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Blind cure? Fish oil may protect older people against losing their sight


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Fish oil could help prepare your eyes for older age, helping to preserve your sight


A chemical found in fish oil boosts the daily survival of cells critical to vision protecting against age-related vision loss.

The discovery could lead to new treatments for a host of degenerative diseases of the retina – based on harnessing its power.

Vision loss affects almost two million people in the UK. 

The leading cause is age-related macula degeneration (AMD) which blights the lives of 600,000. 

Famous sufferers include Dame Judy Dench.

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A component of fish oil prevents retinal cells from dying

Carrots are traditionally touted as being good for the eyes, because they contain Vitamin A. 

But some scientists say this is a myth.

In the last few years a growing body of evidence has suggested oily fish can reduce the risk of vision loss.

Now a US team has shown a component of fish oil prevents retinal cells from dying.

The omega-3 fatty acid DHA, abundant in oily fish, and its derivatives ‘precondition’ two different types.

These are the photoreceptors that are sensitive to light and the RPEs (retinal pigment epithelials) – a layer of support cells under the retina – which process it.

Damage to these leads to the degeneration of the macula – the central area of the retina.

Neuroscientist Professor Nicolas Bazan, of Louisiana State University, said: “Our findings support the proposed concept that DHA and docosanoids, molecules made in the brain at the onset of injury or disease, are responsible for activating sustained cellular mechanisms that elicit long term preconditioning protection.”

The oily fish chemical ‘preconditions’ the cells to counteract future stressors – such as when blood supply is cut off for a short period.

The protective response would carry over to a subsequent blood supply shortage – much like the immunity a vaccine confers against future exposures to disease.

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Fish oil ‘preconditions’ the eye, preparing it to resist damage

Prof Bazan said: “This happens in the heart, brain and retina, as well as other organs. 

“To harness the therapeutic potential of preconditioning, it is very important to identify the molecules directly involved.“

The study published in Cellular and Molecular Neurobiology said fish oil contains two types of polyunsaturated fatty acids (PUFAs) – omega-3 DHA (docosahexaenoic acid) and omega-6 AA (arachidonic acid).

They have distinctly different actions.

The former and their metabolic derivatives, enzymes called docosanoids, have potent anti-inflammatory effects, in contrast to the latter that fuel inflammation.

The researchers found although they are released together, DHA can alter the action of AA.

In lab experiments the researchers exposed human retinal cells, as well as those of living rats, to oxidative stress triggered by constant light. 

But prior supplementation with DHA saved them from destruction.

Explained Prof Bazan: “Our findings demonstrate DHA and the induction of docosanoid synthesis is necessary for preconditioning protection, and thus daily survival, of photoreceptor and RPE cells.

“Since omega-3 impairments are associated with neuroinflammation, which contributes to photoreceptor cell dysfunction and death, enhancing the synthesis of docosanoids may provide an opportunity for halting or ameliorating debilitating retinal degenerative diseases, such as the dry form of age-related macular degeneration.”

There are several retinal diseases. 

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There are several retinal diseases that fish oil could help alleviate

The main two are AMD that causes a progressive loss of central vision, and Retinitis Pigmentosa, a group of genetic eye conditions in which night blindness generally precedes tunnel vision by years or even decades.

There are two forms of forms of AMD, dry and wet, with the former much more common. 

But the latter is much more serious. Without treatment, vision can deteriorate within days.

Previous research has also shown omega-3 helps fight debilitating ‘dry eye’ syndrome.

Dry eyes is the world’s most common eye complaint, affecting up to a third of the population.

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Omega-3 also helps prevent common ‘dry eye’ syndrome

Sufferers experience an itchy, stinging sensation along with pain and a sensitivity to light and if left untreated dry eye can cause long term damage, impaired vision and in some extreme cases even blindness.

In the UK, a quarter of patients who visit ophthalmic clinics report symptoms of dry eye, making it a growing public health problem and one of the most common conditions seen by eye care practitioners.

The elderly are most susceptible, with around a third being affected by the condition.

Glands in the eyelids require omega-3 fatty acids in order to produce oil which floats across the surface of the eyes when you blink, which acts like a cling film, keeping in the tears and reducing evaporation.

Symptoms are worsened by activities in which the rate of blinking is reduced, like prolonged reading, staring at computer screen, driving, or watching TV.


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