Dietary, anthropometric, and lifestyle correlates of serum carotenoids in postmenopausal women

Fresh Tomato (Lycopersicon esculentum Mill.) in the Diet Improves the Features of the Metabolic Syndrome: A Randomized Study in Postmenopausal Women

(1) Background: According to the 2005~2008 Nutrition and Health Survey in Taiwan (NAHSIT), more than half of Taiwanese women (57.3%) had metabolic syndrome during menopause. Metabolic syndrome is a set of risk factors for cardiovascular disease (CVD) that increase the risk of cardiovascular disease, diabetes, and mortality. Epidemiological studies suggest that the consumption of tomato-based foods might reduce the risk factors for CVD. The aim of this study is to examine the effects of tomato consumption on lowering the metabolic syndrome risk factors among overweight postmenopausal women. (2) Methods: We conducted a randomized controlled trial using 8-week open-label dietary intervention. Overweight postmenopausal women aged 45-70 years old were recruited from Taipei Medical University in October 2013. They were randomly assigned into two groups (a control diet vs. a tomato diet). Blood samples were collected at the baseline and at the 4th and 8th weeks. The lipid profile, blood sugar, and antioxidant biomarkers, i.e., the ferric-reducing ability of plasma (FRAP) and serum carotenoids, were analyzed. Blood pressure, body weight, and body fat were also measured every week. (3) Results: After the 8-week dietary intervention, body weight, body mass index, waist circumference, and hip circumference were significantly lower in both groups (p < 0.05). Body fat mass, body fat percentage, waist circumference, and hip circumference were significantly lower in the tomato diet group than in the control diet group. The tomato diet group had significantly lower serum total cholesterol, triglyceride, systolic blood pressure and blood sugar, and higher high-density lipoprotein cholesterol than the control diet group. The antioxidant biomarkers, FRAP, beta-carotenoids, and lycopene were significantly higher in the tomato diet group than in the control diet group. (4) Conclusions: Fresh tomato consumption can increase antioxidant biomarkers to reduce risks of metabolic syndrome in postmenopausal women.

Changes in Plasma Carotenoid Concentrations during the AntioxObesity Weight Reduction Program among Adults with Excessive Body Weight

Plasma carotenoid concentrations are associated with antioxidant defense which might be disturbed in people with excessive body weight (EBW). This study aimed at evaluating the effect of a 6-week weight reduction program on plasma concentration of β-carotene, lycopene, and lutein/zeaxanthin in adults with EBW. A total of 130 adults were recruited for the study; 75 completed the program. Data on food consumption were collected with a 3-day recording method and a semi-quantitative FFQ. Body height, body weight (BW), waist circumference (WC), fat mass (FM), fat-free mass (FFM), abdominal subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) were measured. Lipid profile, β-carotene, lycopene, and lutein/zeaxanthin were analyzed in blood. The AntioxObesity program resulted in a significant reduction in BW, WC, FM, SAT, and VAT. The mean plasma concentrations of β-carotene, lycopene, and lutein/zeaxanthin increased significantly after intervention. A reduction in FM above 4 kg significantly increased the concentration of β-carotene, lutein/zeaxanthin, and total carotenoids. An increase in carotenoid levels correlated with FM reduction, as fruit and vegetable intake remained unchanged. However, this effect may vary due to gender, HDL-cholesterol, body fat content, and obesity status in the weight loss process.

Concurrent Production of α- and β-Carotenes with Different Stoichiometries Displaying Diverse Antioxidative Activities via Lycopene Cyclases-Based Rational System

