| Summary: | 碩士 === 台北醫學院 === 藥學研究所 === 85 === Recently clinical trials indicate that an increasing relative
risk of death from cardiovascular disease following
synthesized beta-carotene supplement. We are
interested in the problem whether synthetic beta-carotene is
suitable for use as a dietary supplement. The purpose of
this study was to investigate the effects of different
sources of beta-carotene and lipids on lipid metabolism and
beta-carotene availability in rats. Forty adult male Wistar
rats were randomly divided into five groups with the
variables including the sources the sources of beta-carotene
(synthetic and natural beta-carotene crude extract from sweet
potato leaves ) and lipids (soybean oil and lard ). Diets and
water were given ad libitum, and was 10g/kg cholesterol
added in diets for forty days. The results showed that for
(-carotene concentration in the serum and liver, the
synthetic (-carotene groups were significantly higher
than the beta-carotene extract groups (P<0.05). Comparison of
the effect of different lipids under the same beta-carotene
source indicated that, the lard groups were
significantly higher in beta-carotene concentration than the
soybean oil groups. Different sources of beta-carotene
and lipid fed did not affect the serum and liver retinol
concentration in both the soybean oil-fed groups and the lard-
fed groups (P>0.05). The effects on lipid metabolism
were as follows: The synthetic beta-carotene groups had
significantly higher ratio between high density lipoprotein
cholesterol (HDL-C) and low density lipoprotein
cholesterol (LDL-C) than the beta-carotene extract
groups (P<0.05), the beta-carotene extract groups is the most
significant. Besides, the synthetic beta-carotene groups
and the beta-carotene extract groups could both cause liver
total cholesterol content decreasing, and the beta-carotene
extract groups is the most significant. The synthetic beta-
carotene groups serum and liver acyltriglyceride
concentration are significant higher than the beta-carotene
extract groups. The rat serum, liver and adrenal gland beta-
carotene concentration in the synthetic beta-carotene
groups are all the lard group significant higher than the
soybean oil group. Under the injection of soybean oil, the beta-
carotene extract group serum and liver acyltriglyceride
concentration are significant lower than the synthetic
beta-carotene group, but the groups under the lard injection are
not statistically different. The effects on fatty acid
were as follows: Among the soybean oil groups, the
serum and liver linoleic acid (18:2,n-6) ratios were
significantly higher in the synthetic beta-carotene groups than
in the beta-carotene extract groups (P<0.05); and Among the
lard groups the serum and liver oleic acid (18:1,n-9)
ratios were significantly higher in the synthetic beta-carotene
groups than in the beta-carotene extract groups (P<0.05).
These results suggest that ingestion of beta-carotene
crude extract from sweet potato leaves, as compared to
injestion of the synthetic beta-carotene, has the benefit of
decreasing serum lipids. Except this, the lard diet could
cause more beta-carotene deposit in the liver and increase
beta-carotene bioavailability.
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