Effects of Milk vs Dark Chocolate Consumption on Visual Acuity and Contrast Sensitivity Within 2 Hours: A Randomized Clinical Trial

Effects of Flavanol-Rich Dark Chocolate on Visual Function and Retinal Perfusion Measured With Optical Coherence Tomography Angiography: A Randomized Clinical Trial

Importance

A recently reported randomized clinical trial suggested beneficial effects of vasodilating flavanols in dark chocolate on visual function without objective quantification of retinal perfusion.

Objective

To assess the effects of dark chocolate flavanols on subjective visual function and retinal perfusion objectively quantified on optical coherence tomography (OCT) angiography.

Design, Setting, and Participants

This randomized, masked double-blind crossover clinical trial analyzed 22 healthy participants at the Department of Ophthalmology, Ludwig-Maximilians-University Munich, Germany, in July 2018. Analysis was intention to treat. Analysis began in July 2018.

Interventions

Participants were randomized to consume 20 g of dark chocolate containing 400 mg of flavanols or 7.5 g of milk chocolate. Two hours later, visual function and retinal perfusion on OCT angiography were evaluated. Systemic blood pressure was measured to rule out artifacts on OCT angiography.

Main Outcomes and Measures

The primary end point was macular retinal perfusion quantified as vessel density on OCT angiography. The secondary end point was subjective visual function (Early Treatment Diabetic Retinopathy Study visual acuity, Pelli-Robson chart, and Mars chart contrast sensitivity).

Results

All 22 participants (13 women [59.1%]; mean [SD] age, 27.3 [11.1] years) completed the trial. No relevant differences in baseline parameters between groups were identified. No change in the primary outcome measure, retinal perfusion, could be detected after consumption of dark vs milk chocolate (superficial plexus 48.0% vs 47.5%, treatment effect: -0.59 [95% CI, -2.68 to 1.50], P = .56; deep plexus 54.1% vs 54.0%, treatment effect: -1.14 [95% CI, -4.01 to 1.73], P = .42). No differences in changes in the secondary outcome parameters Early Treatment Diabetic Retinopathy Study visual acuity, Pelli-Robson chart, or Mars chart contrast sensitivity could be detected. Potentially confounding effects of changes in blood pressure were excluded.

Conclusions and Relevance

In contrast to a previous similarly sized randomized clinical trial reporting beneficial effects on visual function, no short-term effects of flavanol-rich dark chocolate on automatically assessed retinal blood flow on OCT angiography or subjective visual function were observed in this study. As this small trial does not rule out the possibility of benefits, further trials with larger sample sizes would be needed to rule in or out possible long-term benefits confidently.

Trial Registration

German Clinical Trials Register identifier: DRKS00015065.

Impact of cocoa flavanols on human health

Cocoa is a source of flavanols, and these phenolic compounds exert beneficial effects on health and aging, and reduce the risk of suffering chronic diseases (cardiovascular diseases, metabolic disorders, cancer). An increasing body of evidence has emerged to suggest that cocoa flavanols potentially are important chemopreventive natural agents. This review summarizes human studies from the past two decades, providing data related to the effects derived from cocoa intake on health and disease. Most human studies have reported beneficial effects of cocoa consumption on health and chronic diseases; however, outcomes are not unequivocal. Review of human studies enable to identify different mechanisms of action for cocoa, although they are not fully understood at present. In addition, it remains unclear whether cocoa consumption should be recommended to healthy subjects or to patients and what is the appropriate dosage or duration of cocoa consumption. Elucidation of information regarding these crucial issues could lead to cocoa use as an approach for decreasing the risk of certain chronic diseases, as well as improving health and quality of life.

Effect of dietary modification and antioxidant supplementation on intraocular pressure and open-angle glaucoma

Primary open-angle glaucoma (POAG) is an age-dependent, intraocular pressure (IOP)-related degeneration of the retinal ganglion cells (RGC). At present, IOP is the only modifiable factor that has been identified to prevent glaucomatous vision loss. Though the pathogenesis of glaucomatous optic neuropathy is still not well understood, increasing evidence suggests oxidative stress may contribute to the induction and progression of glaucoma. Furthermore, antioxidant use may be protective against glaucoma through various mechanisms, including reducing IOP, preserving vascular health, and preventing ganglion cell loss. This article provides a comprehensive review of the effect of oxidative stress, diet, and antioxidant therapy on IOP and open-angle glaucoma.

Prospective registration and reporting of trial number in randomised clinical trials: global cross sectional study of the adoption of ICMJE and Declaration of Helsinki recommendations

OBJECTIVES

To evaluate the compliance with prospective registration and inclusion of the trial registration number (TRN) in published randomised controlled trials (RCTs), and to analyse the rationale behind, and detect selective registration bias in, retrospective trial registration.

DESIGN

Cross sectional analysis.

DATA SOURCES

PubMed, the 17 World Health Organization's trial registries, University of Toronto library, International Committee of Medical Journal Editors (ICMJE) list of member journals, and the InCites Journal Citation Reports.

STUDY SELECTION CRITERIA

RCTs registered in any WHO trial registry and published in any PubMed indexed journal in 2018.

