Beta-carotene isomers in human serum, breast milk and buccal mucosa cells after continuous oral doses of all-trans and 9-cis beta-carotene

Evaluating the relationship between the nutrient intake of lactating women and their breast milk nutritional profile: a systematic review and narrative synthesis

Maternal diet influences breast milk nutritional profile; however, it is unclear which nutrients and contaminants are particularly responsive to short- and long-term changes in maternal intake, and the impact of specific exclusion diets, such as vegan or vegetarian. This study systematically reviewed the literature on the effects of maternal nutrient intake, including exclusion diets, on both the nutrient and contaminant content of breast milk. The electronic databases, PubMed, CENTRAL, Web of Science and CINALH were systematically searched until 4 June 2023, with additionally searches of reference lists (PROSPERO, CRD42020221577). The quality of the studies was examined using Cochrane Risk of Bias tool and Newcastle-Ottawa scale. Eighty-eight studies (n 6577) met the search criteria. Due to high heterogeneity, meta-analysis was not possible. There was strong evidence of response to maternal intakes for DHA and EPA, vitamins A, E and K, iodine and Se in breast milk composition, some evidence of response for α-linolenic acid, B vitamins, vitamin C and D, ovalbumin, tyrosine and contaminants, and insufficient evidence to identify the effects arachidonic acid, Cu, Fe, Zn and choline. The paucity of evidence and high heterogeneity among studies reflects the need for more high-quality trials. However, this review identified the importance of maternal intake in the nutritional content of breast milk for a wide range of nutrients and supports the recommendation for supplementation of DHA and vitamin B12 for those on restrictive diets.

Human nutritional relevance and suggested nutritional guidelines for vitamin A5/X and provitamin A5/X

In the last century, vitamin A was identified that included the nutritional relevant vitamin A1 / provitamin A1, as well as the vitamin A2 pathway concept. Globally, nutritional guidelines have focused on vitamin A1 with simplified recommendations and calculations based solely on vitamin A. The vitamin A / provitamin A terminology described vitamin A with respect to acting as a precursor of 11-cis-retinal, the chromophore of the visual pigment, as well as retinoic acid(s), being ligand(s) of the nuclear hormone receptors retinoic acid receptors (RARs) α, β and γ. All-trans-retinoic acid was conclusively shown to be the endogenous RAR ligand, while the concept of its isomer 9-cis-retinoic acid, being "the" endogenous ligand of the retinoid-X receptors (RXRs), remained inconclusive. Recently, 9-cis-13,14-dihydroretinoic acid was conclusively reported as an endogenous RXR ligand, and a direct nutritional precursor was postulated in 2018 and further confirmed by Rühl, Krezel and de Lera in 2021. This was further termed vitamin A5/X / provitamin A5/X. In this review, a new vitamin A5/X / provitamin A5/X concept is conceptualized in parallel to the vitamin A(1) / provitamin A(1) concept for daily dietary intake and towards dietary guidelines, with a focus on the existing national and international regulations for the physiological and nutritional relevance of vitamin A5/X. The aim of this review is to summarize available evidence and to emphasize gaps of knowledge regarding vitamin A5/X, based on new and older studies and proposed future directions as well as to stimulate and propose adapted nutritional regulations.

Beta-carotene exerted anti-proliferative and apoptotic effect on malignant mesothelioma cells

High blood levels of β-carotene and increased intake in the diets are inversely proportional to incidence of many cancer types. Antioxidant activity of β-carotene was proposed to be related with its antitumor effect. Despite this plant derivative substance being sought in many cancer types, the effectiveness of β-carotene against malignant mesothelioma remained unclear. Therefore, the present study aims to explore the impact of β-carotene on cell viability, apoptosis, and oxidative stress in mesothelioma cells. Human mesothelioma cell SPC212 were treated with β-carotene (3.125-200 μM) for 24, 48, 72, and 96 h. Cytotoxicity was measured with the MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide). Annexin-V/propidium iodide (PI) and caspase 3/7 biomarkers were used to identify apoptotic cells. Finally, the oxidative stress was evaluated with flow cytometry. The results of the measurements indicated a significant decline in viable mesothelioma cancer cell numbers upon β-carotene treatment in time- and concentration-dependent manner when compared to control cells. Furthermore, β-carotene treatment led to apoptosis induction according to both annexin V/PI and caspase 3/7 assays. Furthermore, β-carotene increased oxidative stress in SPC212 cells. These results show how β-carotene affects proliferative, apoptotic, and oxidative properties in SPC212 malignant pleural mesothelioma cells and provide useful insights into future studies.

