BACKGROUND: The increased level of LDL-c in the serum has a high risk and the increased serum HDL-c level has a low risk for the development of atherosclerosis. The effect of Nigella sativa on levels of cholesterol fractions were determined in this study on rats. METHODS: 24 albino rats of 08 weeks age having equal number of males and females were kept at optimum atmospheric condition. The blood samples were taken at the start and different control and experimental diets were given for 20 weeks. The experimental diets were added with Nigella sativa as 30 mg/kg body weight. The blood samples were taken at the end of study. The blood samples drawn at the start and end of the study were estimated for serum cholesterol. The results of control and experimental groups were compared. RESULTS: Total serum cholesterol in the control group showed increase from 8.3+/-3.30 to 13.96+/-9.3 at 20 weeks. The serum HDL cholesterol showed increase from 44.4+/-6.12 to 80.45+/-5.95 level at 20 weeks. The serum LDL cholesterol showed increase from 8.3+/-3.30 to 13.96+/-9.3 at 20 weeks. The total serum cholesterol in experimental group was increased from 76.9+/-6.5 to 117.5+/-6.65 at 20 weeks. The serum HDL cholesterol levels was increased from 41.7+/-4.9 to 83.42+/-5.92 at 20 weeks as compared with control group. The LDL cholesterol levels were decreased from 12.7+/-6.9 to 8.5+/-7.8 at 20 weeks. CONCLUSION: This study shows significant decrease in serum low density lipoprotein cholesterol level, and increase in serum high density lipoprotein cholesterol levels.

BACKGROUND: Guidelines established by the National Cholesterol Education Program (NCEP) promote exercise and weight loss for the treatment of abnormal lipoprotein levels. Little is known, however, about the effects of exercise or the NCEP diet, which is moderately low in fat and cholesterol, in persons with lipoprotein levels that place them at high risk for coronary heart disease.

METHODS: We studied plasma lipoprotein levels in 180 postmenopausal women, 45 through 64 years of age, and 197 men, 30 through 64 years of age, who had low high-density lipoprotein (HDL) cholesterol levels (125 mg per deciliter but<210 mg per deciliter in women and>125 mg per deciliter but<190 mg per deciliter in men). The subjects were randomly assigned to aerobic exercise, the NCEP Step 2 diet, or diet plus exercise, or to a control group, which received no intervention.

RESULTS: Dietary intake of fat and cholesterol decreased during the one-year study (P<0.001), as did body weight, in women and men in either the diet group or the diet-plus-exercise group, as compared with the controls (P<0.001) and the exercise group (P<0.05), in which dietary intake and body weight were unchanged. Changes in HDL cholesterol and triglyceride levels and the ratio of total to HDL cholesterol did not differ significantly among the treatment groups, for subjects of either sex. The serum level of LDL cholesterol was significantly reduced among women (a decrease of 14.5+/-22.2 mg per deciliter) and men (a decrease of 20.0+/-17.3 mg per deciliter) in the diet-plus-exercise group, as compared with the control group (women had a decrease of 2.5+/-16.6 mg per deciliter, P<0.05; men had a decrease of 4.6+/-21.1 mg per deciliter, P<0.001). The reduction in LDL cholesterol in men in the diet-plus-exercise group was also significant as compared with that among the men in the exercise group (3.6+/-18.8 mg per deciliter, P<0.001). In contrast, changes in LDL cholesterol levels were not significant among the women (a decrease of 7.3+/-18.9 mg per deciliter) or the men (10.8+/-18.8 mg per deciliter) in the diet group, as compared with the controls.

CONCLUSIONS: The NCEP Step 2 diet failed to lower LDL cholesterol levels in men or women with high-risk lipoprotein levels who did not engage in aerobic exercise. This finding highlights the importance of physical activity in the treatment of elevated LDL cholesterol levels.

Olive oil consumption increases HDL-cholesterol levels, while decreasing LDL-cholesterol levels, LDL susceptibility to oxidation and lipid peroxidation. The reduction of cellular oxidative stress, thrombogenicity and the formation of atheroma plague can explain the preventive effects of olive oil on atherosclerosis development. In addition to reducing risk factors for coronary heart disease, olive oil might also help prevent certain types of cancers, and beneficially modify immune and inflammatory responses.