2. DR/R ratio of children fed RPO and
Vitamin A.
Study
2
Table 2 and Figures 3 and 4 depict the retinol and
b-carotene
levels of school children fed RPO and massive vitamin A dose for one
month. Considerable improvement of more than two fold was seen in
retinol levels after supplementation in both groups. Basal b-carotene
levels were low in both groups, but in the RPO group, supplementation
brought about a significant increase (P<0.05) from 0.06 ± 0.002 to 0.21 µmol/L. In the control group there was no difference observed
after the dose.
Table 2. Retinol and b-carotene( µmol/L) levels of school
children fed red palm oil and massive vitamin A dose.
| |
Retinol
|
b-Carotene
|
| Groups |
Initial
(18)
|
Final
(18)
|
Initial
(18)
|
Final
(18)
|
| Massive Vitamin A |
1.40b ± 0.05
|
1.76a ± 0.09
|
0.07 ± 0.005
|
0.06 ± 0.006
|
| Red Palm Oil |
0.95b ± 0.05
|
1.85a ± 0.08
|
0.06 ± 0.006
|
0.21* ± 0.016
|
Values are Mean ± SEM; Alphabets in superscript indicate
significantly different (P<0.05) columns (retinol).
* denotes significantly different (P<0.05) columns (b-carotene). Figures in parenthesis
indicate no. of subjects.
Figure 3. Mean serum retinol (mmol/L) of children fed RPO and massive
vitamin A dose.
Figure 4. Mean b-carotene (mmol/L) of children fed RPO and massive
vitamin A dose.
Study
3
Mean serum vitamin A levels of all three groups are
presented in Table 3 and Figure 5, and the percentages of children
having serum retinol levels < 0.7 µmol/L are shown in Table 4.
In the massive dose group, initial levels were significantly
different (P<0.01) from intermediate and final values. In the 4
RPO group, Intermediate levels were significantly higher (P<0.01)
than Initial and Final levels. In the 8 g RPO group, all three values
were significantly different (P<0.01) from each other. In groups
1 and 3, serum retinol levels were maintained >0.7 µmol/L even
at the end of six months. In the 4 g RPO group, the mean serum retinol
levels at the end of six months were slightly below 0.7 µmol/L (0.67
µmol/L). It can be seen that 33% of children in this group had retinol
levels < 0.7 µmol/L at the end of six months.
Table 3. Mean serum retinol (µmol/l) levels
of children fed red palm oil and massive vitamin a dose.
| Groups |
Initial
(12)
|
Intermediate
(12)
|
Final
(12)
|
| Massive vitamin A dose |
0.56a ± 0.11
|
1.07b ± 0.25
|
0.90b ± 0.23
|
| 4 g RPO |
0.53a ± 0.12
|
1.05b ± 0.27
|
0.67a ± 0.10
|
| 8 g RPO |
0.60a ± 0.13
|
1.79c ± 0.70*
|
0.97b ± 0.62
|
Values are Mean ± SEM; Intermediate: After 1 month
of supplementation; Final: 6 months after cessation of supplementation;
letters in superscript indicate significantly different columns (P<0.01);
* denotes significantly different rows (P<0.01); Figures in parenthesis
indicate no. of subjects.
Figure 5. Mean serum retinol (mmol/L) levels of children of three
groups.
Table 4. Percent distribution of children with
serum retinol levels <0.7 µmol/L.
| Groups |
Initial
(12)
|
Intermediate
(12)
|
Final
(12)
|
| Massive vitamin A dose
|
92
|
0
|
0
|
| 4 g RPO |
92
|
0
|
33
|
| 8 g RPO |
83
|
0
|
0
|
Figures in parenthesis indicate no. of subjects.
Discussion
Study
1
The efficiency of dispersion and absorption of vitamin
A and b-carotene is affected by the presence or absence of many factors, among
which fat in the diet is of utmost importance12. Fat provides
the vehicle for transporting vitamin A and carotenoids from the stomach
into the intestinal lumen, and is also the source of some of the digestion
products which interact with bile salts and micelles and solubilize
the vitamins. In this context RPO, which is a source of carotenoids
in a fat medium, seems to serve as an ideal vehicle by simultaneously
increasing the fat as well as pro-vitamin A intake. This probably
explains the high efficiency of conversion of b-carotene to vitamin A, as demonstrated in
this study.
