Serum Lycopene Research Articles

Serum antioxidant micronutrients and the risk of oral leukoplakia among Japanese.

A population-based case-control study was designed for the investigation of any association between serum micronutrient levels and oral leukoplakia. Out of a total of 9536 subjects over the age of 40 years who participated in the oral mucosal screening programme in Tokoname city, 48 cases detected with oral leukoplakia (38 male:10 female) were recruited. For each case, four controls matched by age and sex were selected from the same cohort. We examined the fasting serum levels of retinol, alpha-tocopherol, zeaxanthin and lutein, cryptoxanthin, lycopene and carotenoids (alpha-carotene and beta-carotene) by high-performance liquid chromatography. Among males with leukoplakia mean serum lycopene and beta-carotene levels (0.175+/-0.202, 0.357+/-0.295 micromol/l) were significantly lower than those of controls (0.257+/-0.252, 0.555+/-0.408 micromol/l) (P<0.05, P<0.005). Logistic regression analysis with leukoplakia as the dependent variable showed that high serum levels of beta-carotene were related to low risk of oral leukoplakia (odds ratio 0.160, 95% C.I.: 0.029-0.866, P<0.05). There were no significant differences in any of the serum nutrients estimated in female subjects. Our results suggest for the first time that high serum levels of beta-carotene may provide protection against oral precancer for the Japanese male.

Tissue Lycopene Concentrations and Isomer Patterns Are Affected by Androgen Status and Dietary Lycopene Concentration in Male F344 Rats

Diets rich in lycopene from tomato products as well as greater concentrations of blood lycopene have been associated with a decreased risk for prostate cancer in epidemiologic studies. However, little is known about factors modulating lycopene absorption, metabolism and tissue distribution in humans and animal models of prostate cancer. A 2 x 4 factorial design was used to measure the effects of androgen status (castrated vs. intact), dietary lycopene concentration (0.00-5.00 g/kg lycopene) and their interaction on tissue lycopene accumulation and isomer patterns in male F344 rats. Male F344 rats ( 14 wk old; 44 castrated, 44 intact) were randomly assigned to one of four diets containing total lycopene concentrations of 0.00, 0.05, 0.50 or 5.00 g/kg as beadlets and fed for 8 wk. Tissue total lycopene and cis/trans lycopene profiles were determined by HPLC. Tissue and serum lycopene concentrations increased significantly (P < 0.01) as dietary lycopene levels increased between 0.00 and 0.50 g/kg. No further increases in serum or tissue concentrations were seen in rats fed dietary lycopene between 0.50 and 5.00 g/kg. As dietary lycopene increased, so did the percentage of cis lycopene in the liver (P < 0.05), due primarily to an increase in the 5-cis isomer. Castrated rats accumulated twice (P < 0.01) the liver lycopene as compared to intact controls, with no effect of castration on serum lycopene or adrenal, kidney, adipose, or lung tissue concentration. Livers from castrated rats had a greater proportion of cis-lycopene than those of intact rats (P < 0.05). A significant interaction between dietary lycopene concentration and androgen status was seen for liver lycopene concentration (P < 0.01). We conclude that serum and tissue lycopene reaches a plateau between 0.05 and 0.50 g/kg dietary lycopene, the tissue cis/trans lycopene ratio increases with greater dietary lycopene and androgens modulate hepatic lycopene metabolism.

