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Carrot, tomato and papaya represent important dietary sources of β-carotene and lycopene. The main objective of the present study was to compare the bioavailability of carotenoids from these food sources in healthy human subjects. A total of sixteen participants were recruited for a randomised cross-over study. Test meals containing raw carrots, tomatoes and papayas were adjusted to deliver an equal amount of β-carotene and lycopene. For the evaluation of bioavailability, TAG-rich lipoprotein (TRL) fractions containing newly absorbed carotenoids were analysed over 9·5 h after test meal consumption. The bioavailability of β-carotene from papayas was approximately three times higher than that from carrots and tomatoes, whereas differences in the bioavailability of β-carotene from carrots and tomatoes were insignificant. Retinyl esters appeared in the TRL fractions at a significantly higher concentration after the consumption of the papaya test meal. Similarly, lycopene was approximately 2·6 times more bioavailable from papayas than from tomatoes. Furthermore, the bioavailability of β-cryptoxanthin from papayas was shown to be 2·9 and 2·3 times higher than that of the other papaya carotenoids β-carotene and lycopene, respectively. The morphology of chromoplasts and the physical deposition form of carotenoids were hypothesised to play a major role in the differences observed in the bioavailability of carotenoids from the foods investigated. Particularly, the liquid-crystalline deposition of β-carotene and the storage of lycopene in very small crystalloids in papayas were found to be associated with their high bioavailability. In conclusion, papaya was shown to provide highly bioavailable β-carotene, β-cryptoxanthin and lycopene and may represent a readily available dietary source of provitamin A for reducing the incidence of vitamin A deficiencies in many subtropical and tropical developing countries.

Dietary fucoxanthin has been reported to exert several physiological functions, and fucoxanthinol is considered to be the primary active metabolite of fucoxanthin. However, there is no information about the pharmacokinetics of fucoxanthinol in human subjects. In the present study, eighteen human volunteers were orally administered kombu extract containing 31 mg fucoxanthin, and their peripheral blood was collected 5 min before and 0·5, 1, 2, 4, 8 and 24 h after the treatment. Plasma fucoxanthinol concentrations were measured by HPLC, and the pharmacokinetics of fucoxanthinol were as follows: maximum concentration, 44·2 nmol/l; time at maximum concentration, 4 h; terminal half-time, 7·0 h; area under the curve (AUC) for 1–24 h, 578·7 nmol/l × h; AUC(∞), 663·7 nmol/l × h. In addition to fucoxanthinol, we also attempted to detect amarouciaxanthin A, a hepatic metabolite of fucoxanthinol, using HPLC, but it was not present in the volunteers' plasma. On the other hand, a peak that was suspected to represent the cis-isomer of fucoxanthinol was found in the HPLC chromatogram. By comparing the present results with those of a previous study using mice, we found that the bioavailability and metabolism of fucoxanthinol differ between human subjects and mice.

Phospholipid hydroperoxides (PLOOH) accumulate abnormally in the erythrocytes of dementia patients, and dietary xanthophylls (polar carotenoids such as astaxanthin) are hypothesised to prevent the accumulation. In the present study, we conducted a randomised, double-blind, placebo-controlled human trial to assess the efficacy of 12-week astaxanthin supplementation (6 or 12 mg/d) on both astaxanthin and PLOOH levels in the erythrocytes of thirty middle-aged and senior subjects. After 12 weeks of treatment, erythrocyte astaxanthin concentrations were higher in both the 6 and 12 mg astaxanthin groups than in the placebo group. In contrast, erythrocyte PLOOH concentrations were lower in the astaxanthin groups than in the placebo group. In the plasma, somewhat lower PLOOH levels were found after astaxanthin treatment. These results suggest that astaxanthin supplementation results in improved erythrocyte antioxidant status and decreased PLOOH levels, which may contribute to the prevention of dementia.

Background and Objective Astaxanthin is a naturally occurring carotenoid with high anti-oxidant properties, but it is a very lipophilic compound with low oral bioavailability. This study was conducted to compare the pharmacokinetic parameters of a novel astaxanthin preparation based on micellar solubilization technology, NovaSOL ® 400-mg capsules (Test product), and those of astaxanthin 400-mg capsules (reference product), after single oral dose administration to healthy male adults. Methods A single oral dose (400 mg equivalent to 8 mg astaxanthin) of test and reference astaxanthin were administered with 240 mL of water to 12 volunteers according to crossover design, in two phases, with a washout period of 1 week in between. Blood samples were collected at hourly intervals for the first 12 h, then at 24.0, 48.0, and 72.0 h after administration. Aliquots of plasma were centrifuged and the clear supernatant was injected into the high performance liquid chromatography–diode array detection (HPLC-DAD) system. Plasma concentration of astaxanthin versus time profiles were constructed, and the primary pharmacokinetic parameters, maximum concentration ( C max ), area under concentration time curve from time of administration (0) to time (t) [AUC 0-t ] or to infinity ∞, [AUC 0-∞ ],  half-life ( T ½ ) and time to reach C max ( T max ) were calculated. Results The test micellar astaxanthin reached a C max of 7.21 µg/ml after 3.67 h compared to only 3.86 µg/ml after 8.5 h for the reference native astaxanthin. Conclusion Micellar formulation of astaxanthin is capable of producing a high concentration of astaxanthin in plasma in a shorter time, thereby expected to provide faster potential therapeutic efficacy.

