In the news: More Anthocyanins Less Myopia? Flavanols Protect Vessels while Sedentary

Anthocyanins Linked to Myopia in Youth

The increasing incidence of myopia or nearsighted-ness in young individuals has led to research focused on alterable risk factors including digital screen time and diet and supplementation.

One flavonoid subclass attracting research interest are the anthocyanins, abundant in colorful foods such as berries, red cabbage and purple sweet potatoes. Anthocyanins act against oxidative stress and inflammation, which may have potential benefits in ocular health.

A 12-week randomized controlled trial reported that a bilberry extract (standardized to anthocyanins) relieved the tonic accommodation of the ciliary muscle caused by visual display terminal and near vision tasks. Another study reported improved visual contrast sensitivity with administration of antho-cyanins in myopia patients with asthenopia (eye strain). In chick myopia models, anthocyanins were found to reduce ocular axial length compared to controls, and an anthocyanin (delphinidin) was shown to have a relaxing effect on bovine ciliary smooth muscle.

Based on these preliminary findings, researchers from the departments of pediatric ophthalmology in several Chinese universities collaborated to assess the relationship of anthocyanin subtypes and myopia in adolescents aged 12-17(1).

Data was extracted from the US National Health and Nutrition Examination Survey. A total of 839 adolescents were included, among them 245 with myopia (defined as spherical equivalent of -1.0 diopters or less).

Malvidin was the anthocyanin subtype with the largest intake followed by cyanidin. Compared to those with low or no anthocyanin intake, higher total anthocyanin intake was associated with 31% (OR = 0.69) lower odds of developing myopia. Of the various subtypes, higher consumption of cyanidin, petunidin and delphinidin were particularly associated with significantly reduced odds of having myopia.

According to the authors, this study supports the potential for dietary anthocyanins to be part of myopia prevention strategies. More prospective trials are needed to validate these cross-sectional findings.

Flavanols Offer Vascular Protection While Sedentary

Dark chocolate is rich in flavanols, another flavonoid subclass, particularly the flavanol (-) epicatechin. Preliminary studies suggest that (-) epicatechin rich dark chocolate can improve blood flow, cognition and visual contrast sensitivity, at least in the short term.

University of Birmingham researchers set out to assess whether flavanol intake could help protect against the vascular risks of prolonged sitting – i.e. sitting-induced vascular endothelial dysfunction as measured by flow-mediated dilation (FMD)(2).

Forty male participants, 20 with a higher level of fitness and 20 with a lower fitness level, consumed a cocoa beverage high in flavanols (150 mg epicatechin) or low in flavanols (< 6 mg epicatechins) prior to 2 hrs. sitting.

Both low and high fitness groups experienced FMD declines in the arteries when drinking the low flavanol beverage prior to sitting, suggesting that higher fitness levels don’t protect from the effects of sitting.

In contrast, both fitness level groups consuming the high flavanol drink had no FMD declines in either of the arteries in the arms or legs after the sitting period.

These findings may be important to long term health as sedentary behavior is common, and previous studies have shown that a 1% decline in vascular function measured by brachial FMD can raise CVD risk 13%.

It is relatively easy to increase dietary intake of (-) epicatechin. In addition to dark chocolate, cocoa (processed to preserve flavanols), black and green tea, apples, plums, berries and nuts are all good sources.

References

1. Chen Y, et al. The association between anthocyanin intake and myopia in adolescents: A cross-sectional study of NHANES. Front in Pediatr. 12:1503926, 2024.
2. Daniele A, et al. Dietary flavonols preserve upper-and lower-limb endothelial function during sitting in high- and low-fit young healthy males. J Physiol. ePub Oct. 29, 2025.