Correlates of Serum Lycopene in Older Women

: Experimental and epidemiological evidence suggests that lycopene, a predominant carotenoid found in human serum, may reduce the risk of certain cancers. We examined the association of dietary, physiological, and other factors with serum lycopene concentrations in a subsample of 946 postmenopausal women participating in the Women's Health Initiative. Pearson partial correlation coefficients and linear regression coefficients were calculated after adjustment for age, ethnicity, and serum low-density-lipoprotein (LDL) cholesterol. Serum lycopene was correlated with serum LDL cholesterol (r = 0.23) and dietary lycopene (r = 0.17, both p < 0.001). Individual food items found to be correlated with serum lycopene after adjustment included fresh tomatoes or tomato juice (r = 0.11), cooked tomatoes, tomato sauce, or salsa (r = 0.17), and spaghetti with meat sauce (r = 0.19, all p < 0.01). Age and body mass index were negatively associated with serum lycopene levels (both p < 0.001). Serum lycopene levels were highest in the summer and highest for those living in the northeastern United States. If we postulate that high serum lycopene levels reduce cancer risk, it becomes apparent that we have limited ability to detect this association from studies of lycopene intake. An understanding of factors associated with serum lycopene levels can be useful for the interpretation of studies of dietary lycopene and disease risk.

Necessity of monitoring HPLC by a X-R control chart on measurement of serum fat-soluble vitamins.

In epidemiologic studies, many serum samples obtained from a large population have to be processed for measurement of fat-soluble vitamins. Quantification results by a high performance liquid chromatography (HPLC) should be stable in both intra- and inter-run, and a quality control may be performed by a X-R control chart. The present study shows that serum retinol, alpha-tocopherol, alpha-carotene, beta-carotene, and lycopene could be measured simultaneously, by 1) use of photodiode-array (POD) detector, 2) selection of some optimal analytical conditions (e.g. column, mobile phase, column temperature), 3) applying 2 internal standards, and 4) monitoring by a X-R control chart. The present procedure yielded relatively low coefficients of variations (CVs) compared to some reported figures. However, determination of CVs only does not ensure the accuracy and precision of an assay system, and application of a X-R control chart may be necessary for a good quality control of measurement, such as serum fat-soluble vitamins.

Serum carotenoids and atherosclerosis: The Rotterdam Study

High circulating levels of carotenoids have been thought to exhibit a protective function in the development of atherosclerosis. We investigated whether aortic atherosclerosis was associated with lower levels of the major serum carotenoids in α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene, and zeaxanthin—in a subsample of the elderly population of the Rotterdam Study. Aortic atherosclerosis was assessed by presence of calcified plaques of the abdominal aorta. The case-control analysis comprised 108 subjects with aortic atherosclerosis and controls. In an age- and sex-adjusted logistic regression model, serum lycopene was inversely associated with the risk of atherosclerosis. The odds ratio for the highest compared to the lowest quartile of serum lycopene was 0.55 (95% CI 0.25–1.22; p trend=0.13). Multivariate adjustment did not appreciably alter these results. Stratification by smoking status indicated that the inverse association between lycopene and aortic calcification was most evident in current and former smokers (OR=0.35; 95% CI 0.13–0.94; p trend=0.04). No association with atherosclerosis was observed for quartiles of serum concentrations of α-carotene, β-carotene, lutein, and zeaxanthin. In conclusion, this study provides evidence for a modest inverse association between levels of serum lycopene and presence of atherosclerosis, the association being most pronounced in current and former smokers. Our findings suggest that lycopene may play a protective role in the development of atherosclerosis.

Serum carotenoids and vitamins and risk of cervical dysplasia from a case-control study in Japan.

The relationships between risk of cervical dysplasia and dietary and serum carotenoids and vitamins were investigated in a case–control study. Cases were 156 women who attended Papanicolaou test screening in nine institutes affiliated with Japan Study Group of Human Papillomavirus (HPV) and Cervical Cancer and had cervical dysplasia newly histologically confirmed. Age-matched controls were selected from women with normal cervical cytology attending the same clinic. Blood sample and cervical exfoliated cells were obtained for measuring serum retinol, α-carotene, β-carotene, zeaxanthin/lutein, cryptoxanthin, lycopene and α-tocopherol and for HPV detection. Higher serum level of α-carotene was significantly associated with decreased risk of cervical dysplasia after controlling for HPV infection and smoking status (odds ratio (OR) = 0.16, 95% confidence interval (CI) 0.04–0.62 for the highest as compared with the lowest tertile). Decreased risk for the highest tertile of serum lycopene (OR = 0.28) was marginally significant. Decreased risks observed for the highest tertiles of β-carotene (OR = 0.65) and zeaxanthin/lutein (OR = 0.53), were not statistically significant. © 1999 Cancer Research Campaign

