Slide 1: Biochemical Description of Trans-Fats

● Unsaturated fatty acids are classified into two types: cis and trans-fat, based on their
chemical structures, and are considered geometric isomers (Slifer & Foist, 2023).
- A geometric isomer has the same number and type of atoms and the same types of
bonds but differs in the spatial arrangement of those atoms (Slifer & Foist, 2023).
● Can be further categorized as monounsaturated and polyunsaturated fats (Moll, 2024).
a. Monounsaturated fats: structure contains only one double bond.
b. Polyunsaturated fats: structure contains two or more bonds.
- Cis-Fat
a. Structure
i. Cis-fats are fatty acids that contain hydrogen atoms on the same
side of the double bond, causing a kink in the fatty acid chain.
1. Linoleic acids are polyunsaturated cis fatty acids with 18
carbons, 32 hydrogens, and 2 oxygens. The position of the
two double bonds is at carbon 9-12 (National Center for
Biotechnology Information, n.d.).
b. Cis-fats in nature
i. Cis fatty acids are typically found in natural foods; such as nuts,
fish, and corn oil (Slifer & Foist, 2023).
- Trans-Fat
a. Structure
i. The double bond contains hydrogen atoms on opposite sides,
resulting in a straight/linear chain.
1. Elaidic acid is a trans-Oleic acid with 18 carbons, 34
hydrogens, and 2 oxygens—with a double bond between
carbon atoms 9 and 10 (Church et al., 2018).
b. Trans-fat in Nature
i. Trans fatty acids are typically made through the partial
hydrogenation process of liquid oils (usually vegetable oils)
(World Health Organization, 2024).
ii. Small amounts of trans-fat also occur naturally in meat and dairy
products from ruminant animals (World Health Organization,
2024).
Difference between trans/cis/saturated fats
- The key differences lie in their chemical structures and physical properties
a. Saturated fats have no double bonds between carbon atoms, resulting in
straight chains that can pack tightly and make them solid at room
temperature (Washmuth & McLaughlin, 2023).
i. Due to its tendency to stay solid at room temperature, it can lead to
atherosclerosis (hardening of the arteries) (Siri-Tarino et al., 2010).
 ii. Unlike cis-fats, high consumption of saturated fats may increase
LDL (bad cholesterol) (Siri-Tarino et al., 2010).
iii. Found in animal meat, plant oils, dairy products, processed meats,
and tropical oils (Heart, 2024).

b. Cis-Fats have one or more cis double bonds, creating kinks and
preventing tight packing; thus, they are liquid at room temperature
(Pressbooks, n.d.).
i. Cis fats aid in increasing the HDL (good cholesterol) within our
bodies, so they are typically considered better for human
consumption than trans fats (Slifer & Foist, 2023).
ii. Geometric isomers
iii. Most fatty acids are cis since they are naturally found in many
foods (Slifer & Foist, 2023).

c. Trans-Fats have double bonds that straighten the chain, allowing them to
pack more tightly than cis-fats but less so than saturated fats, often semi-
solid at room temperature (Khan Academy, 2015).
i. Geometric isomers
ii. Aren’t often found in nature but rather in processed foods and are
formed through a process called hydrogenation (Warwick, 2023).
Slide 2: Trans-fats in Nature
● While trans-fat can occur naturally in small amounts in the gut of certain animals, it is
also produced through an industrial process of any liquid oil by partial hydrogenation.
While artificially made trans fats may lead to health risks, natural trans fats are safe for
human consumption (Warwick, 2023).
- Hydrogenation involves adding hydrogen atoms to the unsaturated bonds with
fatty acid chains connected to the triglyceride backbone. This process transforms
unsaturated fat into saturated fat, thereby raising its melting point (Arellano &
Smith, 2015).
- Involves reacting oil with hydrogen gas using a metallic nickel catalyst (Arellano
& Smith, 2015). The hydrogen targets the reactive unsaturated double bonds in
fatty acids, reducing unsaturated and transforming the oil’s chemical and physical
properties. This process can turn liquid oil into semi-solid or solid fat (Arellano &
Smith, 2015).
- Partial hydrogenation is the process of hydrogen being added to liquid oil
(mostly vegetable oil) to break the double bond(s), converting the
polyunsaturated fatty acids to monounsaturated and saturated fatty acids
(Center for Science in the Public Interest, n.d.).
● Due to the growing awareness of the harmful effects of trans fats, the food industry has
sought ways to reduce their content. Approaches include using different catalysts and/or
improving hydrogenation reactor designs, for example, the process of partial
hydrogenation of liquid oils (Arellano & Smith, 2015).
- Partially hydrogenated oil is used to increase shelf life, therefore making it
inexpensive and less likely to spoil (Mayo Clinic, n.d.).
- Trans fats enhance the taste and texture of foods, making them appealing. Many
restaurants and fast-food chains prefer trans fats for deep-frying, as these oils can
be reused multiple times in commercial fryers (Heart, 2017).
Slide 3: Common Fats
Lauric Acid
a. Sources
i. Found predominantly in coconut milk and kernel oil (ACS, 2018).
ii. Present in human breast milk and some animal fats (NIH, 2020).
b. Structure
i. 12-carbon saturated fatty acid with no double bonds (National Institutes of
Health, n.d.)
ii. Straight saturated fatty chain and a medium-chain fatty acid.
iii. Dodecanoic Acid
- Twelve-carbon and medium-chain fatty acids. Derives from
hydride and dodecane (National Institutes of Health, n.d.).

