Lutein and zeaxanthin are the fat-soluble yellow pigments xanthophylls, which are part of the carotenoid family. Unlike other carotenoids, lutein and zeaxanthin are not precursors of vitamin A, but have strong antioxidant properties.
They are synthesized in orange fruits (oranges, grapefruits), kiwi, green leaf lettuce, vegetables (cabbage, spinach, broccoli), as well as corn, pumpkin, sweet potatoes, carrots, green peas, and eggs. They are synthesized by algae and photosynthetic bacteria. The human body cannot synthesize lutein and zeaxanthin.
In recent years, there has been an increased interest in the biological properties of lutein and zeaxanthin, as they selectively accumulate in the retina of the human eye, are called macular pigments that protect the eyes from oxidative stress, which can cause age-related macular degeneration and cataracts.
Bioavailability
The bioavailability of lutein and zeaxanthin is determined by the structure of plants and the content of ingested lipids, as well as the method of food processing. The highest bioavailability is from fruits (oranges, kiwi, grapefruit) and sweet potatoes, it is almost 100%, from spinach, broccoli 19-38%. However, fresh spinach and broccoli have higher concentrations of lutein and zeaxanthin. During food processing (boiling or frying), their quantity decreases.
Lutein and zeaxanthin are fat-soluble, insufficient dietary fat intake can reduce the absorption of these substances in the body.
Functions and health
Some epidemiological studies show that increasing the intake of lutein in the diet increases the protection against the development of early atherosclerosis. Studies have shown that high dietary intakes of lutein and zeaxanthin reduce the risk of lung cancer.
Lutein, zeaxanthin and eye health
In recent years, much attention has been paid to the role of lutein and zeaxanthin in eye health, which are believed to be the main pigments in the macular of the human eye. They act as antioxidants and as blue light filters to protect the eyes from oxidative stress such as exposure to sunlight. Oxidative stress to the eyes can lead to the development of cataracts and age-related macular degeneration (AMD).
Epidemiological studies show that increased dietary intake of lutein and zeaxanthin (above 10 mg of lutein and 2 mg of zeaxanthin per day) improves visual function, reduces light sensitivity, reduces the risk of cataracts, and reduces the risk of progressive macular degeneration (AMD).
Recommended daily dose
Currently, no specific guidelines have been developed for the daily intake of lutein and zeaxanthin in the general population. The recommendations are more based on vision studies that confirm their role in eye health.
Elderly people at risk of AMD: 10 mg of lutein and 2 mg of zeaxanthin per day is recommended to reduce the progression of AMD.
Best food sources of lutein and zeaxanthin
Lutein and zeaxanthin are present in relatively small amounts in various fruits (oranges, grapefruit, kiwi), although they have higher bioavailability, most of the lutein and zeaxanthin intake comes from eating vegetables, especially dark green leaf vegetables such as kale and spinach. Corn, broccoli and green peas are considered very good sources of lutein and zeaxanthin. You can also get lutein and zeaxanthin with egg yolk, although eggs contain less lutein and zeaxanthin than many other foods, their absorption is good because eggs also contain fat, which ensures better absorption.
Lutein and zeaxanthin are susceptible to free radical damage, usually caused by light, heat and oxygen. Loss can be minimized by eating food while it is fresh or by storing it in closed containers away from light. Food processing and heat treatment accelerate the loss of carotenoids.
- Advice
To maximize dietary intake of lutein and zeaxanthin, it is recommended to consume 2-3 servings of xanthophyll-rich vegetables per day and no more than 3-4 eggs per week.
- Advice
Cooking, for example, green leaf vegetables or broccoli reduces the original lutein and zeaxanthin content, but adding oil or fat-based dressing can increase the absorption of lutein and zeaxanthin from foods.
- Advice
Make sure that foods rich in lutein and zeaxanthin are placed in resealable containers and stored in the refrigerator.
Lutein and zeaxanthin are essential nutrients for eye health, especially for the elderly, who are at increased risk of developing age-related macular degeneration. Lutein and zeaxanthin must be taken with food, because the body will not synthesize them, but it is not always possible to take in sufficient amounts of lutein and zeaxanthin with food, complex food supplements that include lutein and zeaxanthin can be an additional solution, especially when combined with omega 3 fatty acids.