Omega-3 Fatty Acids
Omega-3 and omega-6 fatty acids belong to the family of polyunsaturated fatty acids. They are necessary for the body to develop and function properly.
There are three main types of omega-3 fatty acids:
- Alpha-linolenic acid (ALA)
- Eicosapentaenoic acid (EPA)
- Docosahexaenoic acid (DHA)
All three of these fatty acids are important and must be included in our diets. ALA is considered essential because it cannot be produced by the body. EPA and DHA can be produced by the body, but only in very limited amounts. ALA is present in many plant-based foods, while EPA and DHA are found in fish and other seafood, especially fatty fish.
Omega-3 fatty acids play a number of key roles in our bodies:
- Contributing to cell formation and skin structure
- Supporting cardiovascular health by helping to lower blood pressure and reduce cholesterol and triglycerides in the blood
- Promoting healthy nerve, brain, and eye development
Omega-6 fatty acids are important for the immune system, blood clotting, and gene expression. They occur naturally in many different foods:
- Safflower, grape seed, and sunflower oils
- Wheat germ
- Nuts
- Soy
Most people get more than enough omega-6 fatty acids from their diet, which can lead to an imbalance between omega-6s and omega-3s in the body. These two fatty acids compete for enzymes during metabolism, and an excess of one could interfere with the metabolism of the other. To optimize the health benefits of omega-3s and omega-6s, it's important to include balanced amounts of both in your diet.
Sources
Plant sources of omega-3
| Food | Portion | ALA content |
|---|---|---|
| Flaxseed oil | 15 mL | 7740 mg |
| Flaxseed, ground* | 15 mL | 2460 mg |
| Walnuts | 60 mL | 2300 mg |
| Chia seeds | 15 mL | 1900 mg |
| Canola oil | 15 mL | 1260 mg |
| Soybean oil | 15 mL | 930 mg |
*To maximize omega-3 absorption, flaxseeds should be ground.
Marine sources of omega-3
| Food | Portion | EPA + DHA content |
|---|---|---|
| Atlantic salmon, 12% fat (farmed) | 75 g | 1560 mg |
| Canned anchovies in oil, 10% fat | 75 g | 1550 mg |
| Atlantic herring, 12% fat | 75 g | 1500 mg |
| Black cod, 20% fat | 75 g | 1350 mg |
| Lake whitefish, native, 4% fat | 75 g | 1200 mg |
| Red tuna, 6% fat | 75 g | 1125 mg |
| Atlantic mackerel, 18% fat | 75 g | 925 mg |
| Greenland halibut, 18% fat | 75 g | 900 mg |
| Food | Portion | EPA + DHA content |
|---|---|---|
| Canned pink salmon, 5% fat | 75 g | 800 mg |
| Canned sardines in oil, 11% fat | 75 g | 725 mg |
| Striped bass, 3% fat | 75 g | 725 mg |
| Swordfish, 8% fat | 75 g | 675 mg |
| Arctic char, 5% fat | 75 g | 675 mg |
| Rainbow trout, 7% fat (farmed) | 75 g | 650 mg |
| Blue mussels 4% fat | 75 g | 600 mg |
To meet your omega-3 requirements, it's recommended to eat around two portions (75 g each) of fatty fish a week and consume ALA-rich foods every day.
Some foods are fortified with omega-3s, such as certain eggs, margarines, yogurts, milks, and juices. It's important to read labels carefully to find out the source and amount of added omega-3s. These products may be useful for supplementing your omega-3 intake, but they are not a substitute for foods that naturally contain omega-3s.
Pregnant and breastfeeding women should limit their consumption of certain fish (e.g., tuna, swordfish, marlin, and shark) to 150 g per month, as they have higher mercury concentrations. This recommendation does not apply to most canned tuna. Consult your dietician for advice specific to your situation.
Adequate intake (AI)
AI is the recommended average daily nutrient intake based on estimates of nutrient intake by groups of healthy people.
Because there is a tremendous amount of research being conducted on omega-3 fatty acids, the nutritional requirements are constantly changing.
ALA Requirements
| Age | Men | Women |
|---|---|---|
| 1-3 years old | 700 mg | 700 mg |
| 4-8 years old | 900 mg | 900 mg |
| 9-13 years old | 1200 mg | 1000 mg |
| 14-18 years old | 1600 mg | 1100 mg |
| Age | Men | Women |
|---|---|---|
| 19-50 years old | 1600 mg | 1100 mg |
| > 50 years old | 1600 mg | 1100 mg |
| Pregnancy | 1400 mg | |
| Breastfeeding | 1300 mg |
Although Health Canada has not established specific intake recommendations for EPA and DHA, it is generally recommended that adults have an intake of 250 mg of EPA and 1000 mg of DHA per day.
Deficiency
As omega-3s support optimal fetal development, pregnant women who do not eat fish or seaweed may benefit from a diet that includes plant sources of ALA, as well as foods fortified with ALA, EPA, or DHA. The same applies to nursing mothers and children, as they need higher amounts of these fatty acids.
Vegans and vegetarians are also at risk of developing omega-3 deficiency and may benefit from supplementation in certain cases.
Toxicity
High doses of EPA and DHA, usually from supplements, can cause the following:
- Heartburn
- Nausea
- Diarrhea
- Reflux that tastes like fish
- Unpleasant taste in the mouth
- Nosebleeds
- Reduced blood sugar control
- Increased bad cholesterol
Weight gain is also possible if other sources of dietary fat are not reduced.
While there is no specific recommended amount, more than 3 g per day of EPA and DHA is considered a high dose.
Supplements
In most cases, it's best to increase omega-3 intake through your diet. If this is not possible, supplementation may be considered to ensure adequate nutritional intake.
Omega-3 supplements may be incompatible with certain health issues or interact with your medications. Always speak with a health care professional before taking this product, especially in the following cases:
- You're taking prescription or over-the-counter medications
- You're allergic to aspirin, fish, shellfish, or seafood
- You have a blood clotting disorder
Always watch your diet:
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