Trans Fats – the UGLY Fat

1. Trans Fats – the UGLY Fat Presented by: Dr. Christine Simpson CHIP Alumni - June 20, 2006

2. Walter C. Willett, MD • “Only one type of dietary fat is worse for you than saturated fat---the increasingly common trans fat.” • “...thirty thousand or more premature heart disease deaths each year” are “due to trans fats in our food supply.” Chairman of Dept of Nutrition, Harvard School of Public Health & Professor of Medicine, Harvard Medical School Eat, Drink, and Be Healthy, pp 71, 73

3. What are fatty acids? • Chains of carbon atoms with hydrogen atoms attached • The important way fatty acids differ: • degree of saturation = how many hydrogen atoms the carbon chains carry • saturated fatty acids • monounsaturated fatty acids • polyunsaturated fatty acids

4. Saturated fatty acid • Fully loaded with hydrogen atoms • Only single bonds between carbon atoms • Straight molecule, stiff, pack together

5. Examples: • Animal-based fats (meat and dairy) • Solid plant-based fats, such as coconuts, palm fats, etc. In general, saturated fats tend to increase the risk of heart disease (raise LDL levels, but also raise HDL levels)

6. Monounsaturated fatty acid • One pair of hydrogen atoms missing • One double bond between carbons • Hydrogen on same side of double bond =cis configuration • Bent molecule, flexible, not pack together

7. Examples: • Olive oil • Canola oil • Avocado In general, monounsaturated fats tend to lower the risk of heart disease when consumed in moderate amounts.

8. Polyunsaturated fatty acid • Two or more pairs of hydrogen atoms missing • Two or more double bonds between carbons • Hydrogen on same side of double bond = cis configuration • Bent molecule, more flexible, not pack together

9. Examples: • (these include the omega-3’s and 6’s) • Corn oil • Sunflower oil • Soybean oil • Canola oil • Flaxseed oil • Hemp seed oil In general, polyunsaturated fats tend to lower the risk of heart disease when consumed in moderate amounts.

11. Process of hydrogenation • Oils are reacted under pressure with hydrogen • High temperatures: 248 - 410º F • Metal catalyst: nickel, platinum • ‘Raney’s Nickel: 50% nickel, 50% aluminum • 6 - 8 hours • Creates man-made “saturated fats” • Introduced in 1930s: makes margarines & shortenings as cheaper substitutes for butter, lard, etc.

12. Partial hydrogenation • Some of the double bonds are lost  saturated • Some of the remaining unsaturated double bonds: cis trans configuration • Trans configuration = hydrogen atoms on opposite sides of carbon chain

13. Cis vs trans • Trans = “unnatural” position • Transunsaturated fatty acids behave like saturated fatty acids  straight, stiff, pack together

14. What is a Trans fatty acid/Trans fat • Trans fatty acid: unsaturated fatty acid in which at least one of the double bonds has been changed from the cis to the trans configuration • Trans fat: fat in which most of the fatty acids are trans fatty acids • example: vegetable shortening (Crisco) • Trans fats: man-made, “artificial” fats

15. Where are trans fats found? • Low levels naturally occur in meat and milk (bacterial action in the gut) • Low levels in canola and soybean oils due to the commercial refinement • The rest comes from partial hydrogenation

16. Results of partial hydrogenation • From the food manufacturers point of view: GOOD • more resistant to spoilage • easier to ship and store • longer shelf life • fat is more solid • changes in textures of foods • liquid oils become spreadable margarines • pie crusts flakier

17. Results of partial hydrogenation • From the health professionals point of view: NOT GOOD • unsaturated fatty acids act like saturated fatty acids in the body because of the trans configuration at the double bonds • Evidence that it is actually worse than saturated fats

18. Health effects of trans fats • Increases LDL • Decreases HDL • Increases Lipoprotein (a) – Lpa • Increases risk of preecclampsia in pregnancy • Makes platelets stickier  increases risk of forming clots • May promote insulin resistance • Epidemiological studies: • Increased risk of Alzheimer’s • Increased risk of Diabetes Type 2 • Process of hydrogenation: • destroys vitamin E, carotenoids • destroys essential fatty acids • adds traces of nickel and/or aluminum to the human body which may cause toxicity at high levels

19. Health effects of trans fats cont’d: • Intake associated with increased risk of heart disease • Harvard Nurses Health study • higher trans fat intake (3% of total calories) related to higher incidence of nonfatal heart attacks and death from coronary heart disease • 53% greater risk than those with lowest trans fat intake (1% of total calories) Hu, FB, Stampfer MJ, Manson JE, et al. Dietary fat intake and the risk of coronary heart disease in women. N Eng J Med 1997;337:1491-1499.

