world - wide , at least 2.8 million people die each year as a result of being overweight or obese and an estimated 35.8 million ( 2.3% ) of global dalys are caused by overweight or obesity .
overweight and obesity lead to adverse metabolic effects on blood pressure , cholesterol , triglycerides ( tg ) and insulin resistance .
some natural products have been considered to play a good role as an alternative to synthetic chemicals in this clinical condition .
a wide variety of plants has been reported to have lipid lowering activity . among such plants nigella sativa ( n. sativa ) ( black seed ) in several studies has been investigated for its lipid lowering effects on animals .
the seeds of the plant have been used in the southeast asia , middle and far east as a natural remedy to treat many diseases , including anti - microbial , anti - oxidant , anti - inflammatory , antitumor , hematologica , anti - hypertensive , anti - hypertensive , anti - diabetic , antilipidemic , hypophagic and anti - obesity effects and respiratory health .
in fact , this plant has occupied a special place for its wide range of medicinal value in the islamic civilizations . due to the sayings of the holy prophet ,
mohammad ( peace be upon him ) that  in the black seed there is healing for every illness except death . 
anwar and tayyab reported that n. sativa in the diet has a favorable effect on the lipid profile by lowering the tg , total cholesterol ( tc ) and low - density lipoprotein ( ldl)-cholesterol and increasing the high density lipoprotein ( hdl)-cholesterol in rats .
exercise is most important for every living being ; in other words , we can also say that physical inactivity results in several types of diseases in the body .
a sedentary life - style is associated with an increased risk for an acute myocardial infarction and death from coronary heart disease ( chd ) .
the findings are consistent and show that sedentary people have about twice the risk of developing or dying from chd , compared to active people .
physical inactivity is now recognized by the american heart association as an independent risk factor , comparable to the other established risk factors for chd .
it is well - established that habitual physical activity improves physical fitness in middle - aged men and women .
yar et al . had monitored the effect of n. sativa supplementation on cardiac reserve in rats .
their results suggest that n. sativa generated homogenous cardiac hypertrophy similar to that provoked by exercise training . despite the aforementioned beneficial effects of exercise and n. sativa ,
thus , the purpose of this randomized , double blind , controlled trial was to investigate whether 8 weeks of aerobic training combined with n. sativa supplementation could improve lipid profile and maximal oxygen consumption ( vo2 max ) in sedentary overweight females .
a total of 20 adult females with a mean age of 34.31  7.9 years , body mass index ( bmi ) 25 kg / m and sedentary life - style for at least 2 years participated in this study voluntarily .
the main criterion for entry of adult females was a tc concentration more than 200 mg / dl .
subjects taking lipid - altering medication within 8 weeks prior to the study were excluded .
other exclusion criteria were pregnant , current smoking , lactation , having diabetes mellitus , cardiovascular disease ( cvd ) , renal or liver disease , thyroid dysfunction and myopathy .
physical characteristics of the study participants * according to the subject 's profiles number and the random figures tables , they were randomized to receive either n. sativa capsules ( ns group ) or placebo ( pla group ) .
each black seed capsule contained 500  10 mg n. sativa crushed seeds and subjects had to take 2 g of n. sativa per day for 8 weeks .
they were instructed to take two capsules before breakfast and two capsule in the afternoon prior their food .
subjects were also asked not to change their usual daily diet and physical activity during the study .
subjects in two groups performed slow running ( 10 min ) , stretching muscles and loosening joints ( 10 min ) , aerobic training program ( 30 min ) and cool down ( 10 min ) .
the intensity of training was 60 - 70% of target pulse rate calculated by karvonen et al .
target heart rate ( hr ) zone = ( [ hr maximum hr rest ]  { 60 - 70% } + hr rest ) hr maximum = 220  age .
if the subjects are not able to take a measurement first thing in the morning , make sure subjects lie down for at least 10 min before taking a measurement . measurement was taken from the radial artery with forefinger and the middle finger of the right hand placed horizontally across the subject 's wrist while sitting on the chair .
after that , the number of pulse beats multiplied by two to give the 1 min hr .
cardio - respiratory fitness was determined by 1609 m ( 1 mi ) walk test using rockport fitness test . after a brief warm up , the subject walked as briskly as possible for 1609 m ( 1 mi ) with a hr monitor .