α- and β-carotenes belong to the most essential carotenoids in the human body and display remarkable pharmacological value for health due to their beneficial antioxidant activities. Distinct high α-/β-carotene stoichiometries have gained increasing attention for their effective preventions of Alzheimer’s disease, cardiovascular disease, and cancer. However, it is extremely difficult to obtain α-carotene in nature, impeding the accumulations of high α-/β-carotene stoichiometries and excavation of their antioxidant activities. Herein, we developed a dynamically operable strategy based on lycopene cyclases (LCYB and LCYE) for concurrently enriching α- and β-carotenes along with high stoichiometries in E. coli. Membrane-targeted and promoter-centered approaches were firstly implemented to spatially enhance catalytic efficiency and temporally boost expression of TeLCYE to address its low competitivity at the starting stage. Dynamically temperature-dependent regulation of TeLCYE and TeLCYB was then performed to finally achieve α-/β-carotene stoichiometries of 4.71 at 37 °C, 1.65 at 30 °C, and 1.06 at 25 °C, respectively. In the meantime, these α-/β-carotene ratios were confirmed to result in diverse antioxidative activities. According to our knowledge, this is the first time that both the widest range and antioxidant activities of high α/β-carotene stoichiometries were reported in any organism. Our work provides attractive potentials for obtaining natural products with competitivity and a new insight on the protective potentials of α-/β-carotenes with high ratios for health supply.

α-Carotene: a valuable carotenoid in biological and medical research

α-Carotene, one of the C₄₀ carotenes, is a natural lipid-soluble terpene. The chemical structure of α-carotene is based on the unsaturated polyene chain skeleton, with an ε-ring and a β-ring on each side of the skeleton. α-Carotene is widely found in dietary fruits and vegetables, and the concentration depends on the plant species. In addition, processing methods and storage conditions used in the food and medical industries can alter the concentration of α-carotene in raw materials. This review of α-carotene summarizes the major studies on chemical structure, source, extraction, detection, biosynthesis, processing effect, bioactivity, medicine, and biotechnology. Whether α-carotene supplementation or a diet rich in fruits and vegetables has a positive effect on the prevention of cancer, cardiovascular disease, and other diseases is the focus of this study. © 2022 Society of Chemical Industry.

Regulatory mechanisms of Beta-carotene and BCMO1 in adipose tissues: A gene enrichment-based bioinformatics analysis

Beta-carotene (β-carotene, BC) is one of the carotenoids most commonly consumed by humans. BCMO1 is expressed in various human tissues and is considered to be a key enzyme that converts BC into vitamin A. Studies indicated that BC-derived carotenoid signaling molecules affected the physiological functions of fat cells. In order to investigate the role and possible molecular mechanism of BC in mouse adipocytes, we conducted 4-group and 2-group difference analysis based on the data of GSE27271 chip in the Gene Expression Omnibus database. Genes differentially expressed in the inguinal white adipose tissue of mice were screened out and combined with the STRING database to construct protein-protein interaction (PPI) networks. Among them, Alb (albumin), Mug1 (murinoglobulin-1) and Uox (urate oxidase) genes were at relatively key positions and may affect the action of BC. Besides, Ppara (peroxisome proliferator-activated receptor alpha), Acly (ATP-citrate lyase) and Fabp5 (fatty acid-binding protein 5) genes constituted functional partners with many genes in the PPI network, and these genes may be Bcmo1 targeting molecules. Gene Ontology (GO) function and signaling pathways enrichment analysis were performed on the genes with protein interaction relationship in the PPI network. Fatty acid binding, cholesterol metabolic process, and regulation of fatty acid metabolic process were significantly enriched, and PPAR signaling pathway showed the most significant, indicating that BC and Bcmo1 might synergistically affect body metabolic functions such as fat metabolism. In general, BC and Bcmo1 may play a role in fat metabolism in mice, thereby affecting other functions or diseases.

