Comparison of effects of soft margarine, blended, ghee, and unhydrogenated oil with hydrogenated oil on serum lipids: A randomized clinical trail

Headnote

Abstract

BACKGROUND: Trans fatty acids (TFAs) are known as the most harmful type of dietary fats. Therefore, this study was done to compare the effects of some different oils including unhydrogenated, blended, ghee, and soft magazine with hydrogenated oil on serum lipid profile of healthy adults.

METHODS: This study was a randomized clinical trial conducted on 206 healthy participants of 20 to 60 years of age. Subjects were randomly divided into 5 groups and each of them was treated with a diet containing unhydrogenated oil, ghee, blended oil, soft margarine, or hydrogenated oil for 40 days. Fasting serum lipids were measured before and after the study. The study was registered in the Iranian Randomized Clinical Trail (IRCT) Center (ID: IRCT138905124497N1).

RESULTS: Compared to hydrogenated oil, total cholesterol (TC) and triglyceride (TG) had a significant reduction in all groups, LDL-C declined in unhydrogenated oil and soft margarine groups, and apolipoprotein (Apo) B only in unhydrogenated oil group (all P < 0.05). However, there was a significant enhancement in ApoA of ghee oil (P < 0.001).

CONCLUSION: Consuming unhydrogenated oil, ghee, soft margarine, and blended oil had some beneficial effects on serum lipids.

Keywords: Clinical Trial, Dietary Fat, Commercial Oil, Lipid

Date of submission: 06 11 2013, Date of acceptance: 21 11 2013

Introduction

Diets affect the occurrence, progress, and prevention of non-communicable diseases, including cardiovascular diseases (CVD), cancers, diabetes, and hypertension.1,2 In the last few decades, the reduction of fat intake has been the major recommendation for decreasing CVD risk.3 There is a great amount of evidence confirming that the type of dietary fat is more determinant in CVD development dian its amount.4 Saturated fatty acids (SFAs) cause an increase in serum total cholesterol (TQ and Low-density lipoprotein cholesterol (LDL-Q levels.5

In the past, the effects of fats on increasing plasma TC levels were estimated by their saturation degree.4'6 However, the evidence obtained during diis past decade indicates that the trans fatty acid (TFA) existing in hydrogenated oils not only increases LDL-C, TC, and apolipoprotein (Apo) B levels, but also decreases High-density lipoprotein cholesterol (HDL-Q and ApoA levels.7 Therefore, TFAs are more harmful dian SFAs.8 Scientists at the Public Healdi School of Harvard University estimated diat in the US in 2001, about 30,000 people died of CVD events caused by TFAs.9 It was reported diat the mean TFA content of hydrogenated oils produced in Iran was 34.6 ± 6.6% (Range: 22.5-46.2%), which is much higher dian the World Healdi Organization recommendation.10'11

Thus, now TFA substitutions are needed to preserve the originality of and offer an appealing many packed food textures. Blending is one alternative method to partial hydrogenation for modifying the physical and functional characteristics of edible fats and oils.12 This process can provide nutritional needs with improved oxidative stability for domestic cooking and deep-frying, while, unlike partial hydrogenation, it will not produce TFAs with low content of saturated fatty acids.13

Furthermore, ghee is produced from milk by traditional methods and usually called "yellow oil" or "Kermanshahi oil" in Iran. Although it is produced from animal fat and contains high amounts of SFAs and cholesterol, a few studies reported it was useful for decreasing LDL-C and increasing HDL-C.1446 In an animal study which was conducted in Iran, it has been observed that ghee oil consumption significantly increased HDL-C level, but did not have any significant effect on other serum lipids.17 However, there is no precise scientific information on this issue in human subjects. Thus, there are some controversies about how ghee consumption and serum lipid profile are linked.18'19 As TFAs are considered as the most harmful dietary fats, this study was conducted aiming to compare the effects of soft margarine, unhydrogsnated, blended, and ghee oils with hydrogenated oil as a main source of TFA on serum lipids of Iranian adults.

Materials and Methods

Study design and sampling

This randomized clinical trial has been conducted on 249 healdiy subjects aged 20-60 years in 2009. They were chosen from the Emam-Zaman Beneficiary Organization and consumed only hydrogenated oil in their diet. Normotensive, non-diabetic participants without cardiovascular diseases were invited to the study center. According to the sample size which was calculated 40 in each group and considering the dropout rate, at the beginning we invited 265 volunteers. After overnight fasting, venous blood samples were drawn at 7:00 to 10:00 am. Subjects with TC > 240 mg/dl, TG > 400 mg/dl, LDL-C > 160 mg/dl, or HDL-C < 40 mg/dl, who also had body mass index (BMI) >35 were excluded. However, 16 subjects were excluded because of not meeting the inclusion criteria. Then, the remaining participants were divided into five groups of soft margarine, hydrogenated, unhydrogenated, ghee, and blended oils by simple randomization. Moreover, 43 participants were excluded from the study due to traveling, sickness, unwillingness to participate in the next sampling, or not complying with dietary recommendations. Therefore, 206 healdiy subjects were included in the study. The dow chart of the study is presented in figure 1.

After signing informed written consents, the subjects were referred to the trained nutritionist to obtain socio-demographic characteristics, past medical history, and food habits by 24-hour recall questionnaire. Anthropometrical measurements were taken widi shoes removed and the participants wearing light clothing. BMI was calculated by dividing the weight in kilograms to the square of height in meters. Eligible subjects who consumed hydrogenated oil, based on obtained food habits, were randomly divided into 5 groups. They took a diet consultation with the same amount of oil containing soft margarine, cooking and frying unhydrogenated oil, ghee, and blended or hydrogenated oils for 40 days.20 In order to keep the type of oils similar among each group, oils were given to the subjects (every 10 days) by the project conductor. Ghee was provided from Baklitiari nomads. Soft margarine and blended oil were provided from companies which were their only producers in Iran at that time. The commonest brands of unhydrogenated and hydrogenated oils were bought from the supermarket. Dietary recommendations were given to the subjects by the same dietitian, so that the only difference among the 5 groups was the kind of dietary oil. Oils were provided for all family members, about 20-30 gr per person, even if one of them was chosen in the study. Subjects were followed by phone every two weeks or during their referral to the study center for taking their oil.

Biochemical measurements

Blood samples were taken after the subject had been fasting for 14 hours. Serum lipid levels, including TC, TG, and HDT-C levels, were measured. TC and TG were determined by standard enzymatic mediod using special kits in Hitachi 902 autoanalyzer and using special kits (Diasys Diagnosis Inc., Holzheim, Germany) performed by Pars-Azmun (Tehran, Iran). HDT-C was measured enzymatically after precipitating the other lipoproteins with dextran sulphate magnesium chloride.21 TDT-C was calculated by using the Friedewald formula. ApoAl and ApoBlOO were assayed by immunoturbidimetric methods (Diasys Diagnosis Inc., Holzheim, Germany) performed by Pars-Azmun. Direct measurement of TDT-C was performed with a turbidimetric mediod for those widi TG > 400 mg/dl.22 Apolipoproteins A and B levels were determined by Merk kits. Blood samples were collected before and after the study, at Isfahan Cardiovascular Research Center laboratory, a WHO-collaborating center which meets the criteria of the National Reference Taboratory. The lipid profile changes were the primary endpoint of the study.

Ethics

This study was approved by the Research Council of Isfahan Cardiovascular Research Center and registered in the Iranian Randomized Clinical Trail Center by ID number of IRCT138905124497N1.

Statistical analysis

In the beginning of the study, the mean of age, BMI and serum lipids levels among the three groups were compared by one-way analysis of variance (ANOVA). Comparison of the frequency distribution was conducted using chi-square test based on gender and education level. Mean of serum lipid levels before and after the study were compared by paired t-test in each group. The comparison of changes in serum lipids and ApoA and B levels between 5 groups was done with two-way ANOVA test by adjusting for age, gender, and education level. The post-study mean serum lipid was compared with analysis of co-variances test by adjusting with age, gender, education, and before study serum lipids. P value less than 0.05 was considered significant.

Results

The study was performed on 206 subjects including 41, 43, 39, 42, and 41 subjects in hydrogenated, unhydrogenated, ghee, blended oil, and soft margarine groups, respectively. However, 43 subjects were excluded from the study due to traveling, sickness, unwillingness to participate in the next sampling, or not complying with dietary recommendations. Therefore, 206 healthy subjects were included in the study. Thus, the participation rate was about 82.7%. They included 88 men and 118 women with the mean age of 34.8 ± 11.4 years. As shown in table 1, there is no significant difference in mean of age, serum lipids, including TC, TG, TDT-C, HDT-C, ApoA, and ApoB levels, and also gender, educational, and marital status distribution between 5 groups in the beginning of the study. Table 2 demonstrates the comparison between mean of serum lipids and ApoA and ApoB levels before and after the study in each group.

