Health effects of trans-fatty acids: Experimental and observational evidence

Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
European journal of clinical nutrition (Impact Factor: 2.71). 06/2009; 63 Suppl 2(Suppl 2):S5-21. DOI: 10.1038/sj.ejcn.1602973
Source: PubMed


Growing evidence indicates that trans-fatty acids (TFA) adversely affect cardiovascular health. As part of the World Health Organization (WHO) Scientific Update on TFA, we reviewed the evidence for effects of TFA consumption on coronary heart disease (CHD).
We searched Medline publications examining TFA consumption and CHD risk factors or outcomes, emphasizing results of studies in humans. We evaluated and synthesized evidence from both controlled feeding trials evaluating risk factors and long-term observational studies evaluating risk factors or clinical outcomes, each of which have complementary strengths and limitations, to enable the most robust and reliable inferences of effects.
The effects of TFA consumption on risk factors most consistently seen in both controlled trials and observational studies included adverse lipid effects (for example [upward arrow] low-density lipoprotein cholesterol, [downward arrow] high-density lipoprotein cholesterol (HDL-C), [upward arrow] total/HDL-C ratio), proinflammatory effects (for example [upward arrow] tumor necrosis factor-alpha activity, [upward arrow] interleukin-6, [upward arrow] C-reactive protein) and endothelial dysfunction. These effects were most prominent in comparison with cis unsaturated fats; adverse effects on total/HDL-C and endothelial function were also seen in comparison with saturated fatty acids (SFA). TFA may also worsen insulin sensitivity, particularly among individuals predisposed to insulin resistance; possible effects on weight gain and diabetes incidence require further confirmation. Five retrospective case-control studies and four prospective cohort studies demonstrated positive associations between TFA consumption and CHD events. A meta-analysis of prospective studies indicated 24, 20, 27 and 32% higher risk of myocardial infarction (MI) or CHD death for every 2% energy of TFA consumption isocalorically replacing carbohydrate, SFA, cis monounsaturated fatty acids and cis polyunsaturated fatty acids, respectively. The differential effects of specific TFA isomers may be important but are less well established. The available evidence indicates that trans-18:1 and particularly trans-18:2 isomers have stronger CHD effects than trans-16:1 isomers. The limited data suggest that the experimental effects of ruminant and industrial TFA are similar when consumed in similar quantities, but very few persons consume such high levels of ruminant TFA, and observational studies do not support adverse CHD effects of ruminant TFA in amounts actually consumed.
Controlled trials and observational studies provide concordant evidence that consumption of TFA from partially hydrogenated oils adversely affects multiple cardiovascular risk factors and contributes significantly to increased risk of CHD events. The public health implications of ruminant TFA consumption appear much more limited. The effects of specific TFA isomers require further investigation.

