Biomarkers of Nutrition for Development (BOND)-Vitamin A Review.

The Biomarkers of Nutrition for Development (BOND) project is designed to provide evidence-informed advice to anyone with an interest in the role of nutrition in health. The BOND program provides information with regard to selection, use, and interpretation of biomarkers of nutrient exposure, status, function, and effect, which will be especially useful for readers who want to assess nutrient status. To accomplish this objective, expert panels are recruited to evaluate the literature and to draft comprehensive reports on the current state of the art with regard to specific nutrient biology and available biomarkers for assessing nutritional status at the individual and population levels. Phase I of the BOND project includes the evaluation of biomarkers for 6 nutrients: iodine, folate, zinc, iron, vitamin A, and vitamin B-12. This review of vitamin A is the current article in this series. Although the vitamin was discovered >100 y ago, vitamin A status assessment is not trivial. Serum retinol concentrations are under homeostatic control due in part to vitamin A's use in the body for growth and cellular differentiation and because of its toxic properties at high concentrations. Furthermore, serum retinol concentrations are depressed during infection and inflammation because retinol-binding protein (RBP) is a negative acute-phase reactant, which makes status assessment challenging. Thus, this review describes the clinical and functional indicators related to eye health and biochemical biomarkers of vitamin A status (i.e., serum retinol, RBP, breast-milk retinol, dose-response tests, isotope dilution methodology, and serum retinyl esters). These biomarkers are then related to liver vitamin A concentrations, which are usually considered the gold standard for vitamin A status. With regard to biomarkers, future research questions and gaps in our current understanding as well as limitations of the methods are described.

Application of Key Events Dose Response Framework to defining the upper intake level of leucine in young men.

Leucine is sold in large doses in health food stores and is ingested by weight-training athletes. The safety of ingestion of large doses of leucine is unknown. Before designing chronic high-dose leucine supplementation experiments, we decided to determine the effect of graded doses of leucine in healthy participants. The Key Events Dose Response Framework is an organizational and analytical framework that dissects the various biologic steps (key events) that occur between exposure to a substance and an eventual adverse effect. Each biologic event is looked at for its unique dose-response characteristics. For nutrients, there are a number of biologic homeostatic mechanisms that work to keep circulating/tissue levels in a safe, nontoxic range. If a response mechanism at a particular key event is especially vulnerable and easily overwhelmed, this is known as a determining event, because this event drives the overall slope or shape of the dose-response relationship. In this paper, the Key Events Dose Framework has been applied to the problem of leucine toxicity and leucine's tolerable upper level. After analyzing the experimental data vis a vis key events for leucine leading to toxicity, it became evident that the rate of leucine oxidation was the determining event. A dose-response study has been conducted to graded intakes of leucine in healthy human adult male volunteers. All participants were started at the mean requirement level of leucine [50 mg/(kg · d)] and the highest leucine intake was 1250 mg/( kg · d), which is 25 times the mean requirement. No gut intolerance was seen. Blood glucose fell progressively but remained within normal values without any changes in plasma insulin. Maximal leucine oxidation levels occurred at an intake of 550 mg leucine/( kg · d), after which plasma leucine progressively increased and plasma ammonia also increased in response to leucine intakes >500 mg/( kg · d). Thus, the "key determining event" appears to be when the participants reach their maximal leucine oxidation level, after which the risk of metabolic adverse effects progressively increased.

Spirulina is an effective dietary source of zeaxanthin to humans.

