Essential fatty acids are lipids that humans must obtain from their diet. There are two primary types - Omega-3 and Omega-6 fatty acids. Omega-3 fatty acids include ALA, EPA, and DHA which are important for brain and heart health. Omega-6 fatty acids include LA, AA, and GLA. Essential fatty acids are structural components of cell membranes and are involved in processes like immune response and inflammation regulation. The body can convert some fatty acids but not across Omega-3 and Omega-6 families, so both must be consumed.

1. Essential
Fatty Acids
By: Zeravan Ali Sulaiman

2.  Introduction.
 Types of essential fatty acids.
 Omega 3 and its types.
 Omega 6 and its types.
 Functions of essential fatty acids.
 Metabolism of essential fatty acids.
 References.
Contents:

3.  Essential fatty acids (EFAs) are important constituents of all cell membranes. EFAs
confer on membranes properties of fluidity, and, thus, determine and influence the
behavior of membrane-bound enzymes and receptors.
 Essential fatty acids are lipids that are not metabolized by the body and therefore,
must be obtained from the diet. These fatty acids are involved in various biological
processes, and produce many compounds when they are metabolized.
 They are also called polyunsaturated fatty acids (PUFAs). They remain in a liquid
form even in cold weather unlike saturated oils which solidify.
 There are two primary families of essential fatty acids, Omega-3 and Omega-6, with
constituent lipids within each group. Fatty acids within each of these families may be
converted from each other, but not across families, and therefore both families must be
consumed in food.
Introduction:

4.  There are two types of naturally occurring essential fatty acids (EFAs) in the body,
the ω-6 series derived from cis-linoleic acid (LA, 18:2) and the ω-3 series derived
from α-linolenic acid (ALA, 18:3).
 There is another sequence of fatty acids derived from oleic acid (OA, 18:1 ω-9). OA
is not an EFA since it can be derived from simple precursors in mammals.
 All the three ω-9, ω-6, and ω-3 series of unsaturated fatty acids are metabolized by
the same set of enzymes to their respective long-chain metabolites.
 Since ω-6 and ω-3 EFAs are the EFAs, and further discussion here is centered on
these two series of fatty acids and their metabolites.
 The longer chain metabolites of LA and ALA are particularly important in
regulating membrane function. These long-chain metabolites are of major
importance in the brain, retina, liver, kidney, adrenal glands and gonads.
Introduction:

5.  Humans can synthesize saturated fatty acids and some monounsaturated fatty acids up to
about 20 carbons in length. However, they are limited in the ability to synthesize longer chain
PUFAs, especially those with double bonds at ω3 and ω6 positions. Humans must rely on dietary
sources from plants and animals (mostly fish) to acquire sufficient amounts of u3 and u6 (long
chain) fatty acids.
 Biologically, Conjugated Linoleic Acid (CLA) fatty acids are esterified to phospholipids and
located incorporated into cell membranes. Long chain polyunsaturated fatty acids are important
to our health and have critical roles in metabolism, immune response, prevention of coronary
heart disease (CHD), and brain development in the young.
Introduction:

6. Omega 3 Omega 6
Types of EFTs:
Essential fatty acids
1. LA (linoleic acids)
2. AA (arachidonic acid)
3. GLA (Gamma Linoleic Acid)
1. ALA (alpha-linolenic acid)
2. DHA (docosahexaenoic acid)
3. EPA (eicosapentaenoic acid)

7.  They are polyunsaturated fatty acids with first double bond three carbon from methyl end.
 All omega-3 fatty acids (ω3 or n-3) have at least one double bond between the third and
fourth carbon atom counting from the methyl end of the fatty acid.
 The parent fatty acid of the omega-3 series is alpha-linolenic acid (ALA).
 Humans can synthesize long-chain (20 carbons or more) omega-3 fatty acids, such as
eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3).
Omega 3:

8.  There are three major types of omega-3 fatty acids from ingested food and used by
the body:
1. alpha-Linolenic acid (ALA).
2. Eicosapentanoic acid (EPA).
3. Docosahexanoic acid (DHA).
 Once ingested, the body converts ALA to EPA and DHA, the two kinds of omega-3
fatty acids that can be used more easily by the body.
Omega 3:

9. 1. alpha-Linolenic acid (ALA):
 ALA is an n-3 fatty acid.
 Is the parent fatty acid of the omega-3 series.
 They are necessary for health and can not be produced within the human body.
 Primarily converted to docosahexaenoic acid (DHA) & eicosapentaenoic acid (EPA).
 Sources of ALA:
• Seeds: e.g. flax, chia & hemp seeds
• Plant oils: e.g. flax (linseed), chia, hemp, soybean & walnuts oils
• Nuts: e.g. walnuts
• Legumes: e.g. mung beans & soybeans Green
• vegetables: e.g. brussel sprouts, kale & spinach
Omega 3:

10. Omega 3:
2. Eicosapentaenoic acid (EPA):
 EPA contains a 20 carbons chain and five cis double bonds; the first double bond is located at the third
carbon from the omega end. In physiological literature, it is given the name 20:5.
 Sources:
• Oily fish such as: cod liver oil, herring, salmon, sardines.

