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Artificial trans fats: considering the issues. 1. Evidence for the ill effects of trans fats. Trans fats have adverse effects on blood lipids and lipoproteins Epidemiological studies show a relationship between trans fat intake and coronary heart disease.
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Evidence for the ill effects of trans fats Trans fats have adverse effects on blood lipids and lipoproteins Epidemiological studies show a relationship between trans fat intake and coronary heart disease
Impact of trans fats on plasma lipids: results of a meta-analysis *P<0.05; †P<0.01; ‡P<0.001. Source: Mensink et al. Am J Clin Nutr. 2003;77:1146-1155. 3
Increasing trans fats have increasing impact on LDL:HDL Trans fatty acids Saturated fatty acids Source: Ascherio et al. New Engl J Med. 1999;340:1994-1998. 5
2% increase in energy from trans fats results in 23% increase in CHD risk Source: Mozaffarian et al. New Engl J Med. 2006;354:1601-1613. 6
Potential physiological effects of trans fats Impact on hepatocyte metabolism of lipoproteins and effects on plasma cholesteryl ester transfer protein (CETP) likely cause changes in plasma lipids Altered fatty acid metabolism Altered inflammatory response of adipocytes NO-dependent endothelial dysfunction Increased sICAM-1 and sVCAM-1 seen with trans fat intake Modulation of monocytes and macrophages Increased inflammatory mediators (IL-6, TNF-a) Source: Mozaffarian et al. New Engl J Med. 2006;354:1601-1613. 7
Trans fat from vegetable—but not ruminant—source associated with increased risk of CHD Source: Willett et al. Lancet. 1993;341:581-585; Ascherio et al. Circulation. 1994;89:94-101. 9
Is there a difference between industrial and natural trans fats Two recent studies have given mixed results Motard-Bélanger et al Essentially no difference TRANSFACT Only industrial trans fats reduce HDL cholesterol Absolute impact on CVD risk factors not clear Source: Motard-Bélanger et al. Am J Clin Nutr. 2008;87:593-599. Chardigny et al. Am J Clin Nutr. 2008;87:558-566.
Recent study compared impact of ruminant and industrial trans fats Percent trans fats in study diets Source: Motard-Bélanger et al. Am J Clin Nutr. 2008;87:593-599. 11
Industrial trans fat and high trans fat ruminant diets had significant impact on plasma lipids *† * * * * * * Source: Motard-Bélanger et al. Am J Clin Nutr. 2008;87:593-599. 12
Essentially no difference between industrial and ruminant trans fats Diets high in trans fat have a significant deleterious affect on plasma lipid CVD risk factors Gram for gram, no difference between industrial and ruminant trans fats However, impossible to achieve this level of trans fats in a normal diet Butter fortified with trans fats to achieve this level in study Concluded that current intake of ruminant trans fats in population not likely to have significant impact on CVD risk factors Source: Motard-Bélanger et al. Am J Clin Nutr. 2008;87:593-599. 13
TRANSFACT Randomised double-blind, controlled, crossover study Patients consumed 11-12 g/day TFA from industrial or natural sources ~5% of daily energy 40 patients completed study 19 male 21 female Serum lipids and lipoproteins monitored Source: Chardigny et al. Am J Clin Nutr. 2008;87:558-566.
TRANSFACT: changes in HDL and LDL Significant decrease in HDL (P=0.012) and LDL (P=0.001) in women, but not in men, with trans fat from industrial vs. natural sources. LDL cholesterol HDL cholesterol 120 80 100 60 80 Concentration (mg/dL) Concentration (mg/dL) 60 40 40 20 20 0 0 Male Female Male Female Baseline Industrial Natural Source: Chardigny et al. Am J Clin Nutr. 2008;87:558-566.
TRANSFACT: Conclusions Trans fatty acids from natural and industrial sources have different effects on cardiovascular risk factors in women Absolute impact on CVD risk factors not clear HDL lowering is specific to industrially derived trans fats Source: Chardigny et al. Am J Clin Nutr. 2008;87:558-566.
