The correlation between two dietary assessments of carotenoid intake and plasma carotenoid concentrations: application of a carotenoid food-composition database

A newly available carotenoid food-composition database providing specific carotenoid values for > 2300 foods was linked to dietary data on 57 male nonsmokers to examine the association between dietary carotenoid intake and plasma carotenoid concentrations over 3 wk when free-living. Carotenoid intake was estimated from a food-frequency questionnaire (FFQ) and 7 d of food diaries with concurrent analysis of plasma carotenoid concentrations. After adjustment for energy intake, percentage of energy from alcohol, and plasma lipid concentrations, significant diet-plasma correlations for the FFQ and the food diaries (FD) included alpha-carotene (r = 0.29 and 0.43), beta-carotene (r = 0.36 FFQ only), beta-cryptoxanthin (r = 0.46 and 0.44), lutein (r = 0.44 FD only), and lycopene (r = 0.53 FD only). Dietary carotenoid intakes were associated with plasma carotenoid concentrations for all the carotenoids except for beta-carotene when food diaries were used whereas the diet-plasma correlation for the provitamin A carotenoids were consistently significant when the FFQ was used.     

Essential fatty acids, plasma cholesterol, and fat-soluble vitamins in subjects with age-related maculopathy and matched control subjects

A matched-control study of plasma retinol, alpha-tocopherol, carotenoid, and cholesterol concentrations and the polyunsaturated fatty acid content of plasma and erythrocyte phospholipids was undertaken in 65 elderly patients with age-related maculopathy and 65 control subjects matched for age and sex. Despite the high statistical power of the study and large variations between subjects in the variables under consideration, no significant differences were noted between patients and control subjects. However, several statistically significant differences were noted between male and female subjects independent of their classification with maculopathy or as controls and age: plasma cholesterol, total phospholipids, alpha-tocopherol, and beta-cryptoxanthin concentrations were higher in females than in males. The mean plasma cholesterol concentration for the upper tertile of the whole sample was 7.6 mmol/L. Plasma concentrations of total carotenoids, alpha-carotene, and beta-carotene, but not alpha-tocopherol, were significantly lower in smokers than in non-smokers. The results of this study do not provide any evidence in favor of changing the dietary intake of polyunsaturated fatty acids or fat-soluble vitamins to protect against age-related maculopathy.     

A critical role for transforming growth factor-beta in donor transfusion-induced allograft tolerance

To evaluate the relationship between carotenoid concentrations in serum and breast tissue, we measured serum carotenoid concentrations and endogenous carotenoid levels in breast adipose tissue of women with benign breast tumor (n = 46) or breast cancer (n = 44). Before extraction, serum was digested with lipase and cholesterol esterase, and breast adipose tissue was saponified. Serum and tissue carotenoids were extracted with ether/hexane and measured by using HPLC with a C30 column. Serum retinoic acid was extracted with chloroform/methanol and measured using HPLC with a C18 column. There were no significant differences in serum carotenoids [lutein, zeaxanthin, cryptoxanthin (both alpha- and beta-), alpha-carotene, all-trans beta-carotene, 13-cis beta-carotene and lycopene], retinoids (retinol, all-trans and 13-cis retinoic acids), and alpha- and gamma- tocopherol concentrations between benign breast tumor patients and breast cancer patients. A substantial amount of 9-cis beta-carotene was present in adipose tissue and was the only carotenoid that had a significantly lower level in benign breast tumor patients than in breast cancer patients. Correlations between carotenoid concentrations in serum and in breast adipose tissue were determined by combining the data of the two groups. Concentrations of the major serum carotenoids except cryptoxanthin showed significant correlations with breast adipose tissue carotenoid levels. When the concentrations of serum carotenoids were adjusted for serum triglycerides or LDL, correlations between serum carotenoid concentrations and breast adipose tissue carotenoid levels markedly increased, including that of cryptoxanthin (P <0. 001). The strong correlation between serum carotenoid concentrations and endogenous breast adipose tissue carotenoid levels indicate that dietary intake influences adipose tissue carotenoid levels as well as serum concentrations, and that adipose tissue is a dynamic reservoir of fat-soluble nutrients.     

