Genetic and environmental contributions to serum ascorbic acid concentrations: the Stanislas Family Study

Although numerous environmental factors are documented to influence serum ascorbic concentrations, little is known about the genetic versus environmental contributions to variation of this trait. The aim of this study was to estimate family correlation and, additive genetic heritability and household effects in a variance component analysis for serum ascorbic acid concentrations. In a sample of ninety French families, information was obtained regarding serum ascorbic acid concentrations, usual dietary intake, lifestyle, and other related covariates. Spouse, parent-offspring and offspring-offspring significant correlation coefficients for serum ascorbic acid concentrations, adjusted for age, cigarette consumption and oral contraceptive use, were 0.432, 0.298 and 0.485, respectively, and for adjusted values for additional diet covariates (vitamin C intake and fruit and vegetable consumption), were 0.362, 0.154 and 0.348, respectively. Variance component analysis for serum ascorbic concentrations showed no significant genetic contribution to variability of this trait. Conversely, household common environment accounted for 27.7 and 42.6% in parents and offspring, respectively, after adjustment for age, cigarette consumption and oral contraceptive use. After adjustment for the two additional diet covariates (vitamin C intake and fruit and vegetable consumption) household common variance decreased to 13.6 and 30.5% in parents and offspring, respectively. These results show that serum ascorbic acid concentrations aggregate within healthy families partly due to diet intake but without a significant genetic component.     

Heritabilities and shared environmental effects were estimated from household clustering in national health survey data

OBJECTIVES: The relative contributions of genetic and environmental variables to within-household clustering of quantitative traits in household surveys are poorly characterized. We estimated shared genetic and shared environmental contributions to within-household correlation for anthropometric variables and cardiovascular disease risk factors. STUDY DESIGN AND SETTING: Data were analyzed for the Health Survey for England 1998, a representative national household survey. Two-generation pedigrees were defined using information for relationships within households. After standardizing for age and sex, data were analyzed for 11 quantitative traits. Variance components models were fitted to estimate the proportion of variance due to additive genetic variance or shared environmental effects. RESULTS: Within-household correlation coefficients for all related and unrelated subjects ranged from 0.10 for C-reactive protein to 0.31 for height. Pairwise correlations between related individuals within households were consistently higher than those between unrelated individuals. Estimated heritability ranged from 6% for diastolic blood pressure to 40% for serum cholesterol. The proportion of variance attributable to shared environmental effects ranged from 8% for cholesterol to 24% for height. CONCLUSION: In this large, representative national sample of generally small families, estimates for heritability were generally lower than previously reported, whereas the contribution of shared environment and individual-level variation were greater.     

Plant sterol ester-enriched spread lowers plasma total and LDL cholesterol in children with familial hypercholesterolemia

BACKGROUND: Naturally occurring plant sterol esters (SEs) favorably affect serum cholesterol concentrations in humans and could aid in the treatment of children with familial hypercholesterolemia (FH). OBJECTIVE: We studied the effect of SE-enriched spread on serum lipids, lipoproteins, carotenoids, fat-soluble vitamins, and physiologic variables in children with FH aged 7-12 y. DESIGN: In a randomized, double-blind crossover study comprising two 8-wk interventions, 38 children with FH consumed 18.2 +/- 1.5 g SE spread/d, corresponding to 1.60 +/- 0.13 g SEs, or a control spread. Blood samples were analyzed at the start and end of each diet period. RESULTS: Plasma LDL-cholesterol concentrations decreased by 10.2% (P = 0.003) during the SE period compared with the control period. Total cholesterol and apolipoprotein B concentrations were reduced by 7.4% (P = 0.007 and P = 0.020, respectively) during the SE period. No changes were observed in HDL cholesterol, triacylglycerol, or apolipoprotein A-I. Serum concentration of lipid-adjusted lycopene decreased by 8.1% (P = 0.015) in the SE period, with no changes in the other carotenoids. Lipid-adjusted retinol and alpha-tocopherol concentrations increased by 15.6% (P < 0.001) and 7.1% (P = 0.027), respectively. There was an increase (16.8%, P = 0.04) in alanine transaminase in the SE period, but this was explained by a significantly lower starting concentration in the SE period than in the control period. The children consumed a recommended American Heart Association Step I diet during both intervention periods. CONCLUSION: A daily intake of 1.6 g SEs induces an additional reduction in LDL-cholesterol concentrations in children with FH consuming a recommended diet.     

