Serum carotenoids and vitamins in relation to markers of endothelial

BACKGROUND

Endothelial cell dysfunction may be related to an increase in cellular oxidative stress. Carotenoids and vitamins could have an antioxidant-mediated tempering influence on endothelial function and inflammation, thereby reducing the risk of atherosclerosis.

METHODS

We measured serum carotenoids, alpha-tocopherol and Vitamin C concentrations in 379 subjects sampled from the general population. High-sensitive C-reactive protein (CRP), fibrinogen (Fbg) and leukocytes were measured as markers of inflammation. Furthermore, soluble intercellular adhesion molecule-1 (sICAM-1) and flow-mediated vasodilation (FMD; n= 165) were measured as markers of endothelial function. Relationships between serum carotenoids and vitamins and markers of endothelial function and inflammation were analysed after adjustment for confounding.

RESULTS

In the total study group, lutein and lycopene were inversely related to sICAM-1 with regression-coefficients of -0.38+/-0.19 (p = 0.04) and -0.16+/-0.08 (p = 0.04) per 1 micromol/l, respectively. beta-Carotene was inverse related to leukocytes (-0.23+/-0.07; p = 0.007) and CRP (-1.09+/-0.30; p = 0.0003) per 1 micromol/l. Vitamin C was inverse related to CRP (-0.01+/-0.005; p = 0.04) per 1 micromol/l, whereas alpha-tocopherol was positively related to CRP (0.03+/-0.01; p = 0.02) per 1 micro/l. Zeaxanthin was inversely related to FMD (31.2+/-15.3; p = 0.04) per 1 micromol/l.

CONCLUSION

The inverse relations between carotenoids, Vitamin C and sICAM-1, CRP and leukocytes may help to explain the possible protective effect of carotenoids and Vitamin C on atherosclerosis through an influence on inflammatory processes and endothelial function.

LDL Susceptibility to Copper-Induced Oxidation after Administration of a Single Dose of Free or Esterified Beta-Cryptoxanthin

BACKGROUND

The oxidative modification of LDL is believed to be an initial step in atherosclerosis. Thus, antioxidative substances such as carotenoids may have a role in the prevention of coronary heart disease. We examined the susceptibility of LDL to Cu2+ oxidation in young adults before and after a single dose of beta-cryptoxanthin.

METHODS

1.3 mg of beta-cryptoxanthin was administered to 12 apparently healthy young volunteers. Six of the volunteers received esters, the other six free beta-cryptoxanthin. The plasma concentration of beta-cryptoxanthin and the susceptibility of LDL to copper-induced oxidation ex vivo in terms of the duration of lag time were measured before and 12 h after beta-cryptoxanthin ingestion.

RESULTS

A single dose of beta-cryptoxanthin significantly increased the mean plasma beta-cryptoxanthin concentration and the mean cholesterol adjusted beta-cryptoxanthin concentration by 117 and 133%, respectively. No effect on the length of lag time was assessed. However, in LDL isolated from plasma 12 h after beta-cryptoxanthin administration the lengths of lag time correlated significantly with the plasma beta-cryptoxanthin concentration and with the cholesterol adjusted beta-cryptoxanthin levels. The lag time did not differ significantly between volunteers who received esters and those who received the same dosage as free beta-cryptoxanthin. At both measuring points, smokers, male volunteers and women using oral contraceptives tended to exhibit lower beta-cryptoxanthin concentrations and lower cholesterol adjusted beta-cryptoxanthin concentrations as well as increased LDL oxidizability compared to nonsmokers and women not using oral contraceptives.

CONCLUSION

A single dose of beta-cryptoxanthin does not enhance the duration of LDL lag time ex vivo in healthy young subjects.

The effect of mycoplasmosis on carotenoid plumage coloration in male house finches

Parasites are widely assumed to cause reduced expression of ornamental plumage coloration, but few experimental studies have tested this hypothesis. We captured young male house finches Carpodacus mexicanus in Alabama before fall molt and randomly divided them into two groups. One group was infected with the bacterial pathogen Mycoplasma gallicepticum (MG)and the other group was maintained free of MG infection. All birds were maintained through molt on a diet of seeds with tangerine juice added to their water as a source of β-cryptoxanthin, the natural precursor to the primary red carotenoid pigment in house finch plumage. All males grew drab plumage, but males with MG infection grew feathers that were significantly less red (more yellow), less saturated, and less bright than males that were not infected. MG targets upper respiratory and ocular tissue. Our observations show that a pathogen that does not directly disrupt carotenoid absorption or transportation can still have a significant effect on carotenoid utilization.

Serum carotenoid and retinol levels during childhood infections

BACKGROUND

In recent years, new physiological functions of vitamin A have been identified, including its role in immune defense. The antioxidant potential of carotenoids is thought to account for their health benefits. The aim of this study was to investigate the concentration changes in the provitamin-A (alpha- and-beta-carotene, beta-cryptoxanthin) and of the non-provitamin-A carotenoids (lutein, zeaxanthin and lycopene) in children with acute infections.

