Omega-3 DHA benefits for vision
DHA makes up 93% of the lipid portion of the retina, which comprises a mosaic of two types of photoreceptor cells, namely rods and cones. There are approximately 6 000 000 cones and about 125 million rods in the retina.
Approved EFSA claim
DHA contributes to the maintenance of normal vision. Beneficial effect on the eyes is obtained with a daily intake of 250 mg of DHA.
Background for EFSA claim
As the retina contains very high concentrations of DHA, a deficiency of alpha linolenic acid, the parent fatty acid of the longer chain n-3 polyunsaturated fatty acids (including DHA), results in adverse clinical symptoms related to vision.
Cones and omega-3 DHA
Cones are vital for vision as they enable us to see colours and enable high spatial acuity. They are maximally concentrated at the centre of the retina, known as the fovea area. The development of this area depends on the availability of DHA, hence the omega-3 benefits for vision.
Rods and omega-3 DHA
Rods are as important for vision as cones. They allow us to perceive light and help us distinguish shades of grey, thus enabling vision in low light. The outer segment of rods contains rhodopsin and the highest concentration of DHA of all human cells. This high concentration of DHA in rods has been linked to the physical properties of its membranes, such as DHA g-protein coupled receptors and ion channels, as shown in the illustration below.
Eye and DHA
Retina (DHA 93% of the lipid portion)
Mosaic of 2 basic types of photoreceptors; rods and cones.
Cones – maxiumim concentration in the center og retina – fovea region (responsible for color vision, high spatial acuity).
Rods – vision at low light levels.
Development of fovea – function of availability of DHA.
Omega-3 with documented effects!
It is well documented that omega-3 from cod liver or fish oils is good for the heart, brain and vision of healthy people. The European Food Safety Authority has thoroughly reviewed all research on omega-3 benefits and has approved health claims for the heart, brain and vision.