Zeaxanthin is a predominant xanthophyll in human eyes and may reduce the risk of cataracts and age-related macular degeneration. Spirulina is an algal food that contains a high concentration of zeaxanthin. In order to determine the zeaxanthin bioavailability of spirulina for dietary supplementation in humans, spirulina was grown in nutrient solution with ²H2O for carotenoid labelling. Single servings of ²H-labelled spirulina (4.0-5.0 g) containing 2.6-3.7 mg zeaxanthin were consumed by fourteen healthy male volunteers (four Americans and ten Chinese) with 12 g dietary fat. Blood samples were collected over a 45 d period. The serum concentrations of total zeaxanthin were measured using HPLC, and the enrichment of labelled zeaxanthin was determined using LC-atmospheric pressure chemical ionisation-MS (LC-APCI-MS). The results showed that intrinsically labelled spirulina zeaxanthin in the circulation was detected at levels as low as 10 % of the total zeaxanthin for up to 45 d after intake of the algae. A single dose of spirulina can increase mean serum zeaxanthin concentration in humans from 0.06 to 0.15 µmol/l, as shown in our study involving American and Chinese volunteers. The average 15 d area under the serum zeaxanthin response curve to the single dose of spirulina was 293 nmol × d/µmol (range 254-335) in American subjects, and 197 nmol × d/µmol (range 154-285) in Chinese subjects. It is concluded that the relative bioavailability of spirulina zeaxanthin can be studied with high sensitivity and specificity using ²H labelling and LC-APCI-MS methodology. Spirulina can serve as a rich source of dietary zeaxanthin in humans.

Enzymatic formation of apo-carotenoids from the xanthophyll carotenoids lutein, zeaxanthin and ß-cryptoxanthin by ferret carotene-9',10'-monooxygenase.

Xanthophyll carotenoids, such as lutein, zeaxanthin and ß-cryptoxanthin, may provide potential health benefits against chronic and degenerative diseases. Investigating pathways of xanthophyll metabolism are important to understanding their biological functions. Carotene-15,15'-monooxygenase (CMO1) has been shown to be involved in vitamin A formation, while recent studies suggest that carotene-9',10'-monooxygenase (CMO2) may have a broader substrate specificity than previously recognized. In this in vitro study, we investigated baculovirus-generated recombinant ferret CMO2 cleavage activity towards the carotenoid substrates zeaxanthin, lutein and ß-cryptoxanthin. Utilizing HPLC, LC-MS and GC-MS, we identified both volatile and non-volatile apo-carotenoid products including 3-OH-ß-ionone, 3-OH-α-ionone, ß-ionone, 3-OH-α-apo-10'-carotenal, 3-OH-ß-apo-10'-carotenal, and ß-apo-10'-carotenal, indicating cleavage at both the 9,10 and 9',10' carbon-carbon double bond. Enzyme kinetic analysis indicated the xanthophylls zeaxanthin and lutein are preferentially cleaved over ß-cryptoxanthin, indicating a key role of CMO2 in non-provitamin A carotenoid metabolism. Furthermore, incubation of 3-OH-ß-apo-10'-carotenal with CMO2 lysate resulted in the formation of 3-OH-ß-ionone. In the presence of NAD(+), in vitro incubation of 3-OH-ß-apo-10'-carotenal with ferret hepatic homogenates formed 3-OH-ß-apo-10'-carotenoic acid. Since apo-carotenoids serve as important signaling molecules in a variety of biological processes, enzymatic cleavage of xanthophylls by mammalian CMO2 represents a new avenue of research regarding vertebrate carotenoid metabolism and biological function.

Dietary lycopene and tomato extract supplementations inhibit nonalcoholic steatohepatitis-promoted hepatocarcinogenesis in rats.

Epidemiological and experimental studies provide supportive evidence that lycopene (LY), a major carotenoid from tomatoes and tomato products, may act as a chemopreventive agent against certain types of cancers. We recently showed that high-fat diet (HFD)-induced nonalcoholic steatohepatitis (NASH) promoted diethylnitrosamine (DEN)-initiated hepatocarcinogenesis in a rat model. Using this model, we investigated the efficacy of an equivalent dosage of dietary LY from either a pure compound or a tomato extract (TE) against NASH-promoted hepatocarcinogenesis. Six groups of rats were injected with DEN and then fed either Lieber-DeCarli control diet or HFD with or without LY or TE for 6 weeks. Results showed that both LY and TE supplementations significantly decreased the number of altered hepatic foci expressing the placental form of glutathione S-transferase in the livers of HFD-fed rats. This was associated with significantly lower proliferating cell nuclear antigen positive hepatocytes and cyclinD1 protein, as well as decreased activation of extracellular signal-regulated kinase and nuclear NF-kappaB. Although both LY and TE supplementations reduced HFD-induced lipid peroxidation in the livers, we observed significantly decreased cytochrome P450 2E1, inflammatory foci and mRNA expression of proinflammatory cytokines (TNF-alpha, IL-1beta and IL-12) in the HFD+TE fed group but increased nuclear NF-E2-related factor-2 and heme oxygenase-1 proteins in the HFD+LY fed group, relative to HFD feeding alone. These data indicate that LY and TE can inhibit NASH-promoted hepatocarcinogenesis mainly as a result of reduced oxidative stress, which could be fulfilled through different mechanisms.

