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Journal of Lipid Research Jul 1976The concentrations and distributions of major lipids (cholesterol, phospholipid, and triglyceride), tocopherol and carotenoids were determined in the plasma lipoprotein...
The concentrations and distributions of major lipids (cholesterol, phospholipid, and triglyceride), tocopherol and carotenoids were determined in the plasma lipoprotein fractions (VLDL, LDL, and HDL) of (1) normal human subjects, (2) patients with hyperlipoproteinemia, and (3) patients with erythropoietic protoporphyria treated with oral beta-carotene and/or alpha-tocopherol. The distribution of tocopherol (in percent) was most closely correlated with the distribution of total lipids in the individual lipoproteins, while the major portion of beta-carotene was present in the low density lipoproteins, irrespective of the lipid distribution in the lipoproteins (except for one subject with hyperchylomicronemia). The alpha-tocopherol and beta-carotene concentrations of plasma and RBC in patients treated with tocopherol and carotene were determined periodically for a one-year period. Plasma and RBC tocopherol concentrations showed a rapid, parallel increase in response to tocopherol supplementation. In contrast, the plasma and RBC carotene concentrations showed a much slower and nonparallel increase in response to carotene administration. When carotene supplementation was stopped, the elevated carotene levels in both plasma and RBC persisted for several months; the elevated plasma carotene level persisted longer than the raised RBC carotene levels. These results suggest that alpha-tocopherol and beta-carotene are transported differently in the circulation and that the tissue storage and mobilization of these compounds are different.
Topics: Adult; Biological Transport; Carotenoids; Cholesterol; Female; Humans; Hyperlipidemias; Lipoproteins, HDL; Lipoproteins, LDL; Lipoproteins, VLDL; Male; Middle Aged; Phospholipids; Porphyrias; Triglycerides; Vitamin E
PubMed: 181502
DOI: No ID Found -
Nutrients Nov 2011Vitamin E consists of eight different variants: α-, β-, γ-, and δ-tocopherols (saturated phytyl tail) and α-, β-, γ-, and δ-tocotrienols (unsaturated phytyl... (Review)
Review
Vitamin E consists of eight different variants: α-, β-, γ-, and δ-tocopherols (saturated phytyl tail) and α-, β-, γ-, and δ-tocotrienols (unsaturated phytyl tail). Cancer prevention studies with vitamin E have primarily utilized the variant α-tocopherol. To no avail, a majority of these studies focused on variant α-tocopherol with inconsistent results. However, γ-tocopherol, and more recently δ-tocopherol, have shown greater ability to reduce inflammation, cell proliferation, and tumor burden. Recent results have shown that γ-enriched mixed tocopherols inhibit the development of mammary hyperplasia and tumorigenesis in animal models. In this review, we discuss the possible differences between the variant forms, molecular targets, and cancer-preventive effects of tocopherols. We recommend that a γ-enriched mixture, γ- and δ-tocopherol, but not α-tocopherol, are promising agents for breast cancer prevention and warrant further investigation.
Topics: Apoptosis; Breast Neoplasms; Cell Proliferation; Cyclooxygenase 2; ErbB Receptors; Female; Humans; NF-E2-Related Factor 2; PPAR gamma; Receptors, Estrogen; Tocopherols; Vitamin E; alpha-Tocopherol; gamma-Tocopherol
PubMed: 22254089
DOI: 10.3390/nu3110962 -
Nicotine & Tobacco Research : Official... Jul 2019The Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study demonstrated that β-carotene supplementation increases lung cancer incidence in smokers. Further,... (Randomized Controlled Trial)
Randomized Controlled Trial
INTRODUCTION
The Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study demonstrated that β-carotene supplementation increases lung cancer incidence in smokers. Further, cigarettes with higher tar and nicotine content are associated with a higher risk of lung cancer. However, no studies have examined whether the increased risk associated with β-carotene supplementation in smokers varies by the tar or nicotine content of cigarettes.