The DR/R ratio is a reflection of liver stores of
vitamin A9, and has been reported to be inversely proportional
to retinol levels, providing a valid quantitative measure of vitamin
A nutriture. 3,4-didehydroretinol (DR) is a ligand for binding accumulated
apo-retinol binding protein (RBP) in vitamin A depleted liver. It
is a naturally occurring analog of retinol which is found as an RBP
complex in serum five hours after dosing. A ratio of > 0.03 was
reported to be indicative of poor status. In this study, in both groups,
DR/R ratio was >0.03 before supplementation, and decreased to 0.025
after supplementation. A clear indication has therefore been obtained
that b-carotene
from RPO is bioavailable and comparable to synthetic vitamin A in
improving nutritional status.
Pee et al13, reported that b-carotene from dark green leafy
vegetables was poorly absorbed in comparison with wafers enriched
with synthetic b-carotene in lactating women with low hemoglobin
status.
Hume and Krebs14 stated that bioavailability
of b-carotene from vegetables and carrots was only a third of that of b-carotene in oil. Since RPO is a fat in which b-carotene is naturally present,
it appears to be more bioavailable, as indicated in the study.
Study
2
In this study, children belonging to the lower socio-economic
group and having clinical signs of vitamin A deficiency were examined
for both vitamin A and b-carotene after RPO supplementation.
Both, retinol and b-carotene levels were high in RPO fed group.
This indicates that RPO is supplying b-carotene not only for conversion
to vitamin A, but these high circulating levels could come of use
for it’s other biological functions like anti-oxidant activity.
Study
3
This study was undertaken to ascertain whether high
serum levels of retinol observed on RPO supplementation could sustain
vitamin A status over a period of non-supplementation similar to vitamin
A. When massive doses of vitamin A are administered once in six months,
they afford protection till the next dose is given, because of the
capability of the liver to store in the form of retinyl esters and
release them as retinol bound to RBP when the need arises15.
The results of this study indicate the possibility
that RPO is able to afford similar protection at the end of six months
of non- supplementation in the 8g RPO group which provided the same
amount of vitamin A as control group. The 4g RPO group received only
half the amount of vitamin A as the other two groups, hence serum
retinol levels were depleted to marginal values at the end of six
months. 33% of children in this group had values < 0.7 µmol/L which
is the cut-off point for normal vitamin A status.
Indications are that the children are ready for the
next dose. It can be seen that both groups which received b-carotene from RPO sustained retinol
levels for up to six months, but the only difference was that 8 g
RPO group still had sufficient stores to maintain them on an adequate
status for a further period.
All the above studies confirm the bio-availability
of RPO carotenoids and prove that RPO is a good substitute for synthetic
vitamin A in supplementation programmes and preventive therapy. Moreover,
the third study indicates that probably smaller periods of intermittent
supplementation of RPO may suffice to maintain adequate status, without
the need for regular daily intake. This information could prove useful
while planning programmes to combat vitamin A deficiency. However,
long term studies on larger samples would yield more reliable information.
Conclusion
RPO is a unique vegetable oil with unusual benefits
on health and nutrition. Its inclusion in supplementary feeding programmes
to vulnerable children suffering from morbidity has been demon-strated
to have profound effects. RPO not only improved vitamin A status and
circulating b-carotene levels, but also afforded
protection for as long as six months. Hence, it could be beneficial
if RPO were promoted for consumption as a health food.
Acknowledgements
The authors acknowledge the help and encouragement
given by Dr Vinodini Reddy, former Director of the National Institute
of Nutrition, ICMR, India. The technical help of Mrs Indra Ravindranath,
Mr N Hari Shankar and Mr Chenniah, Technical staff of the National
Institute of Nutrition is also acknowledged. The cooperation rendered
by Mr Prakash Kumar Mohanty, Pathologist, Government Hospital, Bhubaneshwar,
Orissa, Mr PTK Mahapatra, Dr Satyanarayana, Director, Regional medical
research centre, Bhubaneshwar, and Dr Amarendra Mahapatra is acknowledged.
The authors thank the Indian Councils of Agricultural and Medical
Research for financial assistance.
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Red palm oil for
combating Vitamin A deficiency
R Manorama, M Sarita, R Kavita,
C Rukmini
Asia Pacific Journal of Clinical Nutrition (1997) Volume 6, Number
1: 56-59
Copyright © 1993 [Asia Pacific Journal of Clinical
Nutrition]. All rights reserved.
Please contact lshirven@ozemail.com.au if any errors are suspected.
Revised:
February 03, 1999
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