Health & Fitness

Fish Oil: Omega-3 Fatty Acids ‘won’t save your eyesight’

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POPPING a daily fish oil pill won’t save your vision, say scientists. A study found omega-3 fatty acids found in sardines, salmon, mackerel were no better than a dummy tablet of olive oil at relieving dry eyes.

The chronic condition is the world’s most common eye complaint, affecting one in four people in the UK.It becomes more common with increasing age and affects more women than men.Staring at smartphones, laptops and computer screens reduces blinking, causing a loss of tears.

For years patients and eye doctors have turned to the fish oil supplements following research suggesting they dramatically reduced the pain, sensitivity to light and itchy, stinging sensations.

But a three year study across the US, the most extensive to date, found the benefit went no further than the ‘placebo effect.’Data from the 27 centre trial revealed even taking omega-3 at the highest doses ever tested did not improve outcomes.Principal investigator Maureen Maguire, a professor of ophthalmology at the University of Pennsylvania, said: “Our findings provide evidence that, contrary to a long held belief in the ophthalmic community, omega-3 supplements are not significantly better than a placebo at reducing dry eye symptoms.

“Many patients receiving omega-3 supplements did have substantial improvement in their symptoms, but just as many patients taking placebo had improvements.”

If left untreated dry eye can cause long term damage, impaired vision and even blindness in extreme cases.It occurs when the film that coats the eye no longer maintains a healthy surface.More than 16 million Americans suffer from dry eye, with many using fish derived supplements as a treatment.

So Prof Maguire and colleagues enrolled 535 participants with at least a six month history of moderate to severe dry eye, assigning them at random to either a daily supplement of fish oil, or olive oil which acted as a placebo.

Each fish oil dose contained 3 grams of omega-3 in five capsules – the highest ever tested for treating dry eye disease.The placebo had 5 grams, or roughly one teaspoon, of olive oil.

Image: GETTY Caption: Fish oil only gives the ‘placebo effect’

Importantly, unlike in most industry-sponsored trials, all participants were free to continue taking their previous medications for dry eye, such as artificial tears and prescription anti-inflammatory eye drops.

Study chair Dr Penny Asbell, of the Department of Ophthalmology at the Icahn School of Medicine at Mount Sinai in New York City, said: “Omega-3s are generally used as an add-on therapy.

“The study results are in the context of this real-world experience of treating symptomatic dry eye patients who request additional treatment.”After a year the researchers found both the 349 who received the fish oil – 3 grams a day in five capsules and the 186 who had olive oil had improved substantially.But there was no statistically significant difference.

Overall, 61 per cent of those in the omega-3 group and 54 per cent in the control group achieved at least a 10-point improvement in their symptom score.

Likewise, there were no significant differences between the groups in terms of improvement in signs of dry eye.The doses were delivered in identical capsules, and neither the patients nor their eye doctors knew which treatment group they were in.Co author Prof Vatinee Bunya said: “We were surprised the omega-3 supplements had no beneficial effect.

“The results are significant and may change the way a lot of ophthalmologists and optometrists treat their patients.”

The researchers said clinicians and their patients have been inclined to try the supplements for a variety of conditions with inflammatory components, including dry eye, despite insufficient evidence establishing their effectiveness.

Added Prof Maguire: “The findings also emphasise the difficulty in judging whether a treatment really helps a particular dry eye patient.

“More than half the people taking placebo reported substantial symptom improvement during the year-long study.”

Annual sales of fish and animal-derived supplements amount to more than a $1-billion market in the United States, according to the Nutrition Business Journal.

Many formulations are sold over-the-counter, while others require a prescription or are available for purchase from a health care provider.

Dr Maryann Redford, programme officer for clinical research at the National Eye Institute in the US which funded the study, said: “The trial provides the most reliable and generalisable evidence thus far on omega-3 supplementation for dry eye disease.”

“This well-controlled investigation conducted by the independently-led Dry Eye Assessment and Management (DREAM) Research Group shows that omega-3 supplements are no better than placebo for typical patients who suffer from dry eye.”Added Dr Asbell: “The results of the DREAM study do not support use of omega-3 supplements for patients with moderate to severe dry eye disease.”Fish oil supplements have also been linked with offering protection against age related macula degeneration, the leading cause of blindness which affects 600,000 Britons.

As well as medical treatments, the NHS recommends sufferers eat a healthy diet that includes omega-3 and omega-7 fats to prevent dry eye syndrome or reduce the symptoms.

In England in 2014, over 6.4 million prescription items for artificial tears, ocular lubricants, and astringents were prescribed at a cost of over £27 million.

The study published in the New England Journal of Medicine was also presented at the Annual Meeting of the American Society of Cataract and Refractive Surgery in Washington, D.C.

 

Courtesy: express.co.uk

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