Fish Oil

Fish oil is the second most commonly taken dietary supplement in Australia, being consumed by around 12% of the population, second only to multivitamin/mineral supplements.

What’s so special about fish oil?

Fish, and fish oil supplements, are a rich source of Omega-3 fatty acids. This is a type of polyunsaturated fat that cannot be made by the body and therefore must be obtained from the diet. These fatty acids are considered essential fatty acids and are crucial for human health.

Another type of polyunsaturated fat essential fat is Omega-6, which is abundant in most plants and vegetable oils. The average Western diet is characterised by excessive intake of Omega-6, and not enough Omega-3. The result is an increased ratios of omega 6 to omega 3 fatty acids.

An increase in the omega-6/omega-3 fatty acid ratio increases the risk for many health conditions

There are two main types of omega-3 fatty acids: Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are the two key omega-3 fatty acids. They have multiple health benefits, mainly due to their anti-inflammatory actions.  The Australian Dietary Guidelines and the Heart Foundation recommend eating fish and seafood at least 2 times a week as part of a heart healthy eating pattern, which provides between 250-500 mg per day of combined DHA and EPA per day. The Heart Foundation also suggests eating 1 gram of plant-sourced omega-3 each day. Yet, research shows that the vast majority of the Australian population is consuming much lower amounts of Omega-3 than recommended.

What if I don’t like fish?

The best way to get Omega-3 is by eating fish. Fatty fish, such as mullet, salmon, mackerel, sardines, silver perch, rainbow trout, and bream, are especially high in Omega-3’s. But if you don’t like fish, supplementing with fish oil may be a good choice. Vegetarians can find omega-3 supplements derived from algae, as well as plant food sources such as flaxseeds and flax oil, chia seeds, walnuts, canola oil and soybean oil.

Health benefits of fish oil

Heart health

Many studies indicate that omega-3 fatty acids reduce the risk of heart disease in several ways: preventing arrhythmias (abnormal heart rhythm), reducing the risk of clots and plaque, decreasing triglycerides, reducing arterial stiffness, lowering blood pressure and reducing inflammation. They are especially recommended for people with high triglycerides and for use in addition to standard heart failure therapy in patients with heart failure.

How much?

• For patients with existing heart disease, the Heart Foundation recommends 1g of combined EPA and DHA daily.
• For patients with high triglycerides, recommended dose is 2 g of combined EPA and DHA daily.

Joint health

As fish oil is anti inflammatory, it has been shown to reduce joint pain and morning stiffness in patients with Rheumatoid Arthritis. Long-term intake can reduce reliance on Non-Steroidal Anti Inflammatory Drugs (NSAIDs) that are commonly used in arthritis, resulting in decreasing the risk of side effects from these medications.

How much?

• Arthritis Australia suggests the dose needed to reduce inflammation is 2.7 grams of combined EPA and DHA daily.

Brain health

DHA is found at very high concentrations in the retina and in the brain, and as such is important for visual development and brain function. Fish oil supplements might improve cognitive function in older adults with cognitive impairment.

Autism spectrum disorder AND ADHD

As DHA is a major structural component of the brain, Omega-3 fatty acids may be especially important in childhood due to the rapid growth of the brain. Studies show that children with Autism Spectrum Disorders and with Attention Deficit Hyperactivity Disorder (ADHD) have lower DHA and EPA levels in their blood.

Depression

Deficiency of Omega-3 fatty acids is a potential risk factor for depression. A review of over 1200 patients with major depressive disorder demonstrated that omega-3 supplements, in addition to prescription antidepressants, improved depressive symptoms.

How much?

• Under medical supervision

Obesity

Obesity is now recognised as a chronic low-grade inflammatory disease. Fish oil supplements have been found to reduce waist circumference in overweight/obese patients. This is significant because studies show that those with normal weight but central obesity have the worst long-term survival and highest mortality, when compared to obese individuals with a smaller waist size.

Pregnancy and asthma in offspring

The intake of Omega-3 fatty acids by the mother during pregnancy determines the DHA status of the newborn. One study found that taking fish oil in the third trimester of pregnancy reduced the risk of persistent wheeze or asthma and infections of the lower respiratory tract in the offspring.