Surface charge control of electropermeabilization and glycophorin electroinsertion with 1,2-diacyl-sn-glycero-3-phosphocholine (lecithin) liposomes

beta-Carotene has been studied widely as a potential cancer-preventing agent. Recent studies found that subjects who took beta-carotene supplements orally had increases in their serum concentrations of alpha-carotene and lycopene that were large (> 150% increase) and significantly greater than such increases in subjects who received placebo and that similar supplementation was associated with a decrease of approximately 37% in plasma lutein concentrations. A biologic interaction between beta-carotene and other carotenoids was suggested. We measured concentrations of retinol, alpha-tocopherol, and five carotenoids in serum specimens from a random sample of subjects enrolled in a clinical trial of the use of antioxidant vitamins in preventing colonic adenomas. We used serum specimens obtained at enrollment and after the subjects took placebo (n = 54) or 25 mg beta-carotene/d (n = 54) orally for 4 y. In a multivariate analysis, baseline serum concentrations of the analytes, sex, body mass index, diet, smoking status, and age were associated with variable changes in some analytes over the 4-y period but supplementation with beta-carotene was related only to a mean increase in serum beta-carotene itself of 151%. We excluded with 95% confidence an increase in lycopene > 4.9%, an increase in alpha-carotene > 17.6%, and a decrease in lutein > 14.7% in subjects given beta-carotene. These results confirm previous findings that supplementation with beta-carotene given orally does not alter serum concentrations of retinol or alpha-tocopherol. The findings also indicate that beta-carotene supplementation, which results in a moderate increase in serum beta-carotene concentration, does not significantly change serum concentrations of other carotenoids.     

Evidence that breast cancer associated microcalcifications are mineralized malignant cells

Antioxidant activity of carotenoids in multilamellar liposomes assayed by inhibition of formation of thiobarbituric acid-reactive substances was in the ranking: lycopene> alpha-tocopherol > alpha-carotene > beta-cryptoxanthin > zeaxanthin = beta-carotene > lutein. Mixtures of carotenoids were more effective than the single compounds. This synergistic effect was most pronounced when lycopene or lutein was present. The superior protection of mixtures may be related to specific positioning of different carotenoids in membranes.     

Prevalence and incidence of enuresis before puberty

The effects of hypochlorite (HOCl/OCl-) on the content of carotenoids (trans-lycopene, 5-cis-lycopene, alpha- and beta-carotene) and oxycarotenoids (lutein, zeaxanthin, trans- and cis-2',3'-anhydrolutein, alpha-and beta-cryptoxanthin) in human blood low-density lipoproteins (LDL) were compared using HPLC. Hypochlorite decreased the content of all the above-mentioned pigments in LDL. However, it was more reactive towards carotenoids rather than to their oxy derivatives. The ability of carotenoids and oxycarotenoids to scavenge HOCl/OCl- decreases in the series: trans-lycopene approximately 5-lycopene > alpha-carotene > beta-carotene > zeaxanthin > alpha-cryptoxanthin > cis-2',3'-anhydrolutein > beta-cryptoxanthin > trans-2',3'-anhydrolutein > lutein. Preincubation of LDL with hypochlorite decreased their resistance to CU(2+)-induced accumulation of dienic conjugates that are produced in the course of lipid peroxidation. The data suggest that hypochlorite-induced destruction of carotenoids in LDL decreases their resistance to oxidative modification, thus promoting the development of early stages of atherosclerosis.     

Low and high responders to pharmacological doses of beta-carotene: proportion in the population, mechanisms involved and consequences on beta-carotene metabolism

