Minerals are supplemented routinely to dairy cows during the dry period to prevent metabolic issues postpartum. However, limited information exists on the impacts of mineral supplementation on colostrum carotenoids. This study aimed to determine the effects of prepartum supplementation with three micro-nutrients; inorganic selenium (INORG), organic selenium (ORG) or rumen-protected choline (RPC) on the carotenoid content of bovine colostrum and transition milk (TM) from pasture-based dairy cows. A total of 57 (12 primiparous and 45 multiparous) Holstein-Friesian (HF) and HF × Jersey (JEX) cows were supplemented daily for 49 ± 12.9 d before calving. Colostrum samples were collected from all cows immediately postpartum and TM one to five (TM1–TM5) were collected from a sub-set of 15 cows (five per treatment group) at each consecutive milking postpartum. Carotenoid concentration was determined using ultra-high performance liquid chromatography – diode array detection (UHPLC-DAD). With the use of transmittance, the colour index and colour parameters a*, b* and L* were used to determine colour variations over this period. Prepartum supplementation did not have a significant effect on colostrum β-carotene concentration or colour. Positive correlations between β-carotene and colour parameter b* (R2 = 0.671; P < 0.001) and β-carotene and colour index (R2 = 0.560; P < 0.001) were observed. Concentrations of β-carotene were highest in colostrum (1.34 μg/g) and decreased significantly with each milking postpartum (TM5 0.31 μg/g). Breed had a significant effect on colostrum colour with JEX animals producing a greater b* colostrum than HF animals (P = 0.030). Primiparous animals produced colostrum with the weakest colour compared to second or ≥third parity animals (P = 0.042). Despite statistical increases in the b* parameter in colostrum from JEX cows and multiparous cows, β-carotene concentrations did not significantly increase suggesting that other factors may influence colostrum colour. The b* parameter may be used as an indicator for estimating carotenoid concentrations in colostrum and TM, particularly when assessed via transmittance spectroscopy.

The mechanism of decolorization of crude maize and sunflower oils was studied by means of adsorption of β-carotene by a low-grade bentonite, containing mixed-layered illite-smectite. Decolorization depends on temperature and the time required for equilibrium decreases with increasing temperature. The study of the kinetics of adsorption showed that decolorization of maize oil is a first-order process which occurs in two steps: a first fast step with higher activation energy (25.6 kJ mol−1), indicating the influence of a chemical interaction between the pigment and the clay surface, followed by a second slow step with low activation energy (12.3 kJ mol−1), characteristic of physical adsorption on the previously adsorbed molecules. Decolorization of sunflower oil is also a first-order process, described by a single mechanism with intermediate activation energy (19.0 kJ mol−1). Adsorption isotherms of decolorization of maize oil follow the Freundlich equation, indicating the existence of heterogeneous adsorption sites on the solid's surface. Heterogeneity is attributed both to different active centers on the smectite surface (Brönsted and Lewis centers) and to the different phases present in bentonite, such as illitic layers and clinoptilolite, which also have active centers on their surfaces.

A previous analysis of the Alpha-Tocopherol Beta-Carotene (ATBC) Study on male smokers found that β-carotene supplementation increased the risk of pneumonia 4-fold in those who started smoking at the age of ≥21 years and smoked ≥21 cigarettes/d (a subgroup of 7 % of the study population). The present study hypothesised that β-carotene increases mortality in the same subgroup. The ATBC Study (1985–1993) recruited 29 133 Finnish male smokers (≥5 cigarettes/d) aged 50–69 years. Cox regression models were constructed to estimate the effect of β-carotene supplementation in subgroups. β-Carotene increased mortality (risk ratio 1·56; 95 % CI 1·06, 2·3) in those who started to smoke at ≥21 years and smoked ≥21 cigarettes/d. Within this subgroup, there was strong evidence of further heterogeneity. The effect of β-carotene supplementation was further modified by dietary vitamin C intake, fruit and vegetable intake (P = 0·0004), and by vitamin E supplementation (P = 0·011). Thus, harm from β-carotene was not uniform within the study population. Interactions between β-carotene and vitamins C and E were seen only within a subgroup of 7 % of the ATBC participants, and therefore should not be extrapolated to the general population. Heterogeneity of the β-carotene effect on mortality challenges the validity of previous meta-analyses that have pooled many diverse antioxidants for one single estimate of effect using the assumption that a single estimate equally applies to all antioxidants and all people. Trial registration: ClinicalTrials.gov NCT00342992.