Preventive Effects of β-Cryptoxanthin, a Potent Antioxidant and Provitamin A Carotenoid, on Lifestyle-Related Diseases-A Central Focus on Its Effects on Non-Alcoholic Fatty Liver Disease (NAFLD)

Humans usually get dietary carotenoids from foods such as green and yellow vegetables and algae. Carotenoids have been reported to effectively reduce the risk of developing lifestyle-related diseases. β-Cryptoxanthin, which is an antioxidative carotenoid and a type of provitamin A, is metabolically converted to vitamin A. β-Cryptoxanthin has recently gained attention for its risk-reducing effects on lifestyle-related diseases, especially on non-alcoholic fatty liver disease (NAFLD), from epidemiological, interventional, and mechanistic studies. Retinoids (vitamin A) have also been reported to be useful as a therapeutic agent for NAFLD. Provitamin A is known to serve as a supply source of retinoids through metabolic conversion by the regulated activity of β-carotene 15,15′-monooxygenase 1 (BCMO1) to the retina only when retinoids are deficient. From mechanistic studies using NAFLD-model mice, β-cryptoxanthin has been shown to contribute to the improvement of NAFLD through a multifaceted approach, including improved insulin resistance, suppression of oxidative stress and inflammation, a reduction of macrophages and a shift of their subsets, and control of lipid metabolism by peroxisome proliferator-activated receptor (PPAR) family activation, which are also expected to have clinical applications. β-Cryptoxanthin has the potential to prevent lifestyle-related diseases from different angles, not only as an antioxidant but also as a retinoid precursor.

Carotenoids: Therapeutic Strategy in the Battle against Viral Emerging Diseases, COVID-19: An Overview

Carotenoids, a group of phytochemicals, are naturally found in the Plant kingdom, particularly in fruits, vegetables, and algae. There are more than 600 types of carotenoids, some of which are thought to prevent disease, mainly through their antioxidant properties. Carotenoids exhibit several biological and pharmaceutical benefits, such as anti-inflammatory, anti-cancer, and immunity booster properties, particularly as some carotenoids can be converted into vitamin A in the body. However, humans cannot synthesize carotenoids and need to obtain them from their diets or via supplementation. The emerging zoonotic virus severe acute respiratory syndrome coronavirus 2, which causes coronavirus disease 2019 (COVID-19), originated in bats, and was transmitted to humans. COVID-19 continues to cause devastating international health problems worldwide. Therefore, natural preventive therapeutic strategies from bioactive compounds, such as carotenoids, should be appraised for strengthening physiological functions against emerging viruses. This review summarizes the most important carotenoids for human health and enhancing immunity, and their potential role in COVID-19 and its related symptoms. In conclusion, promising roles of carotenoids as treatments against emerging disease and related symptoms are highlighted, most of which have been heavily premeditated in studies conducted on several viral infections, including COVID-19. Further in vitro and in vivo research is required before carotenoids can be considered as potent drugs against such emerging diseases.

From carotenoid intake to carotenoid blood and tissue concentrations - implications for dietary intake recommendations

There is uncertainty regarding carotenoid intake recommendations, because positive and negative health effects have been found or are correlated with carotenoid intake and tissue levels (including blood, adipose tissue, and the macula), depending on the type of study (epidemiological vs intervention), the dose (physiological vs supraphysiological) and the matrix (foods vs supplements, isolated or used in combination). All these factors, combined with interindividual response variations (eg, depending on age, sex, disease state, genetic makeup), make the relationship between carotenoid intake and their blood/tissue concentrations often unclear and highly variable. Although blood total carotenoid concentrations <1000 nmol/L have been related to increased chronic disease risk, no dietary reference intakes (DRIs) exist. Although high total plasma/serum carotenoid concentrations of up to 7500 nmol/L are achievable after supplementation, a plateauing effect for higher doses and prolonged intake is apparent. In this review and position paper, the current knowledge on carotenoids in serum/plasma and tissues and their relationship to dietary intake and health status is summarized with the aim of proposing suggestions for a "normal," safe, and desirable range of concentrations that presumably are beneficial for health. Existing recommendations are likewise evaluated and practical dietary suggestions are included.

