No abstract

Xanthophylls (lutein, L; zeaxanthin, Z) and anthocyanins are often included in food supplements to improve ocular health. There are no dietary reference intakes for them. The aim was to assess the effects of L, Z and anthocyanin supplementation on short and long-term lutein status markers (serum concentration and macular pigment optical density (MPOD)). Seventy-two postmenopausal women were randomized into a parallel study of 8 months: Group A—anthocyanines (60 mg/day); Group X—xanthophylls (6 mg L + 2 mg Z/day); Group X+A—anthocyanines (60 mg/day) + xanthophylls (6 mg L + 2 mg Z/day). At the beginning of the study, 4 and 8 month serum L and Z concentrations were determined (HPLC), as well as L, Z and anthocyanine dietary intake and MPOD (heterochromic flicker photometry). Baseline concentrations of L (0.35 ± 0.19 μmol/L), Z (0.11 ± 0.05 μmol/L), L+Z/cholesterol/triglycerides (0.07 ± 0.04 μmol/mmol) increased in Group X (2.8- and 1.6-fold in L and Z concentrations) and in group XA (2- and 1.4-fold in L and Z concentrations). MPOD (baseline: 0.32 ± 0.13 du) was not modified in any of the groups at the end of the study. There were no differences in the dietary intake of L+Z and anthocyanin at any point in time in any group. Supplementation of L and Z at a dietary level provoked an increase in their serum concentration that was not modified by simultaneous supplementation with anthocyanins.

Carotenoids are bioactive compounds with widely accepted health benefits. Their quantification in human faeces can be a useful non-invasive approach to assess their bioavailability. Identification and quantification of major dietary carotenoids in human faeces was the aim of the present study. Faeces and dietary intake were obtained from 101 healthy adults (45–65 years). Carotenoid concentrations were determined by HPLC in faeces and by 3-day food records in dietary intake. Carotenoids quantified in faeces (μg/g dry weight, median) were: β-carotene (39.5), lycopene (20), lutein (17.5), phytoene (11.4), zeaxanthin (6.3), β-cryptoxanthin (4.5), phytofluene (2.9). α-carotene (5.3) and violaxanthin were found 75.5% and 7.1% of the faeces. The carotenoids found in the highest concentrations corresponded to the ones consumed in the greatest amounts (μg/d): lycopene (13,146), phytoene (2697), β-carotene (1812), lutein+zeaxanthin (1148). Carotenoid concentration in faeces and in dietary intake showed correlation for the total non-provitamin A carotenoids (r = 0.302; p = 0.003), phytoene (r = 0.339; p = 0.001), phytofluene (r = 0.279; p = 0.005), lycopene (0.223; p = 0.027), lutein+zeaxanthin (r = 0.291; p = 0.04) and β-cryptoxanthin (r = 0.323; p = 0.001). A high proportion of dietary carotenoids, especially those with provitamin A activity and some of their isomers, reach the large intestine, suggesting a low bioavailability of their intact forms.

Objective: The dietary carotenoids lutein and zeaxanthin are transported in the bloodstream by lipoproteins and selectively captured in the retina where they constitute macular pigment. There are no lutein and zeaxanthin dietary intake recommendations nor desired blood/tissue concentrations for the general population. The aim of this study was to determine the lutein and zeaxanthin dietary intake, their serum concentrations, lipid profile, macular pigment optical density (MPOD) and the contrast sensitivity (CT), as visual outcome in normolipemic subjects age 45-65 (n=101). Methods: MPOD, L and Z in serum and dietary intake were determined using heterochromatic flicker photometry, high-performance liquid chromatography and 3-day food records. CT was measured with the CGT-1000 Contrast Glaretester at six stimulus sizes, with and without glare. Results: Lutein and zeaxanthin serum concentrations (median): 0.361 and 0.078 µmol/L. Lutein+zeaxanthin intake: 1.1 mg/d (median). MPOD: 0.34 du. Lutein+zeaxanthin intake correlates with their serum concentrations (ρ=0.333, p =0.001), which in turn correlates with MPOD (ρ=0.229, p =0.000) and with the fruit and vegetable consumption (ρ=0.202, p =0.001), but not with the lutein+zeaxanthin dietary intake. HDL-cholesterol correlated with lutein+zeaxanthin serum (ρ=0.253, p =0.000) and with CT under glare conditions (ρ range: 0.016–0.160). MPOD predictors: serum lutein+zeaxanthin, lutein+zeaxanthin/HDL-cholesterol and HDL-cholesterol (R 2 =15.9%). CT predictors: MPOD and sex (β coefficients ranges: -0.950,-0.392; -0.134,-0.393, respectively). Conclusion: There were correlations at all points in time in this sequence between lutein+zeaxanthin intake and the visual outcome and, HDL-cholesterol played a relevant role.

Lutein is mainly supplied by dietary fruit and vegetables, and they are commonly jointly assessed in observational and interventional studies. Lutein bioavailability and health benefits depend on the food matrix. This study aimed to assess the effect of dietary intervention with lutein-rich fruit or vegetables on lutein status markers, including serum and faecal concentrations (by high pressure liquid chromatography), dietary intake (24 h recalls ×3), and macular pigment optical density (MPOD) and contrast threshold (CT) as visual outcomes. Twenty-nine healthy normolipemic subjects, aged 45–65 y, consumed 1.8 mg lutein/day supplied from fruits (14 subjects, 500 g/day of oranges, kiwi and avocados) or vegetables (15 subjects, 180 g/day of green beans, pumpkin, and sweet corn) for four weeks. Serum lutein concentration increased by 37%. The effect of the food group intervention was statistically significant for serum lutein+zeaxanthin concentration (p = 0.049). Serum α- and β-carotene were influenced by food type (p = 0.008 and p = 0.005, respectively), but not by time. Serum lutein/HDL-cholesterol level increased by 29% (total sample, p = 0.008). Lutein+zeaxanthin/HDL-cholesterol increased, and the intervention time and food group eaten had an effect (p = 0.024 and p = 0.010, respectively) which was higher in the vegetable group. The MPOD did not show variations, nor did it correlate with CT. According to correlation matrixes, serum lutein was mainly related to lutein+zeaxanthin expressed in relation to lipids, and MPOD with the vegetable group. In faecal samples, only lutein levels increased (p = 0.012). This study shows that a relatively low amount of lutein, supplied by fruit or vegetables, can have different responses in correlated status markers, and that a longer intervention period is needed to increase the MPOD. Therefore, further study with larger sample sizes is needed on the different responses in the lutein status markers and on food types and consumption patterns in the diet, and when lutein in a “pharmacological dose” is not taken to reduce a specific risk.