20. Health effects of trans fats cont’d: • Authors conclude: replacement of the 2% of calories from trans fat with calories from unhydrogenated, unsaturated fats would reduce heart disease risk by 53% • Practical application: • 2000 calories  .02 = 40 calories • 1 gram of fat yields 9 calories • 40 calories  9 = 4.4 grams of trans fat • Estimated 53% reduction in heart disease if eliminated!!!

21. Where are trans fats found in food? • Many margarines • Commercially fried foods • Bakery products made with margarine, shortening or partially hydrogenated oil • Crackers, cookies, donuts, pastries, muffins, croissants, snack foods ** the trans fat content of these foods can be as high as 45% of the total fat!!

22. Dietary recommendations Food & Nutrition Board, National Institute of Medicine Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Protein and Amino Acids (2002) “Trans fatty acids are not essential and provide no known benefit to human health. Therefore, no AI (Adequate Intake) or RDA (Recommended Dietary Allowance) is set. Similar to saturated fatty acids, there is a positive linear trend between trans fatty acid intake and LDL cholesterol concentration, and therefore increased risk of CHD. An UTL (Upper Tolerable Limit) is not set for trans fatty acids because any incremental increase in trans fatty acid intake increases CHD risk.…it is recommended that trans fatty acid consumption be as low as possible while consuming a nutritionally adequate diet.”

23. In Canada….. • Average consumption of trans fats is 10 grams per day, the highest in the world • Consumption of just 5 grams per day increases the risk of heart disease by almost 20 %.

24. Trans fat on food labels • Ingredient list: trans fat is present if the list includes “partially hydrogenated oil,” or “shortening,” or “margarine” • Definition of “fat-free” = less than 0.5 grams of fat per serving (and no added fat or oil); synonyms include “zero-fat,” “no-fat,” and “nonfat” • hypothetical example: one serving (2 Tbs) contains 0.4 g trans fat • package says “trans free” • you eat 6 servings (3/4 cup) and get 2.4 g trans fat • certainly not trans fat-free!

25. Up until recently, nutrition labeling of foods has been voluntary! As of December 12, 2005: • Legislation in Canada (the first in the world) made it mandatory that the total amount of trans fat must be listed on the nutrition label. • Along with this is included: • Total calories, total fat, saturated fat, cholesterol, sodium, carbohydrate, fiber, sugars, protein, vitamin A, vitamin C, calcium and iron

26. CAUTION!!!! This legislation does not require fast food outlets to label the nutrient content of their products!! To date, only one country (Denmark) has completely banned the use of trans fats

27. Confusion for Consumers: • Some fast foods sold in Canada contain levels of trans fats that are among the highest in the world • At the same time, some fast-food makers have virtually eliminated trans fats, making them world leaders • Levels of trans fats vary from country to country, and from city to city, even on identical products

28. Examples: • Toronto: kids’ meal of chicken nuggets and French Fries at: • KFC – 18.6 g of trans fats • Burger King – 13 g of trans fats • Vancouver: kids’ meals of chicken nuggets • Macdonald’s - 1.8 g of trans fats • Wendy’s – 3.1 g of trans fats

29. How to Avoid them? • Avoid commercially fried foods and high-fat bakery goods • Read the labels on pre-packaged foods (look for the trans fat content AND the term “partially hydrogenated oil”). • Fry foods less, and when you do, use olive oil or grape seed oil. • When you eat out, ask about the trans fat content of foods on the menu.

30. Basic Principle: Eat foods as grown, simply prepared!!