TỔNG ÔN TẬP THI VÀO LỚP 10 MÔN TIẾNG ANH NĂM HỌC 2023 - 2024 CÓ ĐÁP ÁN (NGỮ Â...
Fish Oil
1. Case Conference: Omega-3
Polyunsaturated Fatty Acids
Group II – Section A
ALFONSO, ALJAMA, ALUZAN,
AMURAO, ARELLANO,
ARROYO
2. Case: Omega-3 Fatty Acid
Supplementation
• A 42-year old male with a strong familial
history of coronary heart disease was
presently asymptomatic. He read several
articles in national magazines and in the
newspapers that fish oil capsules may help
prevent coronary thrombosis.
3. Case: Omega-3 Fatty Acid
Supplementation
• Such dietary supplements are available over
the counter without a prescription. In an
attempt to protect himself against coronary
heart disease, he purchased 500 mg fish oil
capsules containing 50% omega-3
polyunsaturated fatty acids and ingested six
capsules daily.
5. Overview and Introduction
• POLYUNSATURATED FATTY ACIDS
• Straight chain derivatives of fatty acids
containing
• Two or more double bonds.
• ESSENTIAL FATTY ACIDS
• Molecules that cannot be synthesized by the
human body but are vital for normal metabolism
•
• One of these essential fatty acids is the
• Omega-3 Polyunsaturated Fatty Acids
6. Omega-3 Polyunsaturated Fatty Acids
• -essential dietary fatty acids, belonging to the
lenolenic family of PUFAs -contain a double
bond on the third carbon from the methyl end
•
• CHIEF DIETARY SOURCES: ocean fishes and fish
oils
• *Fish oil is obtained in the human diet by eating
oily fishes such as herring, mackerel, salmon,
albacore tuna, and sardines, or by consuming
fish oil supplements or cod liver oil
8. Omega-3 Polyunsaturated Fatty Acids
• Nutritionally important n−3 fatty acids
include α-linolenic
acid (ALA), eicosapentaenoic acid (EPA),
and docosahexaenoic acid (DHA), all of
which are polyunsaturated.
9. α-linolenic acid (ALA)
• -type of omega-3 fatty acid found in plants.
• -alpha-linolenic acid can be converted into EPA and DHA
in the body
• -highly concentrated in flaxseed oil and, to a lesser
extent, in canola, soy, perilla, and walnut oils.
•
10. Eicosapentaenoic acid (EPA)
• -EPA acts as a precursor for prostaglandin-
3 (which
inhibits platelet aggregation), thromboxane-
3, and leukotriene-5 groups
11. Docosahexanoic acid (DHA)
• Obtained directly from fish oil
• Present in high concentration in retina, cerebral
cortex, testis and sperm
• Needed for brain and retinal development
19. Omega-3 will alter a host of
biophysical properties of membranes
•
like:
1. formation of metarhodopsin II, is modulated by the degree
of unsaturation of retinal phospholipid. Fatty acids such that DHA-
rich bilayers support the highest levels of metarhodopsin II
formation.
2. DHA-rich membranes reduce the inhibitory effect of cholesterol
on rhodopsin activation
3. enhances the sodium-potassium-ATPase pump
4. enable specialized cellular functions, such as the rapid firing of neurons.
5. they are chemically unstable that they oxidize very quickly. This instability can cause gradual oxidation
reaction especially in the brain thereby participating further in the brain aging process.
22. Eicosanoid Synthesis
• Marine plants, especially the unicellular algae
in phytoplankton, carry out chain elongation
and further desaturation of α-linolenic acid to
yield the long-chain n-3 PUFAs
eicosapentaenoic and docosahexaenoic acids
• It is the formation of these long chain n-3
PUFAs by marine algae and their transfer
through the food chain to fish that accounts for
their abundance in some marine fish oils.
23. ω-3 Fatty Acids
• Marine plants, especially the unicellular algae
in phytoplankton, carry out chain elongation
and further desaturation of α-linolenic acid to
yield the long-chain n-3 PUFAs
eicosapentaenoic and docosahexaenoic acids
• It is the formation of these long chain n-3
PUFAs by marine algae and their transfer
through the food chain to fish that accounts for
their abundance in some marine fish oils.
24. Eicosanoids
• Eicosanoids are family of oxygenated
derivatives of arachidonic (n-6 FA) and
eicosapentaenoic acids (n-3 FA)
• The precursor PUFA is released from membrane
phosphatidylcholine by the action of
phospholipase A2
• Eicosapentaenoic acids, competitively inhibit
the oxygenation of arachidonic acid by
cyclooxygenase and lipoxygenase
25. Eicosanoid Synthesis
• Figure 1. Synthesis of eicosanoids from arachidonic and eicosapentaenoic acids.
26. How are the ω-3 fatty acids related to
eicosanoid synthesis?
• Consumption of fish oil, which contains ω-3
fatty acids (long chain n-3 PUFA of
eicosapentaenoic acid) results in partial
replacement of arachidonic acid in cell
membranes by eicosapentaenoic acid
• This leads to decreased arachidonic acid
available for eicosanoid synthesis
27. Eicosanoid Synthesis
• Figure 2. Basis of the anti-inflammatory effects of eicosapentaenoic acid .
• EPA, eicosapentaenoic acid; COX, cyclooxygenase; LOX, lipoxygenase;
• LT, leukotrien; PG, prostaglandin; TX, thromboxane
28. Eicosanoid Synthesis
• Table 1.2: Physiological and biochemical effects of the most physiologically important eicosanoids.
(LT, leukotrien; PG, prostaglandin; TX, thromboxane)
29. Arachidonic acid vs. Eicosapentaenoic
acid
• Inhibiting metabolism of arachidonic acid,
eicosapentaenoic acid give rise to derivatives
which have a different structure to those
produced from arachidonic acid (i.e., 3-series
PG and TX and 5-series LT).
• Thus, the eicosapentaenoic acid-induced
suppression in the production of arachidonic
acid-derived eicosanoids is accompanied by an
elevation in the production of eicosapentaenoic
acid-derived eicosanoids
30. Arachidonic acid vs. Eicosapentaenoic
acid
• The eicosanoids produced from
eicosapentaenoic acid are considered to be less
biologically potent than the analogues
synthesised from arachidonic acid
• Thus, TXA3 has much lower potency to activate
platelets or to induce vasoconstriction than
TXA2 and LTB5 is much weaker in stimulation
neutrophil activation than LTB4.
31. ω-3 fatty acids
• The reduction in generation of arachidonic acid-
derived mediators which accompanies fish oil
consumption has led to the idea that fish oil is anti-
inflammatory.
• Clinical studies have reported that oral fish oil
supplementation has beneficial effects in multiple
sclerosis, asthmatics diseases and other immunity
depending diseases.
• Supporting the idea that the n-3 PUFAs in fish oil are
anti-inflammatory.