The effect of dietary lycopene on bioavailability, tissue distribution, in vivo antioxidant properties and colonic preneoplasia in rats

Recent studies have suggested a protective role for lycopene, an antioxidant carotenoid, in the prevention of chronic diseases including cancer and coronary heart disease. Tomatoes and tomato products are the major dietary source of lycopene. The aim of this study was to investigate the bioavailability, tissue distribution, and the in vivo antioxidant properties of lycopene and its role in colon carcinogenesis. Male Fischer 344 rats were used in this study. Lycopene in the form of 6% oleoresin was incorporated into an AIN93M diet at a concentration of 10 ppm lycopene. Azoxymethane (AOM) was used as the colon specific chemical carcinogen. Serum and tissue lycopene levels were measured as estimates of lycopene uptake and tissue distribution. Serum TBARS and thiols were measured as indicators of lipid and protein oxidation. Incidence and size of aberrant crypt foci (ACF) were measured as preneoplastic markers. Dietary lycopene was absorbed and distributed to various tissues. An increase in serum thiols and a decrease in serum TBARS was observed in rats fed the lycopene diet. Incidence of ACF in lycopene fed rats showed a trend towards reduced numbers and size. Effects were more pronounced when lycopene was fed during the promotion stage than during the initiation stage. Based on these results it is concluded that dietary lycopene is absorbed by rats and distributed to various tissues. It acts as an antioxidant in reducing oxidation and thereby may protect against AOM induced ACF incidence. Dietary lycopene may play an important role in protecting against oxidative stress and colon carcinogenesis.

Effect of Dietary Lycopene on N-Methylnitrosourea-Induced Mammary Tumorigenesis

Epidemiological studies suggest protective effects of lycopene-rich foods on several types of cancer, including prostate and gastrointestinal tract. Moreover, an inverse association between serum lycopene concentrations and several types of cancer has been reported. However, few studies have focused on breast cancer, and they have shown little association between lycopene consumption and cancer risk. In this report, we used the N-methylnitrosourea (NMU)-induced rat mammary tumor model to compare the effects of pure lycopene with a lycopene-rich tomato carotenoid oleoresin (TCO) on NMU-induced mammary tumorigenesis. Rats were fed diets supplemented with 250 and 500 ppm crystalline lycopene or TCO beginning seven days before initiation with NMU (55 days of age) to termination (18 wk after NMU). Neither pure lycopene nor lycopene in the form of a mixed carotenoid oleoresin exerted an inhibitory effect on tumor incidence, latency, multiplicity, volume, or total tumors per group compared with unsupplemented controls. Weight gains in all groups were similar. Assay of serum lycopene concentrations in lycopene-supplemented groups indicated that median levels of 7,12,60, and 87 ng/ml were attained in blood of groups supplemented with 250 and 500 ppm lycopene and 250 and 500 ppm TCO, respectively. The results of this animal study are consistent with epidemiological reports indicating that lycopene does not protect against breast cancer.

Cis-Lycopene Is More Bioavailable Than Trans-Lycopene In Vitro and In Vivo in Lymph-Cannulated Ferrets