11. 3. Docosahexaenoic acid (DHA):
 DHA is 20 carbons chain and six cis double bonds; the first double bond is located at the third carbon
from the omega end.
 Sources:
• Oily fish such as: Salmon, sardines, tuna, herring, trout, mackerel, anchovies.
• Green-lipped mussels Fish oils: e.g. cod liver oil
Omega 3:

12.  They are polyunsaturated fatty acids with first double bond six carbons from methyl end.
 In all omega-6 (ω6 or n-6) fatty acids, the first double bond is located between the sixth and seventh
carbon atom from the methyl end of the fatty acid.
 The parent fatty acid of the omega-6 series is linoleic acid (LA; 18:2n-6).
 Humans can synthesize long-chain (20 carbons or more) omega-6 fatty acids, such as dihomo-γ-
linolenic acid (DGLA; 20:3n-6) and arachidonic acid (AA; 20:4n-6), from LA
Omega 6:

13.  There are three major types of omega-6 fatty acids from ingested food and used by the body:
1. Linoleic acids (LA):
 LA is an unsaturated omega 6 fatty acid. Chemically it is an 18-carbons chain. The first double bond
is located at the sixth carbon from the omega end of the fatty acid.
 Important for the maintenance of normal metabolism, healthy skin, strong bones and a healthy
reproductive system. It also supports normal development and growth of your brain.
 Sources:
• Vegetable oils: e.g. soybean, safflower, sesame, corn, canola, rice bran, walnut & sunflower oils Seeds:
e.g. sesame & sunflower
• Seeds: e.g. sesame & sunflower seeds
• Nuts: e.g. walnuts, cashews & pecans
Omega 6:

14. 2. Arachidonic acid (AA):
 AA is a 20 carbons chain. Its first double bond is located at the sixth carbon from the omega end of the
fatty acid.
 Sources: AA can be found in meat.
Omega 6:

15. 3. Gamma Linoleic Acid (GLA):
 GLA is categorized as an n−6 (also called ω−6 or omega-6) fatty acid, meaning that the first double bond on
the methyl end (designated with n or ω) is the sixth bond. In physiological literature, GLA is designated as
18:3 (n−6).
 Sources:
Plant oils: e.g. borage, evening primrose & blackcurrant seed oils
Omega 6:

16.  EFAs are important structural components of cell membranes.
 Developing and maintaining good brain function.
 The production of molecules called “hormone-like”.
 They are responsible for regulating immune and inflammatory responses.
 They play important roles in many bodily processes, including heart health.
 They reduce triglycerides in the blood, lower blood pressure, and prevent thrombosis
by inhibiting blood clotting.
 They also may help reduce the risk of some cancers in animals.
Functions of essential fatty acids:

17.  In humans, both EFAs (n-3 and n-6 are 18 carbon atoms fatty acids) are metabolized to long-
chain fatty acids by desaturation and adding extra double bonds to the carboxyl group end of
the molecule. Linoleic acid (LA) is metabolized to arachidonic acid (AA) while
alphalinolenic acid (ALA) is metabolized to eicosapentaenoic acid (EPA) and
decosahexaenoic acid (DHA) as active metabolic end products. 7~ During early life there is
limited metabolic capability to convert ALA to DHA. Therefore, during fetal life, infancy and
early childhood DHA should be consumed de novo.
 Along with other lipids, essential fatty acids are extracted in the small intestine, absorbed into
circulation, and travel through the body. Once transported into cells, essential fatty acids serve
numerous functions.
 Concentrations of fatty acids in blood (i.e., whole blood, plasma, serum, and red blood cells)
reflect both dietary intake and biological processes.
Metabolism of Essential Fatty Acids:

19. 1. Das, U.N., Essential fatty acids-a review. Current pharmaceutical biotechnology, 2006. 7(6): p. 467-
482.
2. Zeece, M., Introduction to the Chemistry of Food2020: Academic Press.
3. Ferrier, D., 2013. Biochemistry (Lippincott Illustrated Review). 6th ed. Lippincott Williams &
Wilkins.
4. https://return2health.nz/articles/efa-how-essential .
5. Simopoulos, A.P., Essential fatty acids in health and chronic disease. The American journal of clinical
nutrition, 1999. 70(3): p. 560s-569s.
6. Singh, M., Essential fatty acids, DHA and human brain. The Indian Journal of Pediatrics, 2005. 72(3): p. 239-242.
References: