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ARS Home » Northeast Area » Beltsville, Maryland (BHNRC) » Beltsville Human Nutrition Research Center » Food Components and Health Laboratory » Research » Publications at this Location » Publication #314506
Title: Vaccenic acid and trans fatty acid isomers from partially hydrogenated oil both adversely affect LDL cholesterol: a double-blind, randomized controlled trial

Author
item Gebauer, Sarah
item DESTAILLATS, FREDERIC - Nestle
item DIONISI, FABIOLA - Nestle
item KRAUSS, RONALD - Children'S Hospital Oakland Research Institute
item Baer, David

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2015
Publication Date: 12/1/2015
Citation: Gebauer, S.K., Destaillats, F., Dionisi, F., Krauss, R.M., Baer, D.J. 2015. Vaccenic acid and trans fatty acid isomers from partially hydrogenated oil both adversely affect LDL cholesterol: a double-blind, randomized controlled trial. American Journal of Clinical Nutrition. 102:1339-1346.

Interpretive Summary: In addition to food products produced using partially hydrogenated vegetable oils, dietary trans fatty acids are found naturally in products from ruminant animals (for example, milk, beef, lamb). Evidence of the adverse effects of industrially-produced trans fatty acids (iTFA) on risk of cardiovascular disease (CVD) is consistent and well-documented in the scientific literature; however, the cardiovascular effects of naturally-occurring TFA synthesized in ruminant animals (rTFA), such as vaccenic acid (VA) and cis-9, trans-11 conjugated linolenic acid (c9,t11-CLA), are less clear. Data from studies of animal models of cardiovascular disease suggest that VA and c9,t11-CLA may reduce cholesterol, data from epidemiological studies that have compared rTFA and iTFA are inconsistent, and human intervention studies have been limited, under-powered, and not well-controlled. We conducted a double-blind, randomized crossover feeding trial in healthy adults (n=106) to determine whether VA, c9,t11-CLA, and iTFA isomers differentially affect lipoprotein risk factors compared to a control diet. Participants were fed four controlled diets designed to have stearic acid (considered to have a neutral effect on LDL-cholesterol) replaced with the following TFA isomers: 0.1% energy from mixed isomers of TFA (control), 3.3% energy from isolated VA (VA), 3.3% of energy from mixed isomers of TFA from partially hydrogenated vegetable oil (iTFA), and 0.9% energy from c9,t11-CLA (CLA). Since the energy from TFA replaced the energy from stearic acid, the total dietary fat (34% of energy) as well as all other macronutrients were similar across treatment diets. VA and iTFA increased total cholesterol (TC), LDL-C, apoB, and the ratios of TC/HDL-C and LDL-C/HDL-C, when compared with the control diet. VA also increased HDL-C and apoAI, whereas iTFA did not. VA lowered fibrinogen compared with both the control and iTFA diets. Consumption of the CLA diet resulted in lower triacylglycerol (TG) concentration and did not adversely affect other lipoprotein risk factors. In conclusion, high intakes of iTFA and VA adversely affected atherogenic lipoproteins. However, VA also increased HDL-C and apoAI, and lowered fibrinogen. CLA beneficially impacted TG concentration, and had a neutral effect on other CVD risk factors. These data are of interest to food manufacturers, allied health and medical professionals, and consumers.

Technical Abstract: Evidence of the adverse effects of industrially-produced trans fatty acids (iTFA) on risk of cardiovascular disease is consistent and well documented in the scientific literature; however, the cardiovascular effects of naturally-occurring TFA synthesized in ruminant animals (rTFA), such as vaccenic acid (VA) and cis-9, trans-11 conjugated linolenic acid (c9,t11-CLA), are less clear. While preclinical data suggest that VA and c9,t11-CLA may be hypocholesterolemic and anti-atherogenic, data from epidemiological studies that have compared rTFA and iTFA are inconsistent and human intervention studies have been limited, under-powered, and not well controlled. We conducted a double-blind, randomized crossover feeding trial in healthy adults [n = 106 (47 males, 59 females); mean age = 47 ± 10.8 yrs, body mass index = 28.5 ± 4.0 kg/m2, LDL-cholesterol (LDL-C) = 125.3 ± 24.5 mg/dl] to determine whether VA, c9,t11-CLA, and iTFA isomers differentially affect lipoprotein risk factors compared to a control diet. Participants were fed four controlled diets (24 days each) designed to have stearic acid replaced with the following TFA isomers, for 24 days each: 0.1% energy from mixed isomers of TFA (control), 3.3% energy from isolated VA (VA), 3.3% of energy from mixed isomers of TFA from partially hydrogenated vegetable oil (iTFA), and 0.9% energy from c9,t11-CLA (CLA). Added energy from TFA replaced energy from stearic acid; thus, total dietary fat (34% of energy) as well as all other macronutrients were matched across treatment diets. VA and iTFA increased total cholesterol (TC), LDL-C, apoB, and the ratios of TC/HDL-C and LDL-C/HDL-C, when compared with the control diet (P = 0.05). VA also increased HDL-C (P = 0.01) and apoAI (P = 0.0001), whereas iTFA did not (P > 0.05). VA lowered fibrinogen compared with both the control and iTFA diets. Consumption of the CLA diet resulted in lower triacylglycerol (TG) (P = 0.01) and did not adversely affect other lipoprotein risk factors. In conclusion, high intakes of iTFA and VA adversely affected atherogenic lipoproteins. VA also increased HDL-C and apoAI, and lowered fibrinogen. CLA beneficially impacted TG and had a neutral effect on other CVD risk factors.