c. Properties
i. Solid at room temperature but melts easily in boiling water
ii. Melting point is around 43.2°C (111°F) (National Institutes of Health,
n.d.).
d. Uses
i. Utilized in soap and cosmetic production due to its antimicrobial
properties
ii. Used for treating viral infections (WebMD, n.d.).
 iii. Non-toxic and inexpensive compound that is often used in laboratory
research (DrugBank, n.d.).
e. Health Implications
i. May increase levels of HDL cholesterol (de Roos et al., n.d.).

Alpha-Linolenic Acid
a. Sources
i. Commonly found in plants
ii. Flaxseed, canola, soy, perilla, and walnut oils (Mount Sinai, n.d.).
b. Structure
i. Omega-3 polyunsaturated fatty acid (ChEBI, n.d.).
ii. 18-carbon chain with three cis double bonds at carbons 9, 12, and 15
(ChEBI, n.d.).
iii. Has a carboxyl group at one end and a methyl group at the other (ChEBI,
n.d.).
c. Properties
i. Liquid at room temperature
ii. Has a lower melting point due to multiple kinks from cis double bonds
(Homework Study, n.d.).

d. Uses
i. Important for normal metabolism
ii. Essential substrate for longer-chain omega-3 fatty acids like EPA and
DHA (Baker & Calder, n.d.).
e. Health Implications
i. Lower the risk of cardiovascular diseases (WebMD, n.d.)
ii. Reduce blood clots (WebMD, n.d.)

Oleic Acid
f. Sources
i. Most widely distributed (Choi, 2010)
ii. Commonly found in various animals and vegetables (eg., olive, grape
seed, buckthorn oil) (gar, 2024).
g. Structure
i. Cis mono-unsaturated fatty acid (National Library of Medicine, n.d.)
ii. 18-carbon chain with one cis double bond at carbon 9-10 (National
Institutes of Health, n.d.).
iii. Contains a carboxyl group at one end
h. Properties
i. A solid with a low melting point due to multiple kinks from cis double
bonds (da Vinci, 2024).
 - α-form, melting point 13.4 °C (da Vinci, 2024).
- β-form, melting point 16.3 °C (da Vinci, 2024).
i. Uses
i. Used to replace saturated fatty acids in diets since they can improve heart
conditions (WebMD, n.d.).
ii. Used in medicines and pharmaceuticals while also acting as an emulsifier
for aerosol products (Choulis, 2011).
j. Health Implications
i. Benefits our heart, brain, mood, skin, cells, waistline, and overall health
(Ruggeri, 2018).
ii. Helps reduce inflammation and fight free radical damage (Ruggeri, 2018).