β-Carotene Inhibits Expression of Matrix Metalloproteinase-10 and Invasion in Helicobacter pylori-Infected Gastric Epithelial Cells

Matrix metalloproteinases (MMPs), key molecules of cancer invasion and metastasis, degrade the extracellular matrix and cell–cell adhesion molecules. MMP-10 plays a crucial role in Helicobacter pylori-induced cell-invasion. The mitogen-activated protein kinase (MAPK) signaling pathway, which activates activator protein-1 (AP-1), is known to mediate MMP expression. Infection with H. pylori, a Gram-negative bacterium, is associated with gastric cancer development. A toxic factor induced by H. pylori infection is reactive oxygen species (ROS), which activate MAPK signaling in gastric epithelial cells. Peroxisome proliferator-activated receptor γ (PPAR-γ) mediates the expression of antioxidant enzymes including catalase. β-Carotene, a red-orange pigment, exerts antioxidant and anti-inflammatory properties. We aimed to investigate whether β-carotene inhibits H. pylori-induced MMP expression and cell invasion in gastric epithelial AGS (gastric adenocarcinoma) cells. We found that H. pylori induced MMP-10 expression and increased cell invasion via the activation of MAPKs and AP-1 in gastric epithelial cells. Specific inhibitors of MAPKs suppressed H. pylori-induced MMP-10 expression, suggesting that H. pylori induces MMP-10 expression through MAPKs. β-Carotene inhibited the H. pylori-induced activation of MAPKs and AP-1, expression of MMP-10, and cell invasion. Additionally, it promoted the expression of PPAR-γ and catalase, which reduced ROS levels in H. pylori-infected cells. In conclusion, β-carotene exerts an inhibitory effect on MAPK-mediated MMP-10 expression and cell invasion by increasing PPAR-γ-mediated catalase expression and reducing ROS levels in H. pylori-infected gastric epithelial cells.

A comprehensive review on carotenoids in foods and feeds: status quo, applications, patents, and research needs

Carotenoids are isoprenoids widely distributed in foods that have been always part of the diet of humans. Unlike the other so-called food bioactives, some carotenoids can be converted into retinoids exhibiting vitamin A activity, which is essential for humans. Furthermore, they are much more versatile as they are relevant in foods not only as sources of vitamin A, but also as natural pigments, antioxidants, and health-promoting compounds. Lately, they are also attracting interest in the context of nutricosmetics, as they have been shown to provide cosmetic benefits when ingested in appropriate amounts. In this work, resulting from the collaborative work of participants of the COST Action European network to advance carotenoid research and applications in agro-food and health (EUROCAROTEN, www.eurocaroten.eu, https://www.cost.eu/actions/CA15136/#tabs|Name:overview) research on carotenoids in foods and feeds is thoroughly reviewed covering aspects such as analysis, carotenoid food sources, carotenoid databases, effect of processing and storage conditions, new trends in carotenoid extraction, daily intakes, use as human, and feed additives are addressed. Furthermore, classical and recent patents regarding the obtaining and formulation of carotenoids for several purposes are pinpointed and briefly discussed. Lastly, emerging research lines as well as research needs are highlighted.

Dietary β-Cryptoxanthin and α-Carotene Have Greater Apparent Bioavailability Than β-Carotene in Subjects from Countries with Different Dietary Patterns

β-carotene, α-carotene and β-cryptoxanthin are greater contributors to vitamin A intake than retinol in the human diet for most people around the world. Their contribution depends on several factors, including bioavailability and capacity of conversion into retinol. There is an increasing body of research showing that the use of retinol activity equivalents or retinol equivalents could lead to the underestimation of the contribution of β-cryptoxanthin and of α-carotene. The aim is to assess their apparent bioavailability by comparing concentrations in blood to their dietary intakes and identifying the major food contributors to their dietary intake. Dietary intake (3-day 24-h records) and serum concentrations (by HPLC) were calculated in normolipemic subjects with adequate retinol status (≥1.1 µmol/L) from our studies (n = 633) and apparent bioavailability calculated from 22 other studies (n = 29,700). Apparent bioavailability was calculated as the ratio of concentration in the blood to carotenoid intake. Apparent bioavailabilities for α-carotene and β-cryptoxanthin were compared to those for β-carotene. Eating comparable amounts of α-carotene, β-cryptoxanthin and β-carotene foods resulted in 55% greater α-carotene (95% CI 35, 90) and 686% higher β-cryptoxanthin (95% CI 556, 1016) concentrations than β-carotene in blood. This suggests differences in the apparent bioavailability of α-carotene and β-cryptoxanthin and even larger differences with β-cryptoxanthin, greater than that of β-carotene. Four fruits (tomato, orange, tangerine, red pepper) and two vegetables (carrot, spinach) are the main contributors to their dietary intake (>50%) in Europeans.

