Rationale and design of the TRANSFACT project phase I: a study to assess the effect of the two different dietary sources of trans fatty acids on cardiovascular risk factors in humans. Do trans fatty acids from industrially produced sources and from natural sources have the same effect on cardiovascular disease risk factors in healthy subjects? Results of the trans Fatty Acids Collaboration (TRANSFACT) study. Differential impact of milk fatty acid profiles on cardiovascular risk biomarkers in healthy men and women Study of the effect of trans fatty acids from ruminants on blood lipids and other risk factors for cardiovascular disease. Consumption of trans fats and estimated effects on coronary heart disease in Iran A high-trans fatty acid diet and insulin sensitivity in young healthy women. Intake of ruminant trans fatty acids in the Danish population aged 1–80 years Effects of trans- and n-3 unsaturated fatty acids on cardiovascular risk markers in healthy males. An 8 weeks dietary intervention study Serum fatty acid, lipid profile and dietary intake of Hong Kong Chinese omnivores and vegetarians Trans, and n-3 polyunsaturated fatty acids and vascular function-a yin yang situation? Effects of margarine and butter consumption on distribution of trans-18∶1 fatty acid isomers and conjugated linoleic acid in major serum lipid classes in lactating women Dietary fatty acids affect plasma markers of inflammation in healthy men fed controlled diets: a randomized crossover study. Dairy and industrial sources of trans fat do not impair peripheral insulin sensitivity in overweight women. Effect of trans-fatty acid intake on insulin sensitivity and intramuscular lipids--a randomized trial in overweight postmenopausal women.
BACKGROUND Detrimental effects of consumption of industrial trans fatty acids ( TFA ) from partially hydrogenated vegetable oils ( PHVO ) on cardiovascular disease ( CVD ) risk factors are well documented . However , very little information is available on the effect of natural sources of TFA coming from milk fat , dairy products and ruminant meat . In fact , due to the naturally low level of TFA in milk fat , it is almost impossible to conduct a clinical trial with a limited number of subjects ( < 200 ) . METHODOLOGY To compare the effects of industrial and natural dietary sources of TFA , two specific test fats have been design ed and produced . A substantial amount of milk fat ( 130 kg ) enriched in TFA has been produced by modification of the cow 's diet and selection of cows with the highest TFA content . The level obtained was approximately 4- to 7-fold higher than typically present in milk fat ( approximately 20 instead of 3 - 6 g/100 g of total fatty acids ) . The control fat is composed of PHVO balanced in saturated fatty acids ( lauric , myristic and palmitic ) . Both experimental fats contain about 20 - 22 % of monounsaturated TFA and the volunteers ' daily experimental fat intake ( 54 g ) , will represent about 12.0 g/day of TFA or 5.4 % of the daily energy ( based on 2000 kcal/day ) . These two test fats have been incorporated into food items and will be provided to 46 healthy subjects under a r and omised , double blind , controlled , cross-over design . The primary outcome is high-density lipoprotein cholesterol ( HDL-C ) , which is an independent risk factor for CVD . Other parameters such as low-density lipoprotein cholesterol ( LDL-C ) , very low-density lipoprotein cholesterol ( VLDL-C ) , and HDL-C level and subclasses will be also to be evaluated . CONCLUSION We have shown that it is technically feasible to perform a clinical trial on the comparative effects of natural and industrial sources of TFA isomers on CVD risk factors . Results are expected by mid-2006 BACKGROUND The consumption of monounsaturated trans fatty acids ( TFAs ) increases the risk of cardiovascular disease ( CVD ) . Putative differences between the effects of TFAs from industrially produced and natural sources on CVD risk markers were not previously investigated in healthy subjects . OBJECTIVE We aim ed to compare the effects of TFAs from industrially produced and natural sources on HDL and LDL cholesterol , lipoprotein particle size and distribution , apolipoproteins , and other lipids in healthy subjects . DESIGN In a r and omized , double-blind , controlled , crossover design , 46 healthy subjects ( 22 men and 24 women ) consumed food items containing TFAs ( 11 - 12 g/d , representing approximately 5 % of daily energy ) from the 2 sources . RESULTS Forty subjects ( 19 men and 21 women ) completed the study . Compared with TFAs from industrially produced sources , TFAs from natural sources significantly ( P = 0.012 ) increased HDL cholesterol in women but not in men . Significant ( P = 0.001 ) increases in LDL-cholesterol concentrations were observed in women , but not in men , after the consumption of TFAs from natural sources . Apolipoprotein (apo)B and apoA1 concentrations confirmed the changes observed in LDL and HDL cholesterol . Analysis of lipoprotein subclass showed that only large HDL and LDL concentrations were modified by TFAs from natural sources but not by those from industrially produced sources . CONCLUSIONS This study shows that TFAs from industrially produced and from natural sources have different effects on CVD risk factors in women . The HDL cholesterol-lowering property of TFAs seems to be specific to industrial sources . However , it is difficult in the present study to draw a conclusion about the effect of TFAs from either source on absolute CVD risk in these normolipidemic subjects . The mechanism underlying the observed sex- and isomer-specific effects warrants further investigation Background / Objectives : The objective of this study was to evaluate the impact of three specific ruminant ( R ) milk fats result ing from modification of the cow 's diet on cardiovascular risk factors in healthy volunteers . R-milk fats were characterized by increased content in total trans fatty acids ( R-TFAs ) and parallel decrease in saturated fatty acids (SFAs).Subjects/ Methods : A total of 111 healthy , normolipemic men and women have been recruited for a monocentric , r and omized , double-blind and parallel intervention , 4-week controlled study . Volunteers consumed three experimental products ( butter , dessert cream and cookies ) made with one of the three specific milk fats ( 55 g fat per day ) . During the first week ( run-in period ) , the subjects consumed on a daily basis dairy products containing 72 % SFA/2.85 % R-TFA ( called ‘ L0 ’ ) . For the next 3 weeks of the study ( intervention period ) , the first group continued to consume L0 products . The second group received dairy products containing 63.3 % SFA/4.06 % R-TFA ( called ‘ L4 ’ ) , and the third group received dairy products containing 56.6 % SFA/12.16 % R-TFA ( called ‘ L9 ’ ) . Results : Plasma concentrations of high-density lipoprotein (HDL)-cholesterol were not significantly altered by either diet ( P=0.38 ) . Compared to L0 diet , L4 diet contributed to reduce low-density lipoprotein (LDL)-cholesterol ( −0.14±0.38 mmol/l , P=0.04 ) , total cholesterol ( −0.13±0.50 mmol/l , P=0.04 ) , LDL-cholesterol/HDL-cholesterol ( −0.14±0.36 , P=0.03 ) and total cholesterol/HDL-cholesterol ( −0.18±0.44 , P=0.02 ) . Conclusions : Different milk fat profiles can change cardiovascular plasma parameters in human healthy volunteers . A limited increase of the R-TFA/SFA ratio in dairy products is associated with an improvement in some cardiovascular risk factors . However , a further increase in R-TFA/SFA ratio has no additional benefit BACKGROUND The intake of trans fatty acids ( TFA ) from industrially hydrogenated vegetable oils ( iTFA ) is known to have a deleterious effect on cardiovascular health , the effects of TFA from ruminants ( rTFA ) are virtually unknown . OBJECTIVE The purpose of the present study was to compare the effects of rTFA and iTFA on plasma LDL concentrations and other cardiovascular disease risk factors in healthy subjects . DESIGN In a double-blind , r and omized crossover controlled study , 38 healthy men were fed each of 4 experimental isoenergetic diets lasting 4 wk each . The 4 diets were high in rTFA ( 10.2 g/2500 kcal ) , moderate in rTFA ( 4.2 g/2500 kcal ) , high in iTFA ( 10.2 g/2500 kcal ) , and low in TFA from any source ( 2.2 g/2500 kcal ) ( control diet ) . RESULTS Plasma LDL-cholesterol concentrations were significantly higher after the high- rTFA diet than after the control ( P = 0.03 ) or the moderate- rTFA ( P = 0.002 ) diet . Plasma LDL-cholesterol concentrations also were significantly ( P = 0.02 ) higher after the iTFA diet than after the moderate-rTFA diet . Plasma HDL-cholesterol concentrations were significantly ( P = 0.02 ) lower after the high-rTFA diet than after the moderate-rTFA diet . Finally , all risk factors were comparable between the control and the moderate-rTFA diets . CONCLUSIONS These results suggest that , whereas a high dietary intake of TFA from ruminants may adversely affect cholesterol homeostasis , moderate intakes of rTFA that are well above the upper limit of current human consumption have neutral effects on plasma lipids and other cardiovascular disease risk factors Objective : To investigate the consumption of industrial trans-fatty acids ( TFAs )  in Iranian homes and the proportion of coronary heart disease ( CHD ) events in Iran attributable to such intake . Design , setting and participants : The consumption of industrial TFAs was