Effects of Dietary Education Program for the Japan Diet on Cholesterol Efflux Capacity: A Randomized Controlled Trial

Aim: Improving cholesterol efflux capacity (CEC) of high-density lipoprotein (HDL) has been regarded as a novel target for preventing cardiovascular disease. HDL reportedly has antioxidant properties which may contribute to its functions. We investigated changes in CEC with intake of the Japan Diet (JD) recommended by the Japan Atherosclerosis Society and the relationship of these changes to serum antioxidant concentrations.

Methods: A randomized parallel controlled clinical trial on JD intake was performed in Japanese patients with dyslipidemia. Ninety-eight participants were randomly divided into the JD (n=49) or the partial JD (PJD) (n=49) group. Nutrition education, based on each diet at baseline and at 3 months, was provided and the participants were followed up for 6 months.

Results: Mean CEC was 1.05 in total and correlated positively with HDL-cholesterol (p＜0.001) at baseline. CEC did not change while oxygen radical absorbance capacity (ORAC) was decreased in both groups (p＜0.001). Although serum total carotenoid increased in both groups, serum α-tocopherol decreased in the JD group as compared to the PJD group (p＜0.05). CEC correlated positively with HDL ORAC at baseline (p=0.021) and with serum total carotenoid at 3 and 6 months (p=0.005, 0.035). Changes in CEC correlated positively with changes in HDL ORAC at 3 months and serum total tocopherol at 3 and 6 months (p＜0.001).

Conclusion: CEC was not changed by JD education in Japanese patients with dyslipidemia who already had normal CEC at baseline. CEC was suggested to be positively associated with serum α- and γ-tocopherol and HDL ORAC.

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.

Nutritional supplements and mother's milk composition: a systematic review of interventional studies

Background

This study aims to systematically review the effects of maternal vitamin and/or mineral supplementation on the content of breast milk.

Methods

We systematically searched electronic databases including Medline via PubMed, Scopus and ISI Web of Science till May 24, 2018. The following terms were used systematically in all mentioned databases: (“human milk” OR “breast milk” OR “breast milk composition” OR “human breast milk composition” OR “composition breast milk” OR “mother milk” OR “human breast milk” OR “maternal milk”) AND (“vitamin a” OR “retinol” OR “retinal” OR “retinoic acid” OR “beta-carotene” OR “beta carotene” OR “ascorbic acid” OR “l-ascorbic acid” OR “l ascorbic acid” OR “vitamin c” OR “vitamin d” OR “cholecalciferol” OR “ergocalciferol” OR “calciferol” OR “vitamin e” OR “tocopherol” OR “tocotrienol” OR “alpha-tocopherol” OR “alpha tocopherol” OR “α-tocopherol” OR “α tocopherol” OR “vitamin k” OR “vitamin b” OR “vitamin b complex” OR “zinc” OR “iron” OR “copper” Or “selenium” OR “manganese” OR “magnesium”) and we searched Medline via Medical subject Headings (MeSH) terms. We searched Google Scholar for to increase the sensitivity of our search. The search was conducted on human studies, but it was not limited to the title and abstract. Methodological quality and risk of bias of included studies were evaluated by Jadad scale and Cochrane risk of bias tools, respectively.

Results

This review included papers on three minerals (zinc, iron, selenium) and 6 vitamins (vitamin A, B, D, C, E and K) in addition to multi-vitamin supplements. Although studies had different designs, e.g. not using random allocation and/or blinding, our findings suggest that maternal use of some dietary supplements, including vitamin A, D, vitamin B1, B2 and vitamin C might be reflected in human milk. Vitamin supplements had agreater effect on breast milk composition compared to minerals. Higher doses of supplements showed higher effects and they were reflected more in colostrum than in the mature milk.