METHODS

Serum retinol and carotenoid concentrations were measured by HPLC in 45 children suffering from acute infections and in 29 healthy controls. In addition 15 healthy children collected food samples over 2 days. C-reactive protein (CRP) levels were measured by turbidimetry.

RESULTS

Serum levels of beta-carotene, alpha-carotene, beta-cryptoxanthin and retinol and non-provitamin-A carotenoid lutein and zeaxanthin concentrations were significantly lower in children with infections compared to healthy controls. There were significant negative correlations between CRP levels and serum beta-carotene and retinol concentrations. The average intake of retinol equivalents was 1.1 +/- 0.6 mg/day.

CONCLUSION

Serum retinol and provitamin-A as well as non-provitamin-A carotenoid concentrations were lower in children with acute phase infections compared to healthy controls. The inverse correlations between CRP and beta-carotene or retinol indicate either decreased synthesis or increased utilization of these antioxidants.

Inhibitory effect of β-cryptoxanthin on osteoclast-like cell formation in mouse marrow cultures

The carotenoid beta-cryptoxanthin has been shown to have an inhibitory effect on bone-resorping factor-stimulated bone resorption in rat bone tissues in vitro. The effect of beta-cryptoxanthin on osteoclast-like cell formation in mouse marrow culture in vitro was investigated. The bone marrow cells were cultured for 7 days in alpha-minimal essential medium containing a bone-resorbing agent [parathyroid hormone (1-34) (PTH), prostaglandin E(2), 1,25-dihydroxyvitamin D(3), lipopolysaccharide, or tumor necrosis factor-alpha (TNFalpha)] with an effective concentration. Osteoclast-like cell formation was estimated by staining for tartrate-resistant acid phosphatase, a marker enzyme of osteoclasts. The presence of PTH (10(-7)M), prostaglandin E(2) (10(-5)M), 1,25-dihydroxyvitamin D(3) (10(-7)M), lipopolysaccharide (10 microg/mL), or TNFalpha (10 ng/mL) induced a remarkable increase in osteoclast-like multinucleated cells. These increases were significantly inhibited in the presence of beta-cryptoxanthin (10(-8) to 10(-6)M). beta-Cryptoxanthin (10(-7) and 10(-6)M) significantly inhibited dibutyryl cyclic adenosine monophosphate (DcAMP) (10(-5)M) or phorbol 12-myristate 13-acetate (PMA) (10(-5)M), an activator of protein kinase C, induced osteoclast-like cell formation. Also, beta-cryptoxanthin (10(-7) and 10(-6)M) had a significant inhibitory effect on osteoclast-like formation induced by receptor activator of NF-kappaB ligand (RANKL) (10 and 20 ng/mL) in the presence of macrophage colony-stimulating factor (M-CSF) (10 and 20 ng/mL). The stimulatory effect of RANKL and M-CSF on osteoclast-like cell formation was significantly enhanced in the presence of PMA, while such an effect was not seen by DcAMP. beta-Cryptoxanthin (10(-6)M) significantly inhibited osteoclast-like cell formation induced by RANKL and M-CSF in the presence of PMA or DcAMP. Moreover, the inhibitory effect of beta-cryptoxanthin on RANKL plus M-CSF-, PTH-, or TNFalpha-induced osteoclast-like cell formation was not observed in the presence of cycloheximide (10(-7)M), an inhibitor of protein synthesis at translational process, or 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (10(-6)M), an inhibitor of transcription. This study demonstrates that beta-cryptoxanthin has a potent inhibitory effect on osteoclast-like cell formation in mouse marrow culture. The inhibitory action of beta-cryptoxanthin may partly involve in a newly synthesized protein component which is related to RANKL stimulation in osteoclastogenesis.

Reasonable estimates of serum vitamin E, vitamin C, and beta-cryptoxanthin are obtained with a food frequency questionnaire in older black and white adults

Few studies provide correlations between different indicators of the dietary intakes of older (>or= 65 y) black and white adults. This study compared the usual intakes of vitamin E, vitamin C, and selected carotenoids estimated by a modified Harvard food frequency questionnaire (FFQ) to those estimated by multiple 24-h recalls, and to blood concentrations of components in a randomly selected sample of participants in the Chicago Health and Aging Project (CHAP). Subjects (n = 59) were interviewed to complete multiple 24-h recalls over a year's time, then completed an FFQ and subsequently provided a fasting blood specimen within 2 mo. Dietary estimates were energy-adjusted separately for men and women. Significant (P < 0.05) correlations between total (diet and supplement) FFQ estimates and serum measures of vitamin E and vitamin C were as follows: 0.49 and 0.39 for blacks, and 0.42 and 0.29 for whites, respectively. The highest correlations between serum and FFQ indicators were for dietary beta-cryptoxanthin (0.46), total alpha-tocopherol (0.46) and total beta-carotene (0.44) among whites; among blacks, the highest correlations were for dietary alpha-carotene (0.81), total alpha-tocopherol (0.53) and total beta-cryptoxanthin (0.50); all were significant (P < 0.05). Further adjustment for age, gender, BMI, and educational level minimally altered these coefficients. These findings indicate that the modified Harvard FFQ provides reasonable estimates of serum levels of vitamin E, vitamin C and beta-cryptoxanthin among CHAP participants.