The aim of this study was to assess the interindividual variability of chylomicron beta-carotene response to a pharmacological load of beta-carotene in the population, to identify the mechanisms responsible for this variability, and to evaluate its consequences on beta-carotene status and metabolism. The variability, as estimated by the 3-h chylomicron beta-carotene response to 120 mg beta-carotene in 79 healthy male volunteers, was high (CV = 61%), but it was unimodal and all the subjects had detectable chylomicron beta-carotene. In 16 subjects randomly selected among the 79, the interindividual variability of the triglyceride-adjusted chylomicron (beta-carotene + retinyl palmitate) response (0-12.5 h area under the curve) was high (CV = 54%), suggesting that there is a high interindividual variability in the efficiency of intestinal absorption of beta-carotene. The chylomicron beta-carotene response was correlated (r = 0.50, P < 0.05) with the chylomicron triglyceride response. The beta-carotene status, as assessed by beta-carotene concentration in buccal mucosal cells, was correlated (r = 0.73, P < 0.05) with the triglyceride-adjusted chylomicron beta-carotene response, i.e., with the ability to respond to beta-carotene. The triglyceride-adjusted chylomicron retinyl-palmitate response was correlated (r = 0.55, P < 0.05) with the triglyceride-adjusted chylomicron beta-carotene response. Plasma all-trans retinoic acid slightly, but significantly, increased (+40%) 3 h after the beta-carotene load, but this increase was not related to the triglyceride-adjusted beta-carotene response. In conclusion, the ability to respond to beta-carotene is highly variable, but there is probably a very small proportion of true non-responders to pharmacological doses of beta-carotene in the healthy population. This variability is apparently mainly due to interindividual differences in the efficiency of intestinal absorption of beta-carotene and in chylomicron metabolism. The ability to respond to beta-carotene can affect the beta-carotene status and the provitamin A activity of beta-carotene, but it has apparently no effect on the amount of retinoic acid appearing in the plasma after the ingestion of a pharmacological dose of beta-carotene.     

Potent preventive action of alpha-carotene against carcinogenesis: spontaneous liver carcinogenesis and promoting stage of lung and skin carcinogenesis in mice are suppressed more effectively by alpha-carotene than by beta-carotene

Although beta-carotene has been considered to be a key cancer preventive agent in green and yellow vegetables, other types of carotenoids, such as alpha-carotene, may also contribute to anticarcinogenic action, since these carotenoids usually coexist with beta-carotene and are detectable in human blood and tissues. In this study, we compared the inhibitory effect of natural alpha-carotene, obtained from palm oil, with that of beta-carotene on spontaneous liver carcinogenesis in C3H/He male mice. The mean number of hepatomas per mouse was significantly decreased by alpha-carotene supplementation (per os administration in drinking water at a concentration of 0.05%, ad libitum) as compared with that in the control group (P < 0.001, Student's t test). On the other hand, beta-carotene, at the same dose as alpha-carotene, did not show any such significant difference from the control group. Furthermore, we also compared the antitumor-promoting activity of alpha-carotene with that of beta-carotene against two-stage mouse lung carcinogenesis (initiator, 4-nitroquinoline 1-oxide; promoter, glycerol). alpha-Carotene, but not beta-carotene, reduced the number of lung tumors per mouse to about 30% of that in the control group (P < 0.001, Student's t test). The higher potency of the antitumor-promoting action of alpha-carotene compared to beta-carotene was confirmed in other experimental systems; e.g., alpha-carotene was also found to have a stronger effect than beta-carotene in suppressing the promoting activity of 12-O-tetradecanoylphorbol-13-acetate on skin carcinogenesis in 7,12-dimethylbenz[a]anthracene-initiated mice. These results suggest that not only beta-carotene, but also other types of carotenoids, such as alpha-carotene, may play an important role in cancer prevention.     

Carotenoids and antioxidant vitamins in patients after burn injury

Oxidative stress may contribute to secondary tissue damage and impaired immune function in patients after burn injury. The purpose of our study was to describe plasma antioxidant micronutrient concentrations in 26 adult patients admitted with extensive burn injuries (> 20 % total burn surface area) to a level-1 trauma burn center during a 21-day period after admission. The effect of administering beta-carotene was also examined with use of a prospective randomized subjects design: patients received either placebo or 30 mg/day in an enteral feeding. Plasma concentrations of alpha- and gamma-tocopherol, carotenoids (alpha and beta-carotene, lycopene, beta-cryptoxanthin, lutein), and retinol were measured with high- performance liquid chromatography, and vitamin C was quantified with spectrophotometry, at baseline and twice per week. Vitamin C, tocopherol, and retinol concentrations were low at baseline, but levels increased significantly over the study period in both groups (p < 0.05). Plasma beta-carotene concentration increased when this carotenoid was provided in the oral feeding. Otherwise, plasma carotenoid concentrations were low at baseline and remained low throughout the study period despite normalization of associated lipids.     

