Trans Fat
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Transcript of Trans Fat
Trans Fatty Acids
Amber Page
Summary
What is Fat? Types of Fat History of Trans Fats Benefits of Trans Fats Trans Fats and Health Risks Trans Fat in the News What is Currently Being Done?
What is Fat?
E-shaped molecule– Glycerol derived backbone
Stays constant
– Three fatty acid groups Can change depending on type of fat
Solid or liquid at room temperature– Depends on composition
Vitamins A, D, E and K are fat-soluble– Can not be absorbed and digested without fats
What is Fat?
Example of a typical fat molecule
http://en.wikipedia.org/wiki/Trans_fats
Types of Fat
Saturated Fat Unsaturated Fat
– Monounsaturated – Polyunsaturated– Trans Fat
Saturated Fats
No double bonds in fatty acid chain Examples
– Butyric acid (butter)– Lauric acid (breast milk, coconut oil, and palm oil)– Myristic acid (cow milk and dairy products)
Diets high in saturated fats can cause Coronary Heart Disease (CHD)
Saturated Fats
Myristic Acid
http://en.wikipedia.org/wiki/Trans_fats
Saturated Fats
Controversy on whether trans-unsaturated fats are better or worse than saturated fats– Big push in the 80s and 90s to replace saturated
fats with trans-unsaturated fats (replace butter with margarine etc.)
– Some say “Big Business” played a role in demonizing saturated fats
Monounsaturated Fats
One double bond present Olive oil is 75% monounsaturated Canola oil is 57-60% monounsaturated Higher melting point than polyunsaturated Lower melting point than saturated Usually thought of as “better” than saturated
fats because of their fluidity
Monounsaturated Fats
Oleic Acid (olive oil)
http://en.wikipedia.org/wiki/Trans_fats
Polyunsaturated Fats
More than one double bond present Lower melting temperature than both
saturated and monounsaturated fats Found in soybeans, fish oils, grain products Necessary for the body and protects against
illness
Polyunsaturated Fats
Linoleic Acid
http://en.wikipedia.org/wiki/Trans_fats
Trans Fat
Type of unsaturated fat– Mono or poly
Same chemical formula as many other unsaturated fats, but are in the trans position– Less fluid– Higher melting point
Occurs naturally in meat and dairy products from ruminants (cattle, sheet, goats etc.)
Trans Fat
Elaidic Acid (hydrogenated vegetable oils)
http://en.wikipedia.org/wiki/Trans_fats
Trans Fat
Elaidic Acid (hydrogenated vegetable oils)
Oleic Acid (olive oil)
Trans
Melting Point: 46.5ºC
Cis
Melting Point: 13.5ºC
http://en.wikipedia.org/wiki/Trans_fats
Trans Fat
Presently, most trans fat is made industrially– Side effect of partial hydrogenation of plant oils
Catalytic hydrogenation of plant oils favors the trans position
– Lower energy than cis position– At equilibrium, trans/cis ratio is about 2:1
Hydrogenation causes essential fatty acids to be destroyed, and fatty acids similar to saturated fats to be created
Trans Fat
Not necessary nor beneficial to health Trans fat increases risk of CHD Some say that trans fat from partial
hydrogenation of plant oils are worse than naturally occurring trans fats.
Trans Fat
Naturally occurring trans fat makes up only 2-5% of total fat in cows, sheep, etc.– Conjugated linoleic acid– Vaccenic acid
Trans fat in hydrogenated vegetable can be up to 45% of total fat– Shortenings-30%– Margarine-15%
Some margarine is reformulated to reduce this number
History of Trans Fat
1890s– Paul Sabatier developed the chemistry of
hydrogenation– Only hydrogenated vapors
1901– Wilhelm Normann developed methods to hydrogenate
liquid oils– Patented the process
1909– Proctor and Gamble bought the rights to Normann’s
patent 1911
– P & G developed Crisco First hydrogenated shortening Hydrogenated cottonseed oil
http://en.wikipedia.org/wiki/Trans_fats
History of Trans Fat
Popularity of hydrogenated fats increased until 1960s– Lower costs– Belief that unsaturated trans fats in margarine were healthier than
saturated fats in butter Center for Science in the Public Interest (CSPI) campaigned
against saturated fats in the fast food industry in 1984– Fast food industries replaced saturated fats with trans fats
In 1987, CSPI defended trans fats in their newsletter In 1992, CSPI started speaking out against trans fats In 1994, it was estimated that trans fats caused over 30,000
deaths a year Currently, CSPI is against trans fats
Benefits of Trans Fats
Partially hydrogenating plant oils– Decreases rancidity
Decomposition of fats by hydrolysis or oxidation
– Increases shelf life– Decreases need for refrigeration– Forms a semi-solid because of increased melting
temperature Malleable fat that melts when cooked or consumed Semi-solid fats are preferred for baking because they
cause a more desirable texture in the baked products
Benefits of Trans Fats
Can replace butter and lard Foods containing trans fats are considered
kosher Can be consumed by vegans, vegetarians,
and people who follow religions banning certain animal products
Trans Fats and Health Risks
Coronary Heart Disease (CHD)– CHD risk doubles with each 2% increase in trans fat
consumed– CHD risk doubles with each 15% increase in sat fat
consumed Trans fat and sat fat increases levels of LDL (bad
cholesterol) in the body Trans fat, but not sat fat, decreases levels of HDL
(good cholesterol) in the body As a result, the increase in the LDL/HDL ratio due to
trans fat is about double that due to sat fat
Trans Fats and Health Risks
LDL– Transports cholesterol throughout the body– When too much is present, builds up in the walls
of arteries Makes arteries hard and narrow