An Iranian sepiolite was activated with 1.5 M HCl. During activation, the specific surface area increased from 105 to 168 m2/g and the SiO2 content increased from 45.4 to 51.6%. The roles of temperature and time and the amount of acid-activated sepiolite used, were investigated and the optimum conditions, where chlorophyll, β-carotene, free fatty acid and peroxide were at their minimum levels, were determined for bleaching of canola oil by applying response surface methodology (RSM). Optimum bleaching conditions were obtained by adding 3% of acid-activated sepiolite at a temperature of 110°C with a bleaching time of 42.46 min during which, the amount of chlorophyll-α, β-carotene, free fatty acid and peroxide were reduced from 12.30 to 0.35 mg/kg, 49.15 to 14.98 mg/kg, 0.62 to 0.15%, and 3.87 to 2.14 meq O2/kg of oil, respectively. At optimum conditions, sepiolite displayed a greater capacity for removal of chlorophyll and β-carotene than a commercial bentonite bleaching agent.

The effects of three postemergence herbicides that inhibit carotenoid biosynthesis were tested on field dodder. Flurochloridone, sulcotrione, and mesotrione treatments led to bleaching symptoms in field dodder stems. The effect of flurochloridone was rapid; 2 d after treatment (DAT) the stem was bleached and contained only 2% β-carotene, with a massive accumulation of phytoene in comparison with the control. However, flurochloridone treatment did not inhibit stem elongation, and full recovery of pigment composition at newly elongated stems was recorded 6 DAT. The effects of sulcotrione and mesotrione were similar, but the recovery was slower than with flurochloridone. The developing stems were fully bleached 6 DAT, with no detectable β-carotene, and subsequently no recovery was observed. All three herbicides led to mass destruction of the plastids in the parenchyma cells of the cortex and pith tissue. This disruption of the plastids was associated with depletion in starch content. Sulcotrione and mesotrione treatments reduced field dodder biomass accumulation, whereas flurochloridone delayed biomass accumulation by 6 d only. The differences in phytotoxicity between flurochloridone, sulcotrione, and mesotrione might be due to their different translocation patterns. Flurochloridone is xylem-mobile and is therefore localized at the applied area because of the low transpiration rate of field dodder. Sulcotrione and mesotrione are phloem-mobile and tend to accumulate in sinks such as the primordial tissue. The massive destruction of the amyloplasts and the rapid decline in starch content in response to all the herbicide treatments may indicate the possible involvement of carotenoids in stabilizing the amyloplast outer membrane in field dodder.

Analyses in nutritional epidemiology usually assume a uniform effect of a nutrient. Previously, four subgroups of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study of Finnish male smokers aged 50–69 years were identified in which vitamin E supplementation either significantly increased or decreased the risk of pneumonia. The purpose of this present study was to quantify the level of true heterogeneity in the effect of vitamin E on pneumonia incidence using the I2 statistic. The I2 value estimates the percentage of total variation across studies that is explained by true differences in the treatment effect rather than by chance, with a range from 0 to 100 %. The I2 statistic for the effect of vitamin E supplementation on pneumonia risk for five subgroups of the ATBC population was 89 % (95 % CI 78, 95 %), indicating that essentially all heterogeneity was true variation in vitamin E effect instead of chance variation. The I2 statistic for heterogeneity in vitamin E effects on pneumonia risk was 92 % (95 % CI 80, 97 %) for three other ATBC subgroups defined by smoking level and leisure-time exercise level. Vitamin E decreased pneumonia risk by 69 % among participants who had the least exposure to smoking and exercised during leisure time (7·6 % of the ATBC participants), and vitamin E increased pneumonia risk by 68 % among those who had the highest exposure to smoking and did not exercise (22 % of the ATBC participants). These findings refute there being a uniform effect of vitamin E supplementation on the risk of pneumonia.