Conclusion

Maternal dietary vitamin and/or mineral supplementation, particularly fat- soluble vitamins, vitamin B1, B2 and C might be reflected in the breast milk composition. No difference was found between mega dose and single dose administration of minerals.

9-Cis-13,14-dihydroretinoic acid, a new endogenous mammalian ligand of retinoid X receptor and the active ligand of a potential new vitamin A category: vitamin A5

The identity of the endogenous RXR ligand has not been conclusively determined, even though several compounds of natural origin, including retinoids and fatty acids, have been postulated to fulfill this role. Filling this gap, 9-cis-13,14-dihydroretinoic acid (9CDHRA) was identified as an endogenous RXR ligand in mice. This review examines the physiological relevance of various potential endogenous RXR ligands, especially 9CDHRA. The elusive steps in the metabolic synthesis of 9CDHRA, as well as the nutritional/nutrimetabolic origin of 9CDHRA, are also explored, along with the suitability of the ligand to be the representative member of a novel vitamin A class (vitamin A5).

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.

Effect of Carotenoid Supplemented Formula on Carotenoid Bioaccumulation in Tissues of Infant Rhesus Macaques: A Pilot Study Focused on Lutein

Lutein is the predominant carotenoid in the developing primate brain and retina, and may have important functional roles. However, its bioaccumulation pattern during early development is not understood. In this pilot study, we investigated whether carotenoid supplementation of infant formula enhanced lutein tissue deposition in infant rhesus macaques. Monkeys were initially breastfed; from 1 to 3 months of age they were fed either a formula supplemented with lutein, zeaxanthin, β-carotene and lycopene, or a control formula with low levels of these carotenoids, for 4 months (n = 2/group). All samples were analyzed by high pressure liquid chromatography (HPLC). Final serum lutein in the supplemented group was 5 times higher than in the unsupplemented group. All brain regions examined showed a selective increase in lutein deposition in the supplemented infants. Lutein differentially accumulated across brain regions, with highest amounts in occipital cortex in both groups. β-carotene accumulated, but zeaxanthin and lycopene were undetectable in any brain region. Supplemented infants had higher lutein concentrations in peripheral retina but not in macular retina. Among adipose sites, abdominal subcutaneous adipose tissue exhibited the highest lutein level and was 3-fold higher in the supplemented infants. The supplemented formula enhanced carotenoid deposition in several other tissues. In rhesus infants, increased intake of carotenoids from formula enhanced their deposition in serum and numerous tissues and selectively increased lutein in multiple brain regions.

Elevated milk β-carotene and lycopene after carrot and tomato paste supplementation

OBJECTIVES

To measure concentrations of β-carotene and lycopene in the breast milk of healthy, well-nourished, lactating women supplemented with fresh carrot or tomato paste.

METHODS

Twelve women were given fresh carrot paste and another 14 were given fresh tomato paste once a day for 3 d with a high-lipid-content meal. The women were instructed to avoid any food containing β-carotene or lycopene, other than the test meal. Milk carotenoid levels were measured before, during, and after the trial. The carrot and tomato meals contained 15 mg of all-trans β-carotene and 15 mg of all-trans lycopene, respectively.

RESULTS

We demonstrated a significant increase in milk β-carotene and elevated milk lycopene levels after the lipid-rich fresh carrot and tomato meals, respectively.

CONCLUSIONS

We suggest that breast milk carotenoid levels reflect the mother's level of intake and can thus be raised by simple nutritional intervention. The results of this study may be relevant to breast-feeding mothers of both preterm and term infants by raising antiinflammatory and antioxidant properties in their milk.