the formula used to calculate vo2 max was : 132.853 ( 0.0349  mass [ kg ] )  ( 0.3877  age [ year ] ) + ( 6.315  gender )  ( 3.2649  time [ min ] )  ( 0.1565  hr [ bpm ] ) .
the validity of the test was nearly high r = 0.88 and standard error of the test was 5 ml / kg / min .
cardio - respiratory measurement was taken before and after 8 weeks of aerobic training program and supplementation .
a total volume of 20 ml blood was drawn from the subjects in their forearm vein after a 12 h overnight fast immediately before and after 8 weeks of aerobic training program and supplementation in the sitting position after a 20-min rest between 8:00 and 9:00 a.m. plasma was separated by centrifugation and samples were stored at 10c until assays were determined ( within 48 h ) in all samples .
the statistical analysis was initially performed using the changes in the one - sample kolmogorov - smirnov test .
data was analyzed using paired t - test for within group 's comparison and unpaired t - test for between - groups comparison .
a total of 20 adult females with a mean age of 34.31  7.9 years , body mass index ( bmi ) 25 kg / m and sedentary life - style for at least 2 years participated in this study voluntarily .
the main criterion for entry of adult females was a tc concentration more than 200 mg / dl .
subjects taking lipid - altering medication within 8 weeks prior to the study were excluded .
other exclusion criteria were pregnant , current smoking , lactation , having diabetes mellitus , cardiovascular disease ( cvd ) , renal or liver disease , thyroid dysfunction and myopathy .
according to the subject 's profiles number and the random figures tables , they were randomized to receive either n. sativa capsules ( ns group ) or placebo ( pla group ) . each black seed capsule contained 500  10 mg n. sativa crushed seeds and subjects had to take 2 g of n. sativa per day for 8 weeks .
they were instructed to take two capsules before breakfast and two capsule in the afternoon prior their food .
subjects were also asked not to change their usual daily diet and physical activity during the study .
subjects in two groups performed slow running ( 10 min ) , stretching muscles and loosening joints ( 10 min ) , aerobic training program ( 30 min ) and cool down ( 10 min ) .
the intensity of training was 60 - 70% of target pulse rate calculated by karvonen et al .
target heart rate ( hr ) zone = ( [ hr maximum hr rest ]  { 60 - 70% } + hr rest ) hr maximum = 220  age .
resting hr was measured in the morning immediately after the participants were awake . if the subjects are not able to take a measurement first thing in the morning , make sure subjects lie down for at least 10 min before taking a measurement .
measurement was taken from the radial artery with forefinger and the middle finger of the right hand placed horizontally across the subject 's wrist while sitting on the chair .
after that , the number of pulse beats multiplied by two to give the 1 min hr .
cardio - respiratory fitness was determined by 1609 m ( 1 mi ) walk test using rockport fitness test . after a brief warm up , the subject walked as briskly as possible for 1609 m ( 1 mi ) with a hr monitor .
the formula used to calculate vo2 max was : 132.853 ( 0.0349  mass [ kg ] )  ( 0.3877  age [ year ] ) + ( 6.315  gender )  ( 3.2649  time [ min ] )  ( 0.1565  hr [ bpm ] ) .
the validity of the test was nearly high r = 0.88 and standard error of the test was 5 ml / kg / min .
cardio - respiratory measurement was taken before and after 8 weeks of aerobic training program and supplementation .
a total volume of 20 ml blood was drawn from the subjects in their forearm vein after a 12 h overnight fast immediately before and after 8 weeks of aerobic training program and supplementation in the sitting position after a 20-min rest between 8:00 and 9:00 a.m. plasma was separated by centrifugation and samples were stored at 10c until assays were determined ( within 48 h ) in all samples .
cardio - respiratory fitness was determined by 1609 m ( 1 mi ) walk test using rockport fitness test . after a brief warm up , the subject walked as briskly as possible for 1609 m ( 1 mi ) with a hr monitor .
the formula used to calculate vo2 max was : 132.853 ( 0.0349  mass [ kg ] )  ( 0.3877  age [ year ] ) + ( 6.315  gender )  ( 3.2649  time [ min ] )  ( 0.1565  hr [ bpm ] ) .
the validity of the test was nearly high r = 0.88 and standard error of the test was 5 ml / kg / min .
cardio - respiratory measurement was taken before and after 8 weeks of aerobic training program and supplementation .