Profiling histidine dipeptides in plasma and urine after ingesting beef, chicken or chicken broth in humans.

The in vitro metabolic stability of histidine-dipeptides (HD), carnosine (CAR) and anserine (ANS), in human serum, and their absorption kinetics after ingesting pure carnosine or HD rich foods in humans have been investigated. Healthy women (n = 4) went through four phases of taking one dose of either 450 mg of pure carnosine, 150 g beef (B), 150 g chicken (C), or chicken broth (CB) from 150 g chicken with a >2-week washout period between each phase. Blood samples were collected at 0, 30, 60, 100, 180, 240, and 300 min, and urine samples before and after (up to 7 h) ingesting pure carnosine or food. Both plasma and urine samples were analyzed for HD concentrations using a sensitive and selective LC-ESI-MS/MS method. CAR was undetectable in plasma after ingesting pure carnosine, B, C or CB. By contrast, plasma ANS concentration was significantly increased (P < 0.05) after ingesting C or CB, respectively. Urinary concentrations of both CAR and ANS were 13- to 14-fold increased after ingesting B, and 14.8- and 243-fold after CB ingestion, respectively. Thus, dietary HD, which are rapidly hydrolyzed by carnosinase in plasma, and excreted in urine, may act as reactive carbonyl species sequestering agents.

Nonalcoholic steatohepatitis induced by a high-fat diet promotes diethylnitrosamine-initiated early hepatocarcinogenesis in rats.

It has been suggested that patients with nonalcoholic steatohepatitis (NASH) may have high risk for liver cancer. However, it is unknown whether high-fat diet (HFD) induced NASH promotes hepatocarcinogenesis. In this study, Sprague-Dawley rats were injected with a low dose of hepatic carcinogen diethylnitrosamine (DEN) and then fed either Lieber-DeCarli control diet (CD) or HFD for 6 weeks. Liver histology and the hepatic placental form of glutathione S-transferase (P-GST) positive foci were examined. Expression levels of proliferating cell nuclear antigen (PCNA), cyclinD1, phosphorylated mitogen-activated protein kinase (MAPK) including extracellular signal-regulated kinase (ERK) and p38, as well as tumor necrosis factor-alpha (TNF-alpha), and nuclear factor-kappaB (NF-kappaB) were measured in the liver. Induction of lipid peroxidation end products (malondialdehyde plus 4-hydroxynonenal) in liver and apoptotic hepatocytes were also assessed. Results showed that HFD-fed rats developed significantly higher incidence and multiplicity of P-GST positive foci along with more fat accumulation, infiltration of inflammatory cells and higher lipid peroxidation in the liver, when compared with rats fed the CD. This high prevalence of hepatic lesions in the liver was accompanied by greater PCNA expression and cyclinD1 protein concentration but little change in hepatocyte apoptosis. HFD feeding elevated hepatic phosphorylated ERK but reduced phosphorylated p38 when compared with the CD feeding. In addition, a significantly higher expression of TNF-alpha mRNA and nuclear NF-kappaB p65 protein were observed in HFD group than in CD group. These data clearly demonstrate that NASH induced by HFD promoted DEN-initiated early hepatocarcinogenesis, which was associated with elevated TNF-alpha/NF-kappaB signaling and MAPK related hepatocyte proliferation.

Total antioxidant performance is associated with diet and serum antioxidants in participants of the diet and physical activity substudy of the Jackson Heart Study.

