Nednapis  Vatanasuchart, Ph.D.

Institute of Food Research and Product Development

Kasetsart University

Eyes are one of the most precious parts of the body. We can tell by such phrase as “You are the apple of my eyes”. Knowing this, how much care have we all put into taking care of it? With modern technologies, we tend to stare at cellphone and computer more than we should and that has caused the eyes much strain. As a result, this prolong condition could lead to theMacular Degeneration (MD) which may cause to permanent blindness. Nutritionists are now looking into “Lutein” for its healthy benefit such as antioxidants and its contributing roles which protect against many diseases such as eye disease, heart disease, cancer, skin disease and especially Macular Degeneration. The lack of lutein could cause blindness, so to prevent it from happening, it’s important to include food sources that contain sufficient lutein amount to maintain our healthy eyes.

The importance of Lutein
Lutein is a type of xanthophylls which consist of carotenoids compound. It’s a phytochemical with antioxidant property .This property protect us from the oxidative stress by absorbing blue light from high energy photons which could destroy retina. Usually, Lutein can be found in macula located in the most important part of the eye, the middle of retina. Thus, they name lutein as macular pigments. Lutein structure is a long chromophore of conjugated double bonds. They are oil soluble but not in water and alsoa good light absorbance. Lutein also reacts with oxidative degradation easily with light and heat but not in acidic condition. However, our body couldn’t synthesize lutein by itself, so it’s crucial to include it in our daily diet.

Many Scientific findings has shown that lutein intake from foods could increase color pigment in our eyes. The rise in pigments decreases the risk of Age-Related Macular Degeneration (AMD). It is crucial to protect ourselves from AMD because it’s a non-curable condition. For best practice,we should routinely includefood that is high in lutein in our diet for healthier eyes. The recommended intake of lutein is about 6-10 mg per day. If consume as recommend, over 43% have been proven to reduce the risk of the Macular Degeneration. Food that are high in lutein are such as Vegetables and Fruits thatcontains lots of colors ; be it green, yellow or red such as kale, spinach , peas , cabbage ,corn, chili, kiwi, cantaloupe, prune, oranges andpapaya. Egg yolks and animal fats are also good source of lutein. Alternatively, we can also choose to take supplements with lutein fortified foods.

Benefits of Lutein
1)   Act as sunglasses to filter blue light that are free radicals which destroy eye cells. Lutein helps strengthen the cells and delay the deterioration of the eyes.
2)   Prevent eyes disease such as Cataracts, Macular degenerations and Age-Related Macular Degeneration.
3)   Filter sunlight which harms our retina.
4)   Maintain the flow of blood circulation and capillary which reduce any blockage of blood near the eyes.
5)   When expose to bright light, eyes could see normally faster.
6)   Increase our vision both in the dark and bright day-light.

Source of Lutein and Scientific findings

Normally Lutein is found from natural foods with Zeaxanthin which is its isomer (difference in double bond position). The laboratory test usually use distillation or filtration method with the soluble solvent which are then compare with standard compound to check for its type and volume with high performance liquid chromatography.

In 2012, NednapisVatanasuchart, et al.were investigated the amount of Lutein and Zeaxanthin in Thai fruits over 21 types which are then divided into 47 varieties over 170 samples. These finding are meant to promote the consumption of Thai fruits and create awareness for its benefit whichprotect us against macular degenerations. It was found that over 122 samples contain lutein which is over 71.8%. However, fruits samples with zeaxanthin are only of 38.2% from 65 samples. When fruit samples were classified according to its sugar content, in group ofsugar less than 10%, Thai-melon contained the highest lutein with an average of 66.1 ± 26.4 mcg./100g.and the highest value was 117.7 ± 4.2mcg./100g. Among all fruit samples, Thai-melon also provided the highest lutein and was found in all six collected samples. Also lutein was found high in roseapple (Phed), watermelon (Torpedoe and Kinaree), guava (Kimju), mango (Pramkaymea) and pamelo (Kaonumpueng), respectively.In group of sugar between 10-20%, banana (Namwa) contained the highest lutein with an average of 26 ± 6.7 mcg./100g.and other banana varieties following with sapote (Lamod) were also a source of lutein.In group of sugar more than 20%, all jackfruit samples contained luteinand Sritongvariety had the highest lutein, containing an average of 22.9 ± 8.2 mcg./100g. Samples with no containing of lutein were ripe mangoes and sweet tamarinds. For determination of zeaxanthin, mango (Munkunsri), in group of sugar less than 10% had the highest content with an average of 24.9 ± 49.8 mcg./100g., following with papaya (Kekdum), mango (Keowsavoy), pamelo (Kaonumpueng), mango (Pramkaymea) and pamelo (Tongdee), respectively. In group of sugar between 10-20%, Maprang showed the highest zeaxanthin, containing an average of 27.2 ± 26.4 mcg./100g. Zeaxanthin was also found high in Mayongchid, mango (keowyai), different varieties of orange, pineapples and starfruit, respectively.Moreover, source of both lutein and zeaxanthin were Thai-melon, pamelo, roseapple, raw mangoes, Maprang, Mafueng, oranges, sapote, purplepassionfruitpineapples. Thai fruits of different varieties are important source of lutein and zeaxanthin, which should be consumed sufficiently to promote eye health. Thus, healthy choice of the fruits with less sugar content and high in those compounds should be recommended.

Summary

Lutein is gaining a lot more attention from Nutritionist including the medical world because of its anti-oxidant property which is the most important role in fighting against many diseases especially to eye disease. It helps reduce the risk of deterioration of retina and protect against the aged-related macular degeneration (AMD). The recommended dosage is 6-10 mg. per day which could be found in egg yolk, animal fats and colorful fruits and vegetables. Thai foods that are high in Lutein are such as Thai melon, bananas, jackfruit, rose apple and watermelon.