determined using ( 1 ) detailed in-home assessment s of dietary intake among 7158 urban and rural households containing 35 924 individuals and ( 2 ) gas chromatography to determine TFA contents of the most commonly consumed partially hydrogenated oils . The population -attributable risk for CHD owing to TFA consumption was calculated on the basis of ( 1 ) documented effects of TFAs on total : high-density lipoprotein ( HDL ) cholesterol in r and omized controlled dietary trials and ( 2 ) relationships of TFA intake with incidence of CHD in prospect i ve observational studies . Results : Partially hydrogenated oils were used extensively for cooking in Iranian homes with average per-person intake of 14 g/1000 kcal .  TFAs  accounted for 33 % of fatty acids in these products , or 4.2 % of all calories consumed ( 12.3 g/day ) . On the basis of total : HDL cholesterol effects alone , 9 % of CHD events would be prevented by replacement of TFA in Iranian homes with cis-unsaturated fats ( 8 % by replacement with saturated fats ) . On the basis of relationships of TFA intake with CHD incidence in prospect i ve studies , 39 % of CHD events would be prevented by replacement of TFA with cis-unsaturated fats ( 31 % by replacement with saturated fats ) . These population -attributable risks may be overestimates owing to competing risks and because not all the fat used for cooking might actually be consumed . If actual TFA consumption were only half as large , the estimated proportion of CHD events prevented by TFA elimination would be 5 % on the basis of total : HDL cholesterol effects and replacement with cis-unsaturated ( 4 % for replacement with saturated fats ) , and 22 % on the basis of prospect i ve studies and replacement with cis-unsaturated fats ( 17 % for replacement with saturated fats ) . These estimates do not include possible additional benefits derived from replacing TFAs with vegetable oils containing n-3 fatty acids . Conclusions : Intake of TFAs is high in Iranian homes and contributes to a sizeable proportion of CHD events . Replacement of partially hydrogenated oils with unhydrogenated oils would likely produce substantial reductions in CHD incidence . Sponsorship : National Heart , Lung and Blood Institute , National Institutes of Health , USA . National Nutrition & Food Technology Research Institute , Tehran , Iran Epidemiological and experimental studies suggest that a diet rich in saturated fat affects insulin sensitivity . Monoenes and dienes that have an usaturated bond with the trans configuration ( trans fatty acids ) resemble saturated fatty acids with respect to structure , but no published data are available on the effect of trans fatty acids on insulin sensitivity . Therefore , the effects of diets high in trans fatty acids ( TFA diet ) and oleic acid ( monounsaturated fat [ MUFA ] diet ) on glucose and lipid metabolism were studied in 14 healthy women . Subjects consumed both experimental diets for 4 weeks according to a r and omized crossover study design . Both experimental diet periods were preceded by consumption of a st and ardized baseline diet for 2 weeks . The diets provided 36.6 % to 37.9 % of energy ( E% ) as fat . In the TFA diet , there was 5.1 E% trans fatty acids , and in the MUFA diet , 5.2 E% oleic acid , substituted for saturated fatty acids in the baseline diet . A frequently sample d intravenous glucose tolerance test ( FSIGT ) was performed at the end of the experimental diet periods . Glucose effectiveness ( S(G ) ) and the insulin sensitivity index ( S(I ) ) did not differ after the two experimental diet periods . There was also no difference in the acute insulin response between the diets . The total cholesterol to high-density lipoprotein ( HDL ) cholesterol ratio and serum total triglyceride , HDL , and low-density lipoprotein ( LDL ) triglyceride and apolipoprotein B ( apoB ) concentrations were higher ( P < .05 ) after the TFA diet . In conclusion , in young healthy women , the TFA diet result ed in a higher total/HDL cholesterol ratio and an elevation in triglyceride and apo B concentrations but had no effect on glucose and insulin metabolism compared with the MUFA diet Objective : To estimate the intake of ruminant trans fatty acids ( TFA ) in the Danish population aged 1–80 years . Design : Descriptive study .Subjects : A sex- and age-stratified r and om sample drawn from the Danish Civil Registration System . A total of 3098 participants ( 51 % female ) aged 1–80 years were included . The participation was 66%.Dietary information : A 7-day dietary record . Results : The estimated median intake of ruminant TFA was 1.4 g/day with the 80 % central range being from 0.9 to 2.1 among children aged 1–6 years and 1.6 g/day ( 1.0–2.4 ) among children