In the hydrogenated oil group, TC increased and ApoA decreased significantiy (P = 0.039 and P = 0.031, respectively). Unhydrogenated oil group had a significant reduction in TC, TG (P < 0.001), and ApoB (P = 0.003) and in the ghee group, ApoA significantiy increased (P < 0001). Blended and soft margarine groups had a significant decline in TG (P = 0.010 and P < 0.001, respectively).

Except for TDT-C, and ApoA and ApoB levels, the comparison of the mean and percentage of serum lipids, changes with age and gender adjustment, revealed a significant difference among the three studied groups (Figures 2-3). TC, TG, and ApoB levels had a significant reduction in die unhydrogenated oil group when compared with the hydrogenated oil group (P < 0.001). In the ghee oil group, TG was significantiy decreased, while ApoA had a significant increase (P < 0.001). Comparing with the ghee group, the unhydrogenated oil group had a significant reduction in HDL-C (P < 0.05).

However TC and TG declined in blended oil and soft margarine groups significantly (P < 0.001 and P < 0.05, respectively).

The adjusted mean level of serum lipids after the intervention and the mean changes of serum lipids in each intervention group versus hydrogenated oil group are presented in table 3. As it shows the soft margarine group had the most significant reduction in TC and TG (ß ± SE: -8.4 ± 2.2; ß ± SE: -11.2 ± 2.5, respectively) (P < 0.001). LDL-C had a significant reduction in unhydrogenated oil and soft margarine (ß ± SE: -3.8 ± 2, P < 0.001; ß ± SE: -2.5 ± 2.3, P < 0.05, respectively). ApoA had a significant increase only in the ghee group and ApoB declined significantly only in the unhydrogenated oil group (ß ± SE: 3.5 ± 2.9, P < 0.001; ß ± SE: -8.2 ± 2.3, P < 0.001, respectively).

Discussion

This study indicated that unhydrogenated oil can generally reduce serum lipid levels when compared with hydrogenated oil. However, changes in serum lipids, except for TG reduction and ApoA enhancement, were not significant when the ghee oil group was compared with the hydrogenated oil group (serum HDL-C levels had an insignificant increase). Moreover, blended oil and soft margarine as 2 new products of oil in Iran could reduce TC and TG.

Several studies have indicated that hydrogenated fat and/or TFAs could increase TC, TG, and TDT-C, decrease HDT-C, and enhance the TDT-C:HDT-C ratio.16'23'24 However, the responsible mechanisms for diese changes are complicated. It has been proposed that the serum lipid-raising effect of hydrogenated fat is due to either delayed TDT-C clearance or enhanced TDT-C production.25 Matthan et al. have reported that hydrogenated oil decreased HDT-C, and raised TDT-C by increasing ApoA-I and decreased TDT ApoB-100 catabolism. Thus, it was indicated that damaging the cholesterol catabolism is responsible to a greater degree than decreasing its synthesis for the higher serum TC seen by intake of high hydrogenated and saturated fat diets.26 However, Kelley et al. showed that a diet containing cotton seed oil could not modify serum lipids including TC, TG, TDT-C, HDT-C, ApoA and ApoB in comparison with a normal diet.27

The study by Al-Amoudi and Abu Araki indicated that a blend of the various specific vegetable oils improved serum lipid profiles due to a synergistic effect of various blending oils.28 Enhancement oxidative stability and the synergistic effect of different vegetable oils might cause the serum lipid improvement in the blended oil group of the current study.

According to the study by Asgary et ab, the average TFA contents in hydrogenated oils, and unhydrogenated cooking and frying oils produced in Iran were 35.2 ± 4.8%, 0.9 ± 0.3%, and 772.6 ± 0.8%, respectively.29 Therefore, serum lipid modification by unhydrogenated oils seems reasonable in this study.

Ghee oil is an important dietary fat used in India and other South Asian countries, which contains high amounts of SFAs (about 59% of its whole fatty acids).14'30 SFAs, except for stearic acid, increase serum TC.8 Therefore, ghee oil, that is high in cholesterol and SFAs, is considered as harmful. On the other hand, ghee is a good source of oleic acid which is capable of protecting LDL-C particles from oxidation and prevents atherosclerosis.14 Furthermore, according to Asgary et ab, the average TFA content in ghee produced by Baklitiari nomads (the kind of ghee that was used in this study) is 8.3 ± 0.7 which is 1.4 times less than the amount of existing TFA in hydrogenated oils.29