Elevated fatty acid binding proteins (FABP) may play a role in obesity and co-morbidities. The role of nutritional interventions in modulating these levels remains unclear. The aim of this post hoc study was to determine the effect of overweight (OW) on FABP4 and FABP5 in boys in relation to indices of adiposity, insulin resistance and inflammation, and to investigate the effects of a 6-month supplementation with an encapsulated fruit and vegetable juice concentrate (FVJC) plus nutritional counselling (NC) on FABP levels. A post hoc analysis of a double-blind, randomised, placebo-controlled study of children recruited from the general paediatric population was performed. A total of thirty age-matched prepubertal boys (nine lean and twenty-one OW; aged 6–10 years) were studied. Patients received NC by a registered dietitian and were randomised to FVJC or placebo capsules for 6 months. FABP4, FABP5, glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR), glucose-induced acute insulin response (AIR), lipid-corrected β-carotene (LCβC), adiponectin, leptin, high-sensitivity C-reactive protein (hs-CRP), IL-6 and body composition by dual-energy X-ray absorptiometry were determined before and after the intervention. FABP were higher (P < 0·01) in the OW v. lean boys and correlated directly with HOMA-IR, abdominal fat mass (AFM), hs-CRP, IL-6, and LCβC (P < 0·05 for all). FABP4 was associated with adiponectin and AIR (P < 0·05). FVJC plus NC reduced FABP4, HOMA-IR and AFM (P < 0·05 for all) but not FABP5. OW boys showed elevated FABP4 and FABP5, but only FABP4 was lowered by the FVJC supplement.

Raman spectroscopy appears to be an ideal technique for the initial detection of biomarkers, molecules that are potentially indicative of life on planetary bodies elsewhere in our solar system. Carotenoids are particularly useful biomarkers as they are used widely across the species, relatively resistant to breakdown and no inorganic source is known. They are used by microorganisms in their cell membranes for protection against UV radiation. In this paper we focus on the detection of carotenoids in microorganisms within a mineral matrix. We compare the Raman signatures of pure compounds with those of laboratory-made mixtures of β-carotene and minerals. Carotenoids covered by 2.5 mm of translucent calcite or 40 mm of transparent halite were detected using a conventional confocal Raman microscope. To improve sensitivity and hence detection levels, Raman measurements were successfully performed under resonant conditions. Raman analysis can be compromised by fluorescence interference. Data are presented to show how the contribution from the fluorescent background in the Raman spectra can be reduced when making use of gated detection in time-resolved Raman spectroscopy. Overall, this study demonstrates some of the potential of Raman spectroscopy as a method for the detection of (past) life signatures during future planetary missions without taking current technical limitations such as instrumental size into account as recent rapid technical developments suggest these limitations will be resolved in time.

Provitamin A biofortification of staple crops may decrease the prevalence of vitamin A (VA) deficiency if widely adopted in target countries. To assess the impact of processing methods on the VA value of plant foods, the unique bioefficacies of cis-βC isomers (formed during cooking) compared with all-trans (at) β-carotene (βC) must be determined. The bioefficacies of 9-cis (9c)- and 13-cis (13c)-βC isomers were compared with those of the at-βC isomer and VA positive (VA+) and negative (VA − ) controls in VA-depleted Mongolian gerbils (Meriones unguiculatus) in two experimental studies (study 1, n 56; study 2, n 57). A 3- or 4-week depletion period was followed by a 3- or 4-week treatment period in which the groups received oral doses of the 9c-, 13c- or at-βC isomers in cottonseed oil (study 1, 15 nmol/d; study 2, 30 nmol/d). In study 1, the βC isomers did not maintain baseline liver VA stores in all groups (0·69 (sd 0·20) μmol/liver) except in the VA+group (0·56 (sd 0·10) μmol/liver) (P= 0·0026). The βC groups were similar to the VA+group, but the 9c- and 13c-βC groups did not differ from the VA − group (0·39 (sd 0·09) μmol/liver). In study 2, the βC isomers maintained baseline liver VA stores in all the βC groups (0·35 (sd 0·13) μmol/liver), and in the VA+group, the VA supplement (0·54 (sd 0·19) μmol/liver) exceeded the baseline VA status (0·38 (sd 0·15) μmol/liver) (P< 0·0001); however, the 9c-βC group did not differ from the VA − group (0·20 (sd 0·07) μmol/liver). In vivo isomerisation of βC was confirmed in both experimental studies. Lower VA bioconversion factor values were obtained for the cis-βC isomers in study 2 when compared with study 1, but higher values were obtained for the at-βC isomer. Dose and VA status clearly affect bioconversion factors. In conclusion, the cis-βC isomers yielded similar liver VA stores to the at-βC isomer in Mongolian gerbils, and liver VA stores of the 9c- and 13c-βC groups did not differ when the doses were provided at physiological levels over time in two studies.

