Written by Tabish Mehraj, PhD. This study showed that long-term supplementation with C. asiatica extract (CA-HE50) significantly improved MPOD, supporting its potential to enhance macular nutritional status. These findings suggest that CA-HE50 may serve as a beneficial dietary intervention for maintaining macular health.

Ageing is a major factor in the progressive, degenerative changes in the macula. The retina, which contains a large concentration of polyunsaturated fatty acids, requires high levels of metabolic demand and oxygen consumption, making it potentially susceptible to oxidation due to increased reactive oxygen species. Macular pigment optical density (MPOD) is a biomarker that shows the antioxidant status of the macula, which is a part of the retina for central and focused vision. The pigment of the macula is composed of lutein and zeaxanthin obtained from the diet and meso-zeaxanthin, carotenoids that filter harmful light, and protect the retina from oxidative damage. Individuals with age-related macular degeneration suffer from reduced MPOD levels. Certain diet or nutritional supplements have been scientifically known to increase macular pigment optical density (MPOD), and this has been confirmed in randomized controlled trials. Centella asiatica (L.) is an herbaceous perennial plant that has been used traditionally for its therapeutic benefits. The major components are saponins, sapogenins, and madecassic acid, which may offer protection from oxidative stress.

Baek et al. (2026) conducted a randomized, double-blind, placebo-controlled clinical trial to evaluate whether long-term supplementation with a standardized Centella asiatica extract (CA-HE50) could improve macular pigment optical density (MPOD). This study enrolled 80 generally healthy individuals aged 45 to 65 years with baseline MPOD values ranging from 0.2 to 0.4. Participants were grouped to receive either 300 mg/day of CA-HE50 (n = 40) or placebo (n = 40) for six months. MPOD was measured at baseline and at 60, 120, and 180 days using heterochromatic flicker photometry. The primary endpoint was the change in MPOD from baseline to Day 180, while secondary parameters included changes at intermediate time points, responder analysis, and safety assessments involving adverse events, vital signs, and laboratory parameters.

Results/ Key Findings

• CA-HE50 significantly increased MPOD compared with placebo, with significant improvements after 120 days and further increasing by 180 days (all p < 0.001).

• Linear mixed-effects and intention-to-treat analyses confirmed sustained, clinically meaningful improvements, with large effect sizes (Cohen’s d = 1.00–1.96), indicating clinically meaningful benefits of CA-HE50 supplementation.

• Responder analysis showed increased MPOD in 94.7% of the CA-HE50 group versus 32.4% of the placebo group (p < 0.001), indicating consistent efficacy.

• CA-HE50 was safe and well tolerated, with only mild to moderate adverse events and no treatment-related serious adverse events or clinically significant changes in laboratory or safety parameters. Vital signs, hematological parameters, and blood biochemistry remained within normal ranges and were comparable between the CA-HE50 and placebo groups, supporting the long-term safety of CA-HE50.

The study possesses several notable strengths. Its randomized, double-blind, placebo-controlled design strengthens internal validity and minimizes bias. The six-month intervention period is appropriate for assessing alterations in MPOD, which occurs slowly over time. The inclusion of both per-protocol and intention-to-treat analyses enhances confidence in the results, while mechanistic evidence from previous preclinical studies provides biological plausibility for the observed effects. Moreover, this is the first clinical trial demonstrating that a non-carotenoid botanical extract can significantly improve MPOD.

Despite these strengths, there are a few limitations. The absence of a positive control group receiving established carotenoid supplementation prevents direct comparison of CA-HE50 with standard nutritional interventions. Functional measures of visual performance, such as contrast sensitivity, glare recovery, and visual acuity improvements, were not evaluated, limiting conclusions regarding clinical vision outcomes. Additionally, the relatively modest sample size restricted subgroup analyses, while the responder definition—based on any increase in MPOD—may have been influenced by minor measurement variability.

Overall, this study provides compelling clinical evidence that long-term supplementation with standardized Centella asiatica extract significantly improves MPOD and may represent a safe, novel nutritional strategy to support macular antioxidant status and promote retinal health in middle-aged adults.

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Posted July 14, 2026.

Dr. Tabish Mehraj is a pharmaceutical scientist with expertise in pharmaceutics, drug delivery, and formulation development. She earned her PhD in Pharmaceutical Sciences from the University of Mississippi, where her research focused on the formulation, optimization, and characterization of lipid-based nanocarriers for targeted liver delivery of antimalarial therapeutics. Dr. Mehraj has also served as an ORISE Fellow at the U.S. Food and Drug Administration (FDA), where she evaluated the effects of formulation and process design on the quality and performance of intravaginal drug delivery systems and developed bio-relevant in vitro drug release testing methods. She has teaching experience in pharmaceutical and life sciences courses and has authored peer-reviewed publications, book chapters, and conference presentations. Dr. Mehraj is an active member of the American Association of Pharmaceutical Scientists and has been recognized by honor societies including Rho Chi and Gamma Beta Phi.

References:

1. Baek, H. I., Kim, I., Bae, J., Kwon, J. E., & Kang, S. C. (2026). Effects of Long-Term Supplementation with Centella asiatica (L.) Urb. Extract (CA-HE50) on Macular Pigment Optical Density: A Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients, 18(6), 905.