A lumbar sympathetic nerve block is a special test to help your doctor find the cause of your symptoms. During the test, an anesthetic (numbing) medication is injected near your spine. This âblocksâ the sympathetic nerves in that region.
Lutein is an antioxidant carotenoid a pigmented nutrient that is responsible for the yellow colors of fruits and vegetables and is present in the highest quantities in dark, leafy green vegetables. You're born with a certain amount of lutein in your eye, but your body doesn't reproduce it.
Lutein is present in plants as fatty-acid esters, with one or two fatty acids bound to the two hydroxyl-groups. For this reason, saponification (de-esterfication) of lutein esters to yield free lutein may yield lutein in any ratio from 1:1 to 1:2 molar ratio with the saponifying fatty acid.he functional difference between lutein (free form) and lutein esters is not entirely known. It is suggested that the bioavailability is lower for lutein esters, but much debate continues. As a food additive, lutein has the E number E161b (INS number 161b) and is extracted from the petals of marigold (Tagetes erecta).