• Nutritional Sciences
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• v.8 no.1
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• pp.10-15
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• 2005

An increase in serum cholesterol is directly associated with high incidences of cardiovascular diseases (CVD) and atherosclerosis. Serum lipid profiles are highly dependent on dietary fatty acids and age. The purpose of this study was to examine the age-related effects of polyunsaturated/saturated fatty acid ratios and antioxidant supplementation under the control of the dietary peroxidizability index (PI) value on serum lipid profiles in rats. While the PI level of dietary fatty acids was controlled at 81.22, the P/S ratios of fatty acids were 0.38 and 4.81 (LP and HP). The diets were supplemented with a vitamin E 1000 mg/kg diet and a selenium 2.5 mg/kg diet (LPS and HPS). Female Sprague-Dawley rats ages 3 weeks (young) and 16 weeks (adult) were fed four different experimental diets for 4 weeks. The serum triglyceride concentration of LPS was significantly higher in young rats than in adult rats. The total-cholesterol concentration of LP and HPS were higher in young rats than in adult rats. The high-density lipoprotein-cholesterol (HDL-C) concentration of LP, LPS and HP was higher in adult rats than in young rats. The low-density lipoprotein-cholesterol (LDL-C) concentration was higher in young rats than in adult rats. T-C/HDL-C and LDL-C/HDL-C ratios were much higher in young rats than in adult rats. In conclusion, P/S ratios and antioxidant supplementation did not affect T-C/HDL-C and LDL-C/HDL-C ratios as risk factors of CVD in adult rats when we controlled the PI value in the diet Probably, the invisible and confounding effects of dietary PI value implicate the beneficial roles of dietary P/S ratios and antioxidants in CVD. Accordingly, controlling the dietary PI value may be advantageous to lower the risk of CVD in adult rats.

• Nutritional Sciences
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• v.9 no.1
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• pp.14-19
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• 2006

Breast cancer may be the consequence of free radical damage, which is partially caused by the excessive intake of dietary fat and imbalances in antioxidant scavenger system;. In this experiment, we examined! the effects of dietary peroxidizability index (PI) values on hepatic thiobmbituric acid reaction substances (TBARS) and antioxidant enzyme activities in rats treated with 7,12-dimethylbenz[$\alpha$]anthracene (DMBA). Female Sprague-Dawley rats were used and 7,12-DMBA (20 mg/kg body weight) was gastrically intubated at seven weeks of age in order to induce mammary tumors (MT). The levels of dietary PI were 36, 81, 126 and 217 (LPI, MLPI, MHPI and HPI), while dietary polyunsaturated/saturated fatty acids ratio was maintained at the same level (1.0). Fat used in the experiment was mixed with soybean oil, com oil, palm oil, perilla oil, sesame oil, fish oil, and beef tallow. Experimental diets were given for the following 20 weeks. We measured tumor numbers and weights, and then assayed the hepatic TBARS levels and antioxidant enzyme activities such as superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione-S-transferase (GST) and glutathione reductase (GR). The incidence of Mr was the lowest in the MHPI group. The hepatic TBARS level was significantly raised with increasing dietary PI value. The hepatic SOD and GR activities were differed significantly by dietary PI value. The hepatic SOD activity was negatively correlated with dietary PI value and GR activity was the highest in the rats fed the MHPI diet. When the dietary P/S ratio is kept at 1.0, adequate dietary PI value (PI value of 126) may reduce the incidence and growth of Mr, but this benefit may be lost with higher dietary PI value. These results suggest that the awareness of dietary PI values may help to decrease breast cancer incidence and growth.

• Journal of Nutrition and Health
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• v.36 no.3
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• pp.245-254
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• 2003

The aim of this study was to investigate the effects of P/S ratio of fatty acid and antioxidant (vitamin E, selenium) supplements on the serum lipid levels and hepatic antioxidant enzyme activity in rats. Female 16-week-old Sprague-Dawley rats were fed 6 different experimental diets for 4 weeks. While the peroxidizability index (PI) levels of fatty acids in the experimental diets were fixed at 81.22, the levels of P/S ratio of fatty acids were formulated at 0.38, 1.00, 4.81 (LP, MP, HP). These diets were supplemented with vitamin E (1,000 mg/kg diet) and selenium (2.5 mg/kg diet) (LP-S, MP-S, HP-S). This study showed that the serum concentrations of total-cholesterol and HDL-C increased with the increasing of the P/S ratio in the diet (p <0.05). Antioxidant supplementation significantly lowered the concentrations of triglyceride (TG) and VLDL-C of serum (p<0.05). Levels of thiobarbituric acid reactive substance (TBARS) in the liver tended to decrease with the increasing of the P/S ratio in the diet (p<0.001), but antioxidant enzyme activity in the liver was not significantly different. In addition, antioxidant supplementation significantly lowered TBARS level in the liver (p<0.05), but had no effect on antioxidant enzyme activity except for glutathione reductase (p<0.05). In conclusion, it is necessary to consider the properties of dietary fatty acids and antioxidants supplementation for the prevention of cardiovascular diseases.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.3
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• pp.181-188
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• 1992

