Have you ever wondered how much time you spend on your screen in a day?
According to the screen time statistics, the average person spends nearly 7 hours looking at a screen each day for all sorts of internet-connected activities such as scrolling through social media for the latest updates, streaming music, podcasts and reading news.1 Imagine if you sleep for 8 hours a day, nearly 44% of your waking hour is spent looking at the screen.
The longer time spent on digital devices means the eyes will expose to the harmful light emitted from these devices for a long hour. Blue light is a short wavelength light that can cause detrimental effects to the eyes. Apart from the digital devices, sunlight and fluorescent light are also the sources of blue light to which we are exposed frequently.
Effects of blue light on the eyes
Excessive exposure to blue light has contributed to the production of highly reactive molecules, which lead to oxidative stress and trigger inflammation of the cornea. It can cause the formation of dry eyes.2
The lens of the eye transmits a light ray onto the retina (the tissue located at the back of the eye) so that we can see clearly. Our lens will absorb and filter the blue light, thus protecting the retinal from blue light damages. In extended time, the lens will reduce its transparency which leads to cataract formation.2
Besides, blue light can cause oxidative stress injury and accelerate the degeneration of the retina in those with age-related macular degeneration (AMD). Another survey found that extended screen reading time among schoolchildren leads to the occurrence of poor eyesight and increases the incidence of nearsightedness.3
Lutein – The defence against blue light
Lutein is a fat-soluble antioxidant belonging to the class of carotenoids. As one of the major compounds concentrated in the macula region of the retina, it is often known as a macular pigment. The protective effects of lutein on eye diseases are mainly due to its antioxidant activity and their potential blue light filtration properties.4 Data has shown that the blue light filtration efficacy of lutein is superior amongst the carotenoids such as zeaxanthin, beta carotene and lycopene.5
Proven health benefits of lutein for the eyes and others
Prevents and slows the progression of age-related macular degeneration (AMD)
Low macular pigment density is linked to visual impairment, such as less contrast sensitivity and slower glare recovery. It is also a risk factor for AMD. Supplementing lutein for 6 months has been shown to increase the macular pigment optical density, thereby improving the visual function of AMD patients.6 The positive effects of lutein on AMD patients have also been demonstrated in a meta-analysis, which suggested supplementing lutein for 10 or 20mg per day has increased the macular pigment density.7
Another follow-up study has confirmed the preventive effect of lutein, whereby consistent intake of lutein plus zeaxanthin had reduced the risk of developing AMD in healthy women younger than 75 years.8
Alleviates dry eye symptoms
Insufficient tears production will lead to eye discomfort, redness and blurred vision. A study found that intake of lutein-containing formula for 90 days has decreased the total score of eye fatigue, improved tear secretion and increased macular pigment optical density of adults with eye fatigue.9
An animal study has also demonstrated that administrating lutein-containing formula to rats for 4 weeks has significantly improved tear volume, tear breakup time and tear film integrity. The study has linked the efficacy in alleviating dry eye conditions to the reduction in overall inflammation and increase in antioxidant levels.10
Reduces risk of cataract
Cataract is the clouding of the lens inside the eye. It is also the leading cause of blindness worldwide. In 2006, a follow-up survey study found that a higher intake of lutein and zeaxanthin in the participants resulted in a lower prevalence of cataracts.11 Other studies have confirmed the same beneficial effects of a high intake of lutein.12,13 Besides, lutein intake may also benefit diabetic patients with cataracts. An animal study demonstrated the positive effect of the combined treatment with lutein and insulin in reducing oxidative stress and preventing the development of cataracts in diabetic rats.14
Enhances cognitive function
Lutein is a major carotenoid in human brains. A high concentration of lutein in the brain tissues reflects better cognitive functions, including memory, attention, processing speed, and executive functioning.15
A double-blinded, placebo-controlled trial found that participants who received lutein supplementation, DHA supplementation, or a combination of the two for four months have improved verbal fluency scores. The combined treatment group has shown significant improvement in memory scores and rate of learning.16
Reduces risk of cardiovascular diseases
A study has shown that those with atherosclerosis (hardening and narrowing of the arteries due to buildup of plaque) have a low serum level of lutein.17 Increases in lutein intake can help prevent arterial plaque formation, thereby reducing the risks of atherosclerosis.18,19
A systematic review that evaluated the effect of lutein intake or concentration in the blood on the chances of having a cardiovascular event has shown that high lutein intake and high blood concentration of lutein lower the risks of heart-related health issues.20 Similarly, individuals with higher serum levels of lutein had a lower risk of future hypertension.21 The positive influence of lutein in preventing heart health issues is often linked to its antioxidant and anti-inflammatory properties.22
Recommendations for lutein intake
Unlike vitamins and minerals, there is no recommended nutrient intake value established for lutein. However, evidence from research studies suggested a daily intake of 6mg to 20mg lutein for protection against progression of diseases in adults.16,23,24 Although these amounts can achieve by consuming a diet that is rich in lutein, such as kale, spinach, broccoli, corn and eggs, most adult population are not consuming enough from diet alone.
Lutein is safe to consume by pregnant and breastfeeding mothers, infants and young children. Maternal supplementation of lutein has benefits both mothers and infants, especially on visual and cognitive function.25 The European Food Safety Agency (EFSA) has evaluated the safety and bioavailability of lutein in infant formulas and established an adequate daily intake of 1 mg lutein/kg body weight for both children and adult.26
Lutein is best to consume after meals or after a high-fat meal to optimize absorption if taken in supplement form.