Abstract
Purpose: :
There is increasing evidence that macular pigment ([MP] composed of lutein [L] and zeaxanthin [Z]) has a protective role in the eye and higher levels have been associated with a reduced risk of age-related macular degeneration (AMD). L and Z accumulate in adipose tissue and some studies suggest a relationship between body fat and MP levels in humans. The relationship between MP and body fat was investigated in a large group of healthy, female volunteers.
Methods: :
A prospective study, within the context of a twin study of heritability, was carried out using 320 healthy female volunteers, (mean age 41 years, range 18-52). Macular pigment optical density (MPOD) was measured by two techniques, a psychophysical method (heterochromatic flicker photometry [HFP]) and an imaging method (fundus autofluorescence [AF] using a Heidelberg dual wavelength SLO). Percentage body fat was measured using dual energy x-ray absorptiometry (DEXA). Univariate and multivariate (adjusting for other risk factors of AMD) regression analysis was used to determine the relationship of body fat with macular pigment.
Results: :
As a high correlation between right and left eyes was observed (r= 0.80, p<0.001) only right eye data are presented. Mean levels of MPOD using HFP and AF were 0.44 (SD 0.214) and 0.41 (SD 0.151) respectively. In both a univariate and adjusted analysis (adjusted for age, smoking status and iris colour), significantly lower MPOD levels were found with higher body fat percent. For each 10% increase of body fat, MPOD measured with HFP was reduced by 0.032 (95%CI: 0.057, 0.007, p=0.013) and using AF measures MPOD was reduced by 0.059 (95%CI: 0.095, 0.022, p=0.002).
Conclusions: :
In this study, higher percentage of body fat was associated with lower MPOD, with a 10% increase resulting in a 7-14% lower MPOD, depending on measurement technique. This raises concern of increasing AMD within the context of the current global obesity epidemic.
Keywords: macular pigment • clinical (human) or epidemiologic studies: risk factor assessment • carotenoids/carotenoid binding proteins