METHODS
The ATBC Study was a randomized, double-blind intervention trial conducted in southwest Finland. A total of 29 133 male smokers, aged 50-69 years, were enrolled and randomly assigned to one of four groups (α-tocopherol, β-carotene, both, or placebo). Cox proportional hazards models were used to estimate the hazard ratio (HR) and 95% confidence intervals (CI) of lung cancer risk by β-carotene trial assignment stratified by a priori categories of cigarette tar and nicotine content.
RESULTS
The β-carotene supplementation group had significantly higher risk of developing lung cancer in all categories of tar content (yes vs. no β-carotene supplementation-ultralight cigarettes [≤7 mg tar]: HR = 1.31, 95% CI = 0.91 to 1.89; nonfiltered cigarettes [≥21 mg tar]: HR = 1.22, 95% CI = 0.91 to 1.64; p for interaction = .91). Similarly, there was no interaction with nicotine content (yes vs. no β-carotene supplementation-ventilated cigarettes [≤0.8 µg nicotine]: HR = 1.23, 95% CI = 0.98 to 1.54; nonfiltered cigarettes [≥1.3 µg nicotine]: HR = 1.22, 95% CI = 0.91 to 1.64; p for interaction = .83).
CONCLUSION
These findings support the conclusion that supplementation with β-carotene increases the risk of lung cancer in smokers regardless of the tar or nicotine content of cigarettes smoked. Our data suggest that all smokers should continue to avoid β-carotene supplementation.
IMPLICATIONS
Previous studies demonstrated that β-carotene supplementation increases risk of lung cancer in smokers. This study moves the field forward by examining the potential for modification of risk of lung cancer with different levels of tar and nicotine in cigarettes smoked, as interaction with carcinogens in these components of cigarette smoke is hypothesized to be the mechanism by which β-carotene increases risk. Our study provides evidence that the increased risk of lung cancer in smokers who take β-carotene supplements is not dependent upon the tar or nicotine level of cigarettes smoked and suggests that all smokers should continue to avoid β-carotene supplementation.
Topics: Aged; Antioxidants; Dietary Supplements; Double-Blind Method; Finland; Follow-Up Studies; Humans; Incidence; Lung Neoplasms; Male; Middle Aged; Nicotine; Provitamins; Smoking; Tars; alpha-Tocopherol; beta Carotene
PubMed: 29889248
DOI: 10.1093/ntr/nty115 -
International Journal of Environmental... Jan 2014Retinol, α-tocopherol, and γ-tocopherol are fat-soluble vitamins acting as antioxidants via the prevention of lipid oxidation. Little is known about circulatory levels...
Retinol, α-tocopherol, and γ-tocopherol are fat-soluble vitamins acting as antioxidants via the prevention of lipid oxidation. Little is known about circulatory levels in healthy individuals. The present cross-sectional study aimed at elucidating the relationship between these antioxidants and clinical biomarkers in 206 male (median age 41 years, range 23-67) employees from companies located in the Okayama Prefecture, Japan. Subjects younger than 40 years (n = 94) showed a positive association of the frequency of alcohol consumption with the circulating retinol (β = 0.344, p = 0.001) and γ-tocopherol levels (β = 0.219, p = 0.041), and an inverse association of fast insulin with serum retinol (β = -0.301, p = 0.009). In participants older than 40 years (n = 112) we found that an inverse association of HOMA-R with serum retinol (β = -0.262, p = 0.021), α-tocopherol (β = -0.236, p = 0.035), and γ-tocopherol levels (β = -0.224, p = 0.052); and cigarette smoking was inversely associated with the levels of serum α-tocopherol (β = -0.286, p = 0.008) and γ-tocopherol (β = -0.229, p = 0.040). We further found negative relationships between serum ferritin and the retinol (β = -0.211, p = 0.032) and α-tocopherol levels (β = -0.223, p = 0.022) in men over 40 years of age. The present study suggests that the circulatory levels of antioxidant vitamins may modulate the action of insulin and that higher levels of iron might decrease the levels of antioxidant vitamins in the blood.