To study the effect of alginic acid on modulation of the aging process, Sprague-Dawley(SD) male rats were fed the diets containing 0, 3, 6 and $9\%$ alginic acid isolated from brown algae(Undaria pinnatifida) for 16 weeks. The effects of alginic acid on body weight, malondialdehyde(MDA) content, peroxidizability index, cholesterol and phospholipid levels, cholesterol/phospholipid(Ch/Ph) molar ratio, and fatty acid compositions in liver membranes were investigated. Increasing alginic acid level in diets did not alter food intakes but effectively decreased body weights gain(p<0.01-0.005). Malondialdehyde(MDA) contents of diets containing 6 and $9\%$ alginic acid were effectively decreased in ranges of $54.1-43.0\%$ in mitochondria, and $65.5-87.7\%$ in microsome compared with $100\%$ of control group. Cholesterol levels of all diets containing alginic acid were significantly decreased in ranges of $87.0-72.3\%$ in mitochondria, and $87.4-68.1\%$ in microsome compared with $100\%$ of control group. Phopholipid levels in microsome were significantly decreased by diets containing 3 and $ 6\%$ alginic acid but Ch/Ph molar ratios in both membranes were decreased by diets containing 3 and $6\%$ alginic acid. Increasing alginic acid level in diets significantly decreased total fatty acid but effectively increased linoleic acid in microsome except for diet containing $9\%$ alginic acid. These data on liver membranes suggest that alginic acid added to diets can modulate the physiological changes if the aging process.

• Journal of Nutrition and Health
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• v.19 no.5
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• pp.304-314
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• 1986

To observe the effect of the different level of PUFA and marginal tocopherol supplement on HDL-chol, tissue tocopherol content and fatty acid composition, the rats were supplied either safflower oil or conconut oil with or without tocopherol supplement to the experimental diet. Plasma tocopherol level was not greatly influenced by the different dietary fat and similar effect was observed in the liver but not in the adipose tissue. HDL-chol level was reduced in the high PUFA diet regardless of tocopherol content. No effect by tocopherol supplement was observed in the fatty acid composition of liver and adipose tissue lipid in both dietary PUFA levels . There was also no increase in the content of tissue polyenoid acid by tocopherol in the high PUFA diet . Fatty acid composition of tissue lipid was rather more influenced by dietary fat. Lauric and myristic acid contents were higher in the low PUFA diet and linoleic acd and total polynoic acid content were higher in the high PUFA diet. With tocopherol supplement tocopherol /PUFA ratio of tissue was increased but the ratio of high PUFA diet was significantly lower than that of low PUFA diet. Marginal tocopherol supplement could not reduce the peroxidizability index of high PUFA diet.

• Journal of Nutrition and Health
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• v.29 no.2
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• pp.232-241
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• 1996

This study was designed to compare the effect of different dietary fats on plasma lipids, the degree of lipid peroxidation and the activity of antioxidant enzymes in RBC and liver rats treated with or wighout 1, 2-dimethylhydrazing (DMH). Male Sprague Dawley rats, at 7 weeks-old, were divided into control and DMH-treated grous, and each group was again subdivided into four were perilla oil (PO), blend fat (BF) containing ten different kinds of dietary oil, beef tallow (BT), corn oil (CO). At the same time, each rat was injected intramusculary with saline(for control) or DMH twice a week for 6 weeks to give total dose of 180 mg/kg body weight. Compared with BT feeding, BF reduced plasma total choesterol level and PO and Co reduced plasma TG levels (p<0.05). DMH injection decreased plasma cholesterol in all dietary groups. However, PO decreased tocopherol levels and increased TBARS levels in RBC compared to BT. The degree of hemolysis in PO group was higher than that of BT group (p<0.05 only in control group. Fatty acid composition of hepatic microsome was reflected by dietary fatty acid profile. The peroxidizability index and TBARS level in hepatic micorsome were significantly increased but tocopherol level was lowered in PO group compared to BT group. Activites of superoxide dismutase and glutathione peroxidase in RBC and hepatic cytosol were not influenced y dietary fats and DMH treatment(p<0.05). Overall, perilla oil rich in $\omega$3 $\alpha$-linolenic acid could be a very important dietary source in reducing plasma lipids and blend fat was also good dietary oil mixture in reducing plasma cholesterol. However, the degree of lipid peroxidation was greater in tissue by perilla oil feeding and it is very difficult to use only perilla oil as oil source for meal preparation, so that it could be suggested to use more perilla oil and fish to give an equal effect of blend fat in order to reduce the risk factors against cardiovascular disease.