Trans Fats – the UGLY FatTrans Fats – the UGLY Fat

Presented by:Presented by:

Dr. Christine SimpsonDr. Christine Simpson

CHIP Alumni - June 20, 2006CHIP Alumni - June 20, 2006

Walter C. Willett, MDWalter C. Willett, MD

““Only one type of dietary fat is worse for you than Only one type of dietary fat is worse for you than saturated fat---the increasingly common trans fat.”saturated fat---the increasingly common trans fat.”

““...thirty thousand or more premature heart disease ...thirty thousand or more premature heart disease deaths each year” are “due to trans fats in our food deaths each year” are “due to trans fats in our food supply.”supply.”

Chairman of Dept of Nutrition,Harvard School of Public Health &

Professor of Medicine, Harvard Medical SchoolEat, Drink, and Be Healthy, pp 71, 73

What are fatty acids?What are fatty acids?

Chains of carbon atoms with Chains of carbon atoms with hydrogen atoms attached hydrogen atoms attached

The important way fatty acids differ:The important way fatty acids differ: degree of saturation degree of saturation = how many = how many

hydrogen atoms the carbon chains carryhydrogen atoms the carbon chains carry saturated fatty acids saturated fatty acids monounsaturated fatty acidsmonounsaturated fatty acids polyunsaturated fatty acidspolyunsaturated fatty acids

Saturated fatty acidSaturated fatty acid

Fully loaded with hydrogen atomsFully loaded with hydrogen atoms Only single bonds between carbon atomsOnly single bonds between carbon atoms Straight molecule, stiff, pack togetherStraight molecule, stiff, pack together

Examples:Examples:

Animal-based fats (meat and dairy)Animal-based fats (meat and dairy) Solid plant-based fats, such as coconuts,Solid plant-based fats, such as coconuts,

palm fats, etc.palm fats, etc.

In general, saturated fats tend to increase In general, saturated fats tend to increase the risk of heart disease (raise LDL the risk of heart disease (raise LDL levels, but also raise HDL levels)levels, but also raise HDL levels)

MonounMonounsaturated fatty acidsaturated fatty acid

One pair of hydrogen atoms missingOne pair of hydrogen atoms missing One double bond between carbonsOne double bond between carbons Hydrogen on same side of double bond =Hydrogen on same side of double bond = cis cis

configurationconfiguration Bent molecule, flexible, not pack togetherBent molecule, flexible, not pack together

Examples:Examples:

Olive oilOlive oil Canola oilCanola oil AvocadoAvocado

In general, monounsaturated fats tend In general, monounsaturated fats tend to lower the risk of heart disease when to lower the risk of heart disease when consumed in moderate amounts.consumed in moderate amounts.

PolyunPolyunsaturated fatty acidsaturated fatty acid

Two or more pairs of hydrogen atoms missingTwo or more pairs of hydrogen atoms missing Two or more double bonds between carbonsTwo or more double bonds between carbons Hydrogen on same side of double bond = Hydrogen on same side of double bond =

ciscis configuration configuration Bent molecule, more flexible, not pack togetherBent molecule, more flexible, not pack together

Examples:Examples:

(these include the omega-3’s and 6’s)(these include the omega-3’s and 6’s) Corn oilCorn oil Sunflower oilSunflower oil Soybean oilSoybean oil Canola oilCanola oil Flaxseed oilFlaxseed oil Hemp seed oilHemp seed oil

In general, polyunsaturated fats tend to lower the In general, polyunsaturated fats tend to lower the risk of heart disease when consumed in moderate risk of heart disease when consumed in moderate amounts.amounts.

Process of hydrogenationProcess of hydrogenation

Oils are reacted under pressure with Oils are reacted under pressure with hydrogenhydrogen

High temperatures: 248 - 410º FHigh temperatures: 248 - 410º F Metal catalyst: nickel, platinumMetal catalyst: nickel, platinum

‘‘Raney’s Nickel: 50% nickel, 50% aluminumRaney’s Nickel: 50% nickel, 50% aluminum 6 - 8 hours6 - 8 hours Creates man-made “saturated fats”Creates man-made “saturated fats” Introduced in 1930s: makes margarines & Introduced in 1930s: makes margarines &

shortenings as cheaper substitutes for shortenings as cheaper substitutes for butter, lard, etc.butter, lard, etc.