Topics: Adult; Aged; Antioxidants; Biomarkers; Cross-Sectional Studies; Ferritins; Humans; Insulin; Male; Middle Aged; Reference Values; Vitamin A; Young Adult; alpha-Tocopherol; gamma-Tocopherol
PubMed: 24487454
DOI: 10.3390/ijerph110201647 -
Pharmaceuticals (Basel, Switzerland) Aug 2021Neurotoxins such as rotenone, 1-methyl-4-phenylpyridinium (MPP) and 6-hydroxydopamine (6-OHDA) are well known for their high toxicity on dopaminergic neurons and are...
Neurotoxins such as rotenone, 1-methyl-4-phenylpyridinium (MPP) and 6-hydroxydopamine (6-OHDA) are well known for their high toxicity on dopaminergic neurons and are associated with Parkinson's disease (PD) in murine models and humans. In addition, PD patients often have glucose intolerance and may develop type 2 diabetes (T2D), whereas T2D patients have higher risk of PD compared to general population. Based on these premises, we evaluated the toxicity of these three toxins on pancreatic β-cell lines (INS-1 832/13 and MIN6) and we showed that rotenone is the most potent for reducing β-cells viability and altering mitochondrial structure and bioenergetics in the low nanomolar range, similar to that found in dopaminergic cell lines. MPP and 6-OHDA show similar effects but at higher concentration. Importantly, rotenone-induced toxicity was counteracted by α-tocopherol and partially by metformin, which are endowed with strong antioxidative and cytoprotective properties. These data show similarities between dopaminergic neurons and β-cells in terms of vulnerability to toxins and pharmacological agents capable to protect both cell types.
PubMed: 34451865
DOI: 10.3390/ph14080767 -
Journal of Nutritional Science and... 2016The purpose of this study was to investigate the status of retinol, beta-carotene, and alpha-tocopherol serum concentrations in adolescents with dyslipidemia. A case...
The purpose of this study was to investigate the status of retinol, beta-carotene, and alpha-tocopherol serum concentrations in adolescents with dyslipidemia. A case series dyslipidemia study was conducted, with an attached control group, including 104 adolescents of public schools in Recife during the months of March/April 2013. Retinol, beta-carotene and alpha-tocopherol serum concentrations were analysed by high efficiency liquid chromatography. Sociodemographic, anthropometric, clinical and biochemical variables were analysed. Dyslipidemic adolescents had high serum concentrations of both retinol (p=0.007) and beta-carotene/apolipoprotein A-I ratio (p=0.034); they also had low concentrations of beta-carotene/total cholesterol (p<0.0001) and beta-carotene/apolipoprotein B ratios (p=0.033) when compared to the controls. The alpha-tocopherol serum status was not associated with dyslipidemia. Overweight, abdominal obesity, lipid profile markers, and systolic and diastolic blood pressures were more prevalent in dyslipidemic adolescents. The findings show an association between vitamin A and dyslipidemia in adolescents. However, additional investigations of this risk group are necessary to clarify the mechanisms of action of this nutrient in the pathogenesis of this syndrome, aiming at reducing cardiometabolic risks as of earlier ages.
Topics: Adolescent; Apolipoprotein A-I; Apolipoproteins B; Biomarkers; Blood Glucose; Blood Pressure; Body Mass Index; Body Weight; Brazil; Child; Cholesterol, HDL; Cholesterol, LDL; Diet; Dyslipidemias; Exercise; Female; Humans; Male; Obesity; Overweight; Socioeconomic Factors; Vitamin A; Waist Circumference; Young Adult; alpha-Tocopherol; beta Carotene
PubMed: 27264090
DOI: 10.3177/jnsv.62.73 -
British Journal of Cancer Nov 2014Micronutrients may influence the development or progression of liver cancer and liver disease. We evaluated the association of serum α-tocopherol, β-carotene, and...
BACKGROUND
Micronutrients may influence the development or progression of liver cancer and liver disease. We evaluated the association of serum α-tocopherol, β-carotene, and retinol with incident liver cancer and chronic liver disease (CLD) mortality in a prospective cohort of middle-aged Finnish male smokers.
