Plasma Lycopene Concentrations Research Articles

Low serum folate concentrations are associated with an excess incidence of acute coronary events: the Kuopio Ischaemic Heart Disease Risk Factor Study.

To test the hypothesis that low serum folate concentrations are associated with an increased risk of acute coronary events in men free of prior coronary heart disease. Research Institute of Public Health, University of Kuopio, Kuopio, Finland. Prospective study in a cohort of 734 men aged 46-64 y examined in 1991-1993 as part of the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) and followed for 5 y and 3 months. Acute coronary events during the follow-up period were obtained by national hospital discharge registry. Baseline serum folate concentrations were measured by radioimmunoassay. During the follow-up, six (2.5%) men with higher serum folate concentrations (highest third>11.3 nmol/1) and 28 (5.7%) men with lower serum folate (two lowest thirds) developed an acute coronary event (P=0.008). In a Cox model adjusting for age, examination years, and plasma lycopene concentration, in men with higher serum folate concentrations the relative risk for an acute coronary event was 0.31 (95% CI 0.11-0.90, P=0.031) when compared with men with lower serum folates. This prospective cohort study in middle-aged men from eastern Finland indicates that moderate-to-high levels of serum folate are associated with a greatly reduced incidence of acute coronary events.

Lymphocyte Lycopene Concentration and DNA Protection from Oxidative Damage Is Increased in Women after a Short Period of Tomato Consumption

Several epidemiologic studies have suggested a role of tomato products in protecting against cancer and chronic diseases. In nine adult women, we evaluated whether the consumption of 25 g tomato puree (containing 7 mg lycopene and 0.3 mg beta-carotene) for 14 consecutive days increased plasma and lymphocyte carotenoid concentration and whether this was related to an improvement in lymphocyte resistance to an oxidative stress (500 micromol/L hydrogen peroxide for 5 min). Before and after the period of tomato intake, carotenoid concentrations were analyzed by HPLC and lymphocyte resistance to oxidative stress by the Comet assay, which detects DNA strand breaks. Intake of tomato puree increased plasma (P <0.001) and lymphocyte (P<0.005) lycopene concentration and reduced lymphocyte DNA damage by approximately 50% (P<0.0001). Beta-carotene concentration increased in plasma (P<0.05) but not in lymphocytes after tomato puree consumption. An inverse relationship was found between plasma lycopene concentration (r = -0.82, P<0.0001) and lymphocyte lycopene concentration (r = -0.62, P<0.01) and the oxidative DNA damage. In conclusion, small amounts of tomato puree added to the diet over a short period can increase carotenoid concentrations and the resistance of lymphocytes to oxidative stress.

Plasma Carotenoids Are Biomarkers of Long-Term High Vegetable Intake in Women with Breast Cancer

We investigated predictors of change in plasma carotenoids from baseline to 3 y and examined plasma carotenoid concentrations at 1 and 3 y in response to a high vegetable diet. Participants were 56 women diagnosed with breast cancer and enrolled in a randomized feasibility study for a trial examining the effect of a diet high in vegetables and fruits on the risk of breast cancer recurrence. Independent t test analysis revealed that the intervention group had significantly higher vegetable and fruit servings and fiber at 12 mo and significantly higher vegetable servings at 36 mo compared with the control group (P < 0.05). Energy intake from fat was significantly lower in the intervention group at 12 and 36 mo. The intervention group had significantly higher consumption of β-carotene, α-carotene, lutein and β-cryptoxanthin at 12 mo (P < 0.05). β-Carotene, α-carotene and lutein intakes also were significantly higher at 36 mo (P < 0.05). At 36 mo, the intervention group had significantly higher plasma concentrations of α-carotene and β-carotene compared with the control group. Repeated-measures ANOVA revealed that the intervention group had significantly increased (P < 0.05 with Bonferroni correction) plasma β-carotene, α-carotene, lutein and lycopene concentrations at 12 and 36 mo compared with baseline. Baseline carotenoid concentrations were significantly inversely predictive (P < 0.05) of plasma carotenoid change. In addition, change in body mass index (BMI) and plasma cholesterol concentrations were predictive of plasma carotenoid change from baseline to 3 y. Results of this study demonstrate that change in plasma carotenoid concentrations is associated with change in BMI, change in plasma cholesterol and baseline carotenoid concentrations. Plasma carotenoid response can be an indicator of long-term high vegetable intake for women at risk of breast cancer recurrence.