Serum levels of carotenoids in patients with osteonecrosis of the femoral head are lower than in healthy, community-living people

PURPOSE

Oxidative stress is closely associated with the pathogenesis of nontraumatic osteonecrosis of the femoral head (ONFH). This study aimed to determine whether the serum levels of antioxidant nutrients were decreased in patients with ONFH.

METHODS

We analyzed the serum levels of antioxidant nutrients in 39 patients with ONFH (ONFH group) and 78 age- and gender-matched healthy people (control group) who voluntarily participated in the Yakumo study, which is a comprehensive health examination program. We measured and compared the serum levels of α-tocopherol (vitamin E) and total carotenoids, including zeaxanthin/lutein, β-cryptoxanthin, lycopene, α-carotene, and β-carotene, in the ONFH and control groups using high-performance liquid chromatography.

RESULTS

The mean serum levels of total carotenoids were significantly lower in the ONFH group than in the control group (2.36 ± 1.26 and 3.79 ± 2.36 µmol/l, respectively, p < 0.001). However, no significant difference was found in α-tocopherol between the two groups (26.37 ± 6.90 µmol/l in the ONFH group and 26.24 ± 6.28 µmol/l in the control group, p = 0.920). Among each carotenoid, the serum levels of zeaxanthin/lutein, lycopene, and β-carotene were significantly lower in the ONFH group than in the control group ( p < 0.001).

CONCLUSIONS

The serum levels of carotenoids were lower in patients with ONFH than in healthy, community-living people. This result suggests that carotenoids may be related to the pathogenesis of ONFH.

Enhanced Z-isomerization of tomato lycopene through the optimal combination of food ingredients

In tomatoes, most lycopene is present in the all-E-configuration and shows very low bioavailability, whereas the Z-isomers show higher bioavailability. Hence, for health reasons, it is expected that the ingestion of lycopene Z-isomers is preferable. Very recently, it was reported that onion and possibly garlic promoted thermal Z-isomerization of (all-E)-lycopene but there are no reports for other food ingredients. Here we show new food ingredients that enhance thermal Z-isomerization of lycopene in tomatoes and from the results, we guessed some causative components having the Z-isomerization promoting effect. A comprehensive investigation of food ingredients revealed that some vegetables (Allium sp., Brassica sp., and Raphanus sp.), shiitake mushroom (Lentinus edodes), and some edible seaweeds (Saccharina sp. and Ecklonia sp.) markedly promoted Z-isomerization of (all-E)-lycopene in tomato puree with heating at 80 °C for 1 h. Moreover, it was revealed that polysulfides, isothiocyanates, carbon disulfide, and iodine, which were commonly contained in the above food ingredients in considerable quantity, enhanced thermal Z-isomerization of (all-E)-lycopene. Our findings on the food ingredients and the food-derived catalysts having a carotenoid Z-isomerization promoting effect are important, not only for the food, drink, and dietary supplement manufacturing industries, but also for daily home cooking.

β-Carotene in the human body: metabolic bioactivation pathways - from digestion to tissue distribution and excretion

β-Carotene intake and tissue/blood concentrations have been associated with reduced incidence of several chronic diseases. Further bioactive carotenoid-metabolites can modulate the expression of specific genes mainly via the nuclear hormone receptors: retinoic acid receptor- and retinoid X receptor-mediated signalling. To better understand the metabolic conversion of β-carotene, inter-individual differences regarding β-carotene bioavailability and bioactivity are key steps that determine its further metabolism and bioactivation and mediated signalling. Major carotenoid metabolites, the retinoids, can be stored as esters or further oxidised and excreted via phase 2 metabolism pathways. In this review, we aim to highlight the major critical control points that determine the fate of β-carotene in the human body, with a special emphasis on β-carotene oxygenase 1. The hypothesis that higher dietary β-carotene intake and serum level results in higher β-carotene-mediated signalling is partly questioned. Alternative autoregulatory mechanisms in β-carotene / retinoid-mediated signalling are highlighted to better predict and optimise nutritional strategies involving β-carotene-related health beneficial mediated effects.