Slide 4: History of Trans-Fats and Our Diet

Trans-fat in 2002
● Began developing policies to limit trans-fat content in foods
- Health Canada initiated efforts to reduce trans-fat consumption to improve
public health in 2002 (Health Canada, n.d.).
- Launched programs to monitor trans-fat levels in Canadian foods
a. This started with requiring information provided to consumers on
the trans fat content in the nutrition facts table of prepackaged
foods (Health Canada, n.d.).
- Regulatory standards were introduced to permit “trans-fat-free” claims on
product labels, aiming to guide consumers towards healthier options
(Health Canada, n.d.).

Trans-fat-free food
● Food labeled as “trans-fat-free” contains less than 0.5 grams of trans fat per
serving (Zelman, 2009)
- However, this does not mean there is absolutely zero trans fat in the
product (Zelman, 2009).
a. Can still contain up to 0.5 grams of trans fat and still be labeled as
zero trans fat (Zelman, 2009).
- Helps consumers make healthier choices but may lead to inadvertent
consumption if multiple servings are eaten (Zelman, 2009).
- Is this a good definition?
- While it does aid in reducing intake of trans fat, it could also be
misleading. As mentioned earlier, “trans-fat-free” does not necessarily
mean there is absolutely no trans fat in the product, so this can mislead
people and cause them to consume more trans fat than usual.
 Trans Fat Task Force
● The Trans Fat Task Force was established in early 2005 to develop strategies for
reducing trans-fats in Canadian diets (Government of Canada, n.d.).
- In 2006, they recommended limiting trans-fat content to 2% of total fat in
vegetable oils and spreadable margarine and 5% in all other foods (Health
Canada, n.d.).
- Their work led to voluntary reductions by industry and informed future
regulations banning trans-fats (Health Canada, n.d.).
- Composed of stakeholders from the government, industry, and health
organizations (Government of Canada, n.d.).
Slide 5: Impact on Cholesterol Levels
What is cholesterol level?
- Cholesterol is a fat-like, waxy substance essential for our body to function
properly and can be found in every cell. However, excess cholesterol in your
blood can adhere to the walls of your arteries, leading to narrowing or blockages
(MedlinePlus, 2024).
a. LDL (Low-Density Lipoprotein)
i. Often referred to as “bad” cholesterol
ii. Carries cholesterol from the livers to the cells (MedlinePlus, 2024).
iii. High levels of LDL can lead to cholesterol buildup in the arteries,
increasing the risk of heart disease and strokes (CDC, 2024).
iv. Analogy: A delivery truck brings cholesterol to where it’s needed,
but when there’s too much, it dumps the excess in your arteries.
b. HDL (High-Density Lipoprotein)
i. Known as “good” cholesterol
ii. Transports cholesterol from the cells and arteries back to the liver,
where it’s either reused or excreted (MedlinePlus, 2024).
iii. High levels of HDL are associated with a lower risk of heart
disease because they help remove excess cholesterol from the
bloodstream (MedlinePlus, 2024).
iv. Analogy: Acts like a cleanup crew, taking the excess cholesterol
back to the liver to be processed and removed.
What affects cholesterol levels?
a. Drinking
i. Raises total cholesterol level (MedlinePlus, 2024).
b. Smoking
i. Lowers HDL cholesterol and raises LDL cholesterol (MedlinePlus, 2024).
c. Lack of exercise
i. No exercise and lots of sitting will lower the HDL cholesterol
(MedlinePlus, 2024).
d. Diet
 i. Unhealthy eating habits will lead to raising your LDL cholesterol
- Eating lots of saturated fats (red meats, sugary sweets, snacks,
deep-fried, and processed foods) (MedlinePlus, 2024).
ii. Trans fat is the most harmful fat to consume. Unlike other dietary fats,
trans fats (or trans-fatty acids) increase LDL and decrease HDL (Mayo
Clinic, n.d.).
- Eating a diet high in trans fats elevates the risk of heart disease, the
top cause of death among adults (Mayo Clinic, n.d.).
- The higher the intake of trans fats, the greater the danger to heart
and blood vessel health (Mayo Clinic, n.d.).
- Due to their severe health risks, the FDA (Food and Drug
Administration) has banned food manufacturers from adding major
sources of artificial trans fats in food and drinks (Mayo Clinic,
n.d.).
- FDA estimates that this regulation will prevent thousands
of heart attacks and deaths annually (Mayo Clinic, n.d.).