PartialPartial hydrogenation hydrogenation

SomeSome of the double bonds are lost of the double bonds are lost saturated saturated

Some of the remaining unsaturated Some of the remaining unsaturated double bonds: double bonds: ciscis trans trans configurationconfiguration

Trans Trans configurationconfiguration = = hydrogen hydrogen atoms on opposite sides of carbon atoms on opposite sides of carbon chainchain

CisCis vs vs transtrans

TransTrans = “unnatural” position = “unnatural” position TransTrans ununsaturated fatty acids behave like saturated fatty acids behave like

saturated fatty acids saturated fatty acids straight, stiff, straight, stiff, pack togetherpack together

What is aWhat is a Trans Trans fatty fatty acid/acid/Trans Trans fatfat

TransTrans fatty acid fatty acid: : ununsaturated fatty acid saturated fatty acid in which at least one of the double in which at least one of the double bonds has been changed from the bonds has been changed from the ciscis to to the the transtrans configuration configuration

TransTrans fat fat: fat in which most of the fatty : fat in which most of the fatty acids are acids are transtrans fatty acids fatty acids example: vegetable shortening (Crisco)example: vegetable shortening (Crisco)

TransTrans fats: man-made, “artificial” fats fats: man-made, “artificial” fats

Where are Where are transtrans fats found? fats found?

Low levels naturally occur in meat Low levels naturally occur in meat and milk (bacterial action in the gut)and milk (bacterial action in the gut)

Low levels in canola and soybean oils Low levels in canola and soybean oils due to the commercial refinementdue to the commercial refinement

The rest comes from partial The rest comes from partial hydrogenationhydrogenation

Results of Results of partialpartial hydrogenationhydrogenation

From the From the food manufacturersfood manufacturers point of point of view: GOODview: GOOD more resistant to spoilagemore resistant to spoilage easier to ship and store easier to ship and store longer shelf life longer shelf life fat is more solidfat is more solid changes in textures of foodschanges in textures of foods

liquid oils become spreadable margarinesliquid oils become spreadable margarines pie crusts flakierpie crusts flakier

Results of Results of partialpartial hydrogenationhydrogenation

From the From the health professionalshealth professionals point of view: NOT GOODpoint of view: NOT GOOD unsaturated fatty acids unsaturated fatty acids act like act like

saturated fatty acids in the bodysaturated fatty acids in the body because of the because of the transtrans configuration at the configuration at the double bondsdouble bonds

Evidence that it is actually Evidence that it is actually worseworse than than saturated fatssaturated fats

Health effects of Health effects of transtrans fats fats

Increases LDLIncreases LDL Decreases HDLDecreases HDL Increases Lipoprotein (a) – LpIncreases Lipoprotein (a) – Lpaa Increases risk of preecclampsia in pregnancyIncreases risk of preecclampsia in pregnancy Makes platelets stickier Makes platelets stickier increases risk of forming clots increases risk of forming clots May promote insulin resistanceMay promote insulin resistance Epidemiological studies:Epidemiological studies:

Increased risk of Alzheimer’sIncreased risk of Alzheimer’s Increased risk of Diabetes Type 2Increased risk of Diabetes Type 2

Process of hydrogenation:Process of hydrogenation: destroys vitamin E, carotenoidsdestroys vitamin E, carotenoids destroys essential fatty acidsdestroys essential fatty acids adds traces of nickel and/or aluminum to the human body adds traces of nickel and/or aluminum to the human body

which may cause toxicity at high levelswhich may cause toxicity at high levels

Health effects of Health effects of transtrans fats fats cont’d:cont’d:

Intake associated with increased risk Intake associated with increased risk of heart disease of heart disease Harvard Nurses Health study Harvard Nurses Health study higher higher transtrans fat intake (3% of total calories) fat intake (3% of total calories)

related to higher incidence of nonfatal heart related to higher incidence of nonfatal heart attacks and death from coronary heart diseaseattacks and death from coronary heart disease

53% greater risk than those with lowest 53% greater risk than those with lowest transtrans fat intake (1% of total calories) 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.

Health effects of Health effects of transtrans fats fats cont’d:cont’d:

• Authors conclude: replacement of the 2% Authors conclude: replacement of the 2% of calories from of calories from transtrans fat with calories fat with calories from unhydrogenated, unsaturated fats from unhydrogenated, unsaturated fats would reduce heart disease risk by 53%would reduce heart disease risk by 53%

• Practical applicationPractical application::• 2000 calories 2000 calories .02 = 40 calories .02 = 40 calories• 1 gram of fat yields 9 calories1 gram of fat yields 9 calories• 40 calories 40 calories 9 = 9 = 4.4 grams of 4.4 grams of transtrans fat fat• Estimated 53% reduction in heart disease if Estimated 53% reduction in heart disease if

eliminated!!!eliminated!!!

Where are Where are transtrans fats found in fats found in food?food?