Diabetes mellitus and serum carotenoids: findings from the Third National Health and Nutrition Examination Survey

Little is known about carotenoids, a diverse group of plant compounds with antioxidant activity, and their association with diabetes, a condition characterized by oxidative stress. Data from phase I of the Third National Health and Nutrition Examination Survey (1988-1991) were used to examine concentrations of alpha-carotene, beta-carotene, cryptoxanthin, lutein/zeaxanthin, and lycopene in 40- to 74-year-old persons with a normal glucose tolerance (n = 1,010), impaired glucose tolerance (n = 277), newly diagnosed diabetes (n = 148), and previously diagnosed diabetes (n = 230) based on World Health Organization criteria. After adjustment for age, sex, race, education, serum cotinine, serum cholesterol, body mass index, physical activity, alcohol consumption, vitamin use, and carotene and energy intake, geometric means of beta-carotene were 0.363, 0.316, and 0.290 micromol/liter for persons with a normal glucose tolerance, impaired glucose tolerance, and newly diagnosed diabetes, respectively (p = 0.004 for linear trend), and geometric means for serum lycopene were 0.277, 0.259, and 0.231 micromol/liter, respectively (p = 0.044 for linear trend). All serum carotenoids were inversely related to fasting serum insulin after adjustment for confounders (p < 0.05 for each carotenoid). If confirmed, these data suggest new opportunities for research that include exploring a possible role for carotenoids in the pathogenesis of insulin resistance and diabetes.     

Guanine nucleotide binding properties of Rac2 mutant proteins and analysis of the responsiveness to guanine nucleotide dissociation stimulator

A case-control study of the associations of retinoids and specific carotenoids with breast cancer using concentrations of these nutrients in breast adipose tissue was conducted among women attending a breast clinic in the Boston area in 1989-1992. Breast adipose tissue was collected during breast biopsy. Cases (n = 46) were women whose biopsies revealed invasive or in situ breast cancer; control subjects (n = 63) were women whose biopsies revealed benign disease. We observed inverse associations between breast adipose concentrations of retinoids and carotenoids and risk of breast cancer, although not all were statistically significant. The multivariate-adjusted odds ratio comparing women above the median value of the control group for retinol with those below or equal to the median was 0.71 (95% CI: 0.26, 1.93; NS); corresponding odds ratios were 0.61 (95% CI: 0.23, 1.64; NS) for retinyl palmitate, 0.30 (95% CI: 0.11, 0.85) for beta-carotene, 0.32 (95% CI: 0.11, 0.94) for lycopene, and 0.68 (95% CI: 0.27, 1.73; NS) for lutein/zeaxanthin. There was a nonsignificant positive correlation (r = 0.23, P = 0.15) between breast adipose tissue concentrations of retinol and dietary intake of preformed vitamin A, including supplements measured by using a food-frequency questionnaire. No correlation was found between breast adipose concentrations of carotenoids and intake of dietary carotenoids. These data suggest that higher breast adipose concentrations of retinoids and some carotenoids may be associated with decreased risk of breast cancer and that further examination of these relations is warranted.     

Dietary supplementation with carotenoids: effects on alpha-tocopherol levels and susceptibility of tissues to oxidative stress

The ability of dietary supplementation with carotenoids to protect chick tissues against oxidative stress in vitro was examined. Male Leghorn chicks were fed on diets supplemented (100 mg supplement/kg diet) with either beta-carotene, zeaxanthin (beta,beta-carotene-3,3'-diol), canthaxanthin (beta,beta-carotene-4,4'-dione) or alpha-tocopherol, or on a control diet, from 1 d old until 37 d of age. Tissues (liver, heart, skeletal muscle and plasma) were removed and assayed for total carotenoids and alpha-tocopherol content and portions subjected to oxidative stress by incubation of homogenates with cumene hydroperoxide and FeSo4. Animals receiving zeaxanthin and canthaxanthin had significantly greater carotenoid concentrations in liver, heart, muscle and plasma compared with untreated controls (P < 0.05); animals fed on diets supplemented with beta-carotene, or alpha-tocopherol did not have significantly different tissue carotenoid contents compared with untreated controls. alpha-Tocopherol supplementation elevated alpha-tocopherol levels in all tissues examined (P < 0.05). Supplementation with carotenoids did not affect tissue alpha-tocopherol levels, but beta-carotene lowered plasma alpha-tocopherol levels by 50% (P < 0.05). Incubation of plasma or tissue homogenates with oxidant stressors induced lipid peroxidation (production of thiobarbituric-acid reactive substances) in all tissues. Animals given alpha-tocopherol, beta-carotene or zeaxanthin had a reduced susceptibility to oxidant stress in liver compared with unsupplemented controls (P < 0.05), and alpha-tocopherol-supplemented animals had reduced susceptibility in skeletal muscle compared with tocopherol-supplemented animals had reduced susceptibility in skeletal muscle compared with unsupplemented controls (P < 0.05). Canthaxanthin supplementation did not influence the susceptibility to oxidant stress in any tissue examined. These results suggest that zeaxanthin, a carotenoid present in animal and human diets, may have significant activity as an antioxidant against oxidative stress in tissues.     