Heritability of Serum Apolipoprotein Concentrations in Middle-Aged Japanese Twins

Background

Studies of the genetic and environmental influences on apolipoproteins have been conducted, but few have used data from Japanese twins. The aim of this study was to quantify and compare the genetic and environmental causes of individual differences in the serum concentrations of apolipoproteins in Japanese middle-aged twins.

Methods

Apo A-I, apo A-II, apo B, apo C-II, apo C-III, and apo E were studied. A total of 142 twin pairs, aged 45 through 65 years, were enrolled: 85 monozygotic pairs (59 male, 26 female) and 57 same-sexed dizygotic pairs (43 male, 14 female). The intraclass correlation coefficient and structural equation modeling were used to estimate the best-fitting model and heritability.

Results

Sixteen percent to 75% of the total variances of apo A-I, apo C-II, and apo C-III were attributable to genetic influence; apo A-I and apo C-II were influenced by dominant genetic factors. Twenty percent to 73% of the total variances of apo A-II, apo B, and apo E were attributable to additive genetic influence; apo B was clearly influenced by common environmental factors. Furthermore, the heritability of all apolipoproteins was higher among females than among males.

Conclusions

Genetic factors, including additive genetic effects (A) and dominant effects (D), influence apolipoprotein levels. However, a common environment does not influence the variances of these apolipoproteins, with the exception of apo B. Furthermore, the heritability of apolipoprotein phenotypes differs by sex.Key words: apolipoprotein, heritability, adult twins     

Familial aggregation of nutrient intake and physical activity: results from the San Antonio Family Heart Study

PURPOSE: To evaluate the extent to which levels of physical activity and nutrient intake aggregate in families, and secondarily, to assess the repeatability of these behavioral measures over a 5-year period. METHODS: Measurements were obtained in a population-based sample consisting of 1364 members of 42 large Mexican American families. Nutrient intake was assessed by a food frequency questionnaire validated for use in this population. Usual level of physical activity was estimated using a 7-day recall questionnaire. RESULTS: Correlations between baseline (obtained 1992-1995) and follow-up (obtained 1996 to 2000) measures of all behaviors were highly significant (p < 0.001), ranging from 0.24 for % of calories derived from fat to 0.44 for % of calories derived from alcohol. Familial effects, estimated using variance component methods, were stronger when modeled as a genetic heritability than as a shared household effect; as a heritability they accounted for a significant portion of the total variation of all traits (9% for physical activity levels, p < 0.05; and 13-26% for nutrient intake, p < 0.001 for all). CONCLUSIONS: Measurements of physical activity and dietary behaviors in this population tracked over 5 years, and there was a significant degree of aggregation of these behaviors within families. Understanding the sources of these family effects may facilitate efforts to improve cardiovascular health.     

