The experts reveal everything you need to know about the supplement that can fight heart disease, ease arthritis - and even stave off blindness.
Something fishy: The health benefits gleaned from the fatty acids of our underwater friends are wide-ranging
WHAT'S SO GREAT ABOUT IT?
- All fish oils contain omega-3s, types of polyunsaturated fatty acid which are essential for health.
- Fish such as mackerel, salmon, trout, sardines, pilchards and fresh tuna, which are known as oily fish, are the richest sources.
- Dr Carrie Ruxton, nutritionist for the Health Supplements Information Service, says: ‘There are different types of omega-3 fatty acids, but the key health benefits are believed to come from the very long chain omega-3s, called docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA].’
- The Food Standards Agency (FSA) recommends we eat a minimum of two portions of fish each week, one of which should be an oily fish (one portion is about 140g). This provides a daily intake of 450mg of EPA and DHA.
- Today many supplements will specify which type they contain and in what concentration.
- EPA and DHA have different roles in the body. Dr Ruxton says: ‘Studies suggest DHA is more important for the brain, retina and infant development, while EPA is more important for vascular health [blood vessels].’
- ‘The difficulty we have in the UK is that two-thirds of people don’t eat oily fish,’ she says. ‘The main source of long chain omega-3s in the diet is oily fish, and if we can’t get them from that, we need to consider a supplement to top up our diet.’
CHOOSE THE RIGHT ONE
- Supplements fall into three categories: fish oil, cod liver oil and krill oil. Which one you choose will depend on how much money you want to spend and what benefit you’re trying to get.
- Shona Wilkinson, head nutritionist at The Nutri Centre, says: ‘Cod liver oil comes direct from the liver, whereas fish oil comes from the flesh of oily fish. Krill are shrimp-like crustaceans that live in the ocean. The oil found in them contains omega-3s similar to those found in fish oils.’
- Dr Ruxton says: ‘If you’re on a budget, cod liver oil or a standard omega-3 are the ones to go for. You don’t need to buy the most expensive brands to get the basic benefits. If you have a specific condition and need a high dose or are pregnant and don’t want the Vitamin A, the cost will go up.’
- Cod liver oil generally has lower levels of EPA and DHA but also differs from fish oil as it naturally provides Vitamin A, which is important for good eyesight and healthy skin, and Vitamin D for bone and immune health. Cod liver oil isn’t suitable for use during pregnancy as it provides too much Vitamin A.
- Dr Ruxton’s advice is not to look at the total amount of omega-3s when choosing a supplement, but at the total amount of EPA and DHA combined that a supplement provides. This should add up to 450mg per day.
- ‘Algae supplements for vegetarians also contain EPA and DHA – fish have EPA and DHA in their flesh in the first place because they feed on algae,’ says Dr Ruxton. Alpha-linolenic acid (ALA) is another omega-3 fatty acid, which is plant-based and found in dietary sources such as vegetable, rapeseed and flaxseed oils. Our bodies can convert ALA into EPA and DHA but the process depends on how much EPA and DHA you take as well.
SUPPLEMENTS HAVE BEEN PROVEN TO TREAT...
Supplements may reduce the risk of early birth
PROOF: Supplementation studies in pregnancy show fish oils may reduce the risk of early birth. As they may provide Vitamin A, it’s essential to choose a supplement suitable for pregnancy – just twice the RDA of Vitamin A early in pregnancy can increase the risk of birth defects.
The guidelines for eating oily fish changed recently from once a week to two or three portions a week. Collins says taking omega-3s while pregnant can have benefits for the expectant mum, too. ‘It’s a boost for your immune system as well as that of your baby.’
Dr Ruxton adds: ‘Evidence from Denmark and Australia suggests the last trimester of pregnancy is the optimum opportunity for programming IQ and immune functions. Taking omega-3s at this stage is crucial.’
DOSE: Choose a specific pregnancy supplement.
TRY: Equazen Mumomega – high in DHA for the development of the baby’s eyes, £9.35, 30 capsules, dolphinfitness.co.uk
PROOF: Studies have shown benefits from fish oils for those suffering from rheumatoid arthritis.
Catherine Collins, principal dietician at St George’s Hospital, London, says: ‘Fish oils have an anti-inflammatory effect which targets the cause of joint pain and helps the body deal with the pain.
‘But this effect is irrelevant if you’re eating a diet full of omega-6 unsaturates [including corn and sunflower oils], and saturated fats. Such foods counteract and lessen the effects of the beneficial oils.’
Fish oils work in synergy with monounsaturated fats, together reducing cell inflammation that reduces pain and maintains health.
DOSE: A minimum of 3,000mg of EPA and DHA combined a day for maximum benefits.
‘These doses are more than six times the daily recommendation, so you must take medical advice,’ says dietician Helen Bond at the Proprietary Association of Great Britain, the regulatory body for over-the-counter medicines and supplements.
‘Fatty acids can interact with other medications.’