Non-telomeric chromosome localization of (TTAGGG)n repeats in the genus Eulemur

Numerous dietary studies and several serum micronutrient studies have produced equivocal results on the relation of vitamins A and E to prostate cancer risk. To evaluate this association further, we conducted a nested case-control study in a cohort of 6860 Japanese-American men examined from 1971 to 1975. At the time of examination, a single blood specimen was obtained, and the serum was frozen. After a surveillance period of more than 20 years, 142 tissue-confirmed incident cases of prostate cancer were identified. Their stored sera and those of 142 matched controls were measured by high-performance liquid chromatography for the following: total carotenoids, lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, beta-carotene, total retinoids, retinol, total tocopherols, alpha-tocopherol, delta-tocopherol, and gamma-tocopherol. Odds ratios for prostate cancer, based on quartiles of serum micronutrient levels, were determined using conditional logistic regression analysis. The odds ratio for the highest quartiles were 1.8 (95% confidence interval, 0.9-3.9) for beta-cryptoxanthin, 1.6 (0.8-3.5) for beta-carotene, 0.8 (0.4-1.5) for retinol, and 0.7 (0.3-1.5) for gamma-tocopherol, but none of the differences was statistically significant. For the other micronutrients, the results were also unremarkable. The findings of this study indicate that none of the micronutrients is strongly associated with prostate cancer risk.     

Quantitation of vitamin E and a carotenoid pigment in cataractous human lenses, and the effect of a dietary supplement

The quantitation of tocopherols and carotenoids in lipid extracts of cataractous human lenses was performed in parallel with those of matched samples of plasma, which was also analysed at the same time. Alpha-tocopherol in cataractous lenses from elderly human subjects was present at 4.4 mumoles/kg wet weight, much less than the mean of 33 mumoles/l in plasma from these subjects. The mean ratio of alpha- and gamma-tocopherols was 3.5 in the lenses, and 11.3 in plasma. Lens extracts contained no detectable alpha- or beta-carotene, lycopene, or beta-cryptoxanthin. However, all the lens extracts contained a pigment with the retention time and spectrum of lutein and zeaxanthin. Using the molar extinction coefficient of lutein this was present at ca. 0.03 microM, compared with 0.2 microM in plasma. Seven patients with bilateral cataracts had one of their cataractous lenses removed and analysed, and were then given either an oral placebo, or an oral supplement of ascorbate, alpha-tocopherol and beta-carotene. Three months later, the second cataractous lens, and a blood sample, were analysed. Three of the seven had received the active supplement, as confirmed by substantially raised blood levels of alpha-tocopherol and beta-carotene, and raised aqueous humour levels of vitamin C. However, lens tocopherol levels remained unchanged, and no beta-carotene could be detected in the lenses after supplementation. This preliminary evidence needs to be confirmed in larger studies.     

Carotenoid analysis of several dark-green leafy vegetables associated with a lower risk of cancers

We have examined the carotenoid contents of several dark green vegetables found to be associated with a lower risk of various epithelial cancers in our epidemiological study and animal study. Samples of these vegetables were quantitatively examined by high-performance liquid chromatography (HPLC) on a C-18 reversed-phase column for individual carotenoid content. Pure reference compounds (alpha-carotene, beta-carotent, lycopene, canthaxanthin, and lutein) and internal standard (beta-Apo-8'-carotenal) were employed to quantify xanthophylls and carotenes in these vegetables. The results indicated that fresh, dark-green, leafy vegetables were high in beta-carotene (0.94-9.36 mg/100 g) and oxygenated carotenoids or xanthophylls, primarily lutein (0.94-7.39 mg/100 g), whereas lycopene and alpha-carotene were not prominent and canthaxanthin was non existent in these vegetables. These analyses suggest that consumption of carotenoids such as lutein in addition to beta-carotene may be associated with a lower risk of cancers.     