Mechanisms involved in the intestinal absorption of dietary vitamin A and provitamin A carotenoids

Vitamin A is an essential nutrient for humans and is converted to the visual chromophore, 11-cis-retinal, and to the hormone, retinoic acid. Vitamin A in animal-derived foods is found as long chain acyl esters of retinol and these are digested to free fatty acids and retinol before uptake by the intestinal mucosal cell. The retinol is then reesterified to retinyl esters for incorporation into chlylomicrons and absorbed via the lymphatics or effluxed into the portal circulation facilitated by the lipid transporter, ABCA1. Provitamin A carotenoids such as β-carotene are found in plant-derived foods. These and other carotenoids are transported into the mucosal cell by scavenger receptor class B type I (SR-BI). Provitamin A carotenoids are partly converted to retinol by oxygenase and reductase enzymes and the retinol so produced is available for absorption via the two pathways described above. The efficiency of vitamin A and carotenoid intestinal absorption is determined by the regulation of a number of proteins involved in the process. Polymorphisms in genes for these proteins lead to individual variability in the metabolism and transport of vitamin A and carotenoids. This article is part of a Special Issue entitled Retinoid and Lipid Metabolism.

Reduction of micronuclei in oral lichen planus supplemented with beta-carotene

An elevated frequency of micronucleated exfoliated cells (MEC) in atrophic and erosive oral lichen planus (OLP) has been reported. To evaluate the effects of supplemental beta-carotene (BC) on MEC frequency in OLP lesions, we performed an open trial in 20 patients with atrophic and/or erosive OLP. Each patient received 15 mg of BC four times daily for 3 months. The frequency of MEC in both lesions and adjacent normal mucosa in each patient was evaluated and compared before and after supplementation. Serum levels of BC and retinol were also determined. After BC supplementation, all patients had higher levels of serum BC and retinol. The MEC frequency in OLP lesions was significantly reduced (P < 0.01). No significant changes were seen in the MEC frequency in adjacent normal mucosa. BC supplementation thus significantly reduces MEC frequency in atrophic and erosive OLP.

Correlation between nutritional biomarkers and breast cancer: a case-control study

A case-control study to explore associations between retinoids, tocopherols, total and beta-carotenes and breast cancer was conducted by analysing concentrations of these biomarkers in adipose tissue, cheek cells and plasma. A total of 414 French-Canadians in Montreal with new diagnoses of breast cancer were age-matched to 429 population-based controls. Subjects were interviewed using a questionnaire, and biological samples from 287 cases and 112 controls were collected within 3 months of the diagnosis. Mean beta carotene concentrations in cheek cells were significantly lower among controls. Odds ratios (ORs) from logistic regression analysis were used to compare higher and lower tercile concentrations. Significant positive associations were observed in adipose tissue for retinoid [OR=2.11; 95% CI (1.09-4.08)] and beta carotene [OR=3.18; 95% CI (1.70-5.93)]; in cheek cells for beta carotene [OR=2.22; 95% CI (1.21-4.50)] and for total carotenes [OR=2.94; 95% CI (1.59-5.42)] and in plasma for beta carotene [OR=1.53; 95% CI (0.80-2.93)] and total carotenes [OR=1.04; 95% CI (0.53-2.05)]. Among the control groups, significant Pearson correlations were observed between cheek cells and adipose tissue for total carotenes (r=0.27; p=0.01) and cheek cells and plasma (r=0.22; p=0.04). In contrast to previous works, this study shows that high concentrations of retinoids and carotenes in adipose tissue and cheek cells are associated with increased risk of breast cancer. However, all these studies are limited by small sample size. Although our study tested a limited number of controls, important associations were observed. These results suggest that the effect of disease on biomarkers is fundamental to the interpretation of epidemiological data. We suggest either that the high levels of these biomarkers found in cancer patients in this study may be due to the disease process that affects the pharmacokinetics of the biomarker or that the disease causes a change in dietary habits. In addition, in studies involving the application of biomarkers to cancer epidemiology it is imperative that a typical biomarker concentration is not associated with breast cancer risk before further examination of the methodological limitations of epidemiological studies investigating this relationship. Therefore, sample size, selection bias, information bias, and confounding should be considered in the design of studies investigating the aetiological relationship between biomarkers and breast cancer.

