The value of omega-3 fatty acids to normal growth and good health has been well known since the 1930s. Awareness of the health benefits increased dramatically after the discovery in the 1970s that omega-3 protects against cardiovascular disease.

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A study of Inuits in Greenland showed that people who consumed large amounts of fat from seafood displayed virtually no symptoms of cardiovascular disease. The high level of omega-3 consumed by the Inuits was found to reduce triglycerides (blood fats), heart rate, blood pressure and atherosclerosis (hardening of the arteries).

Since this study, evidence has emerged about other potential health benefits of omega-3, including relief of arthritis and other inflammatory conditions, and relieving the symptoms of some mental health conditions such as depression and schizophrenia. It is also understood to have beneficial effects on brain and retina development in children.

To gain the optimal health benefits of omega-3 it’s important to know which food sources and supplements are best and how much we need to boost our health.

What is omega-3?

A healthy diet should include fats. They’re an important part of your diet, provided you eat the right ones. According to the Heart Foundation, choosing healthier unsaturated fats instead of saturated and trans fats will reduce your risk of heart disease.

Omega-3 oils are a type of polyunsaturated fat that can be found in marine, animal and plant sources.

Omega-3 marine sources
Docosahexaeonic acid (DHA) and eicosapentaenoic acid (EPA) are found in oily fish (which contain at least 10 per cent fat) such as salmon, blue-eye trevalla, blue mackerel, sardines and tuna. These fish are usually found in colder waters. Other species of fish can contain omega-3 but at lower levels than oily fish.

Omega-3 animal sources
Docosapentaenoic acid (DPA) along with smaller amounts of EPA and DHA are found in animal sources such as free-range eggs, chicken and beef.

Omega-3 plant sources
Alpha-linolenic acid (ALA) is found in canola and soybean oil, chia, linseeds (flaxseeds) and walnuts.

Supplements and omega-3 enriched foods
Omega-3 supplements contain oils from either fish or microalgae. Microalgae-sourced omega-3 (a type of plant-based omega-3) is suitable for vegetarians and vegans and is touted as an eco-friendly option. Omega-3 enriched foods and drinks usually contain marine-based omega-3s.

Which type of omega-3 offers health benefits?

The key message from the Heart Foundation after an extensive review of scientific evidence is that marine-based omega-3 can improve the cardiovascular health of all Australians. Plant-based omega-3 offers many health benefits but is not as beneficial to cardiovascular health as marine-based omega-3.

Fish is also an excellent source of protein, is low in saturated fat and is also a good source of some vitamins and minerals, particularly vitamin D and iodine. Vitamin D is important in the absorption of calcium and the prevention of osteoporosis, while iodine is important for essential hormone development in the human body and ensures healthy brain development.

What is the RDI of omega-3?

To reduce the risk of heart disease, the Heart Foundation recommends that Australian adults consume about 500mg of marine-based omega-3 per day. The Heart Foundation suggests this can be achieved by eating a combination of two to three 150g serves of oily fish per week and by supplementing your intake with fish oil capsules and omega-3 enriched foods and drinks.

In addition, the Heart Foundation recommends that all Australians consume at least 2g of plant-based omega-3 every day. Two slices of soy and linseed bread with canola based margarine or 30g of walnuts will be enough to satisfy your daily quota.

Heart disease sufferers should consume about 1000mg of marine-based omega-3 per day. This can also be achieved by consuming two to three 150g serves of oily fish per week and by supplementing your intake with fish oil and omega-3 enriched foods and drinks.

What about mercury in seafood?

The Australian Dietary Guidelines say you should eat one to two fish meals per week. The good news is that Food Standards Australia New Zealand (FSANZ) has found it is safe for all population groups to eat 2-3 serves per week of most types of fish without any concern over mercury levels. You should limit your intake of only a few types of fish, such as swordfish, marlin, shark (flake), orange roughy and catfish.

Pregnant women, women planning pregnancy and young children should limit their intake of shark (flake), marlin and swordfish to no more than one serve per fortnight (150g for adults and 75g for children), with no other fish to be consumed during that fortnight. For orange roughy and catfish, the advice is to consume no more than one serve per week, with no other fish being consumed during that week. Fish oil capsules available in Australia have zero or near zero mercury content.

What if I don’t eat fish or seafood?

It’s harder to reach your weekly omega-3 targets if you don’t eat fish or seafood. However, with a little thought it is possible to boost your intake sans fish. Here’s how:

  • Choose foods and drinks with added microalgae-sourced omega-3.
  • Incorporate yoghurt, eggs, pizza, bread and soy drinks into your diet.
  • Take capsules. Some omega-3 supplements are now derived from microalgae and are suitable for use by vegetarians and vegans.
  • Eat more plant-based omega-3 found in canola oil and margarines, nuts and seeds (particularly walnuts), flaxseeds (linseeds), hemp oil, soybeans and dark green vegetables.

The word on fats

Unsaturated fats are called good fats because they can improve blood cholesterol levels, ease inflammation, stabilise heart rhythms and play a number of other beneficial roles in the body. They are predominantly found in foods derived from plants, such as vegetable oils, nuts and seeds, and fish.
There are two types of unsaturated fats.

Monounsaturated fats are found in high concentrations in canola, peanut and olive oils; avocados; nuts such as almonds, hazelnuts, and pecans; and seeds such as pumpkin and sesame seeds.
Macadamia nut oil has the highest percentage (about 83 per cent) of monounsaturated fat of any edible oil; however, it is expensive and not commonly used. Olive oil has the highest percentage (about 77 per cent) of monounsaturated fat among commonly used oils. Monounsaturated fats help decrease LDL (bad) cholesterol and increase HDL (good) cholesterol in the blood.

Polyunsaturated fats are found in high concentrations in sunflower, corn, soybean and flaxseed oils, and also in foods such as walnuts, flaxseeds and fish. Omega-3 fats are an important type of polyunsaturated fat as they help to reduce the risk of heart disease, lower blood pressure, guard against plaque build-up in the arteries and aid in brain development.