Consuming 2.5 grams of pure natural cocoa powder improves visual acuity in healthy young adults and in daylight conditions, according to research carried out by experts from the Complutense University of Madrid (UCM) and the Institute of Science and Technology of Food and Nutrition (ICTAN) of the CSIC.
In the work, published in the ‘Journal of Functional Foods’, the effects of two dietary polyphenols have been studied: flavanols from cocoa and anthocyanins from red fruits. “Despite being the starting hypothesis, no effect was seen either on adaptation to darkness or on visual acuity measured in low-mesopic lighting conditions, neither with cocoa nor with red fruits,” said the Researcher at the Department of Optometry and Vision and director of the Applied Vision group at the UCM, María Cinta Puell Marín.
The researchers attribute the positive effects on photopic visual acuity to an improvement in attention or visual information processing due to flavanols and theobromine – a group of central nervous system stimulating alkaloids, similar to the caffeine in coffee. – from cocoa.
To carry out the study, the volunteers ingested a glass of milk with cocoa, berries or milk alone in three visits separated by an intermediate wash period (time to eliminate remains of each food). At three hours, their urine polyphenol levels were measured.
For the measurement of visual acuity, letter cards were used four meters from the individuals and with different illuminations, one high (photopic) and one low (mesopic). Likewise, for adaptation to darkness, a psychophysical method was used that measures the dynamics of recovery of sensitivity after whitening of the photopigments of the retina.
Before these tests, a series of surveys and eye examinations were carried out to demonstrate that there were no dietary factors or previous pathology that could cause any error in the analysis of results and drawing conclusions.
“We need to carry out some more proof-of-concept study to confirm that the effect is real and that there is the possibility of applying the results to the design of products that can serve to improve visual acuity and attention in defined populations”, has settled the ICTAN-CSIC researcher, Sonia de Pascual-Teresa.