β-Carotene breakdown products may impair mitochondrial functions — potential side effects of high-dose β-carotene supplementation

Beta-carotene (BC) and other carotenoids are mainly considered as belonging to the group of micronutrients. As they are contained in fruit and vegetables and thus part of human diet, a regular low-dose intake from natural sources is normally assured. In the last decade high-dose supplementation with synthetic carotenoids has been used successfully in the treatment of diseases believed to be associated with oxidative stress. However, in a few clinical studies harmful effects have been observed as well, e.g., a higher incidence of lung cancer after BC was given in high doses to smokers. Our studies aim at shedding light on the causal mechanisms of the known side effects that we have investigated. Possibilities of preventing them are discussed. Obviously, on certain conditions of high-dose carotenoid supplementation, both the antioxidant and prooxidant reactions may arise. Carotenoid breakdown products (CBP) including very reactive aldehydes and epoxides are formed during oxidative attack in the course of antioxidative action. Carotenoid breakdown products inhibit state 3 respiration of isolated rat liver mitochondria at concentrations between 0.5 and 20 microM. In vivo stimulated neutrophils might represent an important source for the generation of CBP, and the lung might be a critical organ in CBP formation. The inhibition of mitochondrial state 3 respiration by CBP is accompanied by a reduced content of protein sulfhydryl groups, decreasing glutathione levels and redox state, and also elevated accumulation of malondialdehyde. Changes in mitochondrial membrane potential favour functional deterioration of the adenine nucleotide translocator (ANT). The findings reflect a basic mechanism of the side effects of BC supplementation in circumstances of severe oxidative stress induced by CBP representing a class of lipid oxidation products. We are striving for safe conditions of carotenoid supplementation in order to protect patients in need of this kind of medical treatment from possible side effects, such as unwanted prooxidative reactions.

Induction of PXR-mediated metabolism by beta-carotene

beta-carotene is the major carotenoid occurring in the human diet and in the human organism. Besides its function as pro-vitamin A, beta-carotene has been shown to be an activator of the human pregnan X receptor (PXR). PXR is mainly expressed in the liver/intestine and an inducer of enzymes involved in phase I, II and III metabolism. This review is focused on the evaluation of physiological and nutritional relevance of beta-carotene as an inducer of phase I enzymes in the human organism via PXR-mediated mechanisms. Beneficial and detrimental effects of beta-carotene on xenobiotica metabolism and metabolism of various other derivatives will be discussed.

Intestinal absorption and metabolism of carotenoids: insights from cell culture

Cell culture models are useful for studying intestinal absorption and metabolism of carotenoids. The human intestinal cell line, Caco-2, has been the most widely used model for these studies. The PF11 and TC7 clones of Caco-2 exhibit beta-carotene-15,15'-oxygenase activity, a key enzyme in the conversion of carotenoids to vitamin A. Studies on the recent cloning of this enzyme are discussed. An in vitro cell culture system used to study intestinal absorption of carotenoids is presented. Under conditions mimicking the postprandial state, Caco-2 cells on membranes take up carotenoids and secrete them incorporated into chylomicrons. Both the cellular uptake and secretion of beta-carotene are saturable, concentration-dependent processes. The selective absorption of all-trans beta-carotene versus its cis isomers, the differential absorption of individual carotenoids, and the specific interactions between carotenoids during their absorption are discussed. The participation of a specific epithelial transporter in the intestinal absorption of carotenoids is proposed.

Clinical pharmacokinetics of antioxidants and their impact on systemic oxidative stress