Many margarinesMany margarines Commercially fried foodsCommercially fried foods Bakery products made with margarine, Bakery products made with margarine,

shortening or partially hydrogenated oilshortening or partially hydrogenated oil Crackers, cookies, donuts, pastries, Crackers, cookies, donuts, pastries,

muffins, croissants, snack foodsmuffins, croissants, snack foods

** the trans fat content of these foods can ** the trans fat content of these foods can be as high as 45% of the total fat!!be as high as 45% of the total fat!!

Dietary recommendationsDietary recommendationsFood & 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.”

In Canada…..In Canada…..

Average consumption of trans fats is Average consumption of trans fats is 10 grams per day, the highest in the 10 grams per day, the highest in the worldworld

Consumption of just 5 grams per day Consumption of just 5 grams per day increases the risk of heart disease by increases the risk of heart disease by almost 20 %.almost 20 %.

TransTrans fat on food labels fat on food labels

Ingredient listIngredient list: : transtrans fat is present if the list fat is present if the list includes “includes “partially hydrogenated oilpartially hydrogenated oil,” or ,” or ““shorteningshortening,” or “,” or “margarinemargarine””

Definition of “fat-free”Definition of “fat-free” = = less than 0.5 grams less than 0.5 grams of fat per serving (and no added fat or oil); of fat per serving (and no added fat or oil); synonyms include “zero-fat,” “no-fat,” and synonyms include “zero-fat,” “no-fat,” and “nonfat”“nonfat” hypothetical example: one serving (2 Tbs) contains 0.4 g hypothetical example: one serving (2 Tbs) contains 0.4 g

transtrans fat fat package says “package says “transtrans free” free” you eat 6 servings (3/4 cup) and get 2.4 g you eat 6 servings (3/4 cup) and get 2.4 g transtrans fat fat certainly not certainly not transtrans fat-free! fat-free!

Up until recently, nutrition Up until recently, nutrition labeling of foods has been labeling of foods has been

voluntary!voluntary!As of December 12, 2005:As of December 12, 2005:

Legislation in Canada (the first in the world) Legislation in Canada (the first in the world) made it mandatory that the total amount of made it mandatory that the total amount of transtrans fat must be listed on the nutrition label. fat must be listed on the nutrition label.

Along with this is included:Along with this is included: Total calories, total fat, saturated fat, cholesterol, Total calories, total fat, saturated fat, cholesterol,

sodium, carbohydrate, fiber, sugars, protein, sodium, carbohydrate, fiber, sugars, protein, vitamin A, vitamin C, calcium and ironvitamin A, vitamin C, calcium and iron

CAUTION!!!!CAUTION!!!!

This legislation does not require This legislation does not require fast food outlets to label the fast food outlets to label the

nutrient content of their nutrient content of their products!!products!!

To date, only one country (Denmark) has completely To date, only one country (Denmark) has completely banned the use of banned the use of transtrans fats fats

Confusion for Consumers:Confusion for Consumers:

Some fast foods sold in Canada contain Some fast foods sold in Canada contain levels of levels of transtrans fats that are among the fats that are among the highest in the worldhighest in the world

At the same time, some fast-food makers At the same time, some fast-food makers have virtually eliminated have virtually eliminated transtrans fats, fats, making them world leadersmaking them world leaders

Levels of trans fats vary from country to Levels of trans fats vary from country to country, and from city to city, even on country, and from city to city, even on identical productsidentical products

Examples:Examples:

Toronto: kids’ meal of chicken nuggets Toronto: kids’ meal of chicken nuggets and French Fries at:and French Fries at: KFC – 18.6 g of KFC – 18.6 g of transtrans fats fats Burger King – 13 g of Burger King – 13 g of transtrans fats fats

Vancouver: kids’ meals of chicken Vancouver: kids’ meals of chicken nuggetsnuggets Macdonald’s - 1.8 g of Macdonald’s - 1.8 g of transtrans fats fats Wendy’s – 3.1 g of Wendy’s – 3.1 g of transtrans fats fats

How to Avoid them?How to Avoid them?

Avoid commercially fried foods and high-Avoid commercially fried foods and high-fat bakery goodsfat bakery goods

Read the labels on pre-packaged foods Read the labels on pre-packaged foods (look for the (look for the transtrans fat content AND the fat content AND the term “partially hydrogenated oil”).term “partially hydrogenated oil”).

Fry foods less, and when you do, use olive Fry foods less, and when you do, use olive oil or grape seed oil.oil or grape seed oil.

When you eat out, ask about the When you eat out, ask about the transtrans fat fat content of foods on the menu.content of foods on the menu.

Basic Principle:Basic Principle:

Eat foods as Eat foods as grown, simply grown, simply

prepared!!prepared!!