An international evaluation of the cancer preventive potential of carotenoids

The IARC convened a Working Group of experts in December 1997 to evaluate the cancer-preventive potential of carotenoids and to compile the second volume of the IARC Handbooks of Cancer Prevention. In observational epidemiological studies, beta-carotene is associated with reduced risks for cancer at many but not all sites. It is unclear, however, to what extent beta-carotene itself is responsible for the decreased risks observed. Three large, randomized, placebo-controlled clinical trials indicate, however, that, in substantial doses, supplementation with beta-carotene not only does not prevent lung cancer but may actually increase the risk among individuals initially at high risk of lung cancer. These trials do not provide clear evidence concerning cancers at other specific sites. Thus, the Working Group considered that there is evidence suggesting a lack of cancer-preventive activity for beta-carotene when it is used as a supplement at high doses. At usual dietary levels of beta-carotene, the evidence for cancer-preventive activity was considered inadequate. However, there is sufficient evidence that beta-carotene has cancer-preventive activity in experimental animals, based on models of skin carcinogenesis in mice and buccal pouch carcinogenesis in hamsters. The observational epidemiological data on alpha-carotene, lycopene, and lutein are much less extensive than those for beta-carotene. For canthaxanthin, there are no published data regarding associations with cancer risk. These carotenoids have not been studied in human trials for cancer prevention. In animal models, there is sufficient evidence for canthaxanthin and limited evidence for alpha-carotene, lycopene, and lutein of cancer-preventive activity. Pending further research, supplemental beta-carotene, canthaxanthin, alpha-carotene, lutein, and lycopene should not be recommended for cancer prevention in the general population.     

Enhanced plasma level of lipid peroxidation in Iranians could be improved by antioxidants supplementation

OBJECTIVE: To study the influence of supplementation with antioxidants on factors, which might increase the risk of coronary heart disease (CHD) in Iranians. DESIGN: Twenty-one male volunteers enter the prospective, single-blind, randomized study. SETTING: The supplementation was conducted at the Cardiovascular Center, University of Tehran, the biochemical analysis were carried out in the University of Graz. SUBJECTS: Twenty-one male medical students were recruited by advertisement. Five subjects were dropped out due to lack of the compliance. METHODS: One group of Iranians received 30 mg/d beta-carotene and placebo for alpha-tocopherol; the other received beta-carotene plus 400 IU alpha-tocopherol for ten weeks. Concentrations of antioxidants in plasma and low density lipoproteins (LDL), plasma lipid profile, autoantibody against oxidized LDL (oLAb) and malondialdehyde (MDA) concentrations in plasma were measured. Oxidative resistance of LDL was estimated using conjugated diene assay. RESULTS: Iranians had a significantly lower plasma levels of total cholesterol (P < 0.002), LDL-cholesterol (P < 0.01) and high density lipoprotein-cholesterol (P < 0.002), compared to healthy Austrian subjects (n = 13). Although the baseline concentrations of alpha-tocopherol and beta-carotene were comparable with Austrians, lycopene, canthaxanthin and lutein were significantly higher in Iranians (P < 0.03-0.001). In vitro oxidative resistance of LDL, measured as lag-time, was slightly higher (P < 0.01) in Iranians comparing with Austrians. Plasma MDA and oLAb concentrations were significantly higher in Iranians (P < 0.001). Both dietary supplementations reduced plasma MDA concentrations (P < 0.001-0.001). A key finding was that a supplement combined with alpha-tocopherol caused also a significant increase of oLAb concentration (P > 0.01) as well as the significant increase of lag-time (P > 0.005). CONCLUSIONS: This study shows that high plasma MDA level of Iranians can be decreased by beta-carotene supplementation with or without alpha-tocopherol. However, alpha-tocopherol is a more powerful antioxidant, which can increase the resistance of LDL to oxidation, reduce the MDA concentrations in plasma and increase autoantibodies to oLDL.     

alpha-Tocopherol concentrations in plasma but not in lipoproteins fluctuate during the menstrual cycle in healthy premenopausal women