Bioavailability of lutein from vegetables is 5 times higher than that of β-carotene

To gain more insight into the relation between vegetable consumption and the risk of chronic diseases, it is important to determine the bioavailability of carotenoids from vegetables and the effect of vegetable consumption on selected biomarkers of chronic diseases. To assess the bioavailability of beta-carotene and lutein from vegetables and the effect of increased vegetable consumption on the ex vivo oxidizability of LDL. Over 4 wk, 22 healthy adult subjects consumed a high-vegetable diet (490 g/d), 22 consumed a low-vegetable diet (130 g/d), and 10 consumed a low-vegetable diet supplemented with pure beta-carotene (6 mg/d) and lutein (9 mg/d). Plasma concentrations of vitamin C and carotenoids (ie, alpha-carotene, beta-carotene, lutein, zeaxanthin, and beta-cryptoxanthin) were significantly higher after the high-vegetable diet than after the low-vegetable diet. In addition to an increase in plasma beta-carotene and lutein, the pure carotenoid-supplemented diet induced a significant decrease in plasma lycopene concentration of -0.11 micromol/L (95% CI: -0.21, -0.0061). The responses of plasma beta-carotene and lutein to the high-vegetable diet were 14% and 67%, respectively, of those to the pure carotenoid- supplemented diet. Conversion of beta-carotene to retinol may have attenuated its plasma response compared with that of lutein. There was no significant effect on the resistance of LDL to oxidation ex vivo. Increased vegetable consumption enhances plasma vitamin C and carotenoid concentrations, but not resistance of LDL to oxidation. The relative bioavailability of lutein from vegetables is higher than that of beta-carotene.

Plasma Lycopene Concentrations in Humans Are Determined by Lycopene Intake, Plasma Cholesterol Concentrations and Selected Demographic Factors

Higher plasma lycopene concentrations have been associated with a reduced risk of several chronic diseases. Determinants of lycopene concentrations in humans have received limited attention. We had blood lycopene concentrations and lycopene consumption data available from 111 participants in a two-center cancer prevention trial involving β-carotene and examined determinants of plasma lycopene levels cross-sectionally. The median plasma lycopene level was 0.59 μmol/L (range 0.07–1.79). Low plasma concentrations of lycopene were associated with the following variables in univariate analyses: study site (Florida lower than Connecticut, P = 0.001), being nonmarried (P = 0.02), having lower income (P = 0.003), being nonwhite race/ethnicity (P = 0.03), having lower dietary lycopene intake (r = 0.29, P = 0.002), having lower plasma cholesterol (r = 0.43, P = 0.0001) and triglyceride levels (r = 0.26, P = 0.005), and consuming less vitamin C (r = 0.20, P = 0.03). Women had slightly higher plasma lycopene levels than men (0.65 vs. 0.58 μmol/L; P = 0.31), despite lower dietary intake of lycopene (1,040 vs. 1,320 μg/d; P = 0.50). Plasma lycopene levels did not differ in smokers and nonsmokers. In stepwise regression analyses, the determinants of plasma lycopene were plasma cholesterol, dietary lycopene, and marital status; these three variables explained 26% of the variance in plasma lycopene. Relatively few lifestyle and demographic factors were important determinants of plasma lycopene levels, with plasma cholesterol, marital status, and lycopene intake being of greatest importance.

Does tomato consumption effectively increase the resistance of lymphocyte DNA to oxidative damage?

Lycopene, the main carotenoid in tomato, has been shown to be a potent antioxidant in vitro. However, there is no significant evidence of its antioxidant action in vivo. We evaluated the effect of tomato intake on plasma carotenoid concentrations and lymphocyte resistance to oxidative stress. Ten healthy women (divided into 2 groups of 5 subjects each) ate a diet containing tomato puree (providing 16.5 mg lycopene) and a tomato-free diet for 21 d each in a crossover design. Before and after each diet period, plasma carotenoid concentrations and primary lymphocyte resistance to oxidative stress (evaluated by means of single-cell gel electrophoresis) were analyzed. After the first 21-d experimental period, total plasma lycopene concentrations increased by 0.5 micromol/L (95% CI: 0.14, 0.87) in the group that consumed the tomato diet and decreased by 0.2 micromol/L (95% CI: -0.11, -0.30) in the group that consumed the tomato-free diet (P < 0.001). Tomato consumption also had an effect on cellular antioxidant capacity: lymphocyte DNA damage after ex vivo treatment with hydrogen peroxide decreased by 33% (95% CI: 0.8%, 61%; P < 0.05) and by 42% (95% CI: 5.1%, 78%; P < 0.05) in the 2 groups of subjects after consumption of the tomato diet. The consumption of tomato products may reduce the susceptibility of lymphocyte DNA to oxidative damage.