Total antioxidant performance (TAP) measures antioxidant capacities in both hydrophilic and lipophilic compartments of serum and interactions known to exist between them. Our objective was to assess TAP levels in a subset of Jackson Heart Study (JHS) participants and to examine associations with dietary and total (diet + supplement) intakes of alpha-tocopherol, gamma-tocopherol (diet only), beta-carotene, vitamin C, fruit, vegetables, and nuts, and serum concentrations of alpha-tocopherol, gamma-tocopherol, and beta-carotene. We conducted a cross-sectional analysis of 420 (mean age 61 y; 254 women) African American men and women participating in the Diet and Physical Activity Sub-Study of the JHS in Jackson, Mississippi. In multivariate-adjusted models, we observed positive associations between total alpha-tocopherol, total and dietary beta-carotene, and total vitamin C intakes and TAP levels (P-trend < 0.05). Positive associations were also observed for vegetable, fruit, and total fruit and vegetable intakes (P-trend < 0.05). For serum antioxidant nutrients, alpha-tocopherol but not beta-carotene was associated with serum TAP levels. There were inverse associations for serum gamma-tocopherol and TAP levels. Associations for alpha-tocopherol were seen at intake levels much higher than the current Recommended Dietary Allowance. It may, therefore, be prudent to focus on increasing consumption of fruit, vegetables, nuts, and seeds to increase total antioxidant capacity.

Application of a key events dose-response analysis to nutrients: a case study with vitamin A (retinol).

The methodology used to establish tolerable upper intake levels (UL) for nutrients borrows heavily from risk assessment methods used by toxicologists. Empirical data are used to identify intake levels associated with adverse effects, and Uncertainty Factors (UF) are applied to establish ULs, which in turn inform public health decisions and standards. Use of UFs reflects lack of knowledge regarding the biological events that underlie response to the intake of a given nutrient, and also regarding the sources of variability in that response. In this paper, the Key Events Dose-Response Framework (KEDRF) is used to systematically consider the major biological steps that lead from the intake of the preformed vitamin A to excess systemic levels, and subsequently to increased risk of adverse effects. Each step is examined with regard to factors that influence whether there is progression toward the adverse effect of concern. The role of homeostatic mechanisms is discussed, along with the types of research needed to improve understanding of dose-response for vitamin A. This initial analysis illustrates the potential of the KEDRF as a useful analytical tool for integrating current knowledge regarding dose-response, generating questions that will focus future research efforts, and clarifying how improved knowledge and data could be used to reduce reliance on UFs.

A fluorometric assay to determine antioxidant activity of both hydrophilic and lipophilic components in plant foods.

This study aimed to develop a fluorometric method to determine total antioxidant activity of plant foods. The antioxidant activities in plant foods were determined after extracting (1) hydrophilic components with acidified methanol (methanol:glacial acetate acid:water=50:3.7:46.3), (2) lipophilic components with methanol followed by tetrahydrofuran (THF), or (3) both hydrophilic and lipophilic components using sequential extraction of acidified methanol and THF together. Both the hydrophilic assay [using the hydrophilic radical initiator 2,2'-azobis-(2-amidinopropane)dihydrochloride (10 mmol/L) and hydrophilic probe 2,7-dichlorodihydrofluorescein (DCFH)] and the lipophilic assay [using the lipophilic radical initiator [2,2'-azobis (4-methoxiy-2,4-dimethylvaleronitrile), 2 mmol/L], and the lipophilic probe 4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-undecanoic acid (C11-BODIPY 581/591) (BODIPY: 2 micromol/L)] were used to measure antioxidant activity. The inhibition of BODIPY oxidation was significantly increased (P<.01) when both the hydrophilic and lipophilic components were extracted using acidified methanol and organic solvent as compared to those extracted by organic solvent alone. In addition, the rate of DCFH oxidation was significantly delayed (P<.05) when both components coexisted compared to DCFH oxidation of the hydrophilic component alone. The combination of lipophilic and hydrophilic components in these plant foods showed significantly greater antioxidant activity than that of either hydrophilic or lipophilic component alone. Thus, both hydrophilic and lipophilic components in plant foods and their interactions should be considered when determining their antioxidant activity.

Geographic variations and temporal trends of Salmonella-associated hospitalization in the U.S. elderly, 1991-2004: a time series analysis of the impact of HACCP regulation.