Intake of Lutein and Zeaxanthin as a Possible Factor Influencing Gastrointestinal Symptoms in Caucasian Individuals with Ulcerative Colitis in Remission Phase

The vitamin A deficiencies are commonly observed in the case of ulcerative colitis individuals. The decreased antioxidant defence may influence the intestine, inducing higher susceptibility to oxidative damage of tissues and altering the symptoms and course of disease. Intestinal symptoms, ranging from diarrhea to constipation, occur more commonly in remission ulcerative colitis individuals than in general population. The aim of the study was to analyze the association between retinoid intake and gastrointestinal symptoms in Caucasian individuals in the remission phase of ulcerative colitis. Reitnoid (total vitamin A, retinol, β-carotene, α-carotene, β-cryptoxanthin, lycopene, as well as lutein and zeaxanthin) intakes were analyzed on the basis of three-day dietary records. Gastrointestinal symptoms (daily number of bowel movements, and the presence of painful tenesmus, flatulence, and constipation) were self-reported. The study was conducted in a group of 56 ulcerative colitis remission individuals, stratified by the gastrointestinal symptoms. One in every seven individuals reported recurring constipation. Higher intake of lutein and zeaxanthin (median 1386.2 µg, 289.0–13221.3 µg vs. median 639.0 µg, 432.7–1309.0 µg) may lower the incidence of constipation (p = 0.013). The intake of retinoids other than lutein and zeaxanthin was not associated with the incidence of constipation or other gastrointestinal symptoms.

Predicting organ carotenoids levels from analysis of plasma could lead to errors: A study in cynomolgus monkeys

Carotenoids are phytochemicals with strong antioxidant activity against reactive oxygen species that are widely distributed in fruits and vegetables. The beneficial effects of carotenoids on human health have attracted considerable attention. The plasma carotenoid profile in humans is generally recognized to reflect the dietary carotenoid composition. Although carotenoid profile in plasma is believed to correlate well with that in other tissues, the data for tissue accumulation of carotenoids in humans is very limited and poorly understood. In order to test the hypothesis that blood carotenoids reflect tissue accumulation of dietary carotenoids, the cynomolgus monkey was used as a model to determine it's suitable for extrapolation of data on tissue accumulation of carotenoids to humans. Herein, plasma carotenoids were measured in cynomolgus monkeys given a dietary mixture of carotenoids. The findings indicate that cynomolgus monkeys and humans are similar with regard to preferential accumulation of β-cryptoxanthin in the blood and brain. These results suggested that cynomolgus monkeys could be used to collect data on tissue accumulation of carotenoids for extrapolation to humans. The tissue accumulation of carotenoids in other tissues of cynomolgus monkeys that have not yet been evaluated in humans were also investigated, revealing marked differences in carotenoid levels and composition among plasma and various monkey tissues. These results suggest that accumulation of carotenoids in plasma does not reflect necessarily that in tissues, so that predicting the tissue accumulation of carotenoids from plasma carotenoid levels and profiles alone could lead to errors.

Effect of Long-Term Xanthophyll and Anthocyanin Supplementation on Lutein and Zeaxanthin Serum Concentrations and Macular Pigment Optical Density in Postmenopausal Women

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.