Serum selenium and serum lipids in US adults

BACKGROUND: Selenium, an essential micronutrient, has received considerable attention for its antioxidant properties. In addition, selenium may affect several cardiometabolic risk factors, such as glucose homeostasis and lipid concentrations. However, the effects of selenium intake on the lipid profile in selenium-replete populations, such as the United States, are largely unknown. OBJECTIVE: We examined the relation of serum selenium concentrations with serum lipids in a representative sample of US adults. DESIGN: This was a cross-sectional analysis of 5452 men and women aged >/= 20 y participating in the third National Health and Nutrition Examination survey. Serum selenium was measured by atomic absorption spectrometry. RESULTS: The multivariable adjusted differences in total cholesterol, LDL cholesterol, HDL cholesterol, apolipoprotein B (apo B), and apolipoprotein A-I (apo A-I) comparing the highest with the lowest quartile of serum selenium were 16.6 mg/dL (95% CI: 11.6, 21.4 mg/dL), 10.9 mg/dL (95% CI: 6.4, 15.4 mg/dL), 3.2 mg/dL (95% CI: 1.6, 5.0 mg/dL), 8.9 mg/dL (95% CI: 5.6, 12.2 mg/dL), and 6.9 mg/dL (95% CI: 1.7, 12.1 mg/dL), respectively. Participants in the highest quartile of serum selenium had 10% higher concentrations of triacylglycerols than did participants in the lowest quartile (ratio of triacylglycerol concentrations: 1.10; 95% CI: 1.05, 1.17). The difference in the ratios of LDL cholesterol to HDL cholesterol and apo B to apo A-I that compared the highest with the lowest selenium quartiles were 0.11 (95% CI: -0.02, 0.25) and 0.03 (95% CI: 0.00, 0.06), respectively. CONCLUSION: Elevated serum selenium was associated with elevated serum concentrations of total cholesterol, LDL cholesterol, HDL cholesterol, triacylglycerols, apo B, and apo A-I among US adults, a selenium-replete population. Experimental studies are needed to determine cause and effect relations and the potential mechanisms underlying these associations.     

Rapid determination of vitamin A (retinol) and vitamin E (alpha-tocopherol) in human serum by isocratic adsorption HPLC

The simultaneous determination of alpha-tocopherol and retinol in human serum is reported. The separation is carried out by means of isocratic HPLC on adsorption columns. UV-Detection is possible by using either one wavelength for both compounds (300 nm), or after a lambda change mode with typical wavelengths for alpha-tocopherol (292 nm) and retinol (325 nm). According to short retention times (10 min) and rapid extraction the method is useful for clinical research and allows about 50 analyses per day and operator. Blood from 176 human volunteers was collected and alpha-tocopherol and retinol levels in serum determined with this method. Statistical evaluation of different selected groups shows typical significant differences of alpha-tocopherol and retinol concentrations in smokers and oral contraceptive users.     

Sources of variability of human plasma apolipoprotein A-IV levels and relationships with lipid metabolism

Plasma apolipoprotein (apo) A-IV concentration was determined by immunoelectrophoretic assay (EIA) in 119 nuclear families. No significant effect of concomitants such as age, weight, height, body mass index, tobacco, and alcohol consumption was observed on apo A-IV levels in men and in boys. In women, contraceptive use and hormonal status affected apo A-IV levels. In girls, only age influenced the quantitative phenotype. After adjusting by specific concomitants significant correlations were observed between apo A-IV levels and triglycerides, apolipoprotein A-I and apo B levels, suggesting a role of apolipoprotein A-IV in the hepatic lipid metabolism. Intrafamilial correlations were estimated to investigate the plausibility of a common family factor. The results obtained in this study showed a significant correlation between family members with the exception of mother-daughter pairs. Using a variance components model, the contribution of genetic and environmental factors was then investigated. Different statistical models were used and two major hypotheses were statistically acceptable: the first hypothesis supports that shared and specific environmental factors explain 35 and 65%, respectively, of the total adjusted plasma apo A-IV variation. The fraction of apo A-IV variability attributable to genetic factors was null. The second hypothesis supports that the fraction of variability attributable to apo A-IV genetic variation is 67% and the common spouse environmental factors are responsible for 33% of the total variability and no specific environmental effect was found. Among the two hypotheses, taking account of the metabolism function, we support the first one without excluding gene- environment interactions which could mask the genetic influence. © 1994 Wiley-Liss, Inc.     

