Essential Fatty Acids (EFAs)

Question 1

Essential Fatty Acids (EFAs)

Answer 1

There are two fatty acids that cannot be made in the body and so are essential in the diet. They are:
1. Linoleic acid (an omega-6 fatty acid).
2. Alpha linolenic acid (an omega 3 fatty acid).
• Arachidonic acid was once thought to be essential in the diet, but we now know it can be made from linoleic acid.
• Humans lost the ability to introduce double bonds into fatty acids between the carbon atoms 6‒7 and 3‒4, making LA and ALA essential in the diet.

Question 2

Essential Fatty Acids Conversion

Answer 2

ALA and LA have to be obtained from foods so are ‘essential’
From ALA (omega 3) and LA (omega 6), the next in the sequence is manufactured in the body from the preceding fatty acid in the chain, with the help of special enzymes. The most important enzyme that catalyses the chemical reaction to produce GLA and EPA is Delta-6 desaturase

Question 3

Omega-3 Pathways

Answer 3

Question 4

Omega 6 Pathway

Answer 4

Question 5

EFAs: Western Diet

Answer 5

A typical western diet is abundant in omega-6 fatty acids (plant oils, grain fed meat and dairy), and low in omega 3 fatty acids from ALA sources (flaxseeds, pumpkin seeds) and EPA / DHA sources (oily fish).
• Human beings evolved on a diet with an omega 6:omega 3 of 1.
• In Western diets the ratio is generally around 16:1.
• The relatively low rate of conversion of ALA to EPA / DHA suggests that EPA and DHA are conditionally essential nutrients.
• To achieve the EFSA recommended intake of 250 mg EPA / DHA, consume 2 3 portions of oily fish per week or from an algal source.

Question 6

EFAs: Functions

Answer 6

• EFAs are vital components of all cell membranes and help to maintain membrane fluidity . The fluidity of the membrane must be maintained within a certain range for the cell to function properly.
• They act with cell membrane proteins thereby affecting the transport of substances into and out of the cell.
• EFAs are key components of organelle membranes such as those of the mitochondria.
• EFAs are necessary for cell to cell communication.
• They are essential for foetal and child brain development
• EFAs are precursors of eicosanoids , which are ‘local’

Question 7

EFAs: Roles

Answer 7

Skin
Endocrine system
Reproductive system
Circulatory
Musculoskeletal
Immune
Neurological

Question 8

EFAs: Skin

Answer 8

• Dry, flaky, scaly, chapped lips (also dry
• Hyperkeratosis pilaris.
• Delayed wound healing.
• Nails: Dry / brittle, red / swollen cuticles.
• Hair: Dry / oily, split ends, alopecia.
• Acne / eczema / psoriasis / dermatitis.

Question 9

EFAs: Endocrine system

Answer 9

• Weight imbalances (obesity / weight loss).
• PMS / painful menstrual cramps / sore breasts.
• Hyperinsulinaemia

Question 10

EFAs: Reproductive system

Answer 10

• Infertility / impotence / history of repeated miscarriages.
• Ovarian cysts / fibrocystic breast disease.

Question 11

EFAs: Circulatory

Answer 11

• Frequent nosebleeds / bleeding gums.
• Easy bruising.
• Delayed recovery from exercise.

Question 12

EFAs: Musculoskeletal

Answer 12

• Chronic joint pain / arthritis.
• Delayed recovery from injuries.

Question 13

EFAs: Immune

Answer 13

• Susceptibility to infections.

Question 14

EFAs: Neurological

Answer 14

• Dementia / Alzheimer’s.
• Parkinson’s disease.
• Irritability / nervousness.
• Tingling arms and legs.
• CFS / ME.