β-Criptoxanthin stimulates bone formation and inhibits bone resorption in tissue culture in vitro

The effect of beta-cryptoxanthin, which is greatly present in fruits, has not been clarified so far on bone metabolism. The effect of beta-cryptoxanthin on bone formation and bone resorption was investigated in tissue culture in vitro. Rat femoral-diaphyseal (cortical bone) and -metaphyseal (trabecular bone) tissues were cultured for 48 h in Dulbecco's modified Eagle's medium (high glucose, 4.5%) supplemented with antibiotics and bovine serum albumin. The experimental cultures contained 10(-8)-10(-5) M beta-cryptoxanthin. The presence of beta-cryptoxanthin (10(-6) or 10(-5) M) caused a significant increase in calcium content, alkaline phosphatase activity and deoxyribonucleic acid (DNA) content in the diaphyseal and metaphyseal tissues. These increases were completely prevented in the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis. beta-Carotene (10(-6) or 10(-5) M) or xantine (10(-6) or 10(-5) M) had no effect on the diaphyseal and metaphyseal calcium contents. The bone-resorbing factors parathyroid hormone (1-34) (PTH; 10(-7) M) or prostaglandin E2 (PGE2; 10(-5) M) caused a significant decrease in calcium content in the diaphyseal and metaphyseal tissues. The decrease in bone calcium content induced by PTH or PGE2 was completely inhibited by beta-cryptoxanthin (10(-8)-10(-6) M). In addition, beta-cryptoxanthin (10(-8)-10(-6) M) completely inhibited the PTH (10(-7) M)- or PGE, (10(-5) M)-induced increase in medium glucose consumption and lactic acid production by diaphyseal and metaphyseal tissues. The inhibitory effect of beta-cryptoxanthin (10(-7) M) on PTH (10(-7) M)- or PGE2 (10(-5) M)-stimulated decrease in the diaphyseal calcium content was significantly prevented in the presence of 10(-3) M vanadate, an inhibitor of protein tyrosine phosphatase. Vanadate (10(-3) M) did not have a significant effect on calcium content and lactic acid production in control bone tissues. The present study demonstrates that beta-cryptoxanthin has a direct stimulatory effect on bone formation and an inhibitory effect on bone resorption in tissue culture in vitro.

Prospective study of serum retinol, beta-carotene, beta-cryptoxanthin, and lutein/zeaxanthin and esophageal and gastric cancers in China

OBJECTIVE

This study examined the relationship between pretrial serum concentrations of retinol, beta-carotene, beta-cryptoxanthin, and lutein/zeaxanthin and the subsequent risk of developing esophageal squamous cell carcinoma and gastric cardia or non-cardia adenocarcinoma in subjects selected from a randomized nutritional intervention trial in Linxian, China, a region with epidemic rates of esophageal and gastric cardia cancer.

METHODS

We used a stratified case-cohort design to select cohort members for inclusion in this study. In all we measured serum concentrations of the above vitamins in 590 esophageal, 395 gastric cardia, and 87 gastric non-cardia case subjects as well as in 1053 control subjects. Relative risks (RRs) were estimated using Cox proportional hazards models.

RESULTS

Median values in our cohort were low for serum retinol (33.6 microg/dl), beta-carotene (4.3 microg/dl), and beta-cryptoxanthin (3.5 microg/dl), but were high for lutein/zeaxanthin (40.0 microg/dl). Gastric cardia cancer incidence fell 10% for each quartile increase in serum retinol (RR = 0.90, 95% CI = 0.83-0.99). For esophageal cancer, an inverse association with retinol levels was found only in male non-smokers (RR = 0.79 per quartile increase, 95% CI = 0.63-0.99). For gastric non-cardia cancer, an inverse association was limited to subjects 50 years old or younger (RR = 0.58 per quartile, 95% CI = 0.31-0.96). For beta-cryptoxanthin there was a borderline significant protective association for gastric non-cardia cancer (RR = 0.88 per quartile, 95% CI = 0.76-1.0). In contrast, we found the incidence of gastric non-cardia cancer increased (RR = 1.2 per quartile, 95% CI = 1.0-1.3) with increasing concentration of serum lutein/zeaxanthin.

CONCLUSIONS

In this population, we found that low retinol and high lutein/zeaxanthin concentrations increased the risks of gastric cardia and gastric non-cardia cancer respectively. We found that there were no strong associations between any of the other analytes and any of the cancer sites.

