By medical nutritionist Dr Sarah Brewer, an expert in food, herbs and supplements

Fish oil provides two long-chain omega-3s called DHA and EPA. These are important for maintaining healthy cell membranes, and have many benefits on the circulation, brain and eyes. They also help to protect against abnormal heart rhythms. As a result, we are all advised to eat at least two portions of fish per week, including one that’s oily such as salmon, mackerel, herrings or sardines, to provide an average intake of 450mg of DHA plus EPA per day.

Unfortunately, the average UK adult eats just 50g of oily fish per week – equivalent to a third of a portion – and seven out of 10 people eat no oily fish at all. If you don’t meet the oily fish recommendation, then a fish oil supplement is a good idea and there are plenty to choose from. If you want the comfort of knowing that your fish oil supplement is sustainably sourced, look for certification from bodies such as Friend of the Sea or the Marine Stewardship Council.

Omega-3 fish oils are extracted from the flesh of oily fish and are a rich source of both EPA and DHA which are derived from the micro-algae on which the fish feed. Typically, one gram of high-strength fish oil contains around 500mg of the important long-chain EPA and DHA (check label claims).

Cod liver oil is, as its name implies, derived from the liver of cod. This is because the flesh of white fish contains very little DHA or EPA. Cod liver oil is popular because, as well as providing omega-3s, it also contains vitamins A and D for additional health benefits.

Krill oil is derived from a shrimp-like, Antarctic crustacean which, as well as providing EPA and DHA, also contains two powerful antioxidants, astaxanthin and canthaxanthin. These additional ingredients give krill oil its attractive red colour and are the same pigments that are responsible for the attractive pink plumage of flamingos. The combination of omega-3s plus antioxidants make krill a popular ‘super-supplement’ for reducing inflammation.

If you usually eat two or more portions of oily fish per week, you don’t need a fish oil supplement at all. If you tend to opt for white fish, then a fish oil supplement providing at least 300mg EPA/DHA per day will support your nutritional needs. If you rarely eat fish, then a higher strength supplement supplying at least 450mg per day of EPA/DHA is ideal for general health.

If you have health concerns, then a supplement providing double this amount, or more, may be recommended to provide heart, brain, eye and joint health benefits. The European Food Safety Authority have confirmed that long-term intakes of supplements providing up to 5g EPA plus DHA per day to not raise any safety concerns.

NB If you have a clotting disorder or take blood-thinning medication, seek advice from your doctor before taking an omega-3 fish oil supplement. However, no significant increase in blood clotting time is expected at total daily intakes of EPA and DHA of 3g per day, or less.

About Dr Sarah Brewer
Dr Sarah Brewer is a medical nutritionist and an expert in food, herbs and supplements. She qualified from Cambridge University with degrees in natural sciences, medicine and surgery. After working in general practice, she gained a master’s degree in nutritional medicine. Sarah is a licensed medical doctor, a registered nutritionist and a registered nutritional therapist.

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For more information on diet and supplements, visit Dr Sarah Brewer’s websites at www.DrSarahBrewer.com, www.ExpertHealthReviews.com and www.MyLowerBloodPressure.com.