RESULTS

This study included 10 500 manuscripts published in 2105 journals. Overall, 71.2% (7473/10500) reported the TRN and 41.7% (3013/7218) complied with prospective trial registration. The univariable and multivariable analyses reported significant relations (P<0.05) between reporting the TRN and the impact factor and ICMJE membership of the publishing journal. A significant relation (P<0.05) was also observed between prospective trial registration and the registry, region, condition, funding, trial size, interval between paper registration and submission dates, impact factor, and ICMJE membership of the publishing journal. A manuscript published in an ICMJE member journal was 5.8 times more likely to include the TRN (odds ratio 5.8, 95% confidence interval 4.0 to 8.2), and a published trial was 1.8 times more likely to be registered prospectively (1.8, 1.5 to 2.2) when published in an ICMJE member journal compared with other journals. This study detected a new form of bias, selective registration bias, with a higher proportion (85.2% (616/723)) of trials registered retrospectively within a year of submission for publication. Higher rates of retrospective registrations were observed within the first three to eight weeks after enrolment of study participants. Within the 286 RCTs registered retrospectively and published in an ICMJE member journal, only 2.8% (8/286) of the authors included a statement justifying the delayed registration. Reasons included lack of awareness, error of omission, and the registration process taking longer than anticipated.

CONCLUSIONS

This study found a high compliance in reporting of the TRN for trial papers published in ICMJE member journals, but prospective trial registration was low.

Short-Term Effects of Dark Chocolate on Retinal and Choriocapillaris Perfusion in Young, Healthy Subjects Using Optical Coherence Tomography Angiography

(1) Aim: Contrasting results have been published on the effect of dark chocolate on visual function. The aim of this study was to evaluate retinal and choriocapillaris perfusion, using optical coherence tomography angiography (OCT-A), and visual function in healthy subjects following dark chocolate ingestion. (2) Methods: This prospective randomized study was carried out on 18 healthy young subjects at the St. Andrea Hospital, Sapienza, University of Rome. Visual acuity assessment and a complete ophthalmologic examination were carried out at baseline. In session one, each subject was randomized to eat either a 100 g dark chocolate bar or a 100 g white chocolate bar. In session two, the opposite chocolate was given to each participant. OCT-A and best corrected visual acuity (BCVA) were performed before the chocolate was eaten and repeated 1, 2, and 3 h after that. Retinal vessel density and choriocapillaris flow area were assessed. (3) Results: 18 patients with a mean (SD) age of 26.3 (1.5) years were included. No significant differences between dark or white chocolate were found when evaluating foveal density (%), whole density (%), choriocapillaris flow area, and BCVA. (4) Conclusions: Dark chocolate did not result in significant changes in retinal perfusion and choriocapillaris flow area. However, given the results of other studies showing the positive effects of flavonoids on visual function, further studies are warranted using pure chocolate without other components such as caffeine that can potentially affect results. Furthermore, we cannot rule out the possible benefits of higher doses of flavonoids in dietary supplementation over a more extended period and in a larger patient population.

Beneficial Effects of Dark Chocolate for Episodic Memory in Healthy Young Adults: A Parallel-Groups Acute Intervention with a White Chocolate Control

There is good evidence that cocoa flavonoids can acutely improve cognitive function in humans, possibly via mechanisms such as increased cerebral blood flow. To date, much of the evidence is based on measures of executive function with extracts and cocoa-based interventions with a high flavonoid content. The aim of the present study was to explore whether benefits to episodic verbal memory and mood are observed two hours post consumption of a commercially available dark chocolate (DC) bar relative to a 35 g white chocolate bar (WC). Ninety-eight healthy young adults (n = 57 females) aged 18–24 years consumed either a 35 g DC bar or a calorie-matched low flavonoid WC bar. Verbal episodic memory and mood were assessed pre consumption and 2 h post consumption. An ANOVA analysis showed that the DC was associated with better verbal memory performance for several outcome measures of the Rey Auditory Verbal Learning Test relative to the WC, however, there were no effects on mood. These findings lend support to the notion that everyday available portions of dark chocolate can confer benefits to the brain in healthy consumers.

Relationship of lifestyle, exercise, and nutrition with glaucoma

PURPOSE OF REVIEW

Although reducing the intraocular pressure (IOP) through medications, laser or surgery remains the primary means of glaucoma treatment, there is increasing evidence during the last decade that environmentally modifiable factors may help to prevent glaucoma or its progression through different mechanisms that may or may not involve lowering IOP. Additionally, patients are increasingly interested in maintaining a healthy lifestyle and taking an active role in the management of their disease. Therefore, the aim of this review is to summarize the current evidence regarding environmentally modifiable factors such as lifestyle, exercise, and nutrition in the pathogenesis of glaucoma.

RECENT FINDINGS

In the last decade, large population-based studies have helped to identify possible environmentally modifiable protective and risk factors with regard to glaucomatous disease. Smoking cessation; moderate aerobic exercise; recommended weight; and a balanced diet including green leafy vegetables, omega fatty-acids, and moderate intake of hot tea and coffee have been reported to be possibly protective against developing glaucoma or its progression.

SUMMARY

Modifiable environmental factors such as lifestyle, exercise, and nutrition may play a role in glaucoma pathogenesis. Large prospective studies with long-term follow-up should be encouraged to corroborate these findings, which may guide future treatments for our patients, some of which may not be limited to IOP reduction.

Effect of adding milk to black tea on vascular function in healthy men and women: a randomised controlled crossover trial

Addition of milk to black tea alters the acute/short-term benefical effect of regular black tea consumption on vascular function and blood pressure.