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    • "On the other hand, t9-18:1 has been associated with both negative (Gebauer et al., 2011; Wang et al., 2012) and positive (Brenna & Kothapalli, 2014; Tyburczy et al., 2009) effects on CVD risk factors in rats, thus further studies are required to ascertain its health effects. High levels of iTFA, which is a rich source of t10-18:1, have been associated with coronary artery disease in humans (Gebauer et al., 2011; Mozaffarian, Aro, & Willett, 2009). In addition, feeding rabbits butter enriched with t10-18:1 increased plasma levels of very low density lipoprotein cholesterol, low density lipoprotein cholesterol and aortic lipid deposition (Roy et al., 2007), which are risk factors for coronary heart disease and atherosclerosis. "
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    ABSTRACT: In addition to being an important source of macro- and micronutrients, beef can also be a source of trans (t)-18:1 fatty acids (FA). Overall, trans-FA have been associated with an increased incidence of cardiovascular disease in humans. Recent research has, however, shown that t-18:1 FA are a group of distinct isomers which elicit differential biological effects. The current review examines the potential of different nutritional strategies to enrich potentially beneficial or deplete detrimental t-18:1 isomers in beef. The possible contribution of seemingly beneficial t-18:1 isomers to global food and nutrition security is highlighted. The review also describes the importance of developing a regulatory framework to govern the consumption of individual t-18:1 isomers to enhance and sustain their contribution to food and nutrition security.
    Food Research International 05/2015; 76. DOI:10.1016/j.foodres.2015.05.001 · 2.82 Impact Factor
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    • "Several studies have been published that associate trans fat intake with the development of cardiovascular disease [6] [7] [8] [9] [10] and some types of cancer [11] [12] [13] Cardiovascular disease in response to trans fat intake may be due to an increase in low density lipoprotein (LDL-c) levels along with a decrease in high density lipoprotein (HDL-c) levels [14]. Government regulatory agencies in Canada and the United States (Canadian Food Inspection Agency and Food and Drug Administration – FDA) mandated the reporting of the presence of these lipids on food labels in 2003. "
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    ABSTRACT: In Brazil, the National Health Surveillance Agency (ANVISA) made the labeling of trans fats in foods mandatory from July 2006. The claim “trans fat free” can be used only for foods with trans fat content lower than 0.2g and saturated fat content lower than 2g per serving. This study determined fatty acid profile by gas chromatography and total fat content of nine cookie types and three bread types and the results obtained were compared with the values reported on the labels of these products. According to the results, 92% of the products contained trans fat, although only 33% reported this on their labels. There was no significant difference with the experimentally determined levels of the products that reported the presence of trans fat. In 67% of the products that reported an absence of trans fat on their labels, less than 0.2g of trans fat per serving was experimentally detected. The results revealed that the food product manufacturers studied are labeling trans fat content properly according to the law as they report products that have less than 0.2g trans fat as “trans fat free”. However, it bears noting that claiming that a product is free of trans fat on the label does not always guarantee that it is not present in the product and that the maximum suggested daily intake of 2g will not be exceeded relatively easily considering that consumers do not always consume only the amount identified as the serving size on the label. Also, the paper enabled a discussion about the lack of standardization in the description of fat used as ingredient in foods. At a glance: Figures
    Journal of food and nutrition research 12/2014; 2(12):906-913. DOI:10.12691/jfnr-2-12-8 · 0.80 Impact Factor
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    • "Replacing SFA with MUFA or PUFA may be beneficial, but replacing SFA with some other dietary components, such as refined carbohydrates, may increase the risk (Baum et al., 2012). Research suggests that trans fatty acid intake (Hoenselaar, 2012; Mozaffarian, Aro, & Willett, 2009), diets with a high glycemic index (Jakobsen et al., 2010), and high dietary salt may be more significant risk factors for heart disease than dietary SFA (Aaron & Sanders, 2013; Mozaffarian et al., 2009). Furthermore, recent investigations suggest that increased consumption of refined carbohydrates is associated with cardiovascular risk (Baum et al., 2012; Flock, Fleming, & Kris-Etherton, 2014; Siri-Tarino et al., 2010a, 2010b). "
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    ABSTRACT: Dietary patterns are an important concept in dietary recommendations. The Western pattern is most commonly defined as a diet characterized by high intakes of refined grains, sugar and red meat, and has been shown to be associated with increased risks for certain types of cancer, coronary heart disease, diabetes, and obesity. However, isolating the independent effects of individual foods on health outcomes is central to helping individuals choose foods to build healthier dietary patterns to which they can adhere. Red meat is a popular source of high quality protein and provides a variety of essential nutrients that improve overall diet quality. It is also a source of saturated fatty acids, which observational evidence suggest are associated with heart disease, although recent data challenge this. Several studies have shown that lean red meat can be successfully included in recommended heart-healthy dietary patterns without detriment to blood lipids. Furthermore, increased dietary protein has been shown to promote healthy body weight and composition, in part by increasing satiety, and to improve vitality and stamina.
    Meat Science 11/2014; 98(3). DOI:10.1016/j.meatsci.2014.06.028 · 2.62 Impact Factor
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