METHODS
Baseline and 3-year follow-up serum were available from 29,046 and 22,805 men, respectively. After 24 years of follow-up, 208 men were diagnosed with liver cancer and 237 died from CLD. Hazards ratios and 95% confidence intervals were calculated for highest vs lowest quartiles from multivariate proportional hazards models.
RESULTS
Higher β-carotene and retinol levels were associated with less liver cancer (β-carotene: 0.35, 0.22-0.55, P-trend <0.0001; retinol: 0.58, 0.39-0.85, P-trend=0.0009) and CLD mortality (β-carotene: 0.47, 0.30-0.75, P-trend=0.001; retinol: 0.55, 0.38-0.78, P-trend=0.0007). α-Tocopherol was associated with CLD mortality (0.63, 0.40-0.99, P-trend=0.06), but not with liver cancer (1.06, 0.64-1.74, P-trend=0.77). Participants with higher levels of β-carotene and retinol, but not α-tocopherol, at both baseline and year 3 had lower risk of each outcome than those with lower levels.
CONCLUSIONS
Our findings suggest that higher concentrations of β-carotene and retinol are associated with incident liver cancer and CLD. However, such data do not indicate that supplementation should be considered for these diseases.
Topics: Aged; Chronic Disease; Humans; Incidence; Liver Diseases; Liver Neoplasms; Male; Middle Aged; Vitamin A; alpha-Tocopherol; beta Carotene
PubMed: 25314058
DOI: 10.1038/bjc.2014.365 -
The American Journal of Clinical... Jul 2004Plant sterols reduce cholesterol absorption, which leads to a decrease in plasma and LDL-cholesterol concentrations. Plant sterols also lower plasma concentrations of... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
BACKGROUND
Plant sterols reduce cholesterol absorption, which leads to a decrease in plasma and LDL-cholesterol concentrations. Plant sterols also lower plasma concentrations of carotenoids and alpha-tocopherol, but the mechanism of action is not yet understood.
OBJECTIVES
The aims of this clinical study were to determine whether plant sterols affect the bioavailability of beta-carotene and alpha-tocopherol in normocholesterolemic men and to compare the effects of plant sterol esters and plant free sterols on cholesterol absorption.
DESIGN
Twenty-six normocholesterolemic men completed the double-blind, randomized, crossover study. Subjects consumed daily, for 1 wk, each of the following 3 supplements: a low-fat milk-based beverage alone (control) or the same beverage supplemented with 2.2 g plant sterol equivalents provided as either free sterols or sterol esters. During this 1-wk supplementation period, subjects consumed a standardized diet.
RESULTS
Both of the milks enriched with plant sterols induced a similar (60%) decrease in cholesterol absorption. Plant free sterols and plant sterol esters reduced the bioavailability of beta-carotene by approximately 50% and that of alpha-tocopherol by approximately 20%. The reduction in beta-carotene bioavailability was significantly less with plant free sterols than with plant sterol esters. At the limit of significance (P = 0.054) in the area under the curve, the reduction in alpha-tocopherol bioavailability was also less with plant free sterols than with plant sterol esters.
CONCLUSIONS
Both plant sterols reduced beta-carotene and alpha-tocopherol bioavailability and cholesterol absorption in normocholesterolemic men. However, plant sterol esters reduced the bioavailability of beta-carotene and alpha-tocopherol more than did plant free sterols.
Topics: Adult; Antioxidants; Area Under Curve; Biological Availability; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Cross-Over Studies; Diterpenes; Double-Blind Method; Esters; Humans; Intestinal Absorption; Male; Phytosterols; Retinyl Esters; Vitamin A; alpha-Tocopherol; beta Carotene
PubMed: 15213045
DOI: 10.1093/ajcn/80.1.171 -
Nutrients Jun 2023This study aimed to assess associations between forms of vitamin A and E (both individually and collectively) and the risk of prostate cancer, as well as identify...
PURPOSE
This study aimed to assess associations between forms of vitamin A and E (both individually and collectively) and the risk of prostate cancer, as well as identify potential effect modifiers.