TRY: RxOmega-3, 400mg EPA and 200mg DHA, £18.95, foryourhealth.co.uk
PROOF: The anti-inflammatory effects of fish oils also have benefits for the heart. They reduce the blood-vessel inflammation that can lead to heart disease. There are large studies dating back 30 years which show fish oils play a part in preventative cardiology. ‘They also stabilise heart rhythm, especially in patients who have suffered a previous heart attack,’ says Collins.
DOSE: A report reviewed the results of clinical trials involving more than 11,000 survivors of heart attacks and found that supplementing their diet with a gram a day of fatty acids reduced the occurrence of cardiovascular death by 30 per cent and sudden cardiac death by 45 per cent. In a 2009 review, experts recommended healthy people take a daily dose.
TRY: Nature’s Best Fish Oil, 360g EPA and 240g DHA, £14.50, 180 capsules, naturesbest.co.uk
PROOF: Studies have shown there is a link between omega-3s and staving off the deterioration of sight, such as age-related macular degeneration (AMD), which damages the centre of the eye and can lead to blindness. A Harvard University study of 38,000 women found those who ate the most fish oils had a 38 per cent lower risk of developing AMD compared with those who ate the least. The highest concentration of DHA in the body is found in the eye. Collins says: ‘Fish oils also contain Vitamin A which is essential to healthy eyes.’
DOSE: ‘A supplement providing lutein, zeaxanthin and omega-3s could protect eyes against future age-related changes when diet alone fails to deliver,’ says Ian Grierson, professor of ophthalmology at the University of Liverpool.
TRY: Bausch & Lomb Ocuvite Complete, which contains high-quality omega-3 fatty acids (of which 360g is DHA), lutein, zeaxanthin, Vitamins C and E, and zinc, £15.99, 60 gels, boots.com
DON'T BOTHER FOR...
Omega-3s are essential for brain development in the first year or two because this is when the brain is at its most plastic or malleable. Catherine Collins says: ‘If you’re breastfeeding, your body will produce omega-3s regardless of the amount of fish oils in your diet, and if you are bottle-feeding they are added to all formulas.’
But studies show no benefit beyond the second year. Collins adds: ‘Iron deficiency anaemia is more of an issue, affecting verbal learning and memory in children. It is found in fortified toddler milks, red meat and fortified cereals but it could be worth giving your child an iron supplement if they don’t have much of these in their diet.’
Although dietary influences on cancer are complex, research indicates fish oil may have an effect on colorectal, prostate and breast cancers. According to Collins, the reasons are unknown, although it may be to do with reducing inflammation associated with cell changes or that fish oils provide Vitamin D that helps immune cells identify rogue cells for destruction.
‘We don’t know for sure if fish oils will help with cancer. Evidence is speculative and data is limited,’ says Helen Bond.
A review suggested last month there is no evidence omega-3 provides a benefit for memory in later life. ‘It’s a disease of ageing so the notion fish oils can stop its development is unlikely,’ says Collins. ‘Low levels of omega-3 have been reported in Alzheimer’s sufferers,’ says Bond. ‘But we don’t know if it’s a cause or an effect.’
FOOD FOR THOUGHT
According to the International Cod Liver Omega-3 Foundation, many fortified foods contain insignificant levels of omega-3 fats, although 60 per cent of shoppers believe they offer real health benefits.
For an adult to reach the recommended amounts by relying on foods fortified with omega-3 fats, the foundation says they would need to eat 16 slices of fortified bread, five omega-3 enriched eggs, six omega-3 drinks or a litre of omega-3 enriched milk a day.
Another downside is the lingering after-taste such foods can leave. ‘It is simpler to eat oily fish every week rather than trying to get all your needs from fortified foods – and it’s much cheaper,’ says Helen Bond.
WHAT'S THE TOXIN RISK?
Fish oils came under scrutiny in 2006 after the Food Standards Agency discovered some exceeded the recommended levels of toxins linked to cancer.
Batches of all the affected supplements were withdrawn. ‘All UK supplements will have a minimum quality that meets European standards,’ says Dr Ruxton.
‘Be cautious buying non-EU supplements over the internet, though, as quality cannot be guaranteed.’
TAKE THE RIGHT DOSE
It is possible to overdose but ill-effects are unlikely to be more serious than a tummy upset or nausea. In a six-month trial providing 275 patients with 6.9g of EPA and DHA in ten capsules daily, there was no difference between the fish oil and corn oil control groups for any adverse effect.
American regulators report that prolonged bleeding has never been reported in those taking less than 3mg of the above.
Extremely large doses may increase the risk of blood in the urine or nose-bleeds. ‘Stick to the recommended doses to avoid potential side effects,’ says nutrition scientist Dr Elizabeth Weichselbaum at the British Nutrition Foundation.
‘Just because something is good for you doesn’t mean that having more is better.’
Read more: http://www.dailymail.co.uk/health/article-2180298/Are-hooked-fish-oil-The-natural-wonder-drug-proven-treat-range-conditions.html#ixzz222eEbUyY