Omega−3 fatty acids

alpha-linolenic acid (ALA), eicosapentanoic acid (EPA), docosahexanoic acid (DHA)

Efficacy

• Indications with possible efficacy:
  Cardiovascular Protection (ALA - EPA - DHA) (popular use)
  Hypertriglyceridemia
  
• Indications with possible, but poorly documented efficacy:
  Age-related macular degeneration (EPA - DHA)
  Alzheimer's disease (EPA - DHA)
  Asthma
  Attention deficit hyperactivity disorder (DHA)
  Crohn's disease (EPA - DHA)
  Depression (EPA - DHA) (popular use)
  Eczema (EPA - DHA)
  Hyperlipidemia (EPA - DHA)
  Hypertension (ALA - EPA - DHA)
  Menstrual pain (EPA - DHA)
  Psoriasis (EPA - DHA)
  Rheumatoid Arthritis (ALA - EPA - DHA)
  To boost the effects of antidepressants and antipsychotic drugs
  To improve memory (EPA - DHA)
  To improve night vision - in dyslexic children (DHA)
  
• Also used for other indications
  Diabetes (ALA - EPA - DHA)
  

Security

• Risk of Drug Interactions: Low
• Adverse Effects: Rare

Description

Omega−3 and omega−6 fatty acids are part of the polyunsaturated fatty acids. They play an essential role in the proper development and functioning of the body. Our diet should contain a balanced amount of these fatty acids. Since the body cannot synthesize these acids, they must be obtained from the diet or supplement.

These fatty acids play an important role in the formation of the cells and the skin's structure, and they also play a role in the regulation of the inflammatory process and cardiovascular system. They reduce the amount of bad cholesterol and triglycerides found in the blood as well as prevent blood from clotting (coagulation).

There are three types of omega−3 fatty acids: alpha-linolenic acid (ALA), eicosapentanoic acid (EPA) and docosahexanoic acid (DHA). ALA is said to be essential because it must be obtained from food, while the other two can be synthesized in a small amount the body from dietary ALA. EPA and DHA are the main active fatty acids.

In the western diet, omega−6 consumption far outweighs omega−3 consumption. To reach an equilibrium, we need to increase our dietary intake of omega−3 fatty acids.

A typical dose of 5 grams of fish oil contains approximately 169 to 563 mg of EPA and 72 to 312 mg of DHA.

Dietary sources that provide 1.3 g of omega−3 *
Plant-derived omega−3 (ALA) - ½ teaspoon (2 ml) linseed oil - 2 teaspoons (10 ml) crushed linseeds - 1 tablespoon (15 ml) canola oil - 1/4 cup (60 ml) walnuts - 1½ tablespoon (22 ml) soy oil - 13 g hemp seeds	Omega−3 from marine sources (EPA+DHA) - 50 g of blue mackerel - 70 g of Atlantic salmon (farmed) - 75 g of Atlantic herring - 90 g of pink or red salmon (canned) ** - 90 g of sardines - 120 g of albacore (white) tuna (canned) ***
*   Certain foods are enriched with omega−3 fatty acids (eggs, milk, etc.). **  Keta salmon provides half the amount of omega−3 found in other species. *** Albacore tuna provides half the amount of omega−3 found in other species.

There is no consensus on the recommended dietary intake of omega−3 fatty acids. The recommended daily intakes vary from 0.8 to 2.22 grams for ALA and 0.3 to 0.65 grams for EPA + DHA.

Direction of use

• Cardiovascular protection:
  Used doses:
  In good health individual - 500 mg of EPA/DHA daily and 1.2 to 2 g of ALA daily (dietary intake).
  In individual suffering from cardiovascular disease - 1.8 g of EPA and 0.9 g of DHA daily and 1.6 g of ALA daily (dietary intake).
• Depression:
  Used doses: 1 g of EPA daily
• Hyperlipidemia:
  Used doses: 4 g of DHA daily
• Hypertriglyceridemia:
  May reduce triglyceride levels by 10 to 35%. The effect may take from 6 weeks to 3 months to be observed.

  Used doses: 2 to 4 g of EPA/DHA daily (increase dose gradualy)

• Rheumatoid arthritis:
  The effect may take up to 3 months to be observed.

  Used doses: 1.8 g of EPA and 0.9 g of DHA (increase dose gradualy)

• To improve night vision - in dyslexic children:
  Used doses: 480 mg of DHA daily

Precautions

• Side effects
  Omega−3 fatty acids are very well tolerated. Heartburn, bad breath, fish-tasting reflux, nausea, soft stools and nosebleeds have been reported. In addition, there is a possibility of weight gain if the intake of other types of dietary fat is not reduced.
• Pregnancy and breastfeeding
  The intake of dietary omega−3 fatty acids is safe during pregnancy and lactation. However, supplements should probably be avoided, since no safety data are available on their use. Evaluate the mercury content of the different fish and fish oil to limit the amount taken during pregnancy and breastfeeding.
• Interactions
  Patients taking anticoagulants should talk to their doctor before taking fish oil supplements.

Clinical notes

• Due to industrial manufacturing processes, and intensive agriculture and farming techniques, several foods now contain less omega−3 fatty acids.
• According to the American Heart Association, people should eat fish (2 to 3 times a week) and ALA-rich oils and seeds on a regular basis. Fish oil supplements should always be used under medical supervision.
• Diabetes, schizophrenia and excessive alcohol consumption can reduce the body's ability to transform ALA into EPA.

Warning

In 2004, Canada adopted new regulations that control the manufacturing, packaging, labeling and importing of natural health products. The new regulations also include an adverse reaction reporting system. Products that conform to the regulation's criteria are identified with a natural product number (NPN) and can be legally sold in Canada. This number indicates that the product meets specific criteria for safety and purity, not that it is effective for any indication.

Medicinal plant contents vary naturally from plant to plant - just as fruits from the same package may vary in taste and texture. There is no standard to measure the active content of each plant. Thus, efficacy of natural products should be expected to vary from brand to brand as well as from bottle to bottle of the same brand.

For more information about the Natural Health Products Regulations, or to check if a product has been assessed, visit the Health Canada website at www.hc-sc.gc.ca/dhp-mps/prodnatur/index-eng.php.

References

1. Natural Medicines Comprehensive Database, Therapeutic Research Faculty, 2010
2. Passeportsanté.net. Poisson (huiles). www.passeportsante.net
3. Passeportsanté.net. Oméga-3 et oméga-6. www.passeportsante.net
4. The Health Professional's Guide to Popular Dietary Supplements, 2nd edition, American Dietetic Association, 2003
5. Centre de Référence sur la nutrition humaine Extenso, Le point sur les acides gras oméga-3, www.extenso.org
6. PM Kris-Etherton, WS Harris, LJ Appel. AHA Scientific Statements: Fish Consumption, Fish Oil, Omega−3 Fatty Acids, and Cardiovascular Disease. Circulation 2002, 106:2747-2757
7. Natural Therapeutics Pocket Guide, 2000-2001
8. The Review of Natural Products, 6th Edition, 2010