Chronic ingestion of lycopene-rich tomato juice or lycopene supplements significantly increases plasma concentrations of lycopene and related tomato carotenoids in humans

The bioavailability of lycopene from tomato juice and 2 dietary supplements, each containing 70–75 mg lycopene, was studied in 15 healthy volunteers in a randomized, crossover design. Subjects ingested lycopene-rich tomato juice, tomato oleoresin, lycopene beadlets, and a placebo for 4 wk each while consuming self-selected diets. Treatment periods were separated by 6-wk washout periods. Plasma lycopene concentrations, assessed at baseline and weekly throughout the treatment periods, were significantly higher during tomato juice, oleoresin, and lycopene beadlet ingestion than during placebo ingestion. Mean (±SEM) increases in plasma lycopene at week 4 of tomato juice, oleoresin, and lycopene beadlet ingestion were not significantly different: 0.24 ± 0.07, 0.23 ± 0.05, and 0.24 ± 0.06 mmol/L, respectively. Plasma concentrations of phytofluene and phytoene, which were present in small amounts in tomato juice, oleoresin, and lycopene beadlets, increased significantly with ingestion of these 3 products. b-Carotene, z-carotene, and 2,6- cyclolycopene-1,5-diol (a metabolite of lycopene)—also present in tomato juice and supplements—were significantly increased with consumption of the tomato juice and lycopene beadlets, but not with oleoresin consumption. A marked increase in plasma concentrations of an unknown compound was observed; it was detected in trace amounts in tomato juice, oleoresin, and lycopene beadlets, and had a maximum absorbance at 448 nm and a molecular weight of 556. Concentrations of plasma lycopene and other carotenoids with potential for enhancing human health can be increased by ingestion of realistic amounts of tomato juice. Lycopene appears to be equally bioavailable from tomato juice and the supplements used in this study. Am J Clin Nutr 1998;68:1187–95.

Antioxidant vitamin supplementation and lipid peroxidation in smokers

Previous studies have shown that cigarette smoke enhances lipid peroxidation. This study examined the effect of daily consumption of a tomato-based juice supplemented with vitamin C (600 mg), vitamin E (400 IU, or 400 mg), and b-carotene (30 mg) on various indexes of lipid peroxidation (breath pentane excretion and susceptibility of LDL to coppermediated(oxidation) in smokers. In addition, plasma lycopene and vitamin concentrations and total peroxyl radical trappingpotential, a measure of antioxidant defenses, were assessed. Relative to the placebo juice, the vitamin-supplemented juice resulted in a significant decrease in breath-pentane excretion as well as a significant improvement in the resistance of LDL to oxidation. The lag phase of conjugated diene formation lengthened and the propagation rate decreased, indicating a decreased susceptibility of LDL to oxidative modification. Increased concentrations of plasma vitamin C, b-carotene, and lycopene werefound to be significantly correlated with the conjugated diene lag phase and rate of formation. Vitamin E was highly correlated with b-carotene. Plasma total peroxyl radical trapping potential values did not change in response to supplementation. This study thus indicates that an antioxidant-supplemented drink can reduce lipid peroxidation and susceptibility of LDL to oxidation in smokers and may ameliorate the oxidative stress of cigarette smoke. Am J Clin Nutr 1998;68:319–27.

The fluctuation of plasma carotenoid concentrations by phase of the menstrual cycle: a controlled diet study

This is the first controlled diet study to examine the fluctuation of plasma carotenoids, lipoproteins, and serum hormone concentrations by phase of the menstrual cycle. Nonsmoking, premenopausal women (n = 12) with confirmed ovulatory cycles were given a standard diet with 10 mg total carotenoids/d for two cycles under isoenergetic conditions. Blood was drawn for simultaneous measurement of carotenoids, lipoproteins, and hormones on menses days 1-2, 4-6, 11 through 1 d after the luteinizing hormone surge, and 7-8 d after the surge, representing the menses, early and late follicular, and midluteal phases, respectively. Regression modeling with adjustment for plasma cholesterol concentrations was used to compare mean individual and total plasma carotenoid concentrations by phase of the cycle. Plasma carotenoid concentrations were at their lowest at menses and significantly higher thereafter, except for alpha-carotene. Compared with plasma concentrations at menses, beta-carotene peaked (increased by 9%, P = 0.01) in the late follicular phase. Plasma lutein/zeaxanthin and anhydrolutein concentrations were higher by 8-11% (P < or = 0.006) and by 15-31% (P < or = 0.02), respectively, during the last three phases. Plasma lycopene and phytofluene concentrations peaked (increased by 12%, P = 0.004; and by 21%, P = 0.006, respectively) at the midluteal phase. This cyclic fluctuation may affect the estimation of the plasma carotenoid-disease relation in studies of premenopausal women.