BACKGROUND: About 1.4 million Salmonella infections, a common food-borne illness, occur in the U.S. annually; the elderly (aged 65 or above) are most susceptible. In 1997, the USDA introduced the Pathogen Reduction and Hazard Analysis and Critical Control Points Systems (PR/HACCP) which demands regular Salmonella testing in various establishments processing meat products, such as broiler chickens. Impact evaluations of PR/HACCP on hospitalizations related to Salmonella are lacking. METHODS: Hospitalization records of the U.S. elderly in 1991-2004 were obtained from the Centers of Medicare and Medicaid Services. Harmonic regression analyses were performed to evaluate the long-term trends of Salmonella-related hospitalizations in pre- and post-HACCP periods. Seasonal characteristics of the outcome in the nine Census divisions of the contiguous U.S. were also derived and contrasted. RESULTS: Predicted rates decreased in most divisions after 1997, except South Atlantic, East South Central, and West South Central. These three divisions also demonstrated higher overall hospitalization rates, pronounced seasonal patterns, and consistent times to peak at about 32nd to 34th week of the year. CONCLUSION: The impact of HACCP was geographically different. South Atlantic, East South Central, and West South Central divisions should be targeted in further Salmonella preventive programs. Further research is needed to identify the best program type and timing of implementation.

The value of ischemia-modified albumin compared with d-dimer in the diagnosis of pulmonary embolism.

STUDY OBJECTIVE: The primary aim of this study was to investigate whether IMA levels are helpful in the diagnosis of pulmonary embolism (PE). The secondary aim was to determine whether IMA was more effective alone or in combination with clinical probability scores in the diagnosis of PE. Thirdly, the sensitivity and specificity of IMA is compared with D-dimer both with and without clinical probability scores in patients with suspected PE. METHODS: Consecutive patients presenting to the emergency department with suspected PE were prospectively recruited, and healthy volunteers were also enrolled as controls. D-dimer and IMA levels were measured for the entire study group. Wells and Geneva scores were calculated and s-CTPA was performed on all suspected PE patients. RESULTS: The study population consisted of 130 patients with suspected PE and 59 healthy controls. Mean IMA levels were 0.362 +/- 0.11 ABSU for Group A, the PE group (n = 75); 0.265 +/- 0.07 ABSU for Group B, the non-PE group (n = 55); and 0.175 +/- 0.05 ABSU for Group C, the healthy control group (p < 0.0001). At a cut-off point of 0.25 ABSU, IMA was 93% sensitive and 75% specific in the diagnosis of PE. PPV was 79.4% and NPV was 78.6%. Mean D-dimer levels were 12.48 +/- 10.88 microg/ml for Group A; 5.36 +/- 7.80 microg/ml for Group B and 0.36 +/- 0.16 microg/ml for Group C (p < 0.0001). The D-dimer cut-off point was 0.81 microg/ml with a sensitivity of 98.9% and a specificity of 62.7%, PPV of 69.4% and NPV of 83.3%. The use of IMA in combination with Wells and Geneva clinical probability scores was determined to have a positive impact on these scores' sensitivity and negative predictive values. CONCLUSION: IMA is a good alternative to D-dimer in PE diagnosis in terms of both cost and efficiency. Used in combination with clinical probability scores, it has a similar positive effect on NPV and sensitivity to that of D-dimer. The PPV of IMA is better than D-dimer, but it is still unable to confirm a diagnosis of PE without additional investigation.

Modified MyPyramid for Older Adults.