aged 7–14 years . The median TFA intake was 1.8 g/day ( 0.9–2.9 ) among adults aged 15–29 years and among adults aged 30–80 years . The intake expressed as percentage of energy intake was 0.8 , 0.6 , 0.7 , and 0.7 , respectively . Dairy products were the main source of ruminant TFA . Conclusions : The median intake of ruminant TFA in the Danish population aged 1–80 years is estimated to be 1.7 g/day ( 0.9–2.7 ) , corresponding to 0.7 % of energy intake ( 0.5–1.0 ) , with dairy products being the main source of ruminant TFA.Sponsorship : The Danish Heart Foundation ( Grants 02 - 2 - 9 - 8 - 22010 and 03 - 2 - 9 - 4 - 22087 ) and the Female Research ers in Joint Action ( FREJA ) programme from the Danish Medical Research Council Background : Studies of long-term intake of industrially produced trans fatty acids ( TFA ) and n-3 polyunsaturated fatty acids ( PUFA ) suggest opposite effects on cardiovascular disease risk . Common mechanisms of action are probable . Objective : To examine the effects on cardiovascular risk markers of dietary enrichment with TFA or n-3 PUFA . Design : R and omized , double-blind , parallel intervention trial . Setting : Department of Human Nutrition , The Royal Veterinary and Agricultural University . Subjects : In all , 87 healthy males included , 79 completed . Intervention : Subjects were r and omly assigned to 8 weeks of a daily intake of 33 g of experimental fats from either partially hydrogenated soy oil containing 20 g of TFA , 12 g of fish oil with approximately 4 g of n-3 PUFA and 21 g of control fat , or 33 g of control fat . The experimental fats were incorporated into bakery products .  Plasma lipids , blood pressure , heart rate variability ( HRV ) , arterial dilatory capacity , compliance , and distensibility were recorded before and after intervention and at follow-up 12 weeks after the intervention . Results : High-density lipoprotein cholesterol ( HDL-C ) decreased in the TFA group and triglycerides and mean arterial blood pressure decreased in the n-3 PUFA group compared to the control group . HRV , arterial dilatory capacity , compliance , and distensibility were unchanged . Conclusion : The results indicate that the association between coronary heart disease risk and intake of TFA and n-3 PUFA relates only modestly to changes in traditional risk markers . Sponsorship : Danish Medical Research Council ( Grant no. 22 - 01 - 0390 ) , Center of Advanced Food Research ( Copenhagen , Denmark ) ( Grant no. KVL-R-2001 - 107 ) , the Danish Heart Association ( Grant no. 99 - 2 - 3 - 45 - 22748 ) , Novozymes ( Bagsvaerd , Denmark ) , Aarhus Olie ( Aarhus , Denmark ) , and from private sources . The experimental fats were provided by Pronova Biocare ( Aalesund , Norway ) and Aarhus Olie ( Aarhus , Denmark ) Objective : To examine the serum fatty acid and lipid profiles and dietary intake of  Hong Kong Chinese omnivores and vegetarians  with respect to cardiovascular health . Design : R and om population survey stratified by age and sex . Subjects : One-hundred and ninety-four omnivore subjects ( 81 men , 113 women ) age 25–70 y , and 60 ovo-lacto-vegetarian adults ( 15 men , 45 women ) age 30–55 y. Measurements : Nutrient quantitation was by a food frequency method . Serum fatty acids were analysed by  gas chromatography , and serum lipid  by st and ard laboratory methods . Results : Compared with omnivores , vegetarians had higher serum concentrations of polyunsaturated ( PUFA ) and monosaturated fatty acids ( MUFA ) , and lower saturated fatty acids ( SFA ) , long chain omega-3 and trans fatty acids ( TFA ) . They also had lower serum cholesterol and higher apoA-I concentrations , but the LDL/HDL ratio was not different . The ratio of polyunsaturated to saturated fatty acids intake was higher in vegetarians . Compared with results from population s with higher incidences of coronary heart disease , while lower myristic and palmitic acid concentrations and higher eicosapentaneoic ( EPA ) and docosahexanoic acid ( DHA ) may partly account for the difference in incidence , linoleic acid concentration was higher . Although the Chinese vegetarian diet may be beneficial for heart health in that antioxidant and fibre intakes are higher and saturated fat lower , the low EPA and DHA due to omission from dietary source and suppressed formation by high linoleic acid level , and the presence of TFA in the diet , may exert an opposite effect . Conclusion : There are some favourable features in the serum fatty acid profile in the Hong Kong Chinese population with respect to cardiovascular health , but the consumption of TFA is of concern . The Chinese vegetarian diet also contains some adverse features . Sponsorship : This study is partly sponsored by the Hong Kong Health Services Research Grant . European Journal Of Clinical Nutrition ( 2000 ) 24 , Trans fatty acids ( TFA ) and n-3 polyunsaturated fatty acids ( n-3 PUFA ) have opposite effects on several biological functions . We report a study on the effects on risk markers for cardiovascular disease .  