Serum Carotenoids Research Articles

Association between leukocyte telomere length and serum carotenoid in US adults.

Telomere length is a biomarker for aging. It is known that oxidative stress can accelerate telomere shortening, whereas antioxidants can delay their shortening. Carotenoids as antioxidants are favorably associated with health- and aging-related diseases caused by oxidative stress, but their association with telomere length is less certain. We investigated the association between blood carotenoid levels and leukocyte telomere length in a representative sample of US adults. We analyzed 3660 participants aged 20years and older in the 1999-2002 National Health and Nutrition Examination Survey. The levels of carotenoids-alpha-carotene, beta-carotene (trans+cis), beta-cryptoxanthin, combined lutein/zeaxanthin, and trans-lycopene-were measured using high-performance liquid chromatography. The leukocyte telomere length (T/S ratio) was assayed using the quantitative polymerase chain reaction method. A doubling of blood alpha-carotene, beta-carotene (trans+cis), and beta-cryptoxanthin was associated with approximately 2% longer telomeres. Compared with the lowest carotenoid quartile of alpha-carotene, beta-carotene (trans+cis), and beta-cryptoxanthin, telomere length for adults with the highest quartiles was significantly increased by 5-8%. We found that increasing levels of blood carotenoid were significantly associated with longer leukocyte telomeres in US adults. High intake of carotenoid-rich food may play a role in protecting telomeres and regulating telomere length.

Greater serum carotenoid concentration associated with higher bone mineral density in Chinese adults.

This cross-sectional study has been performed to investigate the relationship between serum carotenoids and bone mineral density (BMD) in Chinese population. We found that women with higher serum β-cryptoxanthin, lycopene, or α-carotene exhibited higher BMD at various bone sites. Similar association was observed between α-carotene and BMD in men. Carotenoids may positively regulate bone metabolism through their antioxidant properties; however, few studies have examined the relation between serum carotenoids and bone health. We aimed to determine the associations between the serum concentration of several carotenoid subclasses and BMD in a Chinese population. This study was a community-based cross-sectional study. We measured 1898 women and 933 men aged 59.6years who completed serum β-cryptoxanthin, zeaxanthin + lutein, lycopene, and α-carotene concentration analyses and BMD assessments. Serum individual carotenoids were assessed by the methods of reverse-phase high-performance liquid chromatography. Dual-energy X-ray absorptiometry was applied to determine BMD at whole body, lumbar spine, total hip, femur neck, and trochanter. ANCOVA was used to examine the correlations between categorized individual carotenoids and BMD at measured sites. After adjusting for potential covariates, a monotonic dose-response positive correlation between circulating levels of β-cryptoxanthin, lycopene, and α-carotene and BMD at various skeletal sites was observed in women. Women in the top (vs. bottom) quartiles of serum β-cryptoxanthin, lycopene, or α-carotene exhibited 1.8-2.3, 1.5-2.0, or 1.3-2.7% higher BMD at the bone sites with significant results (P-trend <0.05), respectively. For men, the corresponding values were 2.6-4.0% for α-carotene at the whole body and hip regions (P-trend <0.001-0.023). These results suggest that serum carotenoids have a favorable association with bone health in the study population, especially in women.

Lutein, zeaxanthin and meso-zeaxanthin content of eggs laid by hens supplemented with free and esterified xanthophylls.

The xanthophyll carotenoids lutein (L), zeaxanthin (Z) and meso-zeaxanthin (MZ) are found at the macula, the central part of the retina, where they are referred to as macular pigment (MP). MP is studied in human subjects because of its proven role in enhancing visual function and its putative role in protecting against age-related macular degeneration. These benefits are probably due to the antioxidant and short-wavelength filtering properties of MP. It is known that eggs are a dietary source of L and Z. This experiment was designed to measure the egg yolk carotenoid response to hen supplementation with L, Z and MZ. A total of forty hens were used in the trial and were divided into eight groups of five hens. Each group was supplemented (with about 140mg active xanthophylls/kg feed) with one of the following oil-based carotenoid formulations for 6 weeks: unesterified L (group 1); L diacetate (group 2); unesterified Z (group 3); Z diacetate (group 4); unesterified MZ (group 5); MZ diacetate (group 6); L-MZ (1:1) diacetate mixture (group 7); L-MZ diacetate (1:3) mixture (group 8). Yolk carotenoid content was analysed weekly (in four randomly selected eggs) by HPLC. We found that hens supplemented with Z diacetate and MZ diacetate produced eggs with significantly greater carotenoid concentrations than their free form counterparts. This finding potentially represents the development of a novel food, suitable to increase MP and its constituent carotenoids in serum.

