For instance, Ocular Surface Disease Index (OSDI) which measures ocular symptoms and vision-related function was significantly improved in individuals who took the intervention.
Findings of the 20-day intervention were published in Nutrients. The study was conducted by Malaysia’s UCSI University, University of Leeds, Aston University, as well as Xmegami Manufacturing which supplied the materials used in the study.
A total of 110 individuals with dry eye disease symptoms took part in the study.
Most of them (47.6 per cent) were between 41 and 50 years old, followed by those between 31 and 40 years old (20.8 per cent).
Those who were above 50 years old consisted 17.8 per cent of the total participants, while 13.8 per cent of them were 30 years old or younger.
Notably, about two in three participants (61.4 per cent) were women.
During the study, they were randomised to take either the placebo or a powder sachet supplement consisting of marigold extract, zeaxanthin, elderberry extract, bilberry extract, lycopene extract, multivitamin, and inulin.
Each sachet contained six mg of lutein and one mg of zeaxanthin, along with 100 mg of elderberry extract.
The supplement is a product branded Twinkle Eyez by Malaysian firm Xmegami.
Lutein and zeaxanthin are commonly used in eye health supplements because they could protect against most harmful blue visible light, the researchers explained.
To assess the effects of the intervention on their vision, the participants' Ocular Surface Disease Index (OSDI) and Visual Analog Scale (VAS) were measured. The effects of the intervention on their immune health were also measured using the Immune Status Questionnaire (ISQ).
In addition, all participants had to answer a Food Frequency Questionnaire which records their intake of lutein and zeaxanthin from food sources over the past six months.
Findings showed that OSDI scores in the intervention group were significantly reduced by 52.2 per cent as compared to the placebo group by the end of the study.
In this case, their OSDI scores were reduced from 38.15 ± 11.14 to 18.26 ± 5.57.
The OSDI is assessed on a scale of zero to 100. The higher the score, the more severe the symptoms of dry eye disease.
The intervention group’s VAS also significantly improved from 5.31 ± 1.62 to 6.73 ± 1.74 - which was 26.7 per cent higher as compared to the placebo group.
However, the intervention did not lead to significant improvement in the immune status scores.
While the intervention group did see its immune status scores improve by 15.9 per cent - from 7.92 ± 2.45 to 9.18 ± 1.91 - this was not a statistically significant improvement as compared to the placebo group which saw a 10 per cent improvement in their scores.
In this case, the researchers explained that higher dosages or longer durations of intervention might be needed to observe a meaningful effect.
Low dietary intake of lutein, zeaxanthin
On the other hand, the study also found low dietary intake of lutein and zeaxanthin among the participants.
The average dietary intake of lutein and zeaxanthin was only 5.5 per cent (663.49 µg) of the suggested optimal daily intake, based on results from the Food Frequency Questionnaire.
Cooked kale, cooked spinach, and raw romaine lettuce were the main dietary sources of lutein and zeaxanthin.
The researchers cautioned that the low consumption amount was “concerning”, as this was linked to higher risk of ocular diseases.
“This is concerning, as low consumption of lutein and zeaxanthin has been shown to be inversely correlated with the risk of age-related macular degeneration (AMD), a leading cause of blindness, as well as other ocular diseases.”
Citing data from the 2023 National Health and Morbidity Survey (NHMS), the researchers highlighted that 11 per cent of the Malaysian population had experienced some degree of visual impairment.
The higher prevalence of DED in women is likely driven by lower androgen levels and exogenous estrogen use, said the researchers.
Source: Nutrients
Effect of Dietary Supplementation with Lutein, Zeaxanthin, and Elderberries on Dry Eye Disease (DED) and Immunity: A Randomized Controlled Trial
DOI: 10.3390/nu16244366
Authors: Goh KM, Tan ESS, Lim CSY, Tan PY, Biswas S, Lew LA, Tan CK.