Kumar's study indicated that consumption of ghee in the diet, even with high intakes, does not increase serum lipids.15 This animal study did not show any linking between ghee consumption and hypercholesterolemia and hyperlipidemia, which are considered to be risk factors for heart diseases. Interestingly, consuming increased levels of ghee reduced serum TC and TG levels.15 Another idea was that there is a link between the consumption of anhydrous milk fat, such as ghee, and increased risk of heart diseases.31 However, use of excess intake of ghee as a means for lowering serum TC is not recommended, but the study indicates that there is no reason for apprehension for consuming ghee in the diet, which is an age-old practice that is relished in Indian cuisine.15 Mozaffarian et ab stated that substituting 8% of energy intake from TFA with SFA cause a decrease in CYD by modifying TC:HDL-C ratio.32 Therefore, it confirms the suitable effect of ghee on serum lipid profile.

Limitation

As the subjects used the oils for cooking at home, blinding was not applicable. Thus, it was the limitation of this study.

Conclusion

Blended and soft margarine as two new kinds of oils in Iran had some beneficial effects on serum lipids. Furthermore, ghee was useful in modifying serum, including TG and HDL-C, and unhydrogenated oil and frying oil consumption resulted in a general reduction in serum lipids. Therefore, it can be said diat ghee might be effective on serum lipid modification in metabolic syndrome, but it should not be forgotten that ghee, which is traditionally made from milk fat, has high amounts of SFAs, and also its production method should be carefully supervised.

Acknowledgments

We thank the director and personnel of Imam-e-Zaman organization for their kind support in sampling, and also the participants for their patience during follow-up.

Conflict of Interests

Authors have no conflict of interests.

How to cite this article: Mohammadifard N, Hosseini M, Sajjadi F, Maghroun M, Boshtam M, Nouri F. Comparison of effects of soft margarine, blended, ghee, and unhydrogenated oil with hydrogenated oil on serum lipids: A randomized clinical trail. ARYA Atheroscler 2013; 9(6): ??-??.

References

References

1. Willett WC, Koplan JP, Nugent R, Dusenbury C, Puska P, Gaziano TA. Prevention of Chronic Disease by Means of Diet and Lifestyle Changes. In: Jamison DT, Breman JG, Measham AR, Alleyne G, Claeson M, Evans DB, et al.. Editors. Disease Control Priorities in Developing Countries. 2nd ed. Washington, DC: World Bank Publications; 2006. p. 833-4.

2. Flock MR, Kris-Etherton PM. Dietary Guidelines for Americans 2010: implications for cardiovascular disease. Curr Atheroscler Rep 2011; 13(6): 499-507.

3. Kromhout D. Diet and cardiovascular diseases. J Nutr Health Aging 2001; 5(3): 144-9.

4. Ghafoorunissa. Impact of quality of dietary fat on serum cholesterol and coronary heart disease: focus on plant sterols and other non-glyceride components. Natl Med J India 2009; 22(3): 126-32.

5. Guo Z, Mima K, Turin TC, Hozawa A, Okuda N, Okamura T, et al. Relationship of the polyunsaturated to saturated fatty acid ratio to cardiovascular risk factors and metabolic syndrome in Japanese: the INTERLIPID study. J Atheroscler Thromb 2010; 17(8): 777-84.

6. Volk MG. An examination of the evidence supporting the association of dietary cholesterol and saturated fats with serum cholesterol and development of coronary heart disease. Ahem Med Rev 2007; 12(3): 228-45.

7. Lichtenstein AH, Erkkila AT, Lamarche B, Schwab US, Jalbert SM, Ausman LM. Influence of hydrogenated fat and butter on CVD risk factors: remnant-like particles, glucose and insulin, blood pressure and C-reactive protein. Atherosclerosis 2003; 171(1): 97-107.

8. Sartika RA. Dietary trans fatty acids intake and its relation to dyslipidemia in a sample of adults in Depok city. West Java, Indonesia. Malays J Nutr 2011; 17(3): 337-46.

9. Dorfman SE, Laurent D, Gounarides JS, Li X, Mullarkey TL, Rocheford EC, et al. Metabolic implications of dietary trans-fatty acids. Obesity (Silver Spring) 2009; 17(6): 1200-7.

10. Bahraini Gh, Mirzaeei Sh. The Evaluation of Fatty Acids Profile in Available Hydrogenated Oils and Margarines in Iran. Iranian Heart Journal 2003; 4(3): 59-67.

11. Nishida C, Uauy R. WHO Scientific Update on health consequences of trans fatty acids: introduction. Eur J Clin Nutr 2009; 63(Suppl 2): S1-S4.