Lycopene is the predominant carotenoid in tomatoes and tomato-based foods and is also a predominant carotenoid in human serum and tissues. Intake of lycopene-rich foods was recently associated with decreased risk for several chronic diseases. The observation that serum and tissue lycopene is more than 50% cis-lycopene, whereas tomatoes and tomato-based foods contain mainly all-trans-lycopene, has led to the hypothesis that cis-isomers of lycopene are more bioavailable. We tested this hypothesis both in vitro (study 1) and in vivo (study 2). In study 1, bile acid micelles containing crystalline lycopene were prepared. The crystalline lycopene used for these analyses was 54.4% cis-lycopene. The optically clear micelle preparation contained 75.9% cis-lycopene in repeated analyses . In study 2, mesenteric lymph duct cannulated ferrets were used to study the in vivo absorption of lycopene from Lycored™ (an ethyl acetate extract of tomatoes containing 5% lycopene by weight; of which 91% was all-trans lycopene). Before being anesthetized, male ferrets (n = 7) were dosed orally with 40 mg lycopene per kg body weight in soybean oil. Lymph secretions were collected, on ice, for 2 h. The residual stomach and small intestinal contents, mucosa lining, lymph secretion and serum were analyzed by HPLC. Whereas the dose, stomach and intestinal contents contained 6.2–17.5% cis-lycopene, the mesenteric lymph secretions contained significantly more, 77.4%, cis-lycopene (P < 0.01). These studies demonstrate that in ferrets, cis-isomers of lycopene are more bioavailable than trans-lycopene probably because cis-isomers are more soluble in bile acid micelles and may be preferentially incorporated into chylomicrons.

Serum and Tissue Lycopene and Biomarkers of Oxidation in Prostate Cancer Patients: A Case-Control Study

Dietary intake of tomatoes and tomato products containing lycopene, an antioxidant carotenoid, has been shown in recent studies to reduce the risk of cancer. This study was conducted to investigate the serum and prostate tissue lycopene and other major carotenoid concentrations in cancer patients and their controls. Serum lipid and protein oxidation was also measured. Twelve prostate cancer patients and 12 age-matched subjects were used in the study. Significantly lower serum and tissue lycopene levels (44%, p = 0.04; 78%, p = 0.050, respectively) were observed in the cancer patients than in their controls. Serum and tissue b-carotene and other major carotenoids did not differ between the two groups (p = 0.395 and p = 0.280, respectively). Although there was no difference (p = 0.760) in serum lipid peroxidation between cancer patients and their controls (7.09 ± 0.74 and 6.81 ± 0.56 mmol/l, respectively), serum protein thiol levels were significantly lower among the cancer patients (p = 0.026). This study demonstrates that the status of lycopene but not other carotenoids in prostate cancer patients is different from controls. The role of dietary lycopene in preventing oxidative damage of biomolecules and thereby reducing the risk of prostate cancer needs to be evaluated in future studies.

Serum concentrations of antioxidant nutrients in healthy American, Chinese and Korean adults

Population variabilities of serum carotenoid and tocopherol levels using reverse-phase HPLC in healthy American (Caucasian), Chinese and Korean adults were determined. Considerable variation in serum nutrient concentrations was found among these groups. The mean serum concentration of lutein/zeaxanthin was significantly higher in the Chinese than in the white Americans (p<0.001), whereas serum α-carotene and lycopene concentrations were significantly higher in white Americans than in Chinese (p<0.001). Serum β-carotene concentrations in Koreans were significantly higher than in either white Americans or in Chinese. The mean serum lycopene concentration in Koreans was lower than in Americans. The mean serum retinol concentration was significantly higher in white Americans than in Chinese or Koreans (p<0.005). American serum γ-tocopherol concentrations were significantly higher (p<0.005) than those of the Chinese, whereas γ-tocopherol values were significantly lower (p<0.001) than those of the Chinese. These differences probably reflect differences in dietary intakes among these population groups.

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.

Effect of diet and smoking on serum lycopene and lipid peroxidation

Lycopene, a naturally present carotenoid in tomatoes and other fruits, has been proposed to have antioxidant and potential anticarcinogenic properties in recent studies. This study was conducted to investigate the effect of diet and smoking on serum lycopene and lipid peroxidation expressed as thiobarbituric acid reactive substances (TBARS) in 20 healthy human subjects. A reduction of 50% in the serum lycopene levels and an increase of 25% in TBARS was observed when subjects were maintained on a lycopene-free diet. Serum lycopene levels were also reduced by 25% following a meal compared to the fasting levels. Serum lycopene levels of habitual smokers were compared with non-smokers. Although the levels were not significantly different between the two groups, serum lycopene levels fell by 40% with a 40% increase in TBARS in smokers following smoking three cigarette. This study showed that the levels of serum lycopene were influenced significantly as a result of oxidative stress in the form of diet induced metabolism and smoking, suggesting in vivo antioxidant properties of lycopene.