Eighty-seven healthy males were r and omly assigned to 8 weeks of daily intake of either 20 g of industrially produced TFA ( IP-TFA ) , 4 g n-3 PUFA , or control fat , incorporated in bakery products as part of the daily food . High-density lipoprotein cholesterol decreased in the TFA-group , triglycerides and mean arterial blood pressure decreased in the n-3 group . Heart rate variability ( HRV ) , arterial dilatory capacity , flow mediated vasodilation , compliance , and distensibility were unchanged . Post hoc , we did a subgroup analysis of the results from the subjects with normal initial HRV . In these , 24-h heart rate ( HR ) was significantly increased by approximately three beats/min in the TFA group , with a decrease of the same magnitude in the n-3 group . A high HR is associated to an increased mortality and vice versa . Our results thus support the notion that IP-TFA and n-3 PUFA affect risk for cardiovascular mortality via mechanisms not only related to changes in plasma concentrations of lipids and lipoproteins Trans FA ( TFA ) have at least one trans double bond and comprise several isomers and types , including many of the CLA ( e.g. , c9 , t11–18∶2 CLA ) . Some TFA may have adverse effects ( e.g. , cardiovascular disease ) , whereas some are though to have beneficial effects ( e.g. , anticarcinogenicity ) . The presence of TFA in human tissues and fluids is related to dietary intake , although this relationship is not completely understood — especially in regard to serum lipid fractions . This study was conducted as part of an investigation design ed to test the influence of butter ( B ) , “ low TFA ” margarine ( LT ) , and regular margarine ( RM ) on milk fat content . Here we tested the secondary hypothesis that consumption of B , LT , and RM by lactating women would result in differential distribution of TFA and CLA in major serum lipid classes . Breastfeeding women ( n=11 ) participated in this r and omized Latinsquare study consisting of five periods : intervention I ( 5 d ) , washout I ( 7 d ) , intervention II ( 5 d ) , washout II ( 7 d ) , and intervention III ( 5 d ) . Extracted serum lipid was separated into cholesterol ester ( CE ) , TAG , and phospholipid ( PL ) fractions and analyzed for total and isomeric TFA and CLA concentrations . Data indicate that TAG consistently contained the highest concentration of total t-18∶1 . No interaction between treatment and fraction was found for any of the t-18∶1 isomers identified . Absolute concentration of each t-18∶1 isomer was greatest during the RM period , regardless of fraction . On a relative basis , concentrations of t10–18∶1 and t12–18∶1 were most responsive to treatment in the CE fraction . The concentration of c9 , t11–18∶2 CLA was highest in the TAG fraction and lowest in the PL fraction , regardless of treatment . In summary , these results indicate ( i ) that there is a differential distribution of some isomeric TFA and CLA among human serum lipid fractions and ( ii ) that dietary TFA intake influences absolute and relative concentrations of some of the isomers in selected fractions BACKGROUND The effect of individual dietary fatty acids on emerging risk factors for cardiovascular disease that are associated with sub clinical inflammation is unknown . OBJECTIVE The goal was to evaluate the role of dietary fat and specific fatty acids , especially trans fatty acids , in altering concentrations of markers of inflammation in humans fed controlled diets . DESIGN In a r and omized crossover design , 50 men consumed controlled diets for 5 wk that provided 15 % of energy from protein , 39 % of energy from fat , and 46 % of energy from carbohydrate . Eight percent of fat or fatty acids was replaced across diets with the following : cholesterol , oleic acid , trans fatty acids ( TFAs ) , stearic acid ( STE ) , TFA+STE ( 4 % of energy each ) , and 12:0 - 16:0 saturated fatty acids ( LMP ) . RESULTS Fibrinogen concentrations were higher after consumption of the diet enriched in stearic acid than after consumption of the carbohydrate diet . C-reactive protein concentrations were higher after consumption of the TFA diet than after consumption of the carbohydrate diet , but were not significantly different after consumption of the TFA and TFA+STE diets than after consumption of the LMP diet .  Interleukin 6 concentrations were lower after consumption of the oleic acid diet than after consumption of the LMP , TFA , and STE diets .  