Because premenopausal women experience cyclic fluctuations of plasma carotenoids and their lipoprotein carriers, it was hypothesized that plasma alpha-tocopherol (A-T) fluctuates by phase of the menstrual cycle. Twelve free-living women, with a confirmed ovulatory cycle, were given a controlled diet for two consecutive menstrual cycles. Blood was drawn during the menses, early follicular, late follicular and luteal phases to simultaneously measure serum hormones, plasma lipoproteins and A-T concentrations, and A-T distribution in the lipoprotein fractions. Plasma A-T concentrations were significantly lower during menses than during the luteal phase by approximately 12% in each controlled diet cycle (P < 0.001). Adjustment for serum cholesterol and triglyceride concentrations did not alter these findings. The distributions of A-T in lipoprotein cholesterol fractions were not significantly different by menstrual phase. From 61 to 62% of A-T was concentrated in the LDL fraction, with another 9-14% in HDL2, 17-22% in HDL3 and the remaining 6-8% in VLDL+ IDL. There were no significant differences in lipoprotein cholesterol fractions by menstrual phase, except for a significant increase (P = 0.03) in HDL2 cholesterol from the early follicular to the late follicular phase. Spearman rank correlations from data during the second controlled diet month showed A-T in HDL2 in the late follicular phase was positively correlated with HDL cholesterol in the early follicular (r = 0.88), late follicular (r = 0.86) and luteal phases (r = 0.86) and with luteal apolipoprotein (ApoA-1) level (r = 0.90), and luteal HDL2 cholesterol (r = 0.83). A-T in HDL3 in the early follicular phase was negatively correlated with HDL2 cholesterol (r = -0.96) and ApoA-1 (r = -0.85), whereas luteal A-T in HDL3 was correlated with luteal HDL3 cholesterol (r = -0.79). Late follicular A-T in VLDL was positively correlated with early follicular HDL3 cholesterol and late follicular HDL3 cholesterol (r = 0.83). Fluctuations of A-T concentrations by phase of the menstrual cycle should be taken into consideration in future research concerning premenopausal women and the risk of chronic disease.     

Role of hydrogen peroxide in the cytotoxic effects of UVA/B radiation on mammalian cells

Inhibitory effect of four carotenoids prevalent in human blood and tissues against the formation of colonic aberrant crypt foci was examined in Sprague-Dawley rats. They received three intrarectal doses of N-methylnitrosourea in weak 1, and a daily gavage of de-escalated doses of carotenoids during weeks 2 and 5. Lycopene, lutein, alpha-carotene and palm carotenes (a mixture of alpha-carotene, beta-carotene and lycopene) inhibited the development of aberrant crypt foci quantitated at week 6, but beta-carotene did not. The results suggested that lycopene and lutein in small doses may potentially prevent colon carcinogenesis.     

Plasma vitamin C concentrations in patients with cystic fibrosis: evidence of associations with lung inflammation

Vitamin C status and possible associations with the disease process in cystic fibrosis (CF) patients were investigated. Plasma vitamin C concentrations in patients from two different mid-European populations (Swiss, n = 62; Austrian, n = 60) taking no or low-dose vitamin C from multivitamin supplements did not differ from each other or from control subjects (n = 34). Vitamin C concentrations decreased with age (5.05 mumol.L-1, y-1). When followed up for 12 mo, patients had the highest plasma vitamin C concentrations in February and the lowest in May and August (P < 0.01); the decrease in vitamin C was accompanied by increases in plasma malondialdehyde (P < 0.001) and tumor necrosis factor alpha concentrations (P < 0.01). During supplementation with vitamin E for 2 mo or beta-carotene for 12 mo vitamin C concentrations did not change. They correlated inversely with white blood cell count (r = -0.36, P = 0.008), bands (r = -0.36, P = 0.02), alpha 1-acid glycoprotein (r = -0.45, P = 0.002), interleukin 6 (r = -0.46, P = 0.0006), and neutrophil elastase/alpha 1-proteinase inhibitor complexes (r = -0.34, P = 0.02). In patients with vitamin C concentrations < 40 mumol/L, all indexes of inflammation were relatively high, whereas those with concentrations > 80 mumol/L (upper quartile of control subjects) showed clearly lower values. These results are consistent with the hypothesis that by scavenging oxygen free radicals vitamin C interacts with an inflammation-amplifying cycle of activation of alveolar macrophages and neutrophils, release of proinflammatory cytokines and oxygen free radicals, and inactivation of antiproteases.