Relationship of Lifestyle, Exercise, and Nutrition With Glaucoma

Claudio I. Perez; Kuldev Singh; Shan Lin

Disclosures

Curr Opin Ophthalmol. 2019;30(2):82-88. 

In This Article

Flavonoids

Flavonoids are plant-based polyphenolic compounds ubiquitous in nature, and are particularly abundant in dark chocolate, red wine, berries, citrus fruits, and tea. A recent cross-sectional study showed that hot tea decreased the risk of POAG, whereas no significant associations were found between the consumption of coffee, iced tea, decaffeinated tea, and soft drinks and glaucoma risk.[38] Caffeinated teas have been found to have greater antioxidant capacity compared with decaffeinated teas, which may explain why decaffeinated tea consumption was not correlated with decreased glaucoma risk.[38] In contrast to the protective association between hot tea and glaucoma, the authors found no positive or negative association between coffee consumption and glaucomatous optic neuropathy. Compared with tea, coffee contains more caffeine and a different profile of polyphenols comprising less flavonoids but more hydroxycinnamic acids,[43] which may underlie the observed differences in glaucoma risk modulation. Recently, a prospective study corroborated those findings, showing that total flavonoid intake was not associated with POAG risk, however, a greater consumption of different types of flavonoids like flavanols and monomeric flavanols (both found in tea), showed a modest association with lower risk of POAG.[44] The study showed that consuming ~2 cups/day of tea was associated with 18% lower risk of POAG.[44] Finally, a meta-analysis found a statistically significant effect of flavonoids in maintaining or improving the visual field in patients with glaucoma, even after short interventions of 4 weeks.[25] This effect was more pronounced in a subgroup of glaucoma patients with more severe visual field loss, compared to patients with relatively mild visual field loss. Consistent with the results of previous studies, flavonoids did not influence mean IOP in patients compared to controls. It was proposed that maintenance or improvement of the visual field after treatment with flavonoids could have been the result of improved retinal ganglion cell function, improved cognition, or both.[25] Further, a recent randomized controlled trial among healthy study participants has shown that contrast sensitivity and visual acuity were significantly improved 2 h after consumption of a dark chocolate bar (rich in cacao flavanols) compared with a milk chocolate bar.[45] A neuroprotective and microvascular effect of flavonoids may have played a role in this process, both at the ocular and cerebral level, enhancing blood flow, bioavailability of oxygen and nutrients to these metabolically active sites. Nevertheless, the duration of these effects and their influence in real-world performance await further testing and it should be noted that the quality of evidence is not sufficient to support any recommendations at this point.

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