Lipids - Omega- Fatty Acids

Question 1

Omega 6:
Linoleic Acid (LA)

Answer 1

LA is an omega-6 fatty acid, 18:2 n-6.
* Food sources include vegetable oils, safflower, sunflower, soybean, and corn oils. It is found in nuts, seeds and some vegetables.
* Flax and hemp oil are considered ‘nutritionally superior’ to safflower oil because they also contain omega-3.
* Conversion of LA to GLA requires vitamin C, B3, B6, magnesium and zinc.

Question 2

Break down words

Answer 2

• Lino-= Greek for ‘flax’ (linseed) –indicating its presence also in flaxseeds
• -Oleic = olive oil (‘oleic acid’)

Question 3

Gamma-Linolenic Acid (GLA)

Answer 3

GLA is an omega-6 fatty acid, 18:3 n-6.
* Main food sources include evening primrose oil, blackcurrant seed oil, hemp and borage oils.

Question 4

GLA therapeutic uses: Rheumatoid arthritis

Answer 4

• ↓ joint pain, swelling and morning stiffness in RA.
• GLA is converted to PG1, which has immune-regulatory and anti-inflammatory effects. This includes a reduction in NF-kB activity.
• Dosage: 1.4 g / d of borage seed oil.

Question 5

GLA therapeutic uses: ADHD

Answer 5

• A combination of GLA and EPA shows improvements in attention and impulsivity

Question 6

GLA therapeutic uses:
Eczema

Answer 6

• Reduced inflammation; improves skin symptoms.
• Just be careful not to raise the levels of AA.
• Dosage: 320 mg GLA per day.

Question 7

GLA: Evening Primrose Oil (EPO)

Answer 7

• EPO is abundant in LA, and contains GLA which is also present in borage, blackcurrant seed and hemp seed.

Question 8

GLA: Evening Primrose Oil (EPO): Premenstrual syndrome (PMS)

Answer 8

• GLA is a precursor to PG1, which inhibits prolactin (↑ in women with PMS).
• Dosage: 1500 mg daily for three months.

Question 9

GLA: EPO therapeutic uses: Cyclical mastalgia (breast pain)

Answer 9

• GLA forms PG1 which inhibits the synthesis of arachidonic acid metabolites (= anti-inflammatory).
• Dosage: 1000 mg 3 x daily for four to six months.

Question 10

GLA: EPO therapeutic uses: Female fertility

Answer 10

• Increases and optimises cervical mucus, to sustain sperm during conception.
• Dosage: 1500–2000 mg daily from day 1 of menses.

Question 11

GLA in pregnancy

Answer 11

• Borage seed oil, and possibly other sources of GLA, should not be used during pregnancy.
• Dosages of greater than 3,000 mg / day may increase AA production.

Question 12

GLA Drug interactions:

Answer 12

• Ceftazidime—it may increase the effectiveness of this antibiotic.
• Chemotherapy—it may increase treatment effects.
• Cyclosporine—it may increase the immunosuppressive effects.
• NSAIDs—NSAIDs may counteract the effects of GLA.
• Phenothiazines—they may increase the risk of seizures.

Question 13

Arachidonic Acid (AA)

Answer 13

Arachidonic acid (AA) is an omega-6 fatty acid, 20:4 n-6.
* Arachidonic acid is primarily found in animal products such as meat, eggs and dairy, especially when those animals are intensively raised on grain.
* Dihomo-gamma-linolenic acid (DGLA) can be converted to AA using delta-5-desaturase. However, this enzyme is used preferentially for the omega-3 pathway, so the majority of AA in the diet is from animal products

Question 14

AA and Inflammation

Answer 14

Arachidonic acid is often seen as inflammatory, but:
* Inflammation is a key part of the immune system’s response to injury and infection.
* AA is metabolised by COX-1 and COX-2 enzymes to the inflammatory prostaglandin series 2.
* This causes inflammatory effects including fever, vascular permeability and vasodilation, pain and oedema.
However, to prevent excessive inflammation PG2 induces 15-LOX activity that leads to the formation of lipoxins (anti-inflammatory).