The xanthophylls lutein and zeaxanthin probably play a role in visual function and may participate in the prevention of age-related eye diseases. Although a minimum amount of TAG is required for an optimal bioavailability of these carotenoids, the effect of the type of TAG fatty acids (FA) is less clear. The aim was to assess the effect of the type of TAG FA on bioavailability of these xanthophylls. A total of three complementary models were used: an in vitro digestion model to study bioaccessibility, Caco-2 cells to study uptake efficiency and orally administered rats to study in vivo bioavailability. Results showed that lutein and zeaxanthin bioaccessibility was greater (about 20–30 %, P< 0·05) with butter and palm oil than with olive and fish oils. Mixed micelle size, which was significantly lower (about 8 %, P< 0·05) with SFA than with unsaturated FA, was inversely related to lutein and zeaxanthin bioaccessibility. There was no significant effect of the type of TAG FA on xanthophyll uptake by Caco-2 cells, but some compounds present in natural oils significantly affected xanthophyll uptake. Oral administration of rats with spinach and butter over 3 d led to a higher fasting plasma lutein concentration than oral administration with olive or fish oils. In conclusion, dietary fats rich in SFA lead to a higher bioavailability of lutein and zeaxanthin, as compared with fats rich in MUFA and PUFA. This is due partly to the higher bioaccessibility of these xanthophylls in the smaller mixed micelles produced when SFA are incorporated into mixed micelles.

Oxidative stress plays a critical role in the pathogenesis of low back pain. Higher serum levels of lutein and zeaxanthin are associated with reduced susceptibility to this disease due to their potent antioxidant properties. Our study aimed to assess the correlation between serum lutein and zeaxanthin levels and low back pain. This is a cross-sectional study based on publicly available data from the National Health and Nutrition Examination Survey. The National Health and Nutrition Examination Survey employs a complex, multistage probability sampling design in order to select a nationally representative sample. In our study, information was gathered from individuals who were 20 years old or older who took part in the National Health and Nutrition Examination Survey from 2001 through 2004. Detailed information was collected on low back pain, serum lutein and zeaxanthin levels, and various other crucial factors. Multivariable logistic regression and restricted cubic spline regression analyses were performed in order to investigate the relationship between serum lutein and zeaxanthin levels and the occurrence of low back pain. In our study 7,026 participants were included, of whom 38.21% (2,685 of 7,026) had low back pain. There was a nonlinear relationship (P < 0.001) between serum lutein and zeaxanthin levels and low back pain, depicted as a U-shaped curve in the restricted cubic spline. The occurrence rate for individuals with serum lutein and zeaxanthin levels below 25.3 nmol/dL was 0.975 (95% CI, 0.960-0.990; P < 0.001). In comparison, the occurrence rate for individuals with serum lutein and zeaxanthin levels exceeding 25.3 nmol/dL was 1.006 (95% CI, 1.000-1.013; P = 0.043). This is a cross-sectional study; therefore causality cannot be established. A nonlinear association between serum lutein and zeaxanthin levels and the risk of low back pain was observed in US adults. The ideal serum lutein and zeaxanthin level that corresponds to the lowest risk of low back pain is approximately 25.3 nmol/dL.

This study aimed at comparing antioxidant potential of fucoxanthin (FUCO) with β-carotene in relieving lipid peroxidation (Lpx) caused by retinol deficiency (RD) in rats. RD rats (n = 45) were fed a dose of either β-carotene (0.81 μmol) or FUCO (0.83 μmol). Plasma and liver lipid peroxide levels and activity of antioxidant enzymes catalase (CAT) and glutathione transferase (GST) were measured for 8 h. Results revealed that RD increased (P < 0.05) Lpx in plasma and liver by 34.3% and 19.4%, while the CAT activity in plasma (89%) and liver microsomes (91%) and GST in liver homogenate (31%) and liver microsomes (30%) were decreased (P < 0.05) compared to control (rats fed basal diet). FUCO suppressed (P < 0.05) the Lpx level by 7-85% (plasma) and 24-72% (liver) as compared to β-carotene (51-76%, 33-65%) over a period of 8 h. The activity of CAT in plasma and liver microsomes was higher (P < 0.05) in FUCO (90-95%, 85-93%) and β-carotene (87-96%, 79-91%) groups as compared to RD group. Similarly, the activity of GST in liver and its microsomes was also elevated (P < 0.05) in FUCO (44-51%, 22-51%) and β-carotene (19-54%, 30-43%) groups as compared to RD group. Results demonstrate that FUCO has greater potential than β-carotene in modulating Lpx, CAT, GST in plasma and liver of RD rats.