Intrinsic and Extrinsic Factors Impacting Absorption, Metabolism, and Health Effects of Dietary Carotenoids

Carotenoids are orange, yellow, and red lipophilic pigments present in many fruit and vegetables, as well as other food groups. Some carotenoids contribute to vitamin A requirements. The consumption and blood concentrations of specific carotenoids have been associated with reduced risks of a number of chronic conditions. However, the interpretation of large, population-based observational and prospective clinical trials is often complicated by the many extrinsic and intrinsic factors that affect the physiologic response to carotenoids. Extrinsic factors affecting carotenoid bioavailability include food-based factors, such as co-consumed lipid, food processing, and molecular structure, as well as environmental factors, such as interactions with prescription drugs, smoking, or alcohol consumption. Intrinsic, physiologic factors associated with blood and tissue carotenoid concentrations include age, body composition, hormonal fluctuations, and variation in genes associated with carotenoid absorption and metabolism. To most effectively investigate carotenoid bioactivity and to utilize blood or tissue carotenoid concentrations as biomarkers of intake, investigators should either experimentally or statistically control for confounding variables affecting the bioavailability, tissue distribution, and metabolism of carotene and xanthophyll species. Although much remains to be investigated, recent advances have highlighted that lipid co-consumption, baseline vitamin A status, smoking, body mass and body fat distribution, and genetics are relevant covariates for interpreting blood serum or plasma carotenoid responses. These and other intrinsic and extrinsic factors are discussed, highlighting remaining gaps in knowledge and opportunities for future research. To provide context, we review the state of knowledge with regard to the prominent health effects of carotenoids.

A global perspective on carotenoids: Metabolism, biotechnology, and benefits for nutrition and health

Carotenoids are lipophilic isoprenoid compounds synthesized by all photosynthetic organisms and some non-photosynthetic prokaryotes and fungi. With some notable exceptions, animals (including humans) do not produce carotenoids de novo but take them in their diets. In photosynthetic systems carotenoids are essential for photoprotection against excess light and contribute to light harvesting, but perhaps they are best known for their properties as natural pigments in the yellow to red range. Carotenoids can be associated to fatty acids, sugars, proteins, or other compounds that can change their physical and chemical properties and influence their biological roles. Furthermore, oxidative cleavage of carotenoids produces smaller molecules such as apocarotenoids, some of which are important pigments and volatile (aroma) compounds. Enzymatic breakage of carotenoids can also produce biologically active molecules in both plants (hormones, retrograde signals) and animals (retinoids). Both carotenoids and their enzymatic cleavage products are associated with other processes positively impacting human health. Carotenoids are widely used in the industry as food ingredients, feed additives, and supplements. This review, contributed by scientists of complementary disciplines related to carotenoid research, covers recent advances and provides a perspective on future directions on the subjects of carotenoid metabolism, biotechnology, and nutritional and health benefits.

β-Carotene Concentration and Its Association with Inflammatory Biomarkers in Spanish Schoolchildren

AIM

To examine the correlation between inflammatory biomarkers and plasma β-carotene levels in children.

METHODS

A total of 564 Spanish schoolchildren aged 9-12 were observed and studied. Plasma β-carotene levels were assessed by HPLC. A β-carotene level <4.83 µg/dL (0.09 µmol/L) was considered deficient. Plasma tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured by immunoenzyme assays. Serum high-sensitivity C-reactive protein (hs-CRP) was tested by immunonephelometry.

RESULTS

Subjects who were β-carotene-deficient (23.1% of the studied children) had higher IL-6 levels than subjects with normal β-carotene concentrations. The log-IL-6 and log-hs-CRP concentrations, but not the log-TNF-α level, were strongly and inversely related to the plasma log-β-carotene level (taking into account log-age, energy intake, log-triglycerides, gender, log-body mass index, log-β-carotene intake, energy from lipids and cholesterol as covariables). When the 3 inflammatory biomarkers were introduced into the regression model along with the corresponding covariables, only the log-IL-6 level was related to the plasma log-β-carotene level (β = -0.505 ± 0.078; p < 0.001).

CONCLUSIONS

Inflammatory status, in particular IL-6 levels, appears to be negatively associated with plasma β-carotene levels in schoolchildren.