12. Klonoff DC. Replacements for trans fats-will there be an oil shortage? J Diabetes Sci Technol 2007; 1(3): 415-22.

13. Tarrago-Trani MT, Phillips KM, Lanar LE, Holden JM. New and existing oils and fats used in products with reduced trans-fatty acid content. J Am Diet Assoc 2006; 106(6): 867-80.

14. Gupta R, Prakash H. Association of dietary ghee intake with coronary heart disease and risk factor prevalence in mral males. J Indian Med Assoc 1997; 95(3): 67-9, 83.

15. Kumar MV, Sambaiah K, Lokesh BR. Effect of dietary ghee-the anhydrous milk fat, on blood and liver lipids in rats. J Nutr Biochem 1999; 10(2): 96-104.

16. Ghafoorunissa G. Role of trans fatty acids in health and challenges to their reduction in Indian foods. Asia Pac J Clin Nutr 2008; 17(Suppl 1): 212-5.

17. Alunadi Asi N, Alipour MR, Andalib S, Ebraheimi H. Effect of Ghee Oil on Blood Fat Profile and Passive Avoidance Learning in Male Rats. Med J Tabriz Univ Med Sei 2008; 35(3): 7-10. [In Persian],

18. Soelaiman IN, Merican Z, Mohamed J, Abdul Kadir KB. Serum lipids, lipid peroxidation and glutathione peroxidase activity in rats on long-term feeding with coconut oil or butterfat (ghee). Asia Pacific J Clin Nutr 1996; 5(4): 244-8.

19. Singh RB, Niaz MA, Ghosh S, Beegom R, Rastogi V, Shanna JP, et al. Association of trans fatty acids (vegetable ghee) and clarified butter (Indian ghee) intake with higher risk of coronary artery disease in mral and urban populations with low fat consumption. Int J Cardiol 1996; 56(3): 289-98.

20. Lichtenstein AH, Ausman LM, Jalbert SM, Schaefer EJ. Effects of different forms of dietary hydrogenated fats on serum lipoprotein cholesterol levels. N Engl J Med 1999; 340(25): 1933-40.

21. Wamick GR, Benderson J, Albers JJ. Dextran sulfate-Mg2+ precipitation procedure for quantitation of high-density-lipoprotein cholesterol. Clin Chem 1982; 28(6): 1379-88.

22. Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem 1972; 18(6): 499-502.

23. Hunter JE. Dietary trans fatty acids: review of recent human studies and food industry responses. Lipids 2006; 41(11): 967-92.

24. Brouwer IA, Wanders AL Katan MB. Effect of animal and industrial trans fatty acids on HDL and LDL cholesterol levels in humans-a quantitative review. PLoS One 2010; 5(3): e9434.

25. Mauger JF, Lichtenstein AH, Ausman LM, Jalbert SM, Jauhiainen M, Ehnholm C, et al. Effect of different fonns of dietary hydrogenated fats on LDL particle size. Am J Clin Nutr 2003; 78(3): 370-5.

26. Matthan NR, Welty FK, Barrett PH, Harausz C, Dolnikowski GG, Parks JS, et al. Dietary hydrogenated fat increases high-density lipoprotein apoA-I catabolism and decreases low-density lipoprotein apoB-100 catabolism in hypercholesterolemic women. Arterioscler Thromb Vase Biol 2004; 24(6): 1092-7.

27. Kelley DS, Nelson GJ, Love JE, Branch LB, Taylor PC, Schmidt PC, et al. Dietary alpha-linolenic acid alters tissue fatty acid composition, but not blood lipids, lipoproteins or coagulation status in humans. Lipids 1993; 28(6): 533-7.

28. Al-Amoudi NS, Abu Araki HA. Evaluation of vegetable and fish oils diets for the amelioration of diabetes side effects. J Diabetes Metab Disord 2013; 12(1): 13.

29. Asgary S, Nazari B, Sarrafzadegan N, Saben S, Azadbakht L, Esmaillzadeh A. Fatty acid composition of commercially available Iranian edible oils. J Res Med Sei 2009; 14(4): 211-5.

30. Achaya KT. Fat status of Indians-a review. J Sei IndRes 1987:46(3): 112-26.

31. Noseda G. Fats and oils (including omega3, omega6). Ther Umsch 2005; 62(9): 625-8. [InGennan],

32. Mozaffarian D, Abdollahi M, Campos H, Houshianad A, Willett WC. Consumption of trans fats and estimated effects on coronary heart disease in Iran. EurJ Clin Nutr 2007; 61(8): Í004-10.