Dietary antioxidants play a major role in maintaining the homeostasis of the oxidative balance. They are believed to protect humans from disease and aging. Vitamin C (ascorbic acid), vitamin E (tocopherol), beta-carotene and other micronutrients such as carotenoids, polyphenols and selenium have been evaluated as antioxidant constituents in the human diet. This article addresses data provided from clinical trials, highlighting the clinical pharmacokinetics of vitamin C, vitamin E, beta-carotene, lycopene, lutein, quercetin, rutin, catechins and selenium. The bioavailability of vitamin C is dose-dependent. Saturation of transport occurs with dosages of 200-400 mg/day. Vitamin C is not protein-bound and is eliminated with an elimination half-life (t((1/2))) of 10 hours. In Western populations plasma vitamin C concentrations range from 54-91 micro mol/L. Serum alpha- and gamma-tocopherol range from 21 micro mol/L (North America) to 27 micro mol/L (Europe) and from 3.1 micro mol/L to 1.5 micro mol/L, respectively. alpha-Tocopherol is the most abundant tocopherol in human tissue. The bioavailability of all-rac-alpha-tocopherol is estimated to be 50% of R,R,R-alpha-tocopherol. The hepatic alpha-tocopherol transfer protein (alpha-TTP) together with the tocopherol-associated proteins (TAP) are responsbile for the endogenous accumulation of natural alpha-tocopherol. Elimination of alpha-tocopherol takes several days with a t((1/2)) of 81 and 73 hours for R,R,R-alpha-tocopherol and all-rac-alpha-tocopherol, respectively. The t((1/2)) of tocotrienols is short, ranging from 3.8-4.4 hours for gamma- and alpha-tocotrienol, respectively. gamma-Tocopherol is degraded to 2, 7, 8-trimethyl-2-(beta-carboxyl)-6-hyrdoxychroman by the liver prior to renal elimination. Blood serum carotenoids in Western populations range from 0.28-0.52 micro mol/L for beta-carotene, from 0.2-0.28 for lutein, and from 0.29-0.60 for lycopene. All-trans-carotenoids have a better bioavailability than the 9-cis-forms. Elimination of carotenoids takes several days with a t((1/2)) of 5-7 and 2-3 days for beta-carotene and lycopene, respectively. The bioconversion of beta-carotene to retinal is dose-dependent, and ranges between 27% and 2% for a 6 and 126mg dose, respectively. Several oxidised metabolites of carotenoids are known. Flavonols such as quercetin glycosides and rutin are predominantly absorbed as aglycones, bound to plasma proteins and subsequently conjugated to glucuronide, sulfate, and methyl moieties. The t((1/2)) ranges from 12-19 hours. The bioavailabillity of catechins is low and they are eliminated with a t((1/2)) of 2-4 hours. Catechins are degraded to several gamma-valerolactone derivatives and phase II conjugates have also been identified. Only limited clinical pharmacokinetic data for other polyphenols such as resveratrol have been reported to date.

Carotenoid bioavailability and bioconversion

The possible role of carotenoids and their metabolites in disease prevention is far from fully understood, because the bioavailabilities of carotenoids are complicated by multiple factors that affect their absorption, breakdown, transport, and storage. Rapid progress in developing sophisticated methodologies, including use of stable-isotope dilution methods, now allows for an accurate determination of the true vitamin A activity of provitamin A carotenoids. The recent identification of specific enzymes, which catalyze the breakdown of beta-carotene as well as nonprovitamin A carotenoids, is providing a better understanding of the functions of carotenoids at the molecular level. The pathways and possible mechanisms of carotenoid breakdown and factors affecting the bioavailability of carotenoids, such as carotenoid type, food matrix, interaction with other carotenoids and other food components, nutritional status, aging, and infection, are discussed in this review.

Tomato consumption increases lycopene isomer concentrations in breast milk and plasma of lactating women

OBJECTIVE

To compare plasma and milk lycopene concentrations and the changes in lycopene isomer patterns in lactating women before and after a 3-day dietary intervention with fresh or processed tomato products.

DESIGN

Randomized prospective trial.

SUBJECTS

24 lactating women, 4 to 12 weeks postpartum, aged 22 to 39 years.

INTERVENTION

Subjects initially consumed a low-lycopene diet for 7 days (washout period) and then were randomly assigned to one of 3 dietary groups (n=8 per group) without any other sources of lycopene: control (low-lycopene), fresh tomatoes, or processed tomato sauce. Subjects in each of the tomato groups consumed approximately 50 mg total lycopene over 3 days.

OUTCOME MEASURES

Before and after dietary intervention, plasma and breast milk samples were obtained for high-performance liquid chromotography analysis of lycopene and its geometric isomers (all-trans, 5-cis, all other cis, and total lycopene).

STATISTICAL ANALYSIS

Descriptive statistics, analysis of variance to test for differences among intervention groups, and Spearman's correlation coefficients to test for blood-milk relationships.