Seasonal Changes in the Relationship between Serum Concentration of .BETA.-Cryptoxanthin and Serum Lipid Levels

Beta-cryptoxanthin (beta-CRX) is a carotenoid pigment found especially in Satsuma mandarin (Citrus unshiu Marc.) fruit, which is mainly produced in Japan. Previously, we found that serum beta-CRX concentrations rose to extreme levels as the frequency of consumption of Satsuma mandarin increases. Using 94 non-smoking female volunteers, the present study evaluated the relationship between serum concentration of beta-CRX and serum lipid levels in September, when the Satsuma mandarin is not in season, and in January of the next year, when it is in season. The mean of increment in serum beta-CRX concentrations from September to January was 95.9 +/- 84.0 microg/dl (mean +/- SD). Although the changes in serum lipid levels did not correlate with the changes in serum beta-CRX, the serum HDL-cholesterol and apo-lipoprotein A1 levels in the highest quartile of the increment in serum beta-CRX from September to January were significantly higher than those in the lowest quartile in both September and January. In cross-sectional analyses, serum beta-CRX concentrations were correlated positively with those of LDL-cholesterol and apo-lipoprotein B levels in September, but these correlations were not observed in January. In contrast, serum beta-CRX concentrations were correlated positively with those of HDL-cholesterol and apo-lipoprotein A1 levels in January. These results suggest that habitual eating of Satsuma mandarin while it is in season may influence lipid metabolism throughout the year.

Carotenoid status among preschool children with vitamin A deficiency in the Republic of the Marshall Islands

Although carotenoids are known to be important dietary sources of vitamin A, there have been few epidemiological studies that have characterized the serum concentrations of major dietary carotenoids among preschool children with vitamin A deficiency. We conducted a population-based, cross-sectional study of serum pro-vitamin A carotenoids (alpha -carotene, beta-carotene, beta-cryptoxanthin), non-provitamin A carotenoids (lutein/zeaxanthin, and lycopene), and retinol among 278 children, aged 1-5 y, in the Republic of the Marshall Islands. Vitamin A deficiency was defined as serum retinol <0.70 micromol/L. Geometric mean serum concentrations of carotenoids among children with and without vitamin A deficiency were 0.003 vs 0.006 micromol/L for alpha-carotene (P = 0.0017), 0.011 vs 0.023 micromol/L for beta-carotene (P <0.0001), 0.023 vs 0.034 micromol/L for beta-cryptoxanthin (P = 0.0075), 0.007 vs 0.012 micromol/L for lycopene (P = 0.037), 0.044 vs 0.052 micromol/L for lutein/zeaxanthin (P = 0.2), and 0.045 vs 0.074 micromol/L for total provitamin A carotenoids (P <0.0001) respectively. In a multivariate analysis adjusting for sex, age (Odds Ratio [O.R.] 1.44, 95% confidence interval [C.I.] 1.16-1.78), and serum provitamin A carotenoids (O.R. 0.49, 95% C.I. 0.34-0.71) were associated with vitamin A deficiency, but serum non-provitamin A carotenoids were not associated with vitamin A deficiency (O.R. 0.93, 95% C.I. 0.67-1.28). Preschool children with vitamin A deficiency in the Republic of the Marshall Islands have extremely low serum concentrations of provitamin A carotenoids and interventions are needed to improve the dietary intake of provitamin A carotenoids among Marshallese children.

Effects of LDL-immunoapheresis on plasma concentrations of vitamin E and carotenoids in patients with familial hypercholesterolemia

Recently very potent extracorporeal cholesterol-lowering treatment options have become available for patients with hypercholesterolemia. LDL immunoapheresis treatment selectively removes LDL and lipoprotein(a) from the circulation. Since LDL is the major carrier of lipophilic antioxidants in plasma, the purpose of the present study was to assess the effects of a single LDL apheresis treatment on plasma concentrations of tocopherols (alpha- and gamma-tocopherol) and carotenoids (alpha- and beta-carotene, zeaxanthin, cryptoxanthin, canthaxanthin, lycopene, and retinol). Plasma antioxidant concentrations were determined by HPLC in 7 patients with familial hypercholesterolemia before and after LDL immunoapheresis treatment. Plasma concentrations of both alpha- and gamma-tocopherol and the different carotenoids were significantly reduced by LDL apheresis. However, when standardized for cholesterol to adjust for cholesterol removal, alpha- and gamma-tocopherol, retinol, and the more polar carotenoids lutein and zeaxanthin increased in response to apheresis treatment, while the more unpolar carotenoids such as beta-carotene and lycopene did not change. These data demonstrate that a single LDL immunoapheresis treatment affects tocopherols and individual carotenoids differently. This may be explained by differences in chemical structure and preferential association with different lipoproteins. These results further imply that tocopherols, lutein, zeaxanthin, and retinol, are associated in part with lipoproteins and other carriers such as retinol-binding protein that are not removed during apheresis treatment.