Genetic polymorphisms of tumor necrosis factor-alpha modify the association between dietary polyunsaturated fatty acids and fasting HDL-cholesterol and apo A-I concentrations

BACKGROUND: Heterogeneity in circulating lipid concentrations in response to dietary polyunsaturated fatty acids (PUFAs) may be due, in part, to genetic variations. Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine that can induce hyperlipidemia and is known to be modulated by dietary PUFAs. OBJECTIVE: The objective was to determine whether TNF-alpha genotypes modify the association between dietary PUFA intake and serum lipid concentrations. DESIGN: The study involved 53 men and 56 women aged 42-75 y with type 2 diabetes. Dietary intakes were assessed with the use of a 3-d food record, and blood samples were collected to determine fasting serum lipids. DNA was isolated from blood for genotyping by polymerase chain reaction-restriction fragment length polymorphism for the TNF-alpha -238G-->A and -308G-->A polymorphisms. RESULTS: PUFA intake was positively associated with serum HDL cholesterol in carriers of the -238A allele (beta = 0.06 +/- 0.03 mmol/L per 1% of energy from PUFAs; P = 0.03), but negatively associated in those with the -238GG genotype (beta = -0.03 +/- 0.01, P = 0.03) (P = 0.004 for interaction). PUFA intake was inversely associated with HDL cholesterol in carriers of the -308A allele (beta = -0.07 +/- 0.02, P = 0.002), but not in those with the -308GG genotype (beta = 0.02 +/- 0.02, P = 0.13) (P = 0.001 for interaction). A stronger gene x diet interaction was observed when the polymorphisms at the 2 positions (-238/-308) were combined (P = 0.0003). Similar effects were observed for apolipoprotein A-I, but not with other dietary fatty acids and serum lipids. CONCLUSION: TNF-alpha genotypes modify the relation between dietary PUFA intake and HDL-cholesterol concentrations. These findings suggest that genetic variations affecting inflammation may explain some of the inconsistencies between previous studies relating PUFA intake and circulating HDL.     

Serum concentrations of retinol, alpha-tocopherol and the carotenoids are influenced by diet, race and obesity in a sample of healthy adolescents

An important part of understanding the functions of vitamin A, vitamin E and the carotenoids in nutritional status assessment, health promotion and disease prevention is knowledge of factors that influence their distribution in human tissues. Our objective was to examine serum concentrations of these nutrients and compounds in a sample of 285 healthy participants, 12-17 y old, from three U. S. cities. Pearson correlations between diet measured with a food frequency questionnaire and serum nutrient concentrations among these adolescents (adjusted for total serum cholesterol, age, sex, race and body mass index) were as follows: retinol, 0.23; alpha-tocopherol, 0.16; alpha-carotene, 0.31; beta-carotene, 0.15; beta-cryptoxanthin, 0.38; lycopene, 0.08; and lutein + zeaxanthin, 0.25. Multivariate linear regression modeled associations of demographic, dietary and physiologic variables with serum concentrations of these nutrients. African-American participants had significantly lower concentrations of serum retinol (P < 0.001), alpha-tocopherol (P < 0.01) and alpha-carotene (P < 0.02), but higher concentrations of lutein + zeaxanthin (P = 0.001) compared with Caucasians. Obese participants had serum nutrient concentrations that were 2-10% (P < 0.05) lower than normal weight participants. Dietary intake was a significant predictor of all serum analytes (P < 0.01) except lycopene. These models explained 20% of the variability in serum retinol, 28% of the variability in serum alpha-tocopherol, and 14-24% of the variability in serum carotenoids.     

Effects of soluble fiber (Plantago ovata husk) on plasma lipids, lipoproteins, and apolipoproteins in men with ischemic heart disease

BACKGROUND: New dietary strategies to reduce cardiovascular disease (CVD) risk include the addition of fiber to the diet. The effect of soluble-fiber consumption derived from Plantago ovata husk on lipid risk factors in patients with CVD is unknown. OBJECTIVE: We compared the effects of soluble fiber (P. ovata husk) with those of insoluble fiber (P. ovata seeds) on plasma lipid, lipoprotein, and apolipoprotein (apo) concentrations within a CVD secondary prevention program. DESIGN: In a randomized, crossover, controlled, single-blind design, 28 men with CVD (myocardial infarction or stable angina) and an LDL-cholesterol concentration 相似文献   

Factors influencing blood concentration of retinol, alpha-tocopherol, vitamin C, and beta-carotene in the French participants of the SU.VI.MAX trial