RESULTS

Plasma total lycopene and lycopene isomer concentrations increased in the fresh and processed tomato group but not in the low-lycopene control group during the study. Milk total and cis- and trans-lycopene concentrations (unadjusted for fat) increased in the processed tomato group but did not change in the fresh tomato group. In the control group, milk total and trans-lycopene decreased. Milk total lycopene concentrations were not significantly different from baseline in any group when adjusted for fat content of milk.

APPLICATIONS

The results of this study indicate that consumption of a "standard size portion" of tomato products increases plasma and milk lycopene concentrations in lactating women and, therefore, could increase the lycopene status of nursing infants. For dietary recommendations during lactation, the results suggest that consumption of tomato sauce increases milk lycopene concentrations more effectively than consumption of fresh tomatoes.

Carotenoid composition of human milk during the first month postpartum and the response to beta-carotene supplementation

BACKGROUND

Information is lacking regarding normal changes in milk carotenoid concentrations in healthy, well-nourished women during the first month of lactation.

OBJECTIVES

This study investigated milk carotenoid concentrations during days 4-32 postpartum and assessed the effects of maternal beta-carotene supplementation.

DESIGN

Subjects (n = 21; aged 19-39 y) were randomly assigned to receive beta-carotene (30 mg/d) or placebo from days 4 to 32 postpartum. Each subject provided 8 diet records and 8 milk samples during the study. Diet records were analyzed for energy, macronutrients, vitamins A and E, and carotenoids. Milk samples were analyzed with HPLC for concentrations of carotenoids, retinol, and alpha-tocopherol. Data were analyzed by using repeated-measures analysis and orthogonal contrasts.

RESULTS

No significant differences in average dietary intakes, body mass index, age, or parity were found between groups at baseline or after supplementation. Milk carotenoid concentrations decreased over time (P < 0.01), as did retinol and alpha-tocopherol concentrations (P < 0.003). Concentrations of most carotenoids decreased to those reported for mature milk by day 32 postpartum. Milk lutein concentrations remained elevated throughout the study compared with values reported for mature milk, whereas plasma lutein concentrations decreased significantly over time. beta-carotene supplementation did not significantly change the milk concentrations of beta-carotene, the other carotenoids, retinol, or alpha-tocopherol.

CONCLUSIONS

The lack of increase in milk beta-carotene despite supplementation suggests that transitional milk may be already nearly saturated with beta-carotene. The elevated milk lutein concentration and simultaneous decrease in plasma lutein suggest that lutein metabolism may be altered during early lactation.

Comparison of the effects of supplemental red palm oil and sunflower oil on maternal vitamin A status

BACKGROUND

Conflicting results have been reported on the ability of dietary carotenoids to improve vitamin A status in lactating women. Red palm oil is one of the richest dietary sources of beta-carotene.

OBJECTIVE

We aimed to determine the efficacy of red palm oil in increasing retinol and provitamin A status in pregnant and lactating women.

DESIGN

Ninety rural, pregnant Tanzanian women from 3 randomly selected villages were recruited during their third trimester to participate in 3 dietary intervention groups: a control group, who were encouraged to maintain the traditional practice of eating staples with dark-green leafy vegetables, and 2 study groups, who were given either sunflower or red palm oil for use in household food preparations. The intervention lasted 6 mo. Plasma samples were collected at the third trimester and 1 and 3 mo postpartum, and breast-milk samples were collected 1 and 3 mo postpartum.

RESULTS

Supplementation with red palm oil, which is rich in provitamin A, increased alpha- and beta-carotene concentrations significantly (P < 0.001) in both plasma and breast milk. Plasma retinol concentrations were similar in all dietary groups. Breast-milk retinol concentrations tended to decrease from 1 to 3 mo postpartum in the control group, but were maintained in both oil groups. The difference in change in breast-milk retinol concentration between the red palm oil group and the control group was significant (P = 0.041).

CONCLUSIONS

Consumption of red palm oil increases concentrations of alpha- and beta-carotene in both breast milk and serum and maintains breast-milk retinol concentrations. Sunflower oil consumption seems to conserve breast-milk retinol similarly to consumption of red palm oil. Breast-milk retinol might be maintained through increased dietary intake of these vegetable oils and use of mild cooking preparation methods (such as the addition of oil at the end of cooking and avoidance of frying).

