''Baking soda'' can also help us see better

Washington: It is well known that baking soda serves many purposes, but now scientists have revealed how it may also improve our vision.

The research from the Makino Laboratory at Massachusetts Eye and Ear/Harvard Medical School and colleagues at Salus University, describes how bicarbonate or baking soda alters the way we see by modifying the visual signal generated by rod and cone photoreceptors that detect light.

Within rods and cones, a small soluble molecule, cGMP, links photon absorption to the electrical activity of the photoreceptor. In the light, cGMP is destroyed and ion channels are closed. Positively charged sodium ions cease to enter the rod or cone and the membrane potential becomes more negative or hyperpolarized. Bicarbonate directly stimulates an enzyme called guanylate cyclase that synthesizes cGMP.

Lead author Clint Makino, Ph.D. said that by opposing the effect of light, bicarbonate limits the size of the photon response and quickens its recovery. As a result, sensitivity to light is slightly lower but our ability to track moving objects is improved.

"An intriguing implication is that vision may change with metabolic state, although further research is necessary for confirmation. It is now known that in some types of retinal diseases, a genetic defect causes cGMP in the rods and/or cones to rise to abnormally high, lethal levels. Once lost, rods and cones are not replaced, so an irreversible blindness is the tragic outcome."

The research appears online in Journal of Biological Chemistry.