In 1999 we proposed a Modified Food Guide Pyramid for adults aged 70+ y. It has been extensively used in a variety of settings and formats to highlight the unique dietary challenges of older adults. We now propose a Modified MyPyramid for Older Adults in a format consistent with the MyPyramid graphic. It is not intended to substitute for MyPyramid, which is a multifunctional Internet-based program allowing for the calculation of individualized food-based dietary guidance and providing supplemental information on food choices and preparation. Pedagogic issues related to computer availability, Web access, and Internet literacy of older adults suggests a graphic version of MyPyramid is needed. Emphasized are whole grains and variety within the grains group; variety and nutrient density, with specific emphasis on different forms particularly suited to older adults' needs (e.g. frozen) in the vegetables and fruits groups; low-fat and non-fat forms of dairy products including reduced lactose alternatives in the milk group; low saturated fat and trans fat choices in the oils group; and low saturated fat and vegetable choices in the meat and beans group. Underlying themes stress nutrient- and fiber-rich foods within each group and food sources of nutrients rather than supplements. Fluid and physical activity icons serve as the foundation of MyPyramid for Older Adults. A flag to maintain an awareness of the potential need to consider supplemental forms of calcium, and vitamins D and B-12 is placed at the top of the pyramid. Discussed are newer concerns about potential overnutrition in the current food landscape available to older adults.

Increased apoptosis in high-fat diet-induced nonalcoholic steatohepatitis in rats is associated with c-Jun NH2-terminal kinase activation and elevated proapoptotic Bax.

Hepatocyte apoptosis in addition to oxidative stress could be a key component in the pathogenesis of nonalcoholic steatohepatitis (NASH). However, the underlying mechanisms of hepatocellular apoptotic response associated with oxidative stress have not been investigated in high-fat diet (HFD)-induced NASH models. In this study, Sprague-Dawley rats were fed either a Lieber-DeCarli control diet (CD; 35% energy from fat) or a HFD (71% energy from fat) for 6 wk. Pathologic lesions, lipid peroxidation products, and apoptotic hepatocytes in the liver were examined. The expressions of hepatic tumor necrosis factor-alpha (TNFalpha) and protein concentrations of cleaved caspase-3, cytochrome p4502E1 (CYP2E1), phosphorylated c-Jun NH(2)-terminal kinase (JNK), Bax, Bcl-2, and Bcl-xl were measured. Results showed that the key histological features of NASH, including steatosis, inflammatory cell infiltration, and ballooning degeneration of hepatocytes, were induced by HFD feeding, with increased hepatic TNFalpha mRNA expression. HFD-fed rats had elevated lipid peroxidation products and CYP2E1 protein in the liver. The apoptotic hepatocytes were significantly greater in livers of rats fed HFD than in those fed CD, and these were associated with a higher level of cleaved caspase-3. In addition, HFD feeding increased both hepatic phosphorylated JNK and pro-apoptotic Bax but did not affect anti-apoptotic Bcl-2 and Bcl-xl compared with CD feeding. These data indicate that the increased oxidative stress and its associated JNK activation as well as an imbalance of pro- and anti-apoptotic proteins in the Bcl-2 family all contribute to high hepatocyte apoptosis that may play an important role in the pathogenesis of NASH in this model.

Kinetic analysis shows that vitamin A disposal rate in humans is positively correlated with vitamin A stores.

Vitamin A (VA) kinetics, storage, and disposal rate were determined in well-nourished Chinese and U.S. adults using model-based compartmental analysis. [(2)H(8)]Retinyl acetate (8.9 micromol) was orally administered to U.S. (n = 12; 59 +/- 9 y; mean +/- SD) and Chinese adults (n = 14; 54 +/- 4 y) and serum tracer and VA concentrations were measured from 3 h to 56 d. Using the Windows version of the Simulation, Analysis and Modeling software, we determined that the average time from dosing until appearance of labeled retinol in serum was greater in U.S. subjects (40.6 +/- 8.47 h) than in Chinese subjects (32.2 +/- 5.84 h; P < 0.01). Model-predicted total traced mass (898 +/- 637 vs. 237 +/- 109 micromol), disposal rate (14.7 +/- 5.87 vs. 5.58 +/- 2.04 micromol/d), and system residence time (58.9 +/- 28.7 vs. 42.9 +/- 14.6 d) were greater in U.S. than in Chinese subjects (P < 0.05). The model-predicted VA mass and VA mass estimated by deuterated retinol dilution at 3 and 24 d did not differ. VA disposal rate was positively correlated with VA traced mass in Chinese (R(2) = 0.556), U.S. (R(2) = 0.579), and all subjects (R(2) = 0.808). Additionally, VA disposal rate was significantly correlated with serum retinol pool size (R(2) = 0.227) and retinol concentration (R(2) = 0.330) in all subjects. Our results support the hypothesis that VA stores are the principle determinant of VA disposal rate in healthy, well-nourished adults.