Validity and Reliability of Field Resonance Raman Spectroscopy for Assessing Carotenoid Status.

Carotenoids in fruit and vegetables are important for health, yet determining dietary intake is challenging. This study aimed to establish the validity and reliability of a portable field Resonance Raman Spectroscope (RRS) in reflecting human carotenoid status. A diagnostic accuracy study involving 81 healthy adults was conducted. The RRS was the index test. Serum carotenoids (β-carotene, lycopene, lutein, and zeaxanthin) and consumption of fruit and vegetables were primary and secondary reference standards respectively. Data were collected in two seasons. Validity was determined by the correlation between the RRS score and the two reference standards, and by diagnostic statistics comparing dichotomised RRS scores and serum β-carotene. Reliability was assessed by intra-class correlation from repeated observations within subjects and within repeated measurements using three devices. The RRS score was significantly correlated with the individual and summed serum carotenoids (r range 0.45 to 0.78; p always <0.001), and with fruit and vegetable intake (season one: r=0.38, p=0.016; season two: r=0.42, p<0.001). Sensitivity: 87.5%; specificity: 75.5%; positive and negative predictive values: 35.0% and 97.6% respectively. Within- and between-device reliability was high (r=0.98, p=0.004 and r=0.97, p=0.009 respectively). The RRS field model achieved criterion validity for assessing carotenoid status and fruit and vegetable intake, and also demonstrated reliability. It thus holds promise for the screening of carotenoid status and fruit and vegetable intake.

Daily Intake of a Commercially Available Vegetable Juice Has Beneficial Effects on Metabolic Syndrome-Related Biomarkers in Young, Healthy Japanese Adults

Adequate vegetable intake is important in reducing the risk of lifestyle-related diseases; however, intake amongst young Japanese adults is poor. This study aimed to assess the effect of daily intake of a commercially available vegetable juice on nutritional status and metabolic syndrome-related markers in healthy young adults. Fifty-one healthy adults (14 men, 37 women), age 20 - 22 years were recruited, and their food and nutritional intake was surveyed using an FFQ based on Food Groups. Subjects were divided into either a control group, who were not administered vegetable juice, or an intervention group, who consumed 200 mL vegetable juice daily for 2 months. Anthropometric data, serum carotenoid concentrations, blood and urinary parameters were measured at baseline and at 2 months. The average intake of vegetables in all subjects at baseline was approximately 140 g/day, less than half the dose recommended by the Japanese government. Total serum carotenoid concentration in the intervention group doubled from baseline after 2 months. In particular, serum concentrations of α-carotene, β-carotene, and lycopene were increased. In the intervention group, 24-hour urinary potassium excretion increased significantly, and 24-hour urinary sodium to potassium ratio decreased significantly. Waist circumference and systolic blood pressure also decreased significantly. Daily intake of a commercial vegetable juice for 2 months improved nutritional status in young adults with inadequate vegetable intake, shown by improved serum carotenoid and urine potassium levels. In addition, intake of vegetable juice may be beneficial in reducing the risk of metabolic syndrome.

High Vitamin C Intake with High Serum β-Cryptoxanthin Associated with Lower Risk for Osteoporosis in Post-Menopausal Japanese Female Subjects: Mikkabi Cohort Study.