Oral Administration of .BETA.-Cryptoxanthin Induces Anabolic Effects on Bone Components in the Femoral Tissues of Rats in Vivo

The effect of beta-cryptoxanthin on bone components in the femoral tissues of rats was investigated. Beta-cryptoxanthin was isolated from Satsuma mandarin (Citrus unshiu MARC.). Bone tissues were cultured for 48 h in serum-free Dulbecco's modified Eagle's medium containing either vehicle or beta-cryptoxanthin (10(-7) or 10(-6) M). The presence of beta-cryptoxanthin (10(-7) or 10(-6) M) caused a significant increase in calcium content and alkaline phosphatase activity in the femoral-diaphyseal and femoral-metaphyseal tissues. These increases were completely abolished in the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis. Thus beta-cryptoxanthin had an anabolic effect on bone calcification in vitro. Moreover, beta-cryptoxanthin (10, 25, or 50 microg/100 g body weight) was orally administered once daily for 7 d to young male rats. The administration of beta-cryptoxanthin (10, 25, or 50 microg/100 g body weight) caused a significant increase in calcium content and alkaline phosphatase activity in the femoral-diaphyseal and femoral-metaphyseal tissues. Femoral-diaphyseal and femoral-metaphyseal DNA contents were significantly increased by the dose of 25 or 50 microg/100 g body weight. A significant increase in metaphyseal DNA content was also seen with the dose of 10 microg/100 g body weight of beta-cryptoxanthin. This study demonstrates that beta-cryptoxanthin has an anabolic effect on bone components in rats in vitro and in vivo.

Effect of extraction method on the concentrations of selected bioactive compounds in mandarin juice

A mandarin-type citrus fruit, ponkan (Citrus reticulata), was processed by in-line, chopper pulper, and hand-press extractions to investigate the effect of extraction method on the concentrations of bioactive compounds in processed juice. Concentrations of polymethoxylated flavones (tangeretin, nobiletin, and sinensetin) and beta-cryptoxanthin in juice, and inhibitory activities against arachidonate cyclooxygenase and lipoxygenases of the juice extract were analyzed. The juice processed by hand-press extraction contained the largest amounts of nobiletin (3.56 mg/100 mL), tangeretin (4.10 mg/100 mL), and sinensetin (0.13 mg/100 mL). Concentrations of beta-cryptoxanthin were 0.66, 0.59, 0.55, and 0.50 mg/100 mL in chopper pulper, in-line (5/64 in.), in-line (8/64 in.) and hand-press juices, respectively. Both extracts of in-line juices showed greater inhibitory activity toward platelet 12-lipoxygenase than the others. The inhibitory effect of hand-press juice extract on platelet cyclooxygenase activity was remarkable among juice extracts. All juice extracts effectively inhibited polymorphonuclear 5-lipoxygenase activity at nearly the same rate.

Dietary Intake and Risk of Persistent Human Papillomavirus (HPV) Infection: The Ludwig‐McGill HPV Natural History Study

The association between dietary intake and persistence of type-specific human papillomavirus (HPV) infection, during a 12-month period, among 433 women participating in the Ludwig-McGill HPV Natural History Study was evaluated by use of a nested case-control design. Dietary intake was assessed by a food-frequency questionnaire at the month-4 visit. HPV status was assessed at months 0, 4, 8, and 12 by polymerase chain reaction (MY09/11). Only women who ever tested positive for HPV were included in the present study: 248 had transient HPV infections (1 of 4 positive tests or nonconsecutively positive), and 185 had persistent HPV infections (> or =2 consecutive tests positive for the same HPV type). Risk of type-specific, persistent HPV infection was lower among women reporting intake values of beta-cryptoxanthin and lutein/zeaxanthin in the upper 2 quartiles and intake values of vitamin C in the upper quartile, compared with those reporting intake in the lowest quartile. Consumption of papaya > or =1 time/week was inversely associated with persistent HPV infection.

Low plasma concentrations of diet-derived antioxidants in association with microalbuminuria in Indigenous Australian populations

Microalbuminuria is a risk factor for renal and cardiovascular diseases. Oxidant stress may contribute to vascular disease risk by promoting damage to renal and vascular tissues. This study examined the associations of plasma levels of diet-derived antioxidants with albuminuria in Australian population groups at high risk of renal and cardiovascular disease. Data on microalbuminuria and diet-derived plasma antioxidants were drawn from results of cross-sectional community-based risk factor surveys of Aboriginal and Torres Strait Islander peoples (n =698, 15 years and older). Prevalence of microalbuminuria ranged from 17-21%. After adjustment for age, gender, body mass index, diabetes, smoking status, plasma lipids and blood pressure, microalbuminuria was associated with significantly lower plasma concentrations of lycopene (-29%; P <0.001), beta-carotene (-22%; P <0.001), alpha-carotene (-22%; P <0.001) and cryptoxanthin (-17%; P <0.001) compared with normalbuminuric persons. Significant associations of microalbuminuria with plasma concentrations of alpha-tocopherol, retinol, lutein plus zeaxanthin and homocysteine were absent. The data are consistent with a protective effect of diets rich in carotenoids on vascular endothelium and/or renal tissues, and support the need for interventions to address affordable food supplies and dietary quality among Indigenous Australians.