Vision

Omega-3 fatty acids have shown a potential benefit on the eye, particularly for age-related macular degeneration and dry eye, by resolving inflammation.

Additional benefits

There is some evidence that the anti inflammatory nature of fish oil may improve conditions such as acne, atopic dermatitis, psoriasis, lupus, and inflammatory bowel disease. Research is ongoing.

The bottom line

A wide range of fish oil supplements is available on the market, both in capsules form or liquid, and in varying dosages. Dosing for fish oil supplements should be based on the amount of EPA and DHA, which is the actual omega-3 content of the supplement, and not on the total amount of fish oil, which is the big number that you see on the front label (usually around 1000-2000mg).

For accurate dose consult your doctor, pharmacist or naturopath. Take fish oil with food, preferably with meal that contains some fat.

References

1. Arthritis Australia, 2015. Fish oils, Available at: http://www.arthritisaustralia.com.au/images/stories/documents/info_sheets/2015/Complementary therapies/FishOils.pdf
2. Australian Bureau of Statistics, 2014. Supplements. Available at: http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/4364.0.55.007~2011-12~Main%20Features~Supplements~400
3. Bisgaard, H. et al, 2016. persistent wheeze or asthma and infections of the lower respiratory tract in offspring. N Engl J Med, 26375, pp.2530–9. Available at: http://www.nejm.org/doi/pdf/10.1056/NEJMoa1503734
4. Bo, Y. et al., 2017. The n-3 Polyunsaturated Fatty Acids Supplementation Improved the Cognitive Function in the Chinese Elderly with Mild Cognitive Impairment: A Double-Blind Randomized Controlled Trial. Nutrients, 9(1). Available at: http://www.ncbi.nlm.nih.gov/pubmed/28075381
5. Du, S., Jin, J., Fang, W., & Su, Q. 2015. Does Fish Oil Have an Anti-Obesity Effect in Overweight/Obese Adults? A Meta-Analysis of Randomized Controlled Trials. PLoS ONE, 10(11), e0142652. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4646500/
6. Linus Pauling Institute, 2014, Essential Fatty Acids. Available at: http://lpi.oregonstate.edu/mic/other-nutrients/essential-fatty-acids
7. Maehre, H.K. et al., 2015. ω-3 Fatty Acids and Cardiovascular Diseases: Effects, Mechanisms and Dietary Relevance. International journal of molecular sciences, 16(9), pp.22636–61. Available at: http://www.ncbi.nlm.nih.gov/pubmed/26393581
8. Mazahery, H. et al., 2017. Relationship between Long Chain n-3 Polyunsaturated Fatty Acids and Autism Spectrum Disorder: Systematic Review and Meta-Analysis of Case-Control and Randomised Controlled Trials. Nutrients, 9(2). Available at: http://www.ncbi.nlm.nih.gov/pubmed/28218722
9. McNamara, R.K., 2016. Role of Omega-3 Fatty Acids in the Etiology, Treatment, and Prevention of Depression: Current Status and Future Directions. Journal of nutrition & intermediary metabolism, 5, pp.96–106. Available at: http://www.ncbi.nlm.nih.gov/pubmed/27766299
10. Meyer, B.J., 2016. Australians are not Meeting the Recommended Intakes for Omega-3 Long Chain Polyunsaturated Fatty Acids: Results of an Analysis from the 2011-2012 National Nutrition and Physical Activity Survey. Nutrients, 8(3), p.111. Available at: http://www.ncbi.nlm.nih.gov/pubmed/26927162
11. Mocking, R.J.T. et al., 2016. Meta-analysis and meta-regression of omega-3 polyunsaturated fatty acid supplementation for major depressive disorder. Translational psychiatry, 6(3), p.e756. Available at: http://www.ncbi.nlm.nih.gov/pubmed/26978738
12. Veselinovic, M. et al., 2017. Clinical Benefits of n-3 PUFA and ɤ-Linolenic Acid in Patients with Rheumatoid Arthritis. Nutrients, 9(4). Available at: http://www.ncbi.nlm.nih.gov/pubmed/28346333
13. Wang, H. & Daggy, B.P., 2017. The Role of Fish Oil in Inflammatory Eye Diseases. Biomedicine Hub, 2(1), pp.6–6. Available at: https://www.karger.com/?doi=10.1159/000455818