Recent epidemiological studies show that antioxidant vitamins and carotenoids might be beneficial to the maintenance of bone health. Recently, we found that serum carotenoids were inversely associated with the risk of developing osteoporosis in post-menopausal Japanese female subjects. However, little is known about the vitamin alone and/or the combination of the vitamin and carotenoid with the risk of osteoporosis. The objective of this study was to investigate longitudinally whether antioxidant vitamins and their combination with carotenoids are associated with the risk of developing of osteoporosis. We conducted a follow-up study on 187 post-menopausal female subjects from the Mikkabi prospective cohort study. Those who participated in previous bone mineral density (BMD) surveys and completed four years of follow-up were examined longitudinally. During a four-year follow-up, fifteen of the post-menopausal female subjects developed new-onset osteoporosis. After adjustment for confounders, the odds ratios (OR) for osteoporosis in the highest tertiles of vitamins C and E and retinol intakes against the lowest tertiles were 0.15 (95% confidence interval (CI): 0.02-0.99), 0.50 (CI: 0.08-3.23), and 1.49 (CI: 0.36-6.22), respectively. Furthermore, a significantly lower odds ratio was observed in the higher vitamin C intake group (169-625 mg/d) with higher serum β-cryptoxanthin (1.88-10.53 μM) against the lower vitamin C intake group (47-168 mg/d) with lower serum β-cryptoxanthin (0.24-1.84 μM) used for the reference group (p<0.05). The combination of β-cryptoxanthin and vitamin C is inversely associated with the risk of developing osteoporosis in post-menopausal Japanese female subjects.

Associations of serum carotenoid concentrations and fruit or vegetable consumption with serum insulin-like growth factor (IGF)-1 and IGF binding protein-3 concentrations in the Third National Health and Nutrition Examination Survey (NHANES III).

Dietary intervention may alter the insulin-like growth factor (IGF) system and thereby cancer risk. In a qualitative review, eleven of twenty studies showed a link between one or more carotenoids, vegetable or fruit intake and the IGF system, however, with partly contrary findings, such that no firm conclusion can be drawn. Therefore, we evaluated associations between serum carotenoid concentrations or the intake of fruits and vegetables with IGF-1, IGF binding protein (BP)-3 and their molar ratio (IGF-1:IGFBP-3) within the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994). In our analysis, we included 6061 NHANES III participants and used multivariable-adjusted linear regression models. IGF-1 concentrations were significantly positively associated with serum concentrations of lycopene, β-carotene, α-carotene, β-cryptoxanthin and lutein/zeaxanthin in men and women. Statistically significant positive associations were observed for serum concentrations of α-carotene and lutein/zeaxanthin and intake of fruits with serum IGFBP-3 concentrations in women, but not in men. The IGF-1:IGFBP-3 molar ratio was significantly positively associated with serum concentrations of lycopene, β-carotene and α-carotene in men and with β-carotene in women. In conclusion, dietary interventions with carotenoids, fruits and vegetables may affect the IGF system, although the direction of these effects is currently unclear.

High-serum carotenoids associated with lower risk for developing type 2 diabetes among Japanese subjects: Mikkabi cohort study

ObjectiveRecent epidemiological studies show the association of antioxidant carotenoids with type 2 diabetes, but thorough longitudinal cohort studies regarding this association have not been well conducted. The objective of this...

Pretreatment serum xanthophyll concentrations as predictors of head and neck cancer recurrence and survival.

The purpose of this study was to examine associations of pretreatment serum carotenoids, tocopherols, and quercetin with prognosis in 154 patients newly diagnosed with head and neck cancer. Pretreatment blood and health surveys were collected. Serum micronutrients were measured by high performance liquid chromatography. Data on recurrence and death were collected annually. Cox proportional hazards models measured associations of serum nutrient concentrations with recurrence and overall survival. During a median follow-up time of 37 months, there were 32 recurrences and 27 deaths. After controlling for covariates, subjects with high versus low serum xanthophyll and total carotenoid concentrations had significantly longer recurrence-free time (p = .002 and p = .02, respectively). Overall survival time was significantly longer in patients with high versus low serum xanthophyll concentrations (p = .02). Future research should evaluate the possible benefits of interventions to increase intakes of rich food sources of xanthophylls in this patient population. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1591-E1597, 2016.

Food Access, Chronic Kidney Disease, and Hypertension in the U.S.