Vitamin A equivalency of β-carotene (VEB) is defined as the amount of ingested β-carotene in μg that is absorbed and converted into 1 μg retinol (vitamin A) in the human body. The objective of the present review was to discuss the different estimates for VEB in various types of dietary food matrices. Different methods are discussed such as mass balance, dose–response and isotopic labelling. The VEB is currently estimated by the US Institute of Medicine (IOM) as 12:1 in a mixed diet and 2:1 in oil. For humans consuming β-carotene dissolved in oil, a VEB between 2:1 and 4:1 is feasible. A VEB of approximately 4:1 is applicable for biofortified cassava, yellow maize and Golden Rice, which are specially bred for human consumption in developing countries. We propose a range of 9:1–16:1 for VEB in a mixed diet that encompasses the IOM VEB of 12:1 and is realistic for a Western diet under Western conditions. For a ‘prudent’ (i.e. non-Western) diet including a variety of commonly consumed vegetables, a VEB could range from 9:1 to 28:1 in a mixed diet.

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.

Vitamin A (VA) deficiency causes disability and mortality. Cassava can be crossbred to improve its β-carotene (BC) content; typical white cassava contains negligible amounts of BC. However, cassava contains cyanide and its continued consumption may lead to chronic disability. Our objective was to estimate the risk–benefit of consuming BC-enhanced cassava to increase VA intake. A total of ten American women were fed white and BC-enhanced cassava. BC and cyanide data from the feeding study were combined with African cassava consumption data to model the potential daily BC, VA and cyanide intakes of African women. If BC-enhanced cassava replaced white cassava in the diets, it could theoretically meet recommended VA intakes for the following percentages of individuals from six African countries that consume cassava as a staple crop: Angola (95 %), Central African Republic (95 %), Congo (about 100 %), Ghana (99 %), Mozambique (99 %) and Nigeria (92 %). Cyanide intake after minimal preparation of cassava could be thirteen to thirty-two times the reference dose (RfD), a toxicological exposure reference, but could be completely removed by extensive soaking. This study demonstrates that consumption of BC-enhanced cassava, processed to maintain BC and remove cyanide, theoretically increases VA intakes for African populations and other areas of the world where cassava is a staple crop.

Biofortification of cassava with the provitamin A carotenoid β-carotene is a potential mechanism for alleviating vitamin A deficiency. Cassava is a staple food in the African diet, but data regarding the human bioavailability of β-carotene from this food are scarce. The objective of the present study was to evaluate provitamin A-enhanced cassava as a source of β-carotene and vitamin A for healthy adult women. The study was a randomised, cross-over trial of ten American women. The subjects consumed three different porridges separated by 2 week washout periods. Treatment meals (containing 100 g cassava) included: biofortified cassava (2 mg β-carotene) porridge with added oil (15 ml peanut or rapeseed oil, 20 g total fat); biofortified cassava porridge without added oil (6 g total fat); unfortified white cassava porridge with a 0·3 mg retinyl palmitate reference dose and added oil (20 g total fat). Blood was collected six times from − 0·5 to 9·5 h post-feeding. TAG-rich lipoprotein (TRL) plasma was separated by ultracentrifugation and analysed using HPLC with coulometric array electrochemical detection. The AUC for retinyl palmitate increased after the biofortified cassava meals were fed (P< 0·05). Vitamin A conversion was 4·2 (sd 3·1) and 4·5 (sd 3·1) μg β-carotene:1 μg retinol, with and without added oil, respectively. These results show that biofortified cassava increases β-carotene and retinyl palmitate TRL plasma concentrations in healthy well-nourished adult women, suggesting that it is a viable intervention food for preventing vitamin A deficiency.

