Trans fats in food Why they should be

Trans fats in food Why they should be eliminated Alan Maryon-Davis FRCP FFPH

What exactly are trans fats? • Short for trans fatty acids (TFAs) – ‘trans’ refers to their molecular structure • Non-essential. No known benefits to human health • Small amounts occur naturally in milk and milk products • Vast majority are man-made by partially hydrogenating plant oils – industrially produced TFAs • Commercial advantages: increased bulk, improved texture; longer shelf-life, semi-solid consistency, rancid-resistant, cheaper

Industrially produced trans fats Clear vegetable oils Solid or semi-solid fats by hydrogenation

Trans fats made in cooking Clear cooking oil Low TFAs Repeated re-heating Cloudy cooking oil High TFAs

Trans fats are mainly consumed in fried fast-food, biscuits, pastries, cakes, pies and cooking fats

Impact of trans fats on the body • Push up the level of LDL (‘bad’) cholesterol • Decrease the level of HDL (’good’) cholesterol • Increase the level of triglycerides • Increase vascular endothelial dysfunction • May increase insulin resistance

Risks to health of higher trans fat intakes • Clear evidence of an increased risk of coronary heart disease (CHD) – angina, heart attack, etc • Some evidence suggesting an increased risk of type 2 diabetes • Possible increased risk of prostate cancer • Possible increased risk of breast cancer

Impact on population health • Meta-analysis of five large-scale prospective population studies* found a 24% increase in CHD risk associated with higher TFA intakes • Gram for gram, TFAs carry five times the risk associated with saturated fats *Mozaffarian D, Katan MB, Ascherio A, Stampfer MJ, Willett WC. Trans 2 fatty acids and cardiovascular disease. N Engl J Med 2006; 354: 1601 -13.

Impact on population health • Every gram increase in the average intake increases CHD deaths by 5% • According to a recent review by NICE* the current UK consumption of TFAs causes 5000 -15000 deaths every year. • These deaths are totally avoidable * NICE 2009

COMA 1994 • Recommended that TFAs should contribute no more than 2% of food energy (ie. calorie) intake across the whole population* *Expressed as the maximum recommended contribution these nutrients should make to the population average diet.

Policy history • 1994 – COMA (later SACN) recommends population maximum for TFAs of 2% of food energy intake • 2003 – WHO recommends a population intake of less than 1% of total energy • 2007 – FSA endorses the COMA/SACN population maximum and recommends no change • 2009 – a WHO review emphasised the need ‘to significantly reduce or virtually eliminate industrially produced TFAs from the food supply’

SACN review of trans fats 2007 recommendations • Improved monitoring of specific groups, particularly young adults, at risk of low nutritional status is required. • These population groups …and people (especially adults with children) in lower socio-economic groups could benefit from focused health initiatives.

Progress SACN recommendation (adults) < 2% of food energy 1986/87 2. 2% 2000/01 1. 2% 2010 0. 8%

Limitations of the NDNS • Small sample (<1000 households in the first year) • 43% non-response or inadequate response • A common reason for non-response was ‘language difficulties’ • Around 20% of food intake is not reported

FSA review 2007 • Reviewed the latest evidence • Only considered population average intakes • Concerned that further reductions in TFAs would lead to compensatory increases in sat fats • Sat fat reduction programme considered to be a higher priority • Recommended no change in COMA/SACN population-wide limit of 2% • Recommended continuing the existing voluntary approach rather than mandatory regulation

TFA consumption and health inequalities • There is concern that children and young people, and those on low incomes, are consuming worryingly high levels of TFAs in deep-fried takeaway foods • A recent study in Tower Hamlets suggests that some individuals are consuming 6 -12% of food energy as TFAs • The high intakes among young people and deprived populations was a key consideration in the Denmark legislation

CHD mortality in Scotland, 35 -64 Deprived Affluent

TFAs in fast foods • One in six meals is eaten outside the home • The number of takeaway outlet is rising by about 8% a year • Main customers are children and young people, and those on lower incomes • Cooking practices vary greatly • Very high TFA levels can result from re-heating cooking oil, even when initial levels are low • Deep-fat fryer in small takeaways of particular concern • Relatively little UK data on this (ad hoc studies, eg. Tower Hamlets trading standards study)

Scope for action in UK • Reduce recommended maximum TFA intake (DRV) to <0. 5% of food energy across the population (Denmark has achieved this) • Shift from voluntary to mandatory regulation • Ban IPTFAs in all manufactured foods • Mandatory TFA labelling for specific groups of foods • Improved guidance and tougher regulation for providers of foods eaten outside the home • Improved monitoring of TFA intake in specific subgroups, eg. children, low income groups, ethnic minorities • Regular mini-surveys of TFA content of fast-foods