Greater distance to full-service supermarkets and low income may impair access to healthy diets and contribute to chronic kidney disease (CKD) and hypertension. The study aim was to determine relationships among residence in a "food desert," low income, CKD, and blood pressure. Adults in the 2003-2010 National Health and Nutrition Examination Survey (N=22,173) were linked to food desert data (www.ers.usda.gov) by Census Tracts. Food deserts have low median income and are further from a supermarket or large grocery store (>1 mile in urban areas, >10 miles in rural areas). Weighted regression was used to determine the association of residence in a food desert and family income with dietary intake; systolic blood pressure (SBP); and odds of CKD. Data analysis was performed in 2014-2015. Compared with those not in food deserts, participants residing in food deserts had lower levels of serum carotenoids (p<0.01), a biomarker of fruit and vegetable intake, and higher SBP (1.53 mmHg higher, 95% CI=0.41, 2.66) after adjustment for demographics and income. Residence in a food desert was not associated with odds of CKD (OR=1.20, 95% CI=0.96, 1.49). Lower, versus higher, income was associated with lower serum carotenoids (p<0.01) and higher SBP (2.00 mmHg higher for income-poverty ratio ≤1 vs >3, 95% CI=1.12, 2.89), but also greater odds of CKD (OR=1.76 for income-poverty ratio ≤1 vs >3, 95% CI=1.48, 2.10). Limited access to healthy food due to geographic or financial barriers could be targeted for prevention of CKD and hypertension.

Specific serum carotenoids are inversely associated with breast cancer risk among Chinese women: a case-control study.

Previous epidemiological studies have revealed the anti-cancer effect of dietary circulating carotenoids. However, the protective role of specific individual circulating carotenoids has not been elucidated. The purpose of this study was to examine whether serum carotenoids, including α-carotene, β-carotene, β-cryptoxanthin, lycopene and lutein/zeaxanthin, could lower the risk for breast cancer among Chinese women. A total of 521 women with breast cancer and age-matched controls (5-year interval) were selected from three teaching hospitals in Guangzhou, China. Concentrations of α-carotene, β-carotene, β-cryptoxanthin, lycopene and lutein/zeaxanthin were measured using HPLC. Unconditional logistic regression models were used to calculate OR and 95% CI using quartiles defined in the control subjects. Significant inverse associations were observed between serum α-carotene, β-carotene, lycopene, lutein/zeaxanthin and the risk for breast cancer. The multivariate OR for the highest quartile of serum concentration compared with the lowest quartile were 0·44 (95% CI 0·30, 0·65) for α-carotene, 0·27 (95% CI 0·18, 0·40) for β-carotene, 0·41 (95% CI 0·28, 0·61) for lycopene and 0·26 (95% CI 0·17, 0·38) for lutein/zeaxanthin. However, no significant association was found between serum β-cryptoxanthin and the risk for breast cancer. Stratified analysis by menopausal status and oestrogen receptor (ER)/progesterone receptor (PR) showed that serum α-carotene, β-carotene, lycopene and lutein/zeaxanthin were inversely associated with breast cancer risk among premenopausal women and among all subtypes of ER or PR status. The results suggest a protective role of α-carotene, β-carotene, lycopene and lutein/zeaxanthin, but not β-cryptoxanthin, in breast cancer risk.

Serum Retinol and Carotenoid Concentrations and Prostate Cancer Risk: Results from the Prostate Cancer Prevention Trial.

Findings from epidemiologic studies examining associations of serum retinol and carotenoids with prostate cancer risk have been inconsistent. This case-control study nested in the Prostate Cancer Prevention Trial evaluated associations of serum retinol and carotenoids with total, low-, and high-grade prostate cancer risk in a highly screened study population. We used logistic regression adjusting for age, family history of prostate cancer, race, body mass index, and serum cholesterol to estimate ORs and 95% confidence intervals (CI) of prostate cancer by quartiles of serum retinol and carotenoids, separately in the placebo (975 cases/1,009 frequency-matched controls) and finasteride (708 cases/743 frequency-matched controls) arms of the trial. Serum retinol concentrations were associated with increased risk of total prostate cancer [OR (95% CI) comparing the highest quartile of serum retinol with the lowest: 1.30 (1.00-1.68)] and high-grade prostate cancer [OR (95% CI), 1.74 (1.14-2.68)] in the placebo arm of the trial only. Also in the placebo arm, there was a moderate positive association of α-carotene with risk of total prostate cancer [OR (95% CI), 1.32 (1.01-1.73)]. None of the other carotenoids was associated with prostate cancer risk in the placebo arm. No associations were observed for retinol and carotenoids in the finasteride arm. In the placebo arm of this prospective study, high serum retinol and α-carotene concentrations were associated with increased risk of total and high-grade prostate cancers. Men with higher levels of serum retinol and α-carotene may be at increased risk for prostate cancer.

