Lipids - Omega-3 Fatty Acids Flashcards
Omega 3:
Alpha Linolenic Acid (ALA)
ALA is an omega-3 fatty acid, 18:3 n-3.
* Food sources include flaxseeds, hempseeds, soybeans, and walnuts. It is also found in dark green leaves.
* Many edible plants produce this 18-carbon polyunsaturated fatty acid.
lino-= Greek for ‘flax’ (linseed)
ALA therapeutic uses: Cardiovascular disease (CVD)
- Decreases the risk of myocardial infarctions, atherosclerosis development and strokes.
- Reduces C-reactive protein levels (an inflammatory marker used to evaluate CVD risk).
- Anti-arrhythmic effect – incorporation of ALA into the cell membranes of cardiomyocytes modifies ionic channel currents, stabilising electrical activity.
- Anti-hypertensive—ALA lowers the activity of angiotensin-converting enzyme (ACE).
- Shown to lower LDL cholesterol (whole flaxseed).
ALA therapeutic uses: Neurological
- Strokes – ALA promotes vasodilation in the brain and increases brain-derived neurotropic factor (BDNF), exerting a neuroprotective effect.
- Depression – BDNF plays a critical role in neuronal maintenance, learning and memory. It has also been specifically implicated in mood-boosting effects.
ALA therapeutic uses: Anti-inflammatory
- The anti-inflammatory properties of ALA support its uses in cases such as inflammatory bowel disease, asthma and other autoimmune conditions. These effects are likely dependent on its conversion to EPA & DHA.
Drug interactions:
- Blood-thinning medications:
o Omega-3 fatty acids may increase the anti-coagulant effects of blood-thinning medications, e.g. warfarin and aspirin.
o While the combination of aspirin and omega-3 fatty acids may actually be helpful, under certain circumstances (such as CVD), these should only be taken together under GP supervision. - Cholesterol-lowering medications (i.e. statins):
o May have an agonist effect when combined with statins.
EPA and DHA
- Formed from alpha-linolenic acid (ALA).
- Eicosapentaenoic acid (EPA) is an omega-3 fatty acid, 20:5 n-3.
- Docosahexaenoic acid (DHA) is an omega-3 fatty acid, 22:6 n-3.
- Main food sources include oily fish and human breast milk. Marine algae are a rich source of DHA.
Break down word: Eicosapentaenoic
- eicosa = Greek for 20 (meaning 20 carbons)
- penta= from ‘pentagon’ / 5 (meaning 5 double bonds)
- -enoicacid = a carboxyl group (-COOH)
Break down word: Docosahexaenoic
- docosa = Greek for 22 (meaning 22 carbons)
- hexa= from ‘hexagon’ / 6 (meaning 6 double bonds)
- -enoicacid = a carboxyl group (-COOH)
Therapeutic Uses:
There is much research into the benefits of omega-3s. The majority of this focuses on EPA and DHA as opposed to ALA.
EPA and DHA (i.e. fish oil) therapeutic uses:
Cardiovascular disease
- EPA / DHA supplementation can significantly reduce blood triglyceride levels.
- Can lower blood pressure through the effects of series 3 prostaglandins.
- Preventative against the formation of atherosclerosis. Shown to lower blood fibrinogen levels (which are implicated in atherosclerosis development).
- The DART trial showed a reduction in myocardial reinfarction after a daily intake of 900 mg EPA / DHA.
Supplemental fish oil dosage: - EPA + DHA 0.8 –3g/day
EPA and DHA (i.e. fish oil) therapeutic uses:
Anti-inflammatory
- DHA and EPA have profound anti-inflammatory effects —inhibiting NFκB, TNF-α and Interleukin-6. Inflammation is modulated through changes to the PUFA content of cell membranes.
- Useful in inflammatory conditions, especially various forms of arthritis (e.g. osteo and rheumatoid), inflammatory bowel diseases, eczema and SLE.
- Studies show that supplementing >2.7 g / day of fish oils decreases NSAID use in those with arthritis.
Supplemental fish oil dosage: - EPA 3 –5g/day
- DHA 0.8 –2.7g/day.
EPA and DHA functions:
Neurological health
Functions:
* EPA and DHA have neuroprotective properties and increase brain-derived neurotropic factor (BDNF)
* Lower levels of EPA and DHA are associated with more learning and behavioural problems.
Therapeutic uses:
* Depression and ADHA
* Alzheimer’s disease
Dose:
* EPA: 0.6 – 3g
* DHA: 0.15 – 2g/day
EPA and DHA functions:
Foetal health
Functions:
* Support foetal brain development (language, visual, motor functions).
* There is evidence that mothers who supplement EPA and DHA during pregnancy and breastfeeding may protect their children against allergies.
Therapeutic uses:
* Pregnancy support (for foetal health)
Dose:
* EPA: 800mg,
* DHA: 400mg/day.
EPA / DHA in a Vegetarian or vegan diet
A vegetarian or vegan diet can meet EPA / DHA needs:
* Include good sources of alpha-linolenic acid in the daily diet, such as flaxseed and hempseed.
* Support EFA conversion through increasing dietary intake of enzyme co-factors (zinc, magnesium and B6).
* Moderate the use of oils rich in omega-6 fatty acids, and avoid processed foods rich in these oils.
* Consider algal EPA / DHA supplements.
Factors that determine Omega Fish oil quality
- It is important to assess the sustainability practices of a company when selecting a fish oil. Check if it is made from sustainably caught fish approved by the Marine Stewardship Council, where-by catch of non-targeted species is minimised.
- Check that the oil is independently tested for purity and toxins. This will ensure minimal levels of toxic chemicals such as dioxins, PCB’s and heavy metals.
- When selecting a fish oil, make sure that the EPA and DHA content is listed on the label
