Trans fatty acids (TFA) are unsaturated fats with their bonds in the trans configuration. Ruminant meat and milk contain the natural TFA trans-vaccenic acid, although total intakes of this TFA are small. Industrial TFA that are formed during the processing of vegetable oils to form deodorised and hydrogenated vegetable oil products make up a much larger proportion of total fatty acids in the diet. These oils are produced from their cis-counterparts during heat and chemical treatment of vegetable oils, and evidence is mounting that they are deleterious to health. Because they are structurally different to the natural cis-configuration fatty acids, they can interfere with fatty acid pathways and eicosanoid production. Studies have shown that TFA are associated with systemic inflammation in otherwise healthy people and this inflammation is associated with future development of cardiovascular disease.
Research1 has investigated the association between systemic inflammation in patients with cardiovascular disease and TFA intakes. The TFA content of red blood cell membranes of 86 patients with heart failure were measured because the membrane content is known to be a good marker of TFA intake. A number of different TFA isomers were measured and their quantities summed to created a total TFA content. A number of cytokines and inflammatory markers were also measured from blood samples. The results showed that mean TFA content of red blood cells was 1.8 % of total fatty acids. After adjustments for a number of factors such as smoking, satin use, age, body mass index and diabetes, TFA were positively associated with IL-1, IL-6, IL10, tumour necrosis factor alpha (TNF-α), TNF receptor 1, TNF receptor 2, monocyte chemoattractant protein (MCP-1) and brain natriuretic peptide (BNP).
These results suggest that TFA are positively associated with markers for systemic inflammation in patients with cardiovascular disease. Because TFA are known to cause systemic inflammation it would be advisable that anyone at risk from cardiovascular disease avoid all sources of TFA. Foods that contain high amounts of TFA include any product that contains deodorised or hydrogenated vegetable oil. The results of this study also highlighted that trans isomers of oleic (t-18:1) and linoleic (t-18:2), but not palmitoleic (t-16:1) were associated with higher inflammatory marker concentrations, which supports the authors earlier findings. This would suggest that different TFA isomers have slightly different effects in humans. Research has shown for example that high intakes of t-18:2 are associated with a greater risk of suffering a primary cardiac arrest.
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