Grams trans fats in a “high trans fat menu” around the world Numbers in parentheses are % trans fats in each menu item. Source: Stender et al. Food Nutr Res. 2008; 52. doi: 10.3402/fnr.v52i0.1651. 17
Trans fat intake decreasing but remains well above recommended levels Source: Harnack et al. J Am Diet Assoc. 2003;103:1160-1166. 18
Predicted impact of removing industrial trans fats from US diet Reduced by half (2.1%→1.1%) Near elimination (2.1%→0.1%) 0 -3 -5 -6 -10 Proportion of CHD events preventable in the US (%) -10 -12 -15 -20 -19 -22 -25 Based on total:HDL cholesterol (dietary trials) Based on replacement with carbohydrates (prospective studies) Based on additional replacement with cis fatty acids (prospective studies) Source: Mozaffarian et al. New Engl J Med. 2006;354:1601-1613. 19
Impact of reducing trans fat intake in Denmark Trans fat intake CHD Mortality Curves Source: Stender et al. Food Nutr Res. 2008; 52. doi: 10.3402/fnr.v52i0.1651 . 20
Alternatives to partially hydrogenated fat Source: Eckel et al. Circulation. 2007;115:2231-2246. 21
Alternatives to partially hydrogenated fat (cont’d) Source: Eckel et al. Circulation. 2007;115:2231-2246. 22
Some alternatives to trans fats should be approached with caution Industrial trans fats were originally introduced as an alternative to saturated fats We know the result Do we know that alternatives to trans fats are safe? Interesterified fats are present in many products today Little known about health effects Robinson et al (2009) recently reported on acute metabolic changes with chemically and enzymatically interesterified stearic acid rich spread 85% increase in TAG with CIE vs NIE in obese subjects Increased stearic acid with CIE and EIE vs NIE TAG=triacylglycerol; CIE=chemically interesterified; EIE=enzymatically interesterified; NIE=non-interesterified. Source: Robinson et al. Lipids. 2009;44:17-26. 23
Professional societies have taken stances on trans fat consumption • Foods containing industrially derived TFA should be minimized....TFA replacement strategies [should] not result in a higher TFA and SFA ADA (American Dietetic Association) • A recent meta-analysis…found that a 2% increase in energy intake from trans fatty acids was associated with a 23% increase in the incidence of coronary heart disease • Recommends limiting trans fat consumption to <1% total energy/day AHA (American Heart Association) • There is a positive linear trend between trans fatty acid intake and total and LDL cholesterol concentration, and therefore increased risk of CHD, thus suggesting a Tolerable Upper Intake Level (UL) of zero IOM (Institute of Medicine) FDA (Food and Drug Administraation) • Food manufacturers are allowed to list amounts of trans fat with less than 0.5 grams (1/2 g) as 0g (zero) on the Nutrition Facts panel 24
FDA rounding rule allows for significant trans fats Total trans fats of <0.5g/serving can be listed on Nutrition Facts panel as 0g trans fat Allows for up to 0.49g trans fat per serving Serving size definition is often quite small Results in consumption of 2‒3 or more servings at a time Individual can consume up to 1.5g trans fat and believe they have consumed 0g 25
Example 1. Kellogg’s Rice Krispies Treats Cereal • Actual trans fat: 0.444g/serving • Serving size: ¾ cup U.S. Department of Agriculture, Agricultural Research Service. 2008. USDA National Nutrient Database for Standard Reference, Release 21. Nutrient Data Laboratory Home Page, http://www.ars.usda.gov/ba/bhnrc/ndl 26
Example 2. Malt-O-Meal Cinnamon Toasters • Actual trans fat: 0.324g/serving • Serving size: ¾ cup U.S. Department of Agriculture, Agricultural Research Service. 2008. USDA National Nutrient Database for Standard Reference, Release 21. Nutrient Data Laboratory Home Page, http://www.ars.usda.gov/ba/bhnrc/ndl 27
Example 3: Pillsbury Buttermilk Biscuit Refrigerated Dough • Actual trans fat: 0.350g/serving • Serving size: 3 biscuits (64 g) U.S. Department of Agriculture, Agricultural Research Service. 2008. USDA National Nutrient Database for Standard Reference, Release 21. Nutrient Data Laboratory Home Page, http://www.ars.usda.gov/ba/bhnrc/ndl 28
Example 4: Crème-Filled Sponge Cake Actual trans fat: 0.459g/serving U.S. Department of Agriculture, Agricultural Research Service. 2008. USDA National Nutrient Database for Standard Reference, Release 21. Nutrient Data Laboratory Home Page, http://www.ars.usda.gov/ba/bhnrc/ndl 29
Conclusions Trans fats have negative impact on cardiovascular markers and CHD Evidence that industrial trans fats have worse impact than ruminant trans fats Reducing trans fats could significantly impact CHD Demonstrated in Danish experience Pros and cons to trans fat alternatives Professional societies and FDA recommend limiting trans fats in diet to <1% total energy But zero isn’t necessarily zero on trans fat labels 30