Dietary Modification and Moderate Antioxidant Supplementation Differentially Affect Serum Carotenoids, Antioxidant Levels and Markers of Oxidative Stress in Older Humans

Oxidative stress is thought to be a factor in the progression of chronic diseases, and even the aging process itself. We examined the effect of two moderate vitamin, mineral and phytochemical supplements and a dietary intervention on markers of oxidative stress and antioxidant status in older humans. Subjects (n = 60, 65-85 y old) were enrolled in a 5-wk, double-blind, placebo-controlled study. The subjects were randomly assigned to a group with one of four interventions: antioxidant supplement capsule, antioxidant supplement tablet, high carotenoid diet or placebo. Postintervention serum levels of some of the supplemented carotenoids and alpha-tocopherol were higher in all treated groups compared with the placebo group and with preintervention levels within groups. Markers of oxidative stress or antioxidant capacity were not significantly different from preintervention levels, although the diet and supplement capsule groups had lower levels of some of those markers than the placebo group postintervention. The results suggest that both moderate antioxidant supplementation and a diet high in carotenoids elevate serum carotenoids and antioxidant levels in an older adult population, although with different specific effects.

Plasma response to a single dose of dietary beta-cryptoxanthin esters from papaya (Carica papaya L.) or non-esterified beta-cryptoxanthin in adult human subjects: a comparative study

Many orange-coloured fruits contain beta-cryptoxanthin in its non-esterified as well as its esterified form. Information concerning the absorption of beta-cryptoxanthin, especially with regard to the metabolism of its fatty acid esters, is rather scarce. The present study assessed the plasma concentration reached after consumption of a single dose of native beta-cryptoxanthin esters from papaya (Carica papaya L.) or non-esterified beta-cryptoxanthin in equal total amounts. In a randomized, single-blind crossover study, twelve subjects were served a portion of yoghurt containing esterified or non-esterified beta-cryptoxanthin (1.3 mg absolute) together with a balanced breakfast. Between the two intervention days, there was a 2-week depletion period. After a fasting blood sample had been taken, futher samples were taken from the subjects at 3, 6, 9, 12 and 24 h. The concentration of non-esterified beta-cryptoxanthin in the whole plasma was determined by HPLC; beta-cryptoxanthin identification was confirmed by liquid chromatography-atmospheric pressure chemical ionization-MS analyses. Irrespective of the consumed diet, the plasma beta-cryptoxanthin concentrations increased significantly (P=0.05) and peaked after 6-12 h. The concentration curves, as well as the areas under the curves, were not distinguishable according to two-sided F and t tests (P=0.05). Standardization of beta-cryptoxanthin concentrations to plasma triacylglycerol and cholesterol had no impact on the results. Thus, the present study indicates comparable bioavailability of both non-esterified beta-cryptoxanthin and mixtures of beta-cryptoxanthin esters. The results support the existence of an effective enzymatic cleavage system accepting various beta-cryptoxanthin esters.

Synthetic and tomato-based lycopene have identical bioavailability in humans

BACKGROUND

Bioavailability studies with lycopene have focused on natural sources. A synthetic source has recently become available.

AIM OF THE STUDY

To determine the relative bioavailabilities of synthetic and tomato-based lycopene in free living volunteers in a single-blind, randomized, placebo-controlled, parallel trial.

METHODS

Three groups (n=12/group) of healthy, normolipemic male and female subjects with a mean baseline serum lycopene concentration of 0.36 micro mol/L took a dose of 15 mg/day total lycopene for 28 days from either Lycovit 10% (beadlets, BASF, Germany) or Lyc-O-Mato (beads, LycoRed Natural Products, Israel) or a placebo (without lycopene) together with the main meal. The increase in serum lycopene from baseline was used as the parameter of bioavailability.

RESULTS

Synthetic and tomato-lycopene resulted in significant increases above baseline of serum total lycopene by 0.58 and 0.57 micro mol/L, trans-lycopene by 0.34 and 0.41 micro mol/L, and total-cis-lycopene by 0.24 and 0.16 micro mol/L, whereas no significant changes were found in the placebo treatment. The mean serum total lycopene response to synthetic and natural lycopene was not significantly different. Neither lycopene source affected the other serum carotenoids, viz. alpha-carotene, beta-carotene, beta-cryptoxanthin, zeaxanthin and lutein.