Highlights of This Issue

Because both smoking and excess body weight are major preventable risk factors for premature death, Meyer and colleagues analyzed the single and combined associations with site-specific cancer mortality. The study population comprised 35,784 men and women who participated in population-based health surveys in Switzerland. Heavy smoking (≥20 cigarettes/day) was associated with increased mortality due to cancer of the lung, upper aerodigestive tract, pancreas, bladder, liver, and the total of remaining sites. Obesity was associated with higher risk of dying from cancer of the liver and the female genital tract. Smoking was a much stronger risk factor for cancer than was excess body weight. This study supports recommendations for obese persons to quit smoking despite potential postcessation weight gain.Katz and colleagues performed cross-sectional telephone interviews to evaluate if women living in Appalachia were completing three cancer screening tests (mammography, Pap test, and colorectal cancer test). The authors report that fewer than 10% of women ages 51–75 were within guidelines for three cancer screening tests. Participants with higher incomes and conditions requiring regular medical visits were more likely to be within guidelines for all three screening tests. The low participation rate for cancer test uptake among women in Appalachia Ohio illustrates the need for innovative interventions to improve these rates.Global trends in female breast cancer incidence and mortality estimates were obtained from GLOBOCAN 2012. DeSantis and colleagues analyzed trends from 1993 onward using incidence data from 39 countries from the International Agency for Research on Cancer and mortality data from 57 countries from the World Health Organization. The authors report that in nine countries, mainly in Northern/Western Europe, breast cancer incidence increased and breast cancer mortality decreased. In contrast, incidence and death rates both increased in Colombia, Ecuador, and Japan and death rates increased in Brazil, Egypt, Guatemala, Kuwait, Mauritius, and Moldova. Awareness about the benefits of early breast cancer detection and improved access to treatment must be prioritized in order to successfully implement breast cancer control programs.Findings from studies examining associations of serum retinol and carotenoids with prostate cancer risk have been inconsistent. In this case–control study nested in the Prostate Cancer Prevention Trial, Nash and colleagues evaluated associations of serum retinol and carotenoids with total, low-, and high-grade prostate cancer risk. Serum retinol concentrations were associated with increased risk of total prostate cancer and high-grade prostate cancer in the placebo arm of the trial only. Also in the placebo arm, there was a moderate positive association of α-carotene with risk of total prostate cancer. Men with higher levels of serum retinol and α-carotene may be at increased risk for prostate cancer.

Decennial Change of Pulse Wave Velocity and Serum Carotenoids: the Mikkabi Study.

Decennial Change of Pulse Wave Velocity and Serum Carotenoids: the Mikkabi Study.

High serum carotenoids associated with lower risk for the metabolic syndrome and its components among Japanese subjects: Mikkabi cohort study.

Recent epidemiological studies show the association of carotenoids with the metabolic syndrome (MetS), but thorough longitudinal cohort studies regarding this association have not been well conducted. The objective of this study was to investigate longitudinally whether serum carotenoids are associated with the risk of developing the MetS and its components in Japanese subjects. We conducted a follow-up study on 1073 men and women aged 30-79 years at the baseline from the Mikkabi prospective cohort study. Those who participated in the baseline and completed follow-up surveys were examined longitudinally. Over the 10-year period, 910 subjects (295 men and 615 women) took part in the follow-up survey at least once. Over a mean follow-up period of 7·8 (sd 2·9) years, thirty-six men and thirty-one women developed new MetS. After adjustments for confounders, the hazard ratio (HR) for the MetS in the highest tertile of serum β-carotene against the lowest tertile was 0·47 (95 % CI 0·23, 0·95). On the other hand, significantly lower risks for dyslipidaemia were observed in the highest tertiles of serum α- and β-carotene and β-cryptoxanthin (HR 0·66; 95 % CI 0·46, 0·96; HR, 0·54; 95 % CI 0·37, 0·79; and HR 0·66; 95 % CI 0·44, 0·99, respectively). Other significant associations between the risks for obesity, high blood pressure and hyperglycaemia with serum carotenoids were not observed. Our results further support the hypothesis that eating a diet rich in carotenoids might help prevent the development of the MetS and its complications in Japanese subjects.