OBJECTIVES: The data was collected during the inclusion step of the SUpplémentation en VItamines et Minéraux AntioXydants (SU.VI.MAX) study. This article deals with the study's first stage before any supplementation. The collected data shows factors influencing blood vitamin concentrations and may reflect the vitamin status of volunteers. MATERIAL AND METHODS: A total of 12,741 volunteers were enrolled in the SU.VI.MAX study 7,713 women 35-60 years of age and 5,028 men 50-60 years of age. The serum concentrations of retinol, alpha-tocopherol, and beta-carotene were measured by HPLC, and vitamin C concentration was measured by spectrofluorimetry using a Technicon continuous flow analysis apparatus. The volunteers recorded their 24 h diet by means of a specific terminal that was connected to the main central computer of the SU.VI.MAX study. Volunteers recorded the food they consumed daily and estimated its quantity by comparing pictures of dishes. RESULTS: Retinol concentration was significantly higher in older volunteers, and was higher in male than in female volunteers. Smoking had no effect on serum retinol, but the latter was higher in the autumn than in the winter. Serum retinol concentrations were higher in the Southwest region and lower in the Ile-de-France and East-Centre regions. Serum alpha-tocopherol was slightly higher in older volunteers and also higher in male volunteers. Serum alpha-tocopherol was significantly lower in smokers, and former smokers showed intermediate levels. Like retinol, serum alpha-tocopherol was higher in the autumn, and higher in the Southwest as compared to the East-Centre Serum beta-carotene was slightly higher in younger volunteers, and concentrations were higher in female than in male volunteers. Tobacco smoking decreased serum beta-carotene, which was higher in the autumn, and higher in the East, West, and North regions. Serum vitamin C was higher in female volunteers, and was not age related. Serum vitamin C was lower in smokers, was season-dependant, but contrary to fat-soluble vitamins, concentrations were higher in the winter and spring. Serum vitamin C was higher in the Southeast and East-Centre, but lower in the North region. CONCLUSION: These results suggest that serum retinol concentrations depend on gender, age, seasons, and location of residence. Similarly, serum alpha-tocopherol concentrations were slightly influenced by age, but more by tobacco smoking, seasons, dietary intake, and location of residence. Serum concentrations of beta-carotene depend on gender, age, smoking status, dietary intake, and location of residence. Serum vitamin C concentrations depend on gender, age, smoking status, seasons, dietary intake, and location of residence. Contrary to beta-carotene, retinol concentrations were higher in male than in female volunteers. Such a reversed relation suggests a higher beta-carotene-retinol conversion in male volunteers.     

Effects of simultaneous intakes of indigestible dextrin and diacylglycerol on lipid profiles in rats fed cholesterol diets

OBJECTIVE: Indigestible dextrin (IDex) and diacylglycerol (DG) are food components with physiologic effects on lipid metabolism. Because simultaneous intake of dietary components with similar physiologic functions may produce a beneficial decrease in risk factors for lifestyle-related diseases, we investigated the physiologic effects of simultaneous IDex and DG intake. METHODS: Five-week-old male Wistar rats were fed a cholesterol-containing diet with IDex and DG (separately and combined) for 28 d. RESULTS: IDex significantly decreased serum triacylglycerol concentration and increased the length of small intestinal villi, whereas DG produced significant decreases in serum high-density lipoprotein cholesterol concentration and significant increases in liver cholesterol and triacylglycerol concentrations. CONCLUSIONS: IDex intake characteristically decreased serum triacylglycerol concentrations, although no additive or synergistic interaction between DG and IDex was observed. These results indicate that simultaneous intake of food components with similar physiologic functions do not necessarily produce additive or synergistic physiologic benefits.     

