Abstract
Purpose::
To examine the impact of a low-fat, high fruit and vegetable dietary intervention on levels of lutein and zeaxanthin (L and Z) in the macula of the retina (macular pigment optical density: MPOD)
Methods::
Seven to 19 months after women participated (for an average of 8.3 years) in the Women’s Health Initiative (WHI) Dietary Modification Trial at the Madison, WI , site, MPOD was measured by heterochromatic flicker photometry at 0.5 degrees from the foveal center. The intake of L and Z in the preceding three months was computed from responses to food frequency questionnaires. Four hundred women (58% of the random sample of 691 women selected) participated; 162 from the intervention group and 238 from the comparison group (who maintained their usual diets) in whom MPOD was reliably determined in 391 women.
Results::
Women who had been in the intervention group, compared to the comparison group, ate more fruits and vegetables (mean ± SE = 6.2 ±0.2 vs. 5.0 ± 0.2 servings/day, p<0.0001 ) and had higher levels of lutein and zeaxanthin from foods (3.1 ± 0.2 mg vs 2.5 ± 0.1 mg/day (p=0.005 ). However, mean MPOD (±SE) was not significantly different (0.36 ± 0.02 vs.0.36 ± 0.01) in the intervention and comparison groups, respectively. Removal of potential confounders and extraneous variation by excluding women with diabetes at WHI-baseline (n= 11), and macular degeneration (n=14), and adjusting for waist circumference, intake of supplements containing lutein and zeaxanthin, presence of diabetes since WHI baseline, and use of cholesterol lowering medications did not change the results. In the overall group, MPOD was 18% higher in women with L and Z from foods and supplements in the highest vs. lowest quintile (median 6.3 vs. 1.1 mg/day), but L and Z intake explained less than 1% of the variability in MPOD.
Conclusions::
The increase in level of fruit and vegetable intake in the WHI intervention was not, on average, of a sufficient magnitude to alter MPOD in this sample.
Clinical Trial::
www.clinicaltrials.gov NCT00000611
Keywords: macular pigment • nutritional factors • clinical (human) or epidemiologic studies: risk factor assessment