Trans Fats the UGLY Fat

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Trans Fats the UGLY Fat

• Presented by
• Dr. Christine Simpson
• CHIP Alumni - June 20, 2006

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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

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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

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Saturated fatty acid

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

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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)

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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

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Examples

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

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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

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Examples

• (these include the omega-3s and 6s)
• 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.

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Process of hydrogenation

• Oils are reacted under pressure with hydrogen
• High temperatures 248 - 410º F
• Metal catalyst nickel, platinum
• Raneys 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.

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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

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Cis vs trans

• Trans unnatural position
• Trans unsaturated fatty acids behave like
  saturated fatty acids ?? straight, stiff, pack
  together

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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

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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

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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

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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

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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 Alzheimers
• 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

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Health effects of trans fats contd

• 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 19973371491-1499.

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Health effects of trans fats contd

• 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!!!

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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!!

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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.

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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 .

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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!

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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

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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

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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

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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
• Macdonalds - 1.8 g of trans fats
• Wendys 3.1 g of trans fats

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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.

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Basic Principle

• Eat foods as grown, simply prepared!!