Determination of lycopene, α-carotene and β-carotene in serum by liquid chromatography–atmospheric pressure chemical ionization mass spectrometry with selected-ion monitoring

A selected-ion monitoring (SIM) determination of serum lycopene, α-carotene and β-carotene by an atmospheric pressure chemical ionization mass spectrometry (APCI–MS) was developed. A large amount of serum cholesterols disturbed the SIM determination of carotenoids by contaminating the segment of interface with the LC–MS. Therefore, separation of carotenoids from the cholesterols was performed using a mixed solution of methanol and acetonitrile (70:30) as the mobile phase on a C 18 column of mightsil ODS-5 (75 mm×4.6 mm I.D.). The SIM determination was carried out by introducing only the peak portions of carotenoids and I.S. (squalene) by means of an auto switching valve. In the positive mode of APCI–MS, lycopene, α-carotene and β-carotene were monitored at m/ z 537 and I.S. was monitored at m/ z 411. This method was linear for all analytes in the range of 15–150 ng for lycopene, 7–70 ng for α-carotene and 25–50 ng for β-carotene. The detection limit of LC–APCI–MS-SIM for carotenoids was about 3 ng per 1 ml of serum ( S/ N=3). The repeatabilities, expressed as C.V.s, were 10%, 8.4% and 5.3% for lycopene, α-carotene and β-carotene, respectively. The intermediate precisions, expressed as C.V.s, were 11. 2%, 8.8% and 6.5% for lycopene, α-carotene and β-carotene, respectively.

Relationships of serum carotenoids, retinol, alpha-tocopherol, and selenium with breast cancer risk: results from a prospective study in Columbia, Missouri (United States)

To evaluate relationships of serum carotenoids, alpha-tocopherol, selenium, and retinol with breast cancer prospectively, we conducted a case-control study nested in a cohort from the Breast Cancer Serum Bank in Columbia, Missouri (United States). Women free of cancer donated blood to this bank in 1977-87. During up to 9.5 years of follow-up (median = 2.7 years), 105 cases of histologically confirmed breast cancer were diagnosed. For each case, two women alive and free of cancer at the age of the case's diagnosis and matched on age and date of blood collection were selected as controls. A nonsignificant gradient of decreasing risk of breast cancer with increasing serum beta-cryptoxanthin was apparent for all women. Serum lycopene also was associated inversely with risk, and among women who donated blood at least two years before diagnosis, a significant gradient of decreasing breast cancer risk with increasing lycopene concentration was evident. A marginally significant gradient of decreasing risk with increasing serum lutein/zeaxanthin also was apparent among these women. We did not observe any evidence for protective effects of alpha- and beta-carotene, alpha-tocopherol, retinol, or selenium for breast cancer. Results of this study suggest that the carotenoids beta-cryptoxanthin, lycopene, and lutein/zeaxanthin may protect against breast cancer.

Vitamin A and vitamin E statuses of preschool children of socioeconomically disadvantaged families living in the midwestern United States.