Demographic, dietary and lifestyle factors differentially explain variability in serum carotenoids and fat-soluble vitamins: baseline results from the sentinel site of the Olestra Post-Marketing Surveillance Study

Biochemical measures of nutrients or other dietary constituents can be an important component of nutritional assessment and monitoring. However, accurate interpretation of the nutrient concentration is dependent on knowledge of the determinants of the body pool measured. The purpose of this study was to identify the determinants of serum carotenoid and fat-soluble vitamin concentrations in a large, community-based sample (n = 1042). Multiple linear regression analysis was used to examine effects of demographic characteristics (age, sex, race/ethnicity, education), health-related behavior (exercise, sun exposure, smoking, alcohol consumption), and intake (diet, supplements) on serum retinol, 25-hydroxyvitamin D, alpha-tocopherol, phylloquinone, and carotenoid concentrations. Age, sex, race/ethnicity, vitamin A intake, and alcohol consumption were found to be determinants of serum retinol concentration. Race/ethnicity, vitamin D intake, body mass index, smoking status, and sun exposure were determinants of serum 25-hydroxyvitamin D concentration. Determinants of serum alpha-tocopherol were age, sex, race/ethnicity, alpha-tocopherol intake, serum cholesterol, percentage of energy from fat (inversely related), supplement use, and body mass index. Age, sex, phylloquinone intake, serum triglycerides, and supplement use were determinants of serum phylloquinone concentration. Primary determinants of serum carotenoids were age, sex, race/ethnicity, carotenoid intake, serum cholesterol, alcohol consumption, body mass index, and smoking status. Overall, the demographic, dietary, and other lifestyle factors explained little of the variability in serum concentrations of retinol (R2 = 0.20), 25-hydroxyvitamin D (R2 = 0.24), and the carotenoids (R2 = 0.15-0.26); only modest amounts of the variability in serum phylloquinone concentration (R2 = 0.40); and more substantial amounts of the variability in serum alpha-tocopherol concentration (R2 = 0.62).     

Prevalence and effects of gene-gene and gene-nutrient interactions on serum folate and serum total homocysteine concentrations in the United States: findings from the third National Health and Nutrition Examination Survey DNA Bank

BACKGROUND: Abnormalities of folate and homocysteine metabolism are associated with a number of pediatric and adult disorders. Folate intake and genetic polymorphisms encoding folate-metabolizing enzymes influence blood folate and homocysteine concentrations, but the effects and interactions of these factors have not been studied on a population-wide basis. OBJECTIVE: The objective was to assess the prevalence of these genetic polymorphisms and their relation to serum folate and homocysteine concentrations. DESIGN: DNA samples from 6793 participants in the third National Health and Nutrition Examination Survey (NHANES III) during 1991-1994 were genotyped for polymorphisms of genes coding for folate pathway enzymes 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C-->T and 1298A-->C, methionine synthase reductase (MTRR) 66A-->G, and cystathionine-beta-synthase 844ins68. The influence of these genetic variants on serum folate and homocysteine concentrations was analyzed by age, sex, and folate intake in 3 race-ethnicity groups. RESULTS: For all race-ethnicity groups, serum folate and homocysteine concentrations were significantly related to the MTHFR 677C-->T genotype but not to the other polymorphisms. Persons with the MTHFR 677 TT genotype had a 22.1% (95% CI: 14.6%, 28.9%) lower serum folate and a 25.7% (95% CI: 18.6%, 33.2%) higher homocysteine concentration than did persons with the CC genotype. Moderate daily folic acid intake (mean: 150 microg/d; 95% CI: 138, 162) significantly reduced the difference in mean homocysteine concentrations between those with the MTHFR 677 CC and TT genotypes. We found a significant interaction between MTHFR 677C-->T and MTRR 66A-->G on serum homocysteine concentrations among non-Hispanic whites. CONCLUSIONS: The MTHFR 677C-->T polymorphism was associated with significant differences in serum folate and homocysteine concentrations in the US population before folic acid fortification. The effect of MTHFR 677C-->T on homocysteine concentrations was reduced by moderate daily folic acid intake.     

