Lutein has two forms, free and esterified. Esterified lutein is also called lutein ester. In nature, lutein generally exists in the form of lutein ester. When extracting lutein from nature, the first thing to extract is lutein ester, and then lutein can be extracted from lutein ester.
Free form is the form of lutein that the human body ultimately needs. Esterified lutein needs to be decomposed into lutein before it can be absorbed and utilized by the human body.
Free lutein is unstable and easily degraded by factors such as light and heat. Especially in the human body, free lutein is easily decomposed by gastric acid, which ultimately leads to limited absorption in the intestine.
Lutein ester is an ester compound formed by the combination of lutein and fatty acids, and exists in fruits and vegetables in an esterified form. Due to the protection of the esterification group, most of it can reach the small intestine and then be hydrolyzed into free lutein by intestinal enzymes. This process can improve its bioavailability. Studies have shown that the bioavailability of lutein esters is 61.6% higher than that of free lutein.
We usually say that what we take is mainly lutein, not lutein esters. It is estimated that most of the daily intake of carotenoids is free lutein, and only a small proportion of lutein exists in the form of lutein esters.
The daily intake of lutein health foods cannot exceed 20mg, and the daily intake of lutein ester functional foods is not more than 12mg.
According to the Chinese National Standard for Food Additives (GB 2760), lutein is used as a pigment (colorant) in food. The range of addition is 0.05g-0.15g/kg. According to the general 1g gel candy or capsule calculation, the highest standard addition generally does not exceed 0.15mg.
The U.S. Food Safety Administration (FDA) issued an announcement on June 14, 2004 that lutein can be used in infant food for infants over 4 months old, but the announcement clearly stipulates that the daily upper limit is 1mg.
According to the report of the Food and Agriculture Organization of the United Nations, lutein esters are currently widely used in various foods internationally, including infant foods. In 2003, the US FDA approved the lutein esters as Generally Recognized as Safe (GRAS) review.
The European Food Safety Authority's assessment of lutein is that it cannot be used as an ordinary food, but as a pigment. The limit for adding it to infant foods is 250μg/L.