Greater serum carotenoid levels associated with lower prevalence of nonalcoholic fatty liver disease in Chinese adults.

Previous studies have suggested that serum carotenoids may be inversely associated with liver injury, but limited data are available from population-based studies. We examined the relationship between serum carotenoid levels and the prevalence of nonalcoholic fatty liver disease (NAFLD) in Chinese adults. A total of 2935 participants aged 40–75 years were involved in this community-based cross-sectional study. General information, lifestyle factors, serum levels of carotenoid and the presence and degree of NAFLD were determined. After adjusting for potential covariates, we observed a dose-dependent inverse association between NAFLD risk and each individual serum carotenoid and total carotenoids (all p-values < 0.001). The ORs of NAFLD for the highest (vs. lowest) quartile were 0.44 (95% CI 0.35, 0.56) for α-carotene, 0.32 (95% CI 0.25, 0.41) for β-carotene, 0.62 (95% CI 0.49, 0.79) for β-cryptoxanthin, 0.54 (95% CI 0.42, 0.68) for lycopene, 0.56 (95% CI 0.44, 0.72) for lutein + zeaxanthin and 0.41 (95% CI 0.32, 0.53) for total carotenoids. Higher levels of α-carotene, β-carotene, lutein + zeaxanthin and total carotenoids were significantly associated with a decrease in the degree of NAFLD (p-trend: < 0.001 to 0.003). Serum carotenoids are inversely associated with prevalence of NAFLD in middle aged and elderly Chinese.

Skin Carotenoid Response to a High-Carotenoid Juice in Children: A Randomized Clinical Trial

BackgroundPrevious studies have shown an increase in serum carotenoid status among children when fed carotenoids. This study looked at the effect and dose–response of a known amount of carotenoid consumption on change in skin carotenoid status among children. MethodsParticipants were children aged 5 to 17 years from Cache County, UT (n=58). Children were randomly assigned to one of three groups: high (n=18) or low (n=18) dose of a carotenoid-rich juice (2.75 mg carotenoids/30 mL juice), or placebo juice (n=22). Children were asked to drink an assigned dose of the juice (30 to 120 mL/day) based on the weight of the child and group assignment, every day for 8 weeks. Skin carotenoids were measured every 2 weeks by resonance Raman spectroscopy. Participants were asked to maintain their usual diet throughout the study. Usual diet was assessed using three averaged 24-hour recalls; diet constancy was measured using food frequency questionnaires administered at baseline, Week 4, and Week 8. Repeated measures analysis of variance was used to assess the group differences in skin carotenoid status over time. ResultsThe high-dose and low-dose groups had mean±standard deviation increases in skin carotenoid status of 11,515±1,134 and 10,009±1,439 Raman intensity counts, respectively (both P values <0.001, for change in means compared with baseline) at Week 8, although they showed significant change from baseline by Week 2. The placebo group’s change of 985 Raman intensity counts was not statistically significant. The difference in change between the 2 experimental groups was not significant at Week 2, 4, 6, or 8. ConclusionsConsumption of 30 to 120 mL (2.75 to 11 mg carotenoids) of a carotenoid-rich juice significantly increased skin carotenoid status over an 8-week period among children aged 5 to 17 years. The amount of carotenoids found in this amount of juice is equal to the amount found in approximately 23 to 92 g cooked carrots per day.

High provitamin A carotenoid serum concentrations, elevated retinyl esters, and saturated retinol-binding protein in Zambian preschool children are consistent with the presence of high liver vitamin A stores