The association between serum carotenoids and the metabolic syndrome (MetS) remains uncertain, and little is known about this relationship in the Chinese population. The present study examined the association between serum carotenoid concentrations and the MetS in Chinese adults. We conducted a community-based cross-sectional study in which 2148 subjects (1547 women and 601 men) aged 50–75 years were recruited in urban Guangzhou, China. Dietary data and other covariates were collected during face-to-face interviews. Blood pressure, waist circumference, blood lipids, glucose and serum carotenoids (α-, β-carotene, β-cryptoxanthin, lycopene and lutein/zeaxanthin) were examined. We found dose–response inverse relationships between individual serum carotenoid concentrations and total carotenoids and the prevalence of the MetS after adjusting for potential confounders (P for trend < 0·001). The OR of the MetS for the highest (v. lowest) quartile were 0·31 (95 % CI 0·20, 0·47) for α-carotene, 0·23 (95 % CI 0·15, 0·36) for β-carotene, 0·44 (95 % CI 0·29, 0·67) for β-cryptoxanthin, 0·39 (95 % CI 0·26, 0·58) for lycopene, 0·28 (95 % CI 0·18, 0·44) for lutein+zeaxanthin and 0·19 (95 % CI 0·12, 0·30) for total carotenoids. Higher concentrations of each individual carotenoid and total carotenoids were significantly associated with a decrease in the number of abnormal MetS components (P for trend < 0·001–0·023). Higher serum carotenoid levels were associated with a lower prevalence of the MetS and fewer abnormal MetS components in middle-aged and elderly Chinese adults.

β-Carotene (BC), β-cryptoxanthin (CX) and α-carotene (AC) are common carotenoids that form retinol. The amount of retinol (vitamin A) formed from carotenoid-rich foods should depend chiefly on the bioavailability (absorption and circulation time in the body) of carotenoids from their major food sources and the selectivity and reactivity of carotene cleavage enzymes towards them. The objective of the present study was to estimate the apparent bioavailability of the major sources of provitamin A (AC, BC and CX) from the diet by comparing the concentrations of these carotenoids in blood to their dietary intakes. Dietary intakes were estimated by FFQ (three studies in this laboratory, n 86; apparent bioavailability calculated for six other studies, n 5738) or by food record (two studies in our laboratory, n 59; apparent bioavailability calculated for two other studies, n 54). Carotenoid concentrations were measured by reversed-phase HPLC. Apparent bioavailability was calculated as the ratio of concentration in the blood to carotenoid intake. Then apparent bioavailabilities for AC and CX were compared to BC. Eating comparable amounts of AC-, CX- and BC-rich foods resulted in 53 % greater AC (99 % CI 23, 83) and 725 % greater CX (99 % CI 535, 915) concentrations in the blood. This suggests that the apparent bioavailability of CX from typical diets is greater than that of BC. Thus, CX-rich foods might be better sources of vitamin A than expected.

Progressive renal decline is associated with increasing oxidative stress. However, the majority of studies have investigated endogenous antioxidants in predominantly advanced stages of kidney disease. Many traditional risk factors associated with renal dysfunction have been linked with cognitive decline as the kidneys and brain share comparable anatomic and haemodynamic characteristics that leave them susceptible to common pathogenic mechanisms. The objective of this study was to examine serum dietary antioxidants and their association with renal function characterised by estimated glomerular filtration rate (eGFR) in a cross-sectional analysis of 570 participants. High performance liquid chromatography quantified serum levels of retinol, α-tocopherol, γ-tocopherol and six carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene and zeaxanthin) in participants. Multiple regression analyses were used to evaluate associations while adjusting for potential confounders. A sensitivity analysis was performed in cognitively-intact participants only. Serum levels of the xanthophyll carotenoid lutein were positively associated with eGFR in analyses adjusted for age (years), gender, smoking, APOE4 status and Alzheimer’s disease. Retinol was inversely associated with eGFR, although was no longer significant in the smaller sensitivity analysis. Our findings identify significant associations between the xanthophyll carotenoids and eGFR. Further investigations are required to confirm these findings.