Lutein is a member of the carotenoid family, which are naturally occurring fat-soluble pigments found in plants. Lutein occurs in numerous foods but the highest concentrations occur in marigolds, which are the source of most of the lutein that is used commercially. Lutein specifically concentrates in the macula, which is a small area in the center of the retina in the eye. The macula lies directly behind the lens and is the area of the eye that receives the most light. Lutein protects the macula by filtering out potentially damaging forms of light. Thus, lutein is associated with protection from various diseases of the eyes, especially age-related macular degeneration, which is a leading cause of blindness in older adults. Lutein supplementation resulted in increased macular pigment density.
Zeaxanthin is a carotenoid that occurs at high levels in the retina of the eyes. The greatest amounts of zeaxanthin occur in the macular region of the eye, whereas lutein, a closely related compound, is distributed throughout the entire retina. When these compounds are found in plants, they both seem to occur together. For this reason, zeaxanthin and lutein are often discussed together and in fact they are sometimes referred to as lutein-zeaxanthin. These carotenoids have two main functions; they absorb the potentially harmful blue-violet wavelengths of light energy that come into the eye and they also function as antioxidants.
A recent study sought to investigate whether weight loss is associated with changes in serum levels of lutein and zeaxanthin. Included in the randomized, controlled weight loss study were 104 overweight subjects. Researchers divided the participants into either the intervention group or the control group. Weight and measurements were collected weekly, and body fat and BMI were assessed at baseline, six months and 12 months. They also measured serum levels of lutein and zeaxanthin in the study participants. The subjects in the intervention group were encouraged to lose weight using dietary and exercise programs. The results revealed that those in the intervention group lost a significant amount of weight while those in the control group saw no change in weight. It was determined that there was a positive and significant relationship between loss of body fat and increased serum levels of lutein in the intervention group. These findings confirmed the researcher’s hypothesis that excess fat stores the carotenoid, lutein, and that losing weight can increase circulating carotenoid levels.1
1 Kirby ML, Beatty S, Stack J, et al. Changes in macular pigment optical density and serum concentrations of lutein and zeaxanthin in response to weight loss. Br J Nutr. Apr2011;105(7):1036-46.