Biomarkers of micronutrient status are needed to best define deficiencies and excesses of essential nutrients. We evaluated several supporting biomarkers of vitamin A status in Zambian children to determine whether any of the biomarkers were consistent with high liver retinol stores determined by using retinol isotope dilution (RID). A randomized, placebo-controlled, biofortified maize efficacy trial was conducted in 140 rural Zambian children from 4 villages. A series of biomarkers were investigated to better define the vitamin A status of these children. In addition to the assessment of total-body retinol stores (TBSs) by using RID, tests included analyses of serum carotenoids, retinyl esters, and pyridoxal-5'-phosphate (PLP) by using high-pressure liquid chromatography, retinol-binding protein by using ELISA, and alanine aminotransferase (ALT) activity by using a colorimetric assay. Children (n = 133) were analyzed quantitatively for TBSs by using RID. TBSs, retinyl esters, some carotenoids, and PLP differed by village site. Serum carotenoids were elevated above most nonintervened reference values for children. α-Carotene, β-carotene, and lutein values were >95th percentile from children in the US NHANES III, and 13% of children had hypercarotenemia (defined as total carotenoid concentration >3.7 μmol/L). Although only 2% of children had serum retinyl esters >10% of total retinol plus retinyl esters, 16% of children had >5% as esters, which was consistent with high liver retinol stores. Ratios of serum retinol to retinol-binding protein did not deviate from 1.0, which indicated full saturation. ALT activity was low, which was likely due to underlying vitamin B-6 deficiency, which was confirmed by very low serum PLP concentrations. The finding of hypervitaminosis A in Zambian children was supported by high circulating concentrations of carotenoids and mildly elevated serum retinyl esters. ALT-activity assays may be compromised with co-existing vitamin B-6 deficiency. Nutrition education to improve intakes of whole grains and animal-source foods may enhance vitamin B-6 status in Zambians.

Combining vitamin C and carotenoid biomarkers better predicts fruit and vegetable intake than individual biomarkers in dietary intervention studies.

The aim of this study was to determine whether combining potential biomarkers of fruit and vegetables is better at predicting FV intake within FV intervention studies than single biomarkers. Data from a tightly controlled randomised FV intervention study (BIOFAV; all food provided and two meals/day on weekdays consumed under supervision) were used. A total of 30 participants were randomised to either 2, 5 or 8 portions FV/day for 4weeks, and blood samples were collected at baseline and 4weeks for plasma vitamin C and serum carotenoid analysis. The combined biomarker approach was also tested in three further FV intervention studies conducted by the same research team, with less strict dietary control (FV provided and no supervised meals). The combined model containing all carotenoids and vitamin C was a better fit than either the vitamin C only (P<0.001) model or the lutein only (P=0.006) model in the BIOFAV study. The C-statistic was slightly lower in the lutein only model (0.85) and in the model based upon factor analysis (0.88), and much lower in the vitamin C model (0.68) compared with the full model (0.95). Results for the other studies were similar, although the differences between the models were less marked. Although there was some variation between studies, which may relate to the level of dietary control or participant characteristics, a combined biomarker approach to assess overall FV consumption may more accurately predict FV intake within intervention studies than the use of a single biomarker. The generalisability of these findings to other populations and study designs remains to be tested. Clinical trial Registration Number NCT01591057 ( www.clinicaltrials.gov ).

Analysis of microsamples of human faeces: a non-invasive approach to study the bioavailability of fat-soluble bioactive compounds.

Bioavailability is a critical feature in the assessment of the role of micronutrients in human health. Poorly bioavailable micronutrients like carotenoids may reach significant concentrations in the gastrointestinal tract where they may exert biological actions. We evaluated a simple collection protocol to determine vitamin A, E and carotenoids in microsamples of human faeces as a non-invasive approach for nutritional studies. Microsamples of human faeces were collected using a commercially available device, extracted and analysed on two LC systems. Suitability of the protocol was assessed by evaluating several factors including the effect of simulated colonic conditions and two nutritional scenarios with different dietary components, chemical forms, nutritional goals and target groups. The protocol was reproducible and representative of a faeces sample. The major dietary and serum carotenoids, and several "unidentified" compounds (possibly metabolites) could be detected, and cis-/trans-β-carotene profile reflected dietary intervention. In faeces of neonates, free retinol, retinyl and α-tocopheryl acetate (from infant formula), long-chain fatty acid retinyl esters (from human milk), free γ-tocopherol and α-tocopherol could be detected. Our results show that the analysis of vitamin A, E and carotenoids in microsamples of human faeces is a suitable, non-invasive approach that may provide relevant information regarding responsiveness, nutrient stability and metabolism and may help assess adequacy of chemical forms and delivery systems reaching the colon.