Clinical and analytical evaluation of the simultaneous HPLC assay of retinol and alpha-tocopherol

We describe a method for the simultaneous assay of retinol and alpha-tocopherol using normal-phase, high-performance liquid chromatography (HPLC). Our normal-phase HPLC method gave better resolution (Rs) of retinol (Rs= 1.58) and alpha-tocopherol (Rs = 1.40) when compared with the Rs values for a-tocopherol and retinol from literature. Also, the alpha-tocopherol concentrations obtained by our method agreed well with another normal-phase HPLC method that used fluorometric detection (r = 0.951, p<0.001. Sy.x=0.58 mg/L). The concentrations of retinol in our method agreed well with those determined by a reversed-phase HPLC procedure, although the correlation (r=0.646, p<.001, Sy.x=62 microg/L) was not as good as the method proposed. Our procedure gave acceptable precision: the within-run CV was 7.7% for alpha-tocopherol and 5.9% for retinol. The between-day CV was 9.0% for alpha-tocopherol and 6.8% for retinol. The mean recoveries were 97% for alpha-tocopherol and 107% for retinol. Our assays were linear for alpha-tocopherol concentrations from 0.1 to 30 mg/L and for retinol concentrations from 20 to 2,000 microg/L. In children ages 7 to 12 y, and in adolescents ages 14 to 16 y, the alpha-tocopherol and retinol concentrations in the blood were significantly lower than the concentrations in normal adults. Individuals over 70 y old also showed alpha-tocopherol and retinol values that were lower than those of normal adults between ages 30 and 40 y. In female university students, the inter-individual variation of alpha-tocopherol was reduced by dividing the alpha-tocopherol results by their total cholesterol or total lipid concentrations; however, this was not obtained for retinol. In cancer patients undergoing surgery, the ratio of retinol to retinol-binding protein (RBP) remained fairly constant, although the concentrations of both retinol and RBP decreased to about one-half the preoperative values after surgery. We conclude that our normal-phase HPLC method is a stable and reproducible method for alpha-tocopherol and retinol, and is an easy-to-use analytical tool.     

Plasma lipoprotein fatty acids are altered by the positional distribution of fatty acids in infant formula triacylglycerols and human milk.

BACKGROUND: Triacylglycerol digestion involves hydrolysis of fatty acids esterified at the glycerol 1,3 positions by gastric and pancreatic lipase to produce 2-monoacylglycerols and unesterified fatty acids, which are then absorbed, reesterified to triacylglycerol, and secreted in chylomicrons. Palmitic acid (16:0) is predominantly esterified to the 2 position of human milk triacylglycerol but to the 1,3 positions in the oils used in infant formulas. OBJECTIVE: We aimed to determine whether the position of 16:0 in human milk and infant formula triacylglycerol influences the position of fatty acids in postprandial plasma chylomicron triacylglycerol. DESIGN: Full-term infants were fed formula with 25-27% 16:0 with either 39% of the 16:0(synthesized triacylglycerol) or 6% of the 16:0 (standard formula) esterified at the triacylglycerol 2 position, or were breast-fed (23% 16:0, 81% at the triacylglycerol 2 position) from birth to 120 d of age. Chylomicron fatty acids and plasma lipids were assessed at 30 and 120 d of age. RESULTS: Infants fed the synthesized triacylglycerol formula, standard formula, or breast milk had 15.8%,8.3%, and 28.0% 16:0 in the chylomicron triacylglycerol 2 position (P < 0.05). These results suggest that >/=50% of the dietary triacylglycerol 2-position 16:0 is conserved through digestion, absorption, and chylomicron triacylglycerol synthesis in breast-fed and formula-fed infants. Infants fed the synthesized triacylglycerol formula had significantly lower HDL-cholesterol and apolipoprotein A-I and higher apolipoprotein B concentrations than infants fed the standard formula. CONCLUSION: Dietary triacylglycerol fatty acid distribution may alter lipoprotein metabolism in young infants.     