To determine the vitamin A and vitamin E statuses of socioeconomically disadvantaged preschool American children. Cross-sectional study of preschool children from socioeconomically disadvantaged families. Central Iowa, USA. A group of 77 apparently healthy children was studied with the following characteristics: 5 mo-6 y; 37 males, 40 females, 56 non-Hispanic Caucasians, 3 Hispanics, 18 Afro-Americans. Modified relative dose response (MRDR) test for vitamin A status assessment; serum retinol, alpha-tocopherol, cholesterol, and carotenoids; weight for age. Although the mean weight for age was the 53rd percentile of the NCHS standard, a significant number of children (P = 0.006, chi(2)) were either markedly underweight or overweight. Ratios of 3,4-didehydroretinol to retinol (DR/R) were > 0.030, in 32% of the children. Mean serum retinol, alpha-tocopherol and cholesterol (+/- s.d.) were 1.09 +/- 0.23 microM/L, 16.8 +/- 6.3 microM/L and 4.01 +/- 0.8 microM/L. Three children (3.9%) showed a serum retinol value < 0.7 microM/L. One child with a serum retinol value < 0.7 microM/L and one additional child showed a ratio of alpha-tocopherol to cholesterol < 1.44 mumol/mmol. The mean alpha-tocopherol to cholesterol ratio for the group (4.31 +/- 1.71 mumol/mmol), however, was satisfactory. The only significant (P < or = 0.05) age-related changes were an increase in the serum cholesterol (P = 0.005) and decrease in the alpha-tocopherol to cholesterol ratio (P < 0.005) between the 0-2 y and the 2-4 y groups. Serum cholesterol (P = 0.0165, two-tailed) and lycopene (P = 0.004) concentrations of Afro-Americans were significantly higher than those of Caucasians. Median serum concentrations of alpha-carotene and beta-carotene were lower and, of lycopene higher than those found in children studied in a national survey. Serum carotenoid concentrations generally increased with age. Larger percentages of underweight and overweight children and a significant degree (32%) of inadequate vitamin A status were found in this group of socioeconomically disadvantaged children. Afro-Americans showed higher serum cholesterol and lycopene concentrations than did Caucasians, but otherwise were nutritionally similar. Age-related changes were small. Of nutritional parameters considered, the vitamin A status of socioeconomically disadvantaged segments of our population clearly needs attention.

Ingestion by Men of a Combined Dose of β-Carotene and Lycopene Does Not Affect the Absorption of β-Carotene but Improves That of Lycopene , ,

A double-blind study was conducted in 10 healthy men to investigate serum β-carotene and lycopene responses after ingestion of individual and combined doses of β-carotene (BC) and lycopene. On each dosing day, a baseline blood sample was drawn, followed by an oral dose of 0.11 mmol (60 mg) of either all-trans BC or all-trans lycopene or by a combined oral dose of 0.11 mmol each. Subjects were tested with each of the three doses. The dose type was randomized. Blood (10 mL) was drawn at 1, 3, 5, 7, 9, 12 and 24 h after dosing. At 2 and 4 wk after the first dose, the protocol was repeated with the other doses. After ingestion of the BC dose, serum BC concentrations significantly decreased from baseline at 1 and 3 h followed by a continuous increase from baseline that was significant at 12 and 24 h (P < 0.01). Serum lycopene concentrations significantly increased from baseline at 5 h after the lycopene dose (P < 0.008) and returned to baseline thereafter. Ingestion of a combined dose of BC and lycopene resulted in a significant increase in serum concentrations of both BC and lycopene at 24 h (P < 0.05). The 24-h area under the curve (AUC) for BC was not different when BC was ingested alone or with lycopene, whereas the 24-h AUC for lycopene was significantly greater when lycopene was ingested with BC than when ingested alone (P < 0.05). Our data suggest that ingestion of a combined dose of BC and lycopene has little effect on the absorption of BC but improves that of lycopene in men.

Effects of supplemental beta-carotene, cigarette smoking, and alcohol consumption on serum carotenoids in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study

