Lipids - EFA Metabolism

Question 1

EFA Metabolism

Answer 1

Cell membrane fatty acid composition determines which prostaglandins will predominate; e.g. a diet rich in arachidonic acid leads to the formation of more pro-inflammatory PG2.
* The more abundant fatty acids will occupy the enzyme active sites, which highlights the importance of omega-3 and -6 balance.
* A high consumption of EPA and DHA from omega-3 means that a higher proportion of fatty acids resides in the cell membrane at the expense of AA.
* This can result in immune-suppression. Hence, it is all about balance.

Question 2

Genetic Variability

Answer 2

Genetic variability affects the synthesis of EPA and DHA. Polymorphisms are common in the genes coding for delta-6 and delta-5 desaturase.
* Other omega-6 and omega-3 fatty acids can be synthesised from ALA and LA respectively.
* By desaturation—addition of a double bond between two carbon atoms and / or elongation—addition of two carbon atoms.
* Both LA and ALA compete for the same desaturase and elongase enzymes.
* Only 1–20% of ALA is converted to EPA.
* Women of reproductive age convert ALA 2.5 times better than men.
polymorphism = a genetic variation

Question 3

EFA Metabolism

Answer 3

See Diagram

Question 4

Inhibitors of EFA Metabolism (Delta-6-Desaturase)

Answer 4

Delta-6-Desaturase inhibited by:
* Magnesium, B6, zinc deficiency
* Insulin resistance
* Viruses
* Refined sugars
* Alcohol
* Stress hormones, e.g. cortisol
* High intake of EPA/DHA
* Excess trans fats and cholesterol

Question 5

Inhibitors of EFA Metabolism (Delta-5-Desaturase)

Answer 5

Delta-5-Desaturase inhibited by:
* Insulin resistance
* Zinc deficiency
* Alcohol
* Excess trans fats and cholesterol
* Stress hormones, e.g. cortisol
* High intake of EPA/DHA

Question 6

Omega Testing

Answer 6

EFA testing includes:
* Omega-3 index —a marker for cardiovascular risk.
* Omega-6:3 ratio —a marker for chronic illness.
* AA:EPA ratio —a marker of ‘silent’ inflammation.
Maintaining the balance of omega-3 and omega-6 can be addressed by supplementing EPA / DHA, along with addressing any co-factor deficiencies needed for interconversion.
* Fatty acid profile testing options:
o Genova —essential and metabolic fatty acids test (blood test).
o Wiley’s Finest —omega-3 index test (blood spot).
o Igennus—Opti-O-3 (blood spot).