CONCLUSION

We conclude that synthetic and natural lycopene are equivalent sources of lycopene and that there is no interaction with other circulating carotenoids.

Toenail selenium levels and the subsequent risk of prostate cancer: a prospective cohort study

Results of a randomized controlled trial have suggested a protective effect of selenium against prostate cancer. Few other prospective studies have been conducted to confirm or refute this. The association between prostate cancer and baseline toenail selenium level was evaluated in the Netherlands Cohort Study, conducted among 58,279 men, aged 55-69 years at entry. In September 1986, the cohort members completed a questionnaire on risk factors for cancer and provided toenail clippings for determination of baseline selenium status. After 6.3 years of follow-up, 540 incident prostate carcinoma cases and 1,211 subcohort members with complete toenail selenium data were available for case-cohort analyses. In multivariate survival analysis, an inverse association between toenail selenium level and prostate cancer risk was observed. Incidence rate ratios in increasing selenium quintiles were 1.00 (ref), 1.05, 0.69, 0.75, and 0.69 (95% confidence interval, 0.48-0.99), respectively (P-trend=0.008). This association persisted after exclusion of cases diagnosed during early follow-up. The inverse association was more pronounced in ex-smokers than current smokers, and unclear in never-smokers. Analysis of effect modification by intake of antioxidant vitamins C, E, and the carotenoids alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, and lutein/zeaxanthin showed a strong, significant interaction with beta-cryptoxanthin, and to a lesser extent with vitamin C. These results confirm the hypothesis that higher selenium intake may reduce prostate cancer risk. Future research on optimum dose level is needed.

Dietary cryptoxanthin and reduced risk of lung cancer: the Singapore Chinese Health Study

High prediagnostic serum beta-cryptoxanthin levels have been found to be associated with reduced risk of lung cancer in a recent cohort study of Chinese men in Shanghai, China. Data on dietary beta-cryptoxanthin, and other specific carotenoids and antioxidants in relation to lung cancer, particularly in non-Western populations, are scarce. The aim of the present study was to assess the roles of dietary antioxidants in the development of lung cancer. Between April 1993 and December 1998, 63,257 Chinese men and women ages 45-74 years in Singapore participated in a prospective study of diet and cancer. At baseline, an in-person interview was conducted using a structured questionnaire for information on usual dietary habits, tobacco smoking, and other lifestyle factors. A Singapore food composition database was used to estimate intake of alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein/zeaxanthin, vitamins A, C, and E, and folate in study subjects. During the first 8 years of follow-up, 482 lung cancer cases occurred among cohort members. High levels of dietary beta-cryptoxanthin were associated with reduced risk of lung cancer; relative to the lowest quintile, the self-reported smoking adjusted relative risks (95% confidence intervals) for the highest quintile were 0.73 (0.54-0.98) among all of the subjects and 0.63 (0.41-0.99) among current smokers. Before adjustment for cigarette smoking, dietary vitamin C was associated with a statistically significant reduction in risk of lung cancer. However the inverse vitamin C-lung cancer association was largely explained by smoking and dietary beta-cryptoxanthin. Other carotenoids (alpha-carotene, beta-carotene, lycopene, and lutein/zeaxanthin), vitamins A and E, and folate were not associated significantly with lung cancer risk after adjustment for cigarette smoking. We recognized that potential measurement errors in cigarette smoking may exert an effect on the dietary beta-cryptoxanthin-lung cancer association. After additional adjustments were made for the residual confounding by smoking using statistical models, about 15-40% reduction in risk of lung cancer was seen for subjects in the highest versus lowest 10th percentile of dietary beta-cryptoxanthin. The present study lends additional credence to prior experimental and epidemiological data in support of the hypothesis that dietary beta-cryptoxanthin is a chemopreventive agent for lung cancer in humans.

Plasma carotenoids and tocopherols and risk of myocardial infarction in a low-risk population of US male physicians

BACKGROUND

Increased intake of carotenoids and vitamin E may protect against myocardial infarction (MI). However, prospective data on blood levels of carotenoids other than beta-carotene and vitamin E (tocopherol) and risk of MI are sparse.

METHODS AND RESULTS

We conducted a prospective, nested case-control analysis among male physicians without prior history of cardiovascular disease who were followed for up to 13 years in the Physicians' Health Study. Samples from 531 physicians diagnosed with MI were analyzed together with samples from paired control subjects, matched for age and smoking, for 5 major carotenoids (alpha- and beta-carotene, beta-cryptoxanthin, lutein, and lycopene), retinol, and alpha- and gamma-tocopherol. Overall, we found no evidence for a protective effect against MI for higher baseline plasma levels of retinol or any of the carotenoids measured. Among current and former smokers but not among never-smokers, higher baseline plasma levels of beta-carotene tended to be associated with lower risk (P for interaction=0.02). Men with higher plasma levels of gamma-tocopherol tended to have an increased risk of MI (P for trend=0.01).