We determined whether serum carotenoid or retinol concentrations were altered by beta-carotene supplementation in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and whether such effects were modified by alcohol consumption or cigarette use. Participants in this substudy were 491 randomly selected men aged 58-76 y from the metropolitan Helsinki study center [237 receiving supplemental beta-carotene (20 mg/d) and 254 not receiving such supplementation]. Dietary carotenoids, retinol, and alcohol, and serum beta-carotene, alpha-tocopherol, retinol, and cholesterol were assessed at baseline. After an average of 6.7 y of supplementation, serum was collected and carotenoid, retinol, and alpha-tocopherol concentrations were determined by HPLC. Serum carotenoid fractions were highly correlated with each other (P < or = 0.0001). Compared with the unsupplemented group, the beta-carotene group had significantly higher serum concentrations of beta-carotene (1483%), alpha-carotene (145%), and beta-cryptoxanthin (67%) (P < or = 0.0001). Retinol concentrations were 6% higher (P = 0.03) and lutein was 11% lower (P = 0.02) in the supplemented group. Serum lycopene, zeaxanthin, and alpha-tocopherol did not differ according to beta-carotene-supplementation status. Although these beta-carotene-group differences were not significantly altered by amount of alcohol consumption, higher consumption (> 12.9 g/d, median) was related to lower (10-38%) concentrations of carotenoids, particularly beta-carotene, alpha-carotene, and beta-cryptoxanthin, in both the supplemented and unsupplemented groups. Smoking status did not significantly influence the supplementation-related differences in serum carotenoid and retinol values but concentrations of carotenoids were generally highest in participants who quit smoking while in the study and lowest in current smokers of > or = 20 cigarettes/d. This study showed that serum concentrations of non-beta-carotene carotenoids are altered by long-term beta-carotene supplementation and confirms the adverse effects of alcohol and cigarette smoking on serum carotenoids.

Human Serum Carotenoid Concentrations Are Related to Physiologic and Lifestyle Factors

We examined the concentrations of five carotenoids in the serum and diet of a population-based sample of 400 individuals to determine what physiologic and lifestyle factors were related to serum carotenoid concentrations, how these relationships differed among the carotenoids, and if these relationships reflected differences in carotenoid intake. Lower serum concentrations of alpha-carotene, beta-carotene, beta-cryptoxanthin, and lutein+zeaxanthin generally were associated with male gender, smoking, younger age, lower non-HDL cholesterol, greater ethanol consumption and higher body mass index. Serum lycopene generally was not related to these factors, but lower lycopene levels were associated with older age and lower non-HDL cholesterol. Only the hydrocarbon carotenoids (alpha- and beta-carotene and lycopene) were directly associated with HDL cholesterol. The associations of some factors (gender, age, smoking, and ethanol intake) with serum carotenoids were similar to the associations of these factors with levels in the diet, indicating that serum carotenoids may reflect the influence of these factors on carotenoid intake. Consistent with this notion, correlations between serum and dietary carotenoids did not differ between smokers and nonsmokers. Other factors (HDL and non-HDL cholesterol and body mass index) associated with carotenoids in the serum were not associated with carotenoid intake, indicating that physiologic conditions that affect the absorption, storage, and utilization of carotenoids may influence these associations. These physiologic and behavioral correlates of carotenoids could explain or modify associations of carotenoids with chronic diseases.

Vitamin A inadequacy in socioeconomically disadvantaged pregnant Iowan women as assessed by the modified relative dose response (MRDR) test

The vitamin A status of low-income women (n = 57) during the third trimester of pregnancy was assessed by use of the modified relative dose response (MRDR) test. Non-Hispanic White (45), Hispanic (6), Afro-American (5), and Asian (1) women were recruited from public health programs in central Iowa. Serum retinol, β-carotene, α-carotene, lycopene, α-tocopherol, and cholesterol concentrations were also measured. Twenty six percent of the study population were found to be in a marginal vitamin A status with MRDR values ≥0.03, whereas 9% had values ≥0.06. The Hispanic and Afro-American groups seemed to be most at risk, with 50% and 40% (respectively) of the MRDR values ≥0.03 and 33% and 20% (respectively) ≥0.06. Carotenoid values were similar to those found in women in other like studies, except for the Afro-American group, which had mean values less than half those of the other groups. α-Tocopherol concentrations and α-tocopherol/cholesterol ratios of all ethnic groups fell in the normal range. The somewhat elevated cholesterol levels found in all groups can largely be attributed to pregnancy. Clearly, this study identifies a portion of the U.S. population at high risk of vitamin A inadequacy.