METHODS
Utilizing data from the Singapore Prostate Cancer Study, a hospital-based case-control study, we measured the serum concentrations of 15 different forms of vitamins A and E in 156 prostate cancer patients and 118 control subjects, using a high-performance liquid chromatography technique. These forms included retinol, lutein, zeaxanthin, α-cryptoxanthin, β-cryptoxanthin, α-carotene, β-carotene, lycopene, ubiquinone, δ-tocopherol, γ-tocopherol, α-tocopherol, δ-tocotrienol, γ-tocotrienol, and α-tocotrienol. The odds ratio and 95% confidence interval for associations between vitamin A and E and prostate cancer risk were estimated using logistic regression models after adjustment for potential confounders. The analyses were further stratified by smoking and alcohol consumption status. The mixture effect of micronutrient groups was evaluated using weighted quantile sum regression.
RESULTS
Higher concentrations of retinol, lutein, α-carotene, β-carotene, ubiquinone, α-tocopherol, δ-tocotrienol, γ-tocotrienol, and α-tocotrienol were significantly and positively associated with overall prostate cancer risk. Among ever-smokers, associations were stronger for lutein, β-cryptoxanthin and β-carotene compared with never-smokers. Among regular alcohol drinkers, associations were stronger for lutein, β-cryptoxanthin, ubiquinone, γ-tocotrienol and α-tocotrienol compared with non-regular alcohol drinkers. Retinol and α-tocotrienol contributed most to the group indices 'vitamin A and provitamin A carotenoids' and 'vitamin E', respectively.
CONCLUSIONS
Several serum vitamin A and E forms were associated with prostate cancer risk, with significant effect modification by smoking and alcohol consumption status. Our findings shed light on prostate cancer etiology.
Topics: Male; Humans; Vitamin A; beta Carotene; Tocotrienols; Lutein; alpha-Tocopherol; Beta-Cryptoxanthin; Ubiquinone; Case-Control Studies; Singapore; Prostatic Neoplasms
PubMed: 37375581
DOI: 10.3390/nu15122677 -
Plants (Basel, Switzerland) May 2022Soybean seeds are rich in secondary metabolites which are beneficial for human health, including tocopherols. Tocopherols play an important role in human and animal...
Soybean seeds are rich in secondary metabolites which are beneficial for human health, including tocopherols. Tocopherols play an important role in human and animal nutrition thanks to their antioxidant activity. In this study, the 'Forrest' by 'Williams 82' (F×W82) recombinant inbred line (RIL) population ( = 306) was used to map quantitative trait loci (QTL) for seed α-tocopherol, β-tocopherol, δ -tocopherol, γ-tocopherol, and total tocopherol contents in Carbondale, IL over two years. Also, the identification of the candidate genes involved in soybean tocopherols biosynthetic pathway was performed. A total of 32 QTL controlling various seed tocopherol contents have been identified and mapped on Chrs. 1, 2, 5, 6, 7, 8, 9, 10, 12, 13, 16, 17, and 20. One major and novel QTL was identified on Chr. 6 with an R of 27.8, 9.9, and 6.9 for δ-tocopherol, α-tocopherol, and total tocopherol content, respectively. Reverse BLAST analysis of the genes that were identified in allowed the identification of 37 genes involved in soybean tocopherol pathway, among which 11 were located close to the identified QTLs. The tocopherol cyclase gene () is located close to the QTLs controlling δ-tocopherol (R = 27.8), α-tocopherol (R = 9.96), and total-tocopherol (R = 6.95). The geranylgeranyl diphosphate reductase () gene is located close to a QTL controlling total tocopherol content in soybean (R = 4.42). The two methylphytylbenzoquinol methyltransferase () candidate genes and are located close to a QTL controlling δ-tocopherol content (R = 3.57). The two γ-tocopherol methyltransferase () genes, and , are located close to QTLs controlling (γ+ß) tocopherol content (R = 8.86) and total tocopherol (R = 5.94). The identified tocopherol seed QTLs and candidate genes will be beneficial in breeding programs to develop soybean cultivars with high tocopherol contents.
PubMed: 35567259
DOI: 10.3390/plants11091258