Lutein and zeaxanthin supplementation

Since the original work in monkeys (Malinow et al. 1980), numerous articles have presented evidence that the plasma concentrations of lutein and zeaxanthin as well as MPOD can be modulated by diet, especially by the intake of fruits and vegetables (Hammond et al. 1997), eggs (Handelman et al. 1999), or lutein and zeaxanthin supplements (Schalch et al. 2007). 

Khachik, F, de Moura, FF, Chew, EY, Douglass, LW, Ferris, FL, 3rd, Kim, J, and Thompson, DJ, 2006. The effect of lutein and zeaxanthin supplementation on metabolites of these carotenoids in the serum of persons aged 60 or older. Invest Ophthalmol Vis Sci 47, 5234-5242. 

Dietary intake data from a number of studies in North America and the United Kingdom indicate that intake of lutein from natural sources is in the range of 1 to 2 mg/day (approximately 0.01 to 0.03 mg/kg body weight per day). Simulations considering proposed levels of use as a food ingredient resulted in an estimated mean and 90th percentile of intake of lutein plus zeaxanthin of approximately 7 and 13 mg/day, respectively. Formulations containing lutein and zeaxanthin are also available as dietary supplements, but no reliable estimates of intakes from these sources were available. 

The recognition of the importance of MP in maintaining the health of the retina has led to the development of a number of methods for determining its concentration in situ. These methods, necessarily noninvasive, are routinely employed in dietary supplementation studies with lutein or zeaxanthin to monitor the uptake of the carotenoids into the retina. Every method exploits the optical properties of lutein and zeaxanthin, specifically their absorbance at visible wavelengths. The detection of a light signal, modified by the carotenoids, is accomplished either by the retinal photoreceptors themselves (psychophysical methods) or by a physical detector such as a photomultiplier,... 

The question whether lutein and zeaxanthin can contribute to lowering the risk for AMD cannot be answered unequivocally by epidemiological studies. Only randomized controlled trials (RCTs) during the course of which xanthophylls are supplemented in a double-blind, placebo-controlled, and randomized manner, and in which results are evaluated according to clear predefined efficacy criteria (Seddon and Hennekens 1994) have the potential to provide definitive answers. The specific long-term time-course and intricate nature of AMD make the design of such studies difficult, however. 

Bone, R. A., J. T. Landrum et al. (2003). Lutein and zeaxanthin dietary supplements raise macular pigment density and serum concentrations of these carotenoids in humans. J. Nutr. 133(4) 992-998. 

Handelman, G. J., Z. D. Nightingale et al. (1999). Lutein and zeaxanthin concentrations in plasma after dietary supplementation with egg yolk. Am. J. Clin. Nutr. 70 247-251. 

Johnson, E. J., M. Neuringer et al. (2005). Nutritional manipulation of primate retinas. III. Effects of lutein or zeaxanthin supplementation on adipose and retina of xanthophyll-free monkeys. Invest. Ophthalmol. Vis. Sci. 46(2) 692-702. 

Kvansakul, J., M. Rodriguez-Carmona et al. (2006). Supplementation with the carotenoids lutein and zeaxanthin improves human visual performance. Ophthal. Physiol. Opt. 26(4) 362-371. 

Trieschmann, M., S. Beatty et al. (2007). Changes in macular pigment optical density and serum concentrations of its constituent carotenoids following supplemental lutein and zeaxanthin The LUNA study. Exp. Eye Res. 84(4) 718-728. 

It has been shown in many studies that protective effects of carotenoids can be observed only at small carotenoid concentrations, whereas at high concentrations carotenoids exert pro-oxidant effects via propagation of free radical damage (Chucair et al., 2007 Lowe et al., 1999 Palozza, 1998, 2001 Young and Lowe, 2001). For example, supplementation of rat retinal photoreceptors with small concentrations of lutein and zeaxanthin reduces apoptosis in photoreceptors, preserves mitochondrial potential, and prevents cytochrome c release from mitochondria subjected to oxidative stress induced by paraquat or hydrogen peroxide (Chucair et al., 2007). However, this protective effect has been observed only at low concentrations of xanthophylls, of 0.14 and 0.17 pM for lutein and zeaxanthin, respectively. Higher concentrations of carotenoids have led to deleterious effects (Chucair et al., 2007). 

Interestingly, it has been shown that supplementation of greenfinches with lutein and zeaxanthin at a ratio of 20 1 increases plasma levels of triglycerides and bird body mass (Horak et al., 2006). These data suggest that xanthophylls may affect lipid metabolism. 

Lutein and zeaxanthin seem to exert distinct effects on distribution of the RPE cells in the retina (Leung et al., 2004). In animal studies, Leung and colleagues demonstrated that animals supplemented with either lutein and zeaxanthin on a low n-3 fatty acid diet had a lower RPE cell density than unsupplemented animals on the same diet (Leung et al., 2004). The authors suggested that macular xanthophylls could stimulate the movement of RPE cells away from the central retina (Leung et al., 2004). 

Breithaupt, DE and Schlatterer, J, 2005. Lutein and zeaxanthin in new dietary supplements—Analysis and quantification. Eur Food Res Technol 220, 648-652. 

Bone, R.A. Landrum, J.T. Cao, Y. Howard, A.N. Alvarez-Calderon, F. 2007. Macular pigment response to a supplement containing meso-zeaxanthin, lutein and zeaxanthin. Nutr. Metab. 4 12-19. 

---