E-selectin concentrations were higher after consumption of the TFA diet than after consumption of the carbohydrate diet . Consumption of the TFA but not the TFA+STE diet result ed in higher E-selectin concentrations than did the LMP diet . CONCLUSIONS These data provide evidence that dietary fatty acids can modulate markers of inflammation . Although stearic acid minimally affects LDL cholesterol , it does appear to increase fibrinogen concentrations BACKGROUND The 2 major dietary sources of trans fatty acids ( TFAs ) are partially hydrogenated oils and ruminant-derived products . Epidemiologic data suggest that chronic consumption of industrial sources of TFAs could be damaging to insulin sensitivity , but intervention studies on this issue have remained inconclusive . OBJECTIVE The trial was design ed to compare the effects of dairy compared with industrial sources of TFAs on insulin sensitivity in overweight women . DESIGN Sixty-three healthy women with abdominal obesity [ waist circumference > 88 cm and a body mass index ( in kg/m(2 ) ) > 28 ] were recruited . After a run-in period , the volunteers were r and omly assigned to consume 1 of 3 four-week diets : 60 g low-TFA lipids/d ( 0.54 g/d ; n = 21 ) , ruminant TFA-rich lipids ( 4.86 g/d ; n = 21 ) , or industrial TFA-rich lipids ( 5.58 g/d ; n = 21 ) . Changes in peripheral insulin sensitivity were assessed by using hyperinsulinemic-euglycemic clamps . RESULTS After the intervention period , fasting glycemia and insulinemia and insulin sensitivity were not significantly modified in either group ( P > 0.05 ) . CONCLUSIONS These data indicate that consumption of dairy- and industrial- source TFAs for 4 wk at nutritional levels do not impair peripheral insulin sensitivity in insulin-resistant women . Our study may not preassess the effects of TFAs in normal insulin-sensitive individuals . This trial was registered at Clinical Trials.gov as NCT00617435 Intake of industrially produced trans-fatty acids ( TFA ) has been linked to increased risk of type 2 diabetes mellitus in observational studies . We investigated the causality of this association by examining if a high intake of TFA impairs measures of glucose homeostasis and induces intramuscular lipid deposition in abdominally obese women . In a double-blind , parallel dietary intervention study , 52 healthy but overweight postmenopausal women were r and omized to receive either partially hydrogenated soybean oil ( 15 g/d TFA ) or a control oil ( mainly oleic and palmitic acid ) for 16 weeks . Three markers of glucose homeostasis and 4 markers of lipolysis were derived from glucose , insulin , C-peptide , nonesterified fatty acid , and glycerol concentrations during a 3-hour frequent sampling oral glucose tolerance test . Intramuscular lipids were assessed by magnetic resonance spectroscopy . Forty-nine women completed the  study .  Insulin sensitivity ( assessed by ISI(composite ) ) , β-cell function ( the disposition index ) , and the metabolic clearance rate of insulin were not significantly affected by the dietary intervention . Neither was the ability of insulin to suppress plasma nonesterified fatty acid and glycerol during oral glucose ingestion nor the intramuscular lipid deposition . In conclusion , high TFA intake did not affect glucose metabolism over 16 weeks in postmenopausal overweight women . A study population with a stronger predisposition to insulin resistance and /or a longer duration of exposure may be required for insulin sensitivity to be affected by intake of industrial TFA
We found no relationship between  R-TFA intake levels of up to 4.19 % of daily energy intake ( EI ) and changes in cardiovascular risk factors such as TC : HDL-C and LDL-cholesterol (LDL-C):HDL-C ratios .
In addition , a multivariate regression analysis that included other dietary variables , as well as subject baseline characteristics , confirmed that doses of R-TFA did not significantly influence the changes in the lipid ratio .
Our findings showed that doses of R-TFA did not influence the changes in the ratios of plasma TC : HDL-C and LDL-C : HDL-C. These data suggest that TFA from natural sources , at least at the current levels of intake and up to 4.19 % EI , have no adverse effects on these key CVD risk markers in healthy people
The effects of ruminant ( R ) trans-fatty acids ( TFA ) on the risk of CVD are still under debate .
It could be argued that the lack of the effect of R-TFA may be the result of the small amount of their intake .
Taking into consideration the growing available data from intervention studies , we carried out a systematic review and meta-regression to assess the impact of R-TFA intake levels on changes in the total cholesterol : HDL-cholesterol ( TC : HDL-C ) ratio .