CONCLUSIONS

These prospective data do not support an overall protective relation between plasma carotenoids or tocopherols and future MI risk among men without a history of prior cardiovascular disease.

Antioxidant intake and primary open-angle glaucoma: a prospective study

The relation between dietary antioxidant intake and primary open-angle glaucoma risk was examined in participants aged over 40 years in the Nurses' Health Study (n = 76,200) and the Health Professionals Follow-up Study (n = 40,284). They were followed biennially from 1980 and 1986, respectively, to 1996, during periods when they received an eye examination. Dietary intakes were measured repeatedly from 1980 in the Nurses' Health Study and from 1986 in the Health Professionals Follow-up Study using validated food frequency questionnaires. The authors analyzed 474 self-reported glaucoma cases confirmed by medical chart review to have primary open-angle glaucoma with visual field loss. The authors used Cox proportional hazards models for cohort-specific multivariate analyses, and results were pooled using random effects models. The pooled multivariate rate ratios for primary open-angle glaucoma comparing the highest versus lowest quintile of cumulative updated intake were 1.17 (95% confidence interval (CI): 0.87, 1.58) for alpha-carotene, 1.10 (95% CI: 0.82, 1.48) for beta-carotene, 0.95 (95% CI: 0.70, 1.29) for beta-cryptoxanthin, 0.82 (95% CI: 0.60, 1.12) for lycopene, 0.92 (95% CI: 0.69, 1.24) for lutein/zeaxanthin, 1.05 (95% CI: 0.59, 1.89) for vitamin C, 0.97 (95% CI: 0.62, 1.52) for vitamin E, and 1.11 (95% CI: 0.82, 1.51) for vitamin A. In conclusion, the authors did not observe any strong associations between antioxidant consumption and the risk of primary open-angle glaucoma.

Effect of carotenoid on calcium content and alkaline phosphatase activity in rat femoral tissues in vitro: the unique anabolic effect of beta-cryptoxanthin

The effects of various carotenoids and rutin on calcium content and alkaline phosphatase activity in the femoral-diaphyseal and femoral-metaphyseal tissues of young rats in vitro were investigated. Bone tissues were cultured for 48 h in serum-free Dulbecco's modified Eagle's medium containing either vehicle or a compound (10(-8)-10(-6) M). The presence of beta-cryptoxanthin (10(-7) or 10(-6) M) caused a significant increase in calcium content and alkaline phosphatase activity in the femoral-diaphyseal and femoral-metaphyseal tissues. Also, the lowest concentration (10(-8) M) of beta-cryptoxanthin used caused a significant increase in diaphyseal and metaphyseal calcium content. Lutein (10(-8)-10(-6) M) had no effect on diaphyseal and metaphyseal calcium contents and diaphyseal alkaline phosphatase activity, while 10(-7) and 10(-6) M lutein significantly decreased metaphyseal alkaline phosphatase activity. Lycopene (10(-8)-10(-6) M) or rutin (10(-8)-10(-6) M) did not have a significant effect on bone calcium content and alkaline phosphatase activity. The present study suggests that the carotenoid beta-cryptoxanthin has a unique anabolic effect on bone calcification in vitro.

Effects of a high monounsaturated fat, tomato-rich diet on serum levels of lycopene

OBJECTIVE

To compare the effect of a modified fat, monounsaturated-fat-enriched diet and a high-carbohydrate low-fat diet with high lycopene content on the serum concentration of lycopene and other carotenoids.

DESIGN

A randomised crossover dietary intervention study.

SETTING

Melbourne, Australia--Healthy free-living men.

SUBJECTS

A total of 13 healthy males between the age of 20 and 70 y, recruited via advertisements in newspapers and university newsletter.

INTERVENTION

A randomised dietary intervention with two diets of 14 days each. The two diets were--(1) high-fat monounsaturated-fat-enriched (MUFA) and (2) high-carbohydrate low-fat (HCLF). Both the diets contained the same basic foods and a controlled carotenoid content high in lycopene.

RESULTS

A significant increase in serum total lycopene occurred, by 126% on the MUFA diet (P <0.001) and 108% on the HCLF diet (P=0.001). A reduction in serum cryptoxanthin (27% on MUFA diet and 25% on HCLF) and alpha-carotene (43% on the MUFA diet and 25% on the HCLF diet) was observed. No change was observed for the other carotenoids. Comparing the end of the two diets, no statistically significant difference was observed for lycopene or the other carotenoids.

CONCLUSION

In all, 15% of energy from fat or 38% of energy from fat (predominantly monounsaturated fat) in the diet does not have a significant differential effect on serum lycopene.

SPONSORSHIP

The study was partially funded by the Grains Research Development Corporation, Canberra and Meadow Lea Foods Ltd, Mascot, Australia. HJ Heinz, Melbourne, Australia provided the tomato products and some funds for their carotenoid analysis.