Muscle atrophy increases the production of reactive oxygen species and the expression of atrophy-related genes, which are involved in the ubiquitin–proteasome system. In the present study, we investigated the effects of β-carotene on oxidative stress (100 μm-H2O2)-induced muscle atrophy in murine C2C12 myotubes. β-Carotene (10 μm) restored the H2O2-induced decreased levels of myosin heavy chain and tropomyosin (P< 0·05, n 3) and decreased the H2O2-induced increased levels of ubiquitin conjugates. β-Carotene reduced the H2O2-induced increased expression levels of E3 ubiquitin ligases (Atrogin-1 and MuRF1) and deubiquitinating enzymes (USP14 and USP19) (P< 0·05, n 3) and attenuated the H2O2-induced nuclear localisation of FOXO3a. Furthermore, we determined the effects of β-carotene on denervation-induced muscle atrophy. Male ddY mice (8 weeks old, n 30) were divided into two groups and orally pre-administered micelle with or without β-carotene (0·5 mg once daily) for 2 weeks, followed by denervation in the right hindlimb. β-Carotene was further administered once daily until the end of the experiment. At day 3 after denervation, the ratio of soleus muscle mass in the denervated leg to that in the sham leg was significantly higher in β-carotene-administered mice than in control vehicle-administered ones (P< 0·05, n 5). In the denervated soleus muscle, β-carotene administration significantly decreased the expression levels of Atrogin-1, MuRF1, USP14 and USP19 (P< 0·05, n 5) and the levels of ubiquitin conjugates. These results indicate that β-carotene attenuates soleus muscle loss, perhaps by repressing the expressions of Atrogin-1, MuRF1, USP14 and USP19, at the early stage of soleus muscle atrophy.

Prospective studies have indicated an age-related impairment of the immune response. Carotenoids have been hypothesised to enhance immune cell function. The aim of the present study was to describe the age-related effects and the impact of in vivo dietary carotenoid depletion and repletion on specific and non-specific immunity. A total of ninety-eight healthy male subjects (aged 20–75 years) received a carotenoid-depleted diet for 3 weeks and were then supplemented daily for 5 weeks with 30 mg β-carotene, 15 mg lycopene and 9 mg lutein. Blood samples were collected at study entry, after depletion and supplementation, and biomarkers of immune status were determined. We found that serum IgA levels were positively correlated with ageing. Lymphocyte phenotyping indicated an increase with age in the memory T-helper cell subpopulation (CD4+CD45RO+) concomitantly with a decrease in naive T-helper cells (CD4+CD45RA+). A significant increase in the natural killer cells subpopulation and a small decrease in B lymphocytes were also observed, especially for the oldest volunteers. From ex vivo cell function exploration, a positive correlation was observed between age and IL-2 production of phytohaemagglutinin-stimulated lymphocytes. Neutrophils' bactericidal activity was significantly impaired with age (from 50 years) and was modulated by carotenoid status. An age effect was found on neutrophils' spontaneous migration but not on directed migration. Immune response in healthy human subjects is mostly affected by age rather than by dietary carotenoid depletion and repletion. Even in carefully selected healthy volunteers, some age-related immune changes occur predominantly from 50 years onwards. This immunosenescence could generate a loss in the immune system adjustment capacity.

The aim of the present study was to compare the effect of lutein- and zeaxanthin-rich foods and supplements on macular pigment level (MPL) and serological markers of endothelial activation, inflammation and oxidation in healthy volunteers. We conducted two 8-week intervention studies. Study 1 (n 52) subjects were randomised to receive either carrot juice (a carotene-rich food) or spinach powder (a lutein- and zeaxanthin-rich food) for 8 weeks. Study 2 subjects (n 75) received supplements containing lutein and zeaxanthin, β-carotene, or placebo for 8 weeks in a randomised, double-blind, placebo-controlled trial. MPL, serum concentrations of lipid-soluble antioxidants, inter-cellular adhesion molecule 1, vascular cell adhesion molecule 1, C-reactive protein and F2-isoprostane levels were assessed at baseline and post-intervention in both studies. In these intervention studies, no effects on MPL or markers of endothelial activation, inflammation or oxidation were observed. However, the change in serum lutein and zeaxanthin was associated or tended to be associated with the change in MPL in those receiving lutein- and zeaxanthin-rich foods (lutein r 0·40, P = 0·05; zeaxanthin r 0·30, P = 0·14) or the lutein and zeaxanthin supplement (lutein r 0·43, P = 0·03; zeaxanthin r 0·22, P = 0·28). In both studies, the change in MPL was associated with baseline MPL (food study r − 0·54, P < 0·001; supplement study r − 0·40, P < 0·001). We conclude that this 8-week supplementation with lutein and zeaxanthin, whether as foods or as supplements, had no significant effect on MPL or serological markers of endothelial activation, inflammation and oxidation in healthy volunteers, but may improve MPL in the highest serum responders and in those with initially low MPL.