a total volume of 20 ml blood was drawn from the subjects in their forearm vein after a 12 h overnight fast immediately before and after 8 weeks of aerobic training program and supplementation in the sitting position after a 20-min rest between 8:00 and 9:00 a.m. plasma was separated by centrifugation and samples were stored at 10c until assays were determined ( within 48 h ) in all samples .
the statistical analysis was initially performed using the changes in the one - sample kolmogorov - smirnov test . all variables presented normal distribution .
data was analyzed using paired t - test for within group 's comparison and unpaired t - test for between - groups comparison . statistical significance was accepted as p  0.05 .
numbers of four subjects were excluded during the study , because of altering their usual aerobic training program and being irregular in taking capsules , so we did our statistical analysis on 16 subjects ( 8 subjects in ns group and 8 subjects in pla group ) who fully completed the study [ figure 1 ] .
there were no differences among groups for age , bodyweight , height and bmi [ table 1 ] .
changes of lipid profiles after 8 weeks for two groups are shown in table 2 . tc ( p < 0.001 ) and ldl - cholesterol ( p < 0.01 ) were reduced in pla group and vo2 max ( p < 0.01 ) increased .
however , these changes were not statistically significant for tg , bmi and hdl - cholesterol ( p > 0.05 ) .
the schematic diagram of the study changes in the health related physical fitness parameters and blood lipids in pla and ns group in the ns group tc ( p < 0.01 ) , tg ( p < 0.001 ) and ldl - cholesterol ( p < 0.001 ) levels were decreased by 4.79% , 7.97% and 5.02% respectively and bmi ( p < 0.01 ) was significantly reduced by 2.76% and hdl - cholesterol ( p < 0.01 ) and vo2 max ( p < 0.01 ) significantly increased by 5.76% and 2.53% respectively .
furthermore , there were significant differences between the ns and pla groups for ldl - cholesterol ( p < 0.05 ) and hdl - cholesterol ( p < 0.05 ) values [ table 2 ] .
the relationship between ldl - cholesterol and chd risk is continuous over a broad range of ldl - cholesterol levels : the higher the ldl - cholesterol level , the greater the chd risk .
the increased permeability of the endothelium in the presence of elevated concentration of ldl promotes accumulation of ldl particles in the intima .
these particles undergo oxidative modification , which may lead to inflammatory reactions and initiate atherosclerosis process .
therefore , lowering ldl - concentration and improving antioxidant defense of the body are two important ways to prevent atheriovascular disease .
the relationship between the dietary fats and cvd , especially chd , has been extensively investigated , with strong and consistent associations emerging from a wide body of evidence accrued from animal experiments , as well as observational studies , clinical trials and metabolic studies conducted in diverse human populations .
the evidence shows that intake of saturated fatty acids is directly related to cardiovascular risk and raise total and ldl - cholesterol . when substituted for saturated fatty acids in metabolic studies with unsaturated fatty acids lower plasma total and ldl - cholesterol concentrations ; polyunsaturated fatty acids are somewhat more effective in this respect , especially linoleic acid .
this double - blind , randomized placebo - control study examined the long - term n. sativa supplementation and aerobic training on lipid profile and vo2 max in sedentary overweight females .
the main finding of this study was that 8 weeks of aerobic training with n. sativa supplementation improved hdl - cholesterol and impaired ldl - cholesterol .
results of the present study are in consistent with other previous studies that found improvements in health related parameters of overweight and obesity females participants as a result of aerobic exercise program also n. sativa for the treatment of hyperlipidemia .
since , we asked all subjects not to change their usual daily diet , it seems that this changes may be due to the result of consuming black seeds and regular aerobic training .
furthermore , these results are also in agreement with the results obtained by anwar and tayyab who observed that polyunsaturated fat have hypotriglyceridemic effect .
the choleretic function of n. sativa is either by reducing the synthesis of cholesterol by hepatocytes or by decreasing its fractional reabsorption from the small intestine .
furthermore , it has been proved that volatile oil of n. sativa has two main constituents , i.e. nigellone and thymoquinone which play a key role in heart disease prevention .