HDL– Picks up extra cholesterol and brings it back to
the liver
Trans Fats and Health Risks
Increases triglycerides– Another type of fat– Can also build up in the arteries– Can cause heart disease
Causes more inflammation– Process by which your body responds to injury– Inflammation may play a role in fatty blockages in the heart
blood vessels– Trans fat appears to damage cells lining blood vessels
Leads to inflammation
Trans Fats and Health Risks
Cancer– No significant evidence that trans fat increases
risk– Current studies are finding it may have a
connection to prostate cancer Diabetes
– Some evidence suggests that risk of type-2 diabetes increases with trans fat consumption
– No conclusions have been made
Trans Fats and Health Risks
Obesity– No scientific evidence that specifically links trans fat intake
to obesity– People who eat a lot tend to eat a lot of trans fat
Does not mean that trans fat is the specific cause of obesity
Fertility– Research showed that increases in trans fat may cause
increases in infertility in women CHD is the only health risk with strong evidence
linking it to trans fat intake
Trans Fats and Health Risks
It has been found that trans fat found in breast milk varies with maternal trans fat intake– 1% in Spain– 2% in France– 7% in Canada
Trans Fats and Health Risks
New England Journal of Medicine (NEJM)– "from a nutritional standpoint, the consumption of trans fatty
acids results in considerable potential harm but no apparent benefit.“
National Academy of Sciences (NAS)– "trans fatty acids are not essential and provide no known
benefit to human health“– "that dietary trans fatty acids are more deleterious with
respect to CHD than saturated fatty acids“– NAS reported that there is no level of trans fat consumption
that can be considered safe Even a small increase in trans fat consumption increases risk
of CHD
Trans Fats and Health Risks
NAS has not recommended removing all trans fats from diets– Trans fats occur naturally in meat and dairy
products– Removing trans fats from diets would possibly
cause malnutrition and undesirable side effects
World Health Organization recommended a level of less than 1% of overall energy intake
Trans Fats and Health Risks
Have been some suggestions that trans fat naturally present in dairy and meat are different than those synthetically made– US National Dairy Council claims that natural
trans fats do not have the same negative effects– However, this may just be due to the fact that
levels of trans fats found in dairy and animal products are low
Trans Fats and Health Risks
Eating unsaturated but not trans fats decreases risk of CHD– Replacing 2% of trans fat intake with non-trans
unsaturated fats reduces risk of CHD by 53%– Replacing 5% of sat fat intake with non-trans
unsaturated fat reduces risk of CHD by only 43%
Consumption of polyunsaturated fats are linked to a decrease in mortality
Trans Fat in the News
July 11, 2003– All trans fat must be labeled on food products– Trans fat levels of less than 0.5 g/serving can be labeled 0
g/serving– Trans fat, as defined by FDA, is a system with one or more
trans linkages not in a conjugated system Naturally occurring trans fats are not included
– Some think that 0.5 g/serving is too high to be considered “trans fat free”
– In Canada, 0.2 g/serving is considered “trans fat free”
Trans Fat in the News
May 2003– BanTransFats.com sued Kraft Foods for having too much
trans fat in Oreos– Lawsuit dropped after Kraft agreed to try to reformulate
Oreos May 2005
– Tiburon, CA is the first American city where restaurants voluntarily cook using trans-fat-free oils
2006– CSPI sues KFC over use of trans fat in foods– KFC agreed to replace its partially hydrogenated soybean
oil with trans-fat-free soybean oil
Trans Fat in the News
December 5, 2006– New York City is the first American city to limit
uses of trans fats in restaurants– By July 1, 2007, no more use of oils and
shortenings containing more than 0.5 g/serving of trans fat
– By July 1, 2008, all items on menu must not contain more than 0.5 g/serving of trans fat
Chicago is considering a ban on trans fats
What is Currently Being Done?
Many food companies and fast food restaurants are voluntarily reducing or eliminating trans fat from their foods
– Walt Disney will get rid of trans fats from their theme parks by end of 2007
Crisco, now owned by J.M. Smucker Company, released a trans-fat-free version of Crisco
– Now have removed all but 1 g/serving of trans fats from their products
– These have replaced the trans-fat-free version
What is Currently Being Done?
Partial hydrogenation of plant oils without production of trans fat
– Varied pressure (much higher)– Under normal processing conditions, trans fat makes up
around 40% of total fat– Under high pressure conditions, trans fat makes up only
around 17% of total fat Can then be mixed with non-hydrogenated oil to make
margarine containing 5-6% trans fat Can be considered “trans-fat-free”
– Can also possibly change temperature and length of time for hydrogenation to control trans fat
References
American Heart Association-Trans Fat Overviewhttp://www.americanheart.org/presenter.jhtml?identifier=4776
American Journal of Clinical Nutritionhttp://intl.ajcn.org/cgi/content/abstract/66/4/1006S
FDA-Revealing Trans Fatshttp://www.fda.gov/fdac/features/2003/503_fats.html
Mayo Clinic-Trans Fat:Avoid This Cholesterol Double Whammyhttp://www.mayoclinic.com/health/trans-fat/CL00032
Wikipediahttp://en.wikipedia.org/wiki/Transfat
http://heartdisease.about.com/cs/cholesterol/a/Transfat.htm
Questions?