High dose lycopene supplementation increases hepatic cytochrome P4502E1 protein and inflammation in alcohol-fed rats.

Recent in vitro evidence suggests that the antioxidant lycopene can prevent alcohol-induced oxidative stress and inflammation. However, knowledge of possible interactions in vivo between escalating doses of lycopene and chronic alcohol ingestion are lacking. In this study, we investigated potential interactions between alcohol ingestion and lycopene supplementation and their effect on hepatic lycopene concentration, cytochrome P4502E1 (CYP2E1) induction, and inflammation. Fischer 344 rats (6 groups, n = 10 per group) were fed either a liquid ethanol Lieber-DeCarli diet or a control diet (isocaloric maltodextrin substituted for ethanol) with or without lycopene supplementation at 2 doses (1.1 or 3.3 mg x kg body weight(-1) x d(-1)) for 11 wk. Plasma and hepatic concentrations of lycopene isomers were assessed by HPLC analysis. We examined expressions of hepatic CYP2E1 and tumor necrosis factor-alpha (TNFalpha) and the incidence of hepatic inflammatory foci. Both plasma and hepatic lycopene concentrations were greater in alcohol-fed rats than in control rats supplemented with identical doses of lycopene. In contrast, alcohol-fed rats had a lower percentage of lycopene cis isomers in the plasma and the liver compared with control rats fed the same dose of lycopene. Notably, lycopene supplementation at the higher dose significantly induced hepatic CYP2E1 protein, TNFalpha mRNA, and the incidence of inflammatory foci in the alcohol-fed rats but not in the control rats. These data indicate an interaction between chronic alcohol ingestion and lycopene supplementation and suggest a need for caution among individuals consuming high amounts of both alcohol and lycopene.

Nutrition and gastric cancer risk: an update.

Data from epidemiologic, experimental, and animal studies indicate that diet plays an important role in the etiology of gastric cancer. High intake of fresh fruits and vegetables, lycopene and lycopene-containing food products, and potentially vitamin C and selenium may reduce the risk for gastric cancer. Data also suggest that high intake of nitrosamines, processed meat products, salt and salted foods, and overweight and obesity are associated with increased risk for gastric cancer. However, current data provide little support for an association of beta-carotene, vitamin E, and alcohol consumption with risk for gastric cancer.

Determination of 9-cis beta-carotene and zeta-carotene in biological samples.

Concentrations of 9-cis beta-carotene (9-cis betaC) and zeta-carotene (zetaC) in biological samples may provide crucial information on the biological activities of these carotenoids. However, in high-performance liquid chromatography (HPLC) these carotenoids are often co-eluted. Therefore, there is an urgent need to develop a method for 9-cis betaC and zetaC quantitation. Both 9-cis betaC and zetaC have peak absorbance at 400 and 450 nm, respectively, whereas only 9-cis betaC has peak absorbance at 475 nm. We developed a HPLC method to quantitate 9-cis betaC and zetaC by using peak absorbance ratios. The 9-cis betaC/zetaC peak area was monitored at 475, 450 and 400 nm. The 9-cis betaC was quantified by using absorbance value at 475 nm; zetaC was then calculated from the 9-cis betaC/zetaC peak at 400 nm by subtracting 9-cis betaC contribution at 400 nm using the 400-nm/475-nm peak absorbance ratio of 9-cis betaC (0.39). This method was applied to determine 9-cis betaC and zetaC concentrations in serum and breast milk samples (n=12) from American lactating women and serum and breast adipose tissue samples (n=16) from Korean women with either benign or malignant breast tumors. 9-cis betaC concentrations in serum and breast milk of American women, and serum and adipose tissue of Korean women were 7.1+/-0.8 and 1.1+/-0.2 nM, and 15.6+/-1.1 nM and 0.2+/-0.1 nmol/g, respectively. zetaC concentrations in the above samples were 54.2+/-7.2 and 8.3+/-1.8 nM, and 49.0+/-3.9 nM and 0.3+/-0.1 nmol/g, respectively.