Docosahexanoic acid (DHA), a polyunsaturated fatty acid found in mackerel, herring, tuna, and halibut, is known to be present in high concentrations in the retina but is not synthesized in the body.
In a recent study from Loughborough University, researchers found that fish oil supplements can strongly improve ‘night vision’.
The study is published at ChemRxiv.org. The lead authors of the study are Dr. Paul Kelly and Dr. Jim Reynolds.
The team wanted to know whether DHA improved ‘dark adaptation capabilities’ – the process the eyes go through when adjusting to new light levels.
In the study, a group of 19 people was asked to identify a series of numbers, of ever-decreasing brightness, shown to them on a handheld meter—the results were recorded.
They then took four omega-3 tablets every day for four weeks—each tablet contained 260mg DHA and 780mg EPA (another fatty acid which is converted to DHA).
After the one-month ‘dosing’ period, they visited the labs again and repeated the same test.
The researchers found that, on average, people were able to identify images that were 25% fainter the second time around—after the course of fish oil.
Six weeks after finishing the supplements, their ‘night vision’ returned to original levels.
The team says that they were able to directly link fatty acid levels in the body to changes in visual capability.
This is the first-time dark adaptation that has been linked to fish oil’s fatty acids via direct measurement of amounts making it into the blood.
The rise and fall in the levels of the acids mirror the rise and fall in visual acuity.
This finding may benefit anyone who requires their night vision to be as good as possible—police, people in the military, forensic scientists looking for fluorescent evidence in the dark for example.
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