Serum retinol, alpha-tocopherol and systemic inflammatory response in metastatic colorectal carcinoma patients treated with combination chemotherapy and cetuximab

Cetuximab is a chimeric antibody registered for the therapy of advanced colorectal carcinoma. Cancer and anticancer therapy are associated with oxidative stress, and disorders of antioxidant balance may be involved in the toxicity associated with anticancer treatment. The aim of the present study was to investigate the changes of serum retinol, alpha-tocopherol and C-reactive protein during the first month of treatment with cetuximab and chemotherapy. Twenty-five consecutive patients with metastatic colorectal carcinoma treated with a combination of chemotherapy and cetuximab were included in the present study. Serum retinol and alpha-tocopherol were determined by high-performance liquid chromatography and serum C-reactive protein was determined using commercial kits. Significant correlation was observed between baseline concentrations of retinol and C-reactive protein (r(s)=-0.54, p<0.01). Median survival of patients who had baseline serum retinol below 1.25 μmol/L was 10 mo compared to 18 mo for patients who had serum retinol equal or above 1.25 μmol/L (p<0.05); median survival of patients who had serum C-reactive protein below 24 mg/L was significantly longer compared to patients with C-reactive protein levels equal or above 24 mg/L (18 vs. 7 mo, p<0.05), but no difference in survival was observed based on alpha-tocopherol levels. Twenty-two patients had evaluation of retinol, alpha-tocopherol and C-reactive protein at least once during the follow up. Serum concentration of alpha-tocopherol decreased significantly during the therapy, but retinol and C-reactive protein concentrations remained unchanged. In conclusion, a significant correlation was observed between serum retinol and C-reactive protein. Serum alpha-tocopherol decreased significantly during the first month of combination therapy with cetuximab. Low retinol and high C-reactive protein concentrations were predictive of poor prognosis in this patient population.     

Serum lipid and apolipoprotein concentrations in healthy men on diets enriched in either canola oil or safflower oil

This randomized, blind study measured changes in serum lipid and apolipoprotein concentrations in 16 men consuming 39 +/- 1% of energy (en%) as fat either from safflower- or canola-oil-based diets for 8 wk. Initially, the men were stabilized for 3 wk on a typical American (baseline) diet. Compared with baseline, the vegetable-oil-based diets reduced serum total cholesterol 9-15% (P less than 0.002), low-density-lipoprotein (LDL)-cholesterol 12-20% (P less than 0.002), and apolipoprotein B-100 21-24% (P less than 0.001). There were no significant changes from baseline to the end of the study in serum triglycerides, total high-density-lipoprotein (HDL) cholesterol, HDL3 cholesterol, HDL2 cholesterol, or apolipoprotein A-I. These data suggest that even if total fat intake remains at 39-40 en%, many men show lowered LDL cholesterol if saturated fatty acid intake is minimized and that diets high in polyunsaturated fatty acids do not necessarily lower HDL-cholesterol concentrations.     

Apolipoprotein E polymorphism and plasma lipid, lipoprotein, and apolipoprotein levels in Italian children.

We have investigated the effect of apolipoprotein (apo) E polymorphism on serum lipid, lipoprotein, and apolipoprotein levels in a sample of 195 children, aged 8-11 years, from Sezze, Central Italy. The relative frequencies of e2, e3, and e4 alleles were 0.062, 0.867, and 0.072, respectively. Variation at the apo E gene locus explained 5.1% of the sample variance in serum total cholesterol levels, 7.6% in low-density lipoprotein (LDL) cholesterol levels, 7.3% in apo B levels, and 14.1% in high-density lipoprotein-apo E (HDL-E) levels. The effect of the e2 allele was to lower levels of total cholesterol, LDL-cholesterol, and apo B and to raise levels of HDL-E, while the effect of the e4 allele was the opposite. Variation at the apo E gene locus was not associated with differences in serum triglyceride, HDL-cholesterol, or apo AI levels. The effects of common apo E polymorphisms and genetic variation associated with the PvuII RFLP of the apo B gene on serum apo B levels were additive, explaining 11.3% of the phenotypic variance in this sample. When the effect of apo E polymorphism on serum lipid traits was estimated in boys and girls separately, variation at the apo E gene locus explained 10.4, 13.3, 13.3, and 13.5% of the phenotypic variance in serum total cholesterol, LDL-cholesterol, apo B, and HDL-E levels, respectively, in boys, while in girls only the effect on HDL-E levels (19.3%) reached statistical significance. This study has demonstrated that genetic variations at the apo E locus contribute to the determination of serum lipid, lipoprotein, and apolipoprotein levels in youths and that the effects are gender specific.