Acute phase response and plasma carotenoid concentrations in older women: Findings from the nun study

This cross-sectional study investigated whether the acute phase response was associated with suppressed circulating levels of antioxidants in a population of 85 Catholic sisters (nuns) ages 77–99 y. Fasting blood was drawn to determine the presence of an acute phase response, as defined by an elevation in the serum concentration of C-reactive protein. Serum concentrations of albumin, thyroxine-binding prealbumin, zinc, copper, and fibrinogen were determined as were plasma concentrations of carotenoids and alpha tocopherol. Results showed that the presence of an acute phase response was associated with ( 1) an expected significant decrease in the serum concentrations of albumin ( p < 0.001) and thyroxinebinding prealbumin ( p < 0.001); ( 2) an expected significant increase in copper ( p < 0.001) and fibrinogen ( p = 0.003); and ( 3) a significant decrease in the plasma concentrations of lycopene ( p = 0.03), alpha carotene ( p = 0.02), beta carotene ( p = 0.02), and total carotenoids ( p = 0.01). The acute phase response was associated with decreased plasma levels of the antioxidants lycopene, alpha carotene, and beta carotene. This decrease in circulating antioxidants may further compromise antioxidant status and increase oxidative stress and damage in elders.

Skin Lycopene Is Destroyed Preferentially over β-Carotene during Ultraviolet Irradiation in Humans

This placebo-controlled study examined in healthy women the effects of ingestion of a single large dose of β-carotene (120 mg) on the concentrations of β-carotene and lycopene in plasma and skin, and the effects of UV light exposure on the concentrations of β-carotene and lycopene in the skin. Ingestion of β-carotene increased plasma β-carotene concentration by 127%, from 0.26 ± 0.06 (mean ± SEM) to 0.59 ± 0.07 µmol/L after 1 d, and the level remained elevated at 0.54 ± 0.11 µmol/L after 5 d. β-Carotene in skin, analyzed after 6 d, increased by 23%, from 1.41 ± 0.74 to 1.74 ± 0.72 nmol/g. β-Carotene ingestion had no effect on the lycopene concentrations of plasma (0.37 ± 0.11 µmol/L) or skin (1.60 ± 0.62 nmol/g). A single exposure of a small area of one volar forearm to a dose of solar-simulated light (three times the individually determined minimal erythema dose) resulted in 31 to 46% reductions in skin lycopene concentration compared with an adjacent non-exposed area. The same UV dose did not result in significant changes in skin β-carotene concentration. We conclude that a single 120-mg dose of β-carotene increases plasma and skin β-carotene concentrations and has no effect on plasma and skin lycopene concentrations. The amounts of lycopene in plasma and skin are comparable to or even greater than those of β-carotene. When skin is subjected to UV light stress, more skin lycopene is destroyed compared with β-carotene, suggesting a role of lycopene in mitigating oxidative damage in tissues.

Decreased antioxidant status and increased lipid peroxidation in patients with septic shock and secondary organ dysfunction.

To determine antioxidant vitamin concentrations, lipid peroxidation, and an index of nitric oxide production in patients in the intensive care unit (ICU) with septic shock and relate the findings to the presence of secondary organ failure. A prospective, observational study. A nine-bed ICU in a University teaching hospital. Sixteen consecutive patients with septic shock, defined as: a) clinical evidence of acute infection; b) hypo- or hyperthermia (< 35.6 degrees C or > 38.3 degrees C); c) tachypnea (> 20 breaths/min or being mechanically ventilated); d) tachycardia (> 90 beats/min); e) shock (systolic pressure < 90 mm Hg) or receiving inotropes. Fourteen patients also had secondary organ dysfunction. None. Antioxidant vitamin concentrations were significantly lower in the patients than the reference range obtained from a comparable group of healthy controls. The mean plasma retinol (vitamin A) concentration was 26.5 +/- 19.3 micrograms/dL compared with 73.5 +/- 18.3 micrograms/dL in healthy subjects (p < .01). Additionally, 13 (81%) patients had retinol values below the lower limit of our reference range (< 37.0 micrograms/dL). Tocopherol (vitamin E) plasma concentrations were below the reference range in all patients (< 9.0 mg/L), with a mean value of 3.6 +/- 2.0 mg/L compared with 11.5 +/- 1.3 mg/L in healthy subjects (p < .001). Plasma beta carotene and lycopene concentrations were undetectable (< 15 micrograms/L) in eight (50%) patients, and below our reference range (< 101 micrograms/L and < 154 micrograms/L, respectively) in the remaining patients. In the five patients with three or more dysfunctional secondary organs, plasma thiobarbituric acid-reactive substances were significantly increased (p < .05), suggesting increased lipid peroxidation. Concentrations of thiobarbituric acid-reactive substances correlated negatively with both plasma retinol and plasma tocopherol (r2 = .42, p < .01 and r2 = .48, p < .005, respectively). In the five patients from whom we were able to collect urine, nitrite excretion was increased approximately 400-fold (p < .001). These data indicate decreased antioxidant status in the face of enhanced free radical activity, and suggest potential therapeutic strategies involving antioxidant repletion.