The objective of the present study was to assess the intake of naturally occurring plant sterols and β-carotene via the overall diet of Belgian pre-school children and adults. Two different Belgian food consumption databases were used: (1) one with consumption data of pre-school children (2·5–6·5 years old) and (2) one with consumption data of adults ( ≥ 15 years old). These consumption data were combined with a newly developed database containing the plant sterol and β-carotene content in all relevant food items based on international food composition databases and scientific literature. The results show that Flemish pre-school children have a median plant sterol intake of 172 (interquartile range (IQR) = 47) and 184 (IQR = 52) mg/d for girls and boys, respectively. Their median β-carotene intake was 1857 (IQR = 1250) μg/d, without significant difference between girls and boys. Belgian women and men have a median plant sterol intake of 218 (IQR = 113) and 280 (IQR = 158) mg/d, respectively, and a median β-carotene intake of 2086 (IQR = 1254) μg/d (not significantly different between the sexes). The main food source of naturally occurring plant sterols was bread and other cereal products. For β-carotene, the main food source was vegetables.

Animal studies were conducted to evaluate the influence of dietary spice compounds, piperine, capsaicin and ginger, on the absorption of orally administered β-carotene and its conversion to vitamin A. In rats maintained on these spice-containing diets for 8 weeks, concentrations of β-carotene and retinol were determined in the serum, liver and intestine 4 h after a single oral administration of β-carotene. β-Carotene concentration was significantly increased in the serum, liver and intestine of piperine- and ginger-fed rats, suggesting improved absorption of β-carotene. However, retinol concentration was not significantly changed in these animals, suggesting that the bioconversion of β-carotene to vitamin A was not similarly influenced. Between the two enzymes involved in the bioconversion of β-carotene to vitamin A, the activity of intestinal and hepatic β-carotene 15,15′-dioxygenase was either unaffected or lowered by these spice treatments. The activity of intestinal and hepatic retinal reductase was unaffected by the dietary spices. Activities of these two enzymes involved in the bioconversion of β-carotene to retinal were inhibited by the test spices in vitro, thus corroborating with the in vivo observation. Although the bioconversion of β-carotene was not promoted, increased absorption and tissue levels of β-carotene by the dietary spices may contribute to a higher antioxidant protection.

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.

Anthocyanins, phenolic acids and carotenoids are the predominant phytochemicals present in purple carrots. These phytochemicals could be useful in treatment of the metabolic syndrome since anthocyanins improve dyslipidaemia, glucose tolerance, hypertension and insulin resistance; the phenolic acids may also protect against CVD and β-carotene may protect against oxidative processes. In the present study, we have compared the ability of purple carrot juice and β-carotene to reverse the structural and functional changes in rats fed a high-carbohydrate, high-fat diet as a model of the metabolic syndrome induced by diet. Cardiac structure and function were defined by histology, echocardiography and in isolated hearts and blood vessels; liver structure and function, oxidative stress and inflammation were defined by histology and plasma markers. High-carbohydrate, high-fat diet-fed rats developed hypertension, cardiac fibrosis, increased cardiac stiffness, endothelial dysfunction, impaired glucose tolerance, increased abdominal fat deposition, altered plasma lipid profile, liver fibrosis and increased plasma liver enzymes together with increased plasma markers of oxidative stress and inflammation as well as increased inflammatory cell infiltration. Purple carrot juice attenuated or reversed all changes while β-carotene did not reduce oxidative stress, cardiac stiffness or hepatic fat deposition. As the juice itself contained low concentrations of carotenoids, it is likely that the anthocyanins are responsible for the antioxidant and anti-inflammatory properties of purple carrot juice to improve glucose tolerance as well as cardiovascular and hepatic structure and function.