n. sativa is a rich source of unsaturated fatty acids , mainly linoleic acid ( 50 - 60% ) , oleic acid ( 20% ) , eicosadienoic acid ( 3% ) and dihomo linolenic acid ( 10% ) that cholesterol lowering effect of n. sativa may be attributed to the presence of phytosterols like beta - sitosterol , polyunsaturated fatty acids and its antioxidant activity
. n. sativa may be able to reduce synthesis of cholesterol by hepatocytes and lower its absorption from the small intestine .
it may also activate ldl - receptor by decreasing intracellular cholesterol , which leads to rapid clearance of ldl - cholesterol from blood circulation .
the effect of n. sativa on increasing cholesterol secretion in the bile is another probable mechanisms , which can enhance its cholesterol lowering properties .
furthermore , physical exercises performed regularly have effects on obesity , cardiovascular system , physical fitness and healthy life of the middle - aged individuals .
exercise may promote reverse cholesterol transport by increasing pre- hdl - cholesterol recycling from  hdl - cholesterol substrates that have been induced by exercise itself .
this mechanism can explain the greater cholesterol efflux from cultured human fibroblasts when exposed to serum of activity people 's versus sedentary controls .
several studies have confirmed this belief and the results of the present study are in agreement with the above statement .
results of the present study is consistent with arazi et al . in pla group that applied at the end of 8-week of regular aerobic exercises on middle - aged sedentary women ,
found that decreased in ldl - cholesterol and increased in the hdl - cholesterol levels .
in addition , bemelmans et al . applied at the end of 12-day of walking exercises on middle - aged sedentary men and women , found in their study that decreased in the ldl - cholesterol and tc levels and increased in the hdl - cholesterol levels .
in addition , aerobic exercise training increases the percentage of skeletal slow - twitch fibers , which have a higher capacity to metabolize fatty acids liberated by lipoprotein lipase from tg - rich lipoproteins .
also , exercise decreases the presence of small , dense ldl - cholesterol and increases that of larger , more buoyant ldl - cholesterol particles , in a relationship that appears dose - dependent with the amount and intensity of exercise . because over the last 10 years , there have been a growing number of studies that show the benefits of moderate intensity physical activity for cardiovascular health so in our study intensity of training was 60 - 70% of target pulse rate . despite the aforementioned results , n. sativa supplementation may facilitate additional lipid profile improvements in exercise by hypotriglyceridaemic effect and increasing cholesterol secretion in the bile .
our results suggest that 2 g / day of n. sativa combined with an aerobic exercise program provides significant improvements in ldl - cholesterol and hdl - cholesterol that are known to influence cvd risk in sedentary overweight females .
however , further studies with a larger sample size and diet assessment are still needed .
 background : regular moderate intensity physical activity and lipid lowering effects of nigella sativa ( n. sativa ) supplementation may be appropriate management for sedentary overweight females . therefore , the aim of the present study was to examine the effects of long - term n. sativa supplementation and aerobic training on lipid profile and maximal oxygen consumption ( vo2 max ) in sedentary overweight females.methods:in this randomized , double - blind , controlled trial , which was conducted in kerman city ( iran ) , 20 sedentary overweight females were divided into two groups and assigned to n. sativa supplementation ( n. sativa capsules ) or a placebo for the 8 weeks , both groups participated in an aerobic training program ( 3 times / week ) . each n. sativa capsule contained 500  10 mg n. sativa crushed seeds and subjects had to take 2 g n. sativa per day for 8 weeks . 
 blood lipids and vo2 max were determined at baseline and at the end of 8 weeks.results:n . 
 sativa supplementation lowered total cholesterol ( tc ) ( p < 0.01 ) , triglyceride ( p < 0.001 ) , low - density lipoprotein ( ldl ) ( p < 0.001 ) and body mass index ( p < 0.01 ) and increased high density lipoprotein ( hdl ) and vo2 max ( p < 0.01 ) . aerobic training program lowered tc ( p < 
 0.001 ) and ldl ( p < 0.01 ) and increased vo2 max ( p < 0.01 ) . 
 furthermore , we observed a significant effect of aerobic training program and n. sativa supplementation lowered ldl and hdl ( p < 0.05).conclusions : the present study demonstrates that 8-week aerobic training plus n. sativa supplementation have a synergistic effect in improve profile lipid parameters . 
INTRODUCTION
METHODS
Subjects
Supplementation
Training program
Resting HR
Measurements
Cardio-respiratory assessment
Blood samples
Statistical analysis
RESULTS
DISCUSSION
CONCLUSIONS