Carotenoids in human buccal mucosa cells after 4 wk of supplementation with tomato juice or lycopene supplements

BACKGROUND

Lycopene has been identified as a phytochemical with potentially protective health benefits.

OBJECTIVE

Our objective was to monitor lycopene changes in buccal mucosa cells (BMCs) in response to 3 vehicles for oral delivery of lycopene.

DESIGN

Fifteen healthy subjects ingested lycopene-rich tomato juice, tomato oleoresin, lycopene beadlets (each containing 70-75 mg lycopene) and a placebo for 4 wk each in a randomized crossover design while consuming self-selected diets. A 6-wk washout period separated the treatment periods. BMCs were collected at baseline and after 4 wk of supplementation.

RESULTS

Lycopene in BMCs increased significantly ( approximately 2-fold) after 4 wk of ingestion of oleoresin and of beadlets to 4.95 (P < 0.001) and 3.75 microg/g protein (P = 0.053), respectively, but was not significantly affected by tomato juice treatment. The placebo treatment produced a significant decrease in BMC lycopene concentrations (P = 0.018). We observed significant treatment differences between oleoresin and tomato juice, oleoresin and placebo, and beadlets and placebo. BMC concentrations of phytofluene and beta-carotene, which were present in small amounts in the lycopene-containing treatments, increased significantly with ingestion of these products. Strong correlations were found between plasma and BMC concentrations of lutein, beta-cryptoxanthin, alpha-carotene, and beta-carotene. In contrast, correlations between lycopene concentrations in plasma and in BMCs were weak and not significant for any treatment.

CONCLUSIONS

The cellular content of lycopene and other tomato-related carotenoids with proposed beneficial health effects can be increased through prolonged supplementation.

Accumulation of astaxanthin all-E, 9Z and 13Z geometrical isomers and 3 and 3' RS optical isomers in rainbow trout (Oncorhynchus mykiss) is selective

Concentrations of all-E-, 9Z- and 13Z- geometrical and (3R,3'R), (3R, 3'S) and (3S,3'S) optical isomers of astaxanthin were determined in rainbow trout liver, gut tissues, kidney, skin and blood plasma to evaluate their body distribution. Two cold-pelleted diets containing predominantly all-E-astaxanthin (36.9 mg/kg astaxanthin, 97% all-E-, 0.4% 9Z-, 1.5% 13Z-astaxanthin, and 1.1% other isomers, respectively) or a mixture of all-E- and Z-astaxanthins (35.4 mg/kg astaxanthin, 64% all-E-, 18.7% 9Z-, 12.3% 13Z-astaxanthin, and 2.0% other isomers, respectively), were fed to duplicate groups of trout for 69 d. Individual E/Z isomers were identified by VIS- and 1H-NMR-spectrometry, and quantified by high-performance liquid chromatography. Significantly higher total carotenoid concentration was observed in plasma of trout fed diets with all-E-astaxanthin (P < 0.05). The relative E/Z-isomer concentrations of plasma, skin and kidney were not significantly different among groups, whereas all-E-astaxanthin was higher in intestinal tissues and 13Z-astaxanthin was lower in liver of trout fed all-E-astaxanthin (P < 0.05). The relative amount of hepatic 13Z-astaxanthin (39-49% of total astaxanthin) was higher than in all other samples (P < 0.05). Synthetic, optically inactive astaxanthin was used in all experiments, and the determined dietary ratio between the 3R,3'R:3R, 3'S (meso):3S,3'S optical isomers was 25.3:49.6:25.1. The distribution of R/S-astaxanthin isomers in feces, blood, liver and fillet was similar to that in the diets. The ratio between (3S,3'S)- and (3R,3'R)-astaxanthin in the skin and posterior kidney was ca. 2:1 and 3:1, respectively, regardless of dietary E/Z-astaxanthin composition. The results show that geometrical and optical isomers of astaxanthin are distributed selectively in different tissues of rainbow trout.