What is the real impact of trans fat and saturated fat on your health? – IMACE’s comment on the latest research

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huile bien grasseThe British Medical Journal recently published a study conducted by Canadian researchers, which examines the link between two types of fatty acids (namely saturated fats and trans fats) and the risk of mortality and cardiovascular disease. This study has sparked a lot of debate in the national media of several countries, with most articles stating that only trans fats, as opposed to saturated fats are associated with a risk of mortality, heart disease or type-2 diabetes.

But how to understand these conclusions which apparently contradict the long-term advice to limit one’s intake of saturated fats? The European Margarine Association helps you to see clearer through the “war on fats” and provides you with the key messages of the study.

Key findings of the study

The aim of the study was to review the association between intakes of saturated fats and trans fats on all-cause mortality, cardiovascular disease, and type-2 diabetes. Researchers concluded that saturated fat was not associated with any of the latter, while the consumption of trans fat was associated with a 24% increase in death and a 21% increase in the risk of cardiovascular disease.

No consideration of the possible replacement of saturated fats by polyunsaturated fats

However, it is important to note that the analysis was conducted without considering the possibility to replace saturated fats by other nutrients. Victoria Taylor, Senior Dietitian at the British Heart Foundation explains: “when one nutrient is reduced it will be replaced by another and, depending on what this is, it can have positive or negative health consequences” [1]. This is why the choice of comparison nutrient (poly-unsaturated fat (PUFA), mono-unsaturated fat (MUFA) or carbohydrates) must be carefully considered, as highlighted by the researchers. They also stress on the fact that the replacement of saturated fat with poly-unsaturated fat reduces the risk of cardiovascular disease, which is one of IMACE’s key messages.

Trans fat are not anymore considered as a heath issue in Europe

The findings on trans fat have to be balanced with the idea that trans fats are not considered as a health issue anymore in Europe. According to a European dietary survey on trans fatty acids, the average intake of trans fatty acids in most European countries is already below the recommended daily limit of 1% energy [2]. This results partly from the efforts of the margarine industry, which has set up voluntary commitments to drastically reduce trans fats in their products, both in the retail and business to business (B2B) sectors. The average trans fat content in B2B margarines is now 1.4% on fat basis, while retail margarines contain today less than 2% trans fat of their total fat amount. Nowadays, the intake of TFA originates mostly from ruminant sources, which include meat products, dairy products and butter [3],[4].

A study in line with the previous research on fatty acids

All in all, “there is nothing new in this study” despite what the media has said about it, according to Prof. Martijn Katan. Thus the conclusions should not leave us to embrace saturated fats unreservedly, as stated by Professor Tom Sanders, from King’s College London: “It would be foolish to interpret these findings to suggest that it is OK to eat lots of fatty meat, lashings of cream and oodles of butter” [5]. Consequently, the study does not eliminate any of the valid nutritional recommendations, and it is in line with IMACE’s messages on fatty acids.

[1] The Telegraph, Butter unlikely to harm health, but margarine could be deadly , Sarah Knapton, 11.08.2015

[2] Hulshof KFAM, van Erp-Baart MA, Anttolainen M, et al. (1999) Intake of fatty acids in Western Europe with emphasis on trans fatty acids: the TRANSFAIR study. Eur J Clin Nutr 1999; 53:143-57

[3] AFSSA (2009) Avis de l’Agence française de sécurité sanitaire des aliments sur l’estimation des apports en acides gras trans de la population française

[4] Pot GK, Prynne CJ, Roberts C, Olson A, Nicholson SK, et al. (2012) National Diet and Nutrition Survey: fat and fatty acid intake from the first year of the rolling programme and comparison with previous surveys. Br J Nutr 107: 405–415. doi:10.1017/S0007114511002911

[5] Cf. Reference 1

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