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Kevin B Hicks - One of the best experts on this subject based on the ideXlab platform.
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Phytosterols and their derivatives structural diversity distribution metabolism analysis and health promoting uses
Progress in Lipid Research, 2018Co-Authors: Robert A Moreau, Laura Nystrom, Bruce D Whitaker, Jill K Winklermoser, David J Baer, Sarah K Gebauer, Kevin B HicksAbstract:Phytosterols (plant sterols) occur in the cells of all plants. They are important structural components that stabilize the biological membranes of plants. Sterols can occur in the "free" unbound form or they can be covalently bound via an ester or glycosidic bond. Since our previous 2002 review on Phytosterols and phytosterol conjugates, phytosterol glucosides have been found to be important structural components in the lipid rafts of the plasma membrane of plant cells, where they are thought to be essential to the function of plasma membrane enzymes and perhaps other proteins. Phytosterols also serve as precursors in the synthesis of important bioactive compounds such as steroidal saponins, steroidal glycoalkaloids, phytoecdysteroids, and brassinosteroids. Methods for the analysis of Phytosterols range from traditional gas chromatography of free Phytosterols to modern sophisticated forms of mass spectrometry which have been used for the new field of sterol lipidomics, sometimes called "sterolomics." Phytosterol-enriched functional foods first appeared about twenty years ago and many clinical studies have confirmed the low density lipoprotein (LDL) cholesterol-lowering properties of various types of Phytosterols. In recent years additional clinical studies and more than ten important meta-analyses have provided insights to better understand the cholesterol-lowering and other biological effects of plant sterols.
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Phytosterols phytostanols and their conjugates in foods structural diversity quantitative analysis and health promoting uses
Progress in Lipid Research, 2002Co-Authors: Robert A Moreau, Bruce D Whitaker, Kevin B HicksAbstract:Phytosterols (plant sterols) are triterpenes that are important structural components of plant membranes, and free Phytosterols serve to stabilize phospholipid bilayers in plant cell membranes just as cholesterol does in animal cell membranes. Most Phytosterols contain 28 or 29 carbons and one or two carbon–carbon double bonds, typically one in the sterol nucleus and sometimes a second in the alkyl side chain. Phytostanols are a fully-saturated subgroup of Phytosterols (contain no double bonds). Phytostanols occur in trace levels in many plant species and they occur in high levels in tissues of only in a few cereal species. Phytosterols can be converted to phytostanols by chemical hydrogenation. More than 200 different types of Phytosterols have been reported in plant species. In addition to the free form, Phytosterols occur as four types of “conjugates,” in which the 3β-OH group is esterified to a fatty acid or a hydroxycinnamic acid, or glycosylated with a hexose (usually glucose) or a 6-fatty-acyl hexose. The most popular methods for phytosterol analysis involve hydrolysis of the esters (and sometimes the glycosides) and capillary GLC of the total Phytosterols, either in the free form or as TMS or acetylated derivatives. Several alternative methods have been reported for analysis of free Phytosterols and intact phytosteryl conjugates. Phytosterols and phytostanols have received much attention in the last five years because of their cholesterol-lowering properties. Early phytosterol-enriched products contained free Phytosterols and relatively large dosages were required to significantly lower serum cholesterol. In the last several years two spreads, one containing phytostanyl fatty-acid esters and the other phytosteryl fatty-acid esters, have been commercialized and were shown to significantly lower serum cholesterol at dosages of 1–3 g per day. The popularity of these products has caused the medical and biochemical community to focus much attention on Phytosterols and consequently research activity on Phytosterols has increased dramatically.
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Phytosterols phytostanols and their conjugates in foods structural diversity quantitative analysis and health promoting uses
Progress in Lipid Research, 2002Co-Authors: Robert A Moreau, Bruce D Whitaker, Kevin B HicksAbstract:Phytosterols (plant sterols) are triterpenes that are important structural components of plant membranes, and free Phytosterols serve to stabilize phospholipid bilayers in plant cell membranes just as cholesterol does in animal cell membranes. Most Phytosterols contain 28 or 29 carbons and one or two carbon-carbon double bonds, typically one in the sterol nucleus and sometimes a second in the alkyl side chain. Phytostanols are a fully-saturated subgroup of Phytosterols (contain no double bonds). Phytostanols occur in trace levels in many plant species and they occur in high levels in tissues of only in a few cereal species. Phytosterols can be converted to phytostanols by chemical hydrogenation. More than 200 different types of Phytosterols have been reported in plant species. In addition to the free form, Phytosterols occur as four types of "conjugates," in which the 3beta-OH group is esterified to a fatty acid or a hydroxycinnamic acid, or glycosylated with a hexose (usually glucose) or a 6-fatty-acyl hexose. The most popular methods for phytosterol analysis involve hydrolysis of the esters (and sometimes the glycosides) and capillary GLC of the total Phytosterols, either in the free form or as TMS or acetylated derivatives. Several alternative methods have been reported for analysis of free Phytosterols and intact phytosteryl conjugates. Phytosterols and phytostanols have received much attention in the last five years because of their cholesterol-lowering properties. Early phytosterol-enriched products contained free Phytosterols and relatively large dosages were required to significantly lower serum cholesterol. In the last several years two spreads, one containing phytostanyl fatty-acid esters and the other phytosteryl fatty-acid esters, have been commercialized and were shown to significantly lower serum cholesterol at dosages of 1-3 g per day. The popularity of these products has caused the medical and biochemical community to focus much attention on Phytosterols and consequently research activity on Phytosterols has increased dramatically.
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comparison of oil and phytosterol levels in germplasm accessions of corn teosinte and job s tears
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Robert A Moreau, Vijay Singh, Kevin B HicksAbstract:Seeds of 49 accessions of corn (Zea mays ssp. mays), 9 accessions of teosinte (Zea species that are thought to be ancestors and probable progenitors to corn), and 3 accessions of Job's tears (Coix lacryma), obtained from a germplasm repository, were ground and extracted with hexane. Whole kernel oil yields and levels of four phytonutrients (free Phytosterols, fatty acyl phytosterol esters, ferulate phytosterol esters, and γ-tocopherol) in the oils were measured. Among the seeds tested, oil yields ranged from 2.19 to 4.83 wt %, the levels of ferulate phytosterol esters in the oil ranged from 0.047 to 0.839 wt %, the levels of free Phytosterols in the oil ranged from 0.54 to 1.28 wt %, the levels of phytosterol fatty acyl esters in the oil ranged from 0.76 to 3.09 wt %, the levels of total Phytosterols in the oil ranged from 1.40 to 4.38 wt %, and the levels of γ-tocopherol in the oil ranged from 0.023 to 0.127 wt %. In general, higher levels of all three phytosterol classes were observed in seed oils from ...
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effect of alternative milling techniques on the yield and composition of corn germ oil and corn fiber oil
Cereal Chemistry, 2001Co-Authors: Vijay Singh, Robert A Moreau, Kevin B Hicks, S R EckhoffAbstract:ABSTRACT The effects of alternative corn wet-milling (intermittent milling and dynamic steeping (IMDS), gaseous SO2 and alkali wet-milling) and dry grind ethanol (quick germ and quick fiber with chemicals) production technologies were evaluated on the yield and phytosterol composition (ferulate phytosterol esters, free Phytosterols, and fatty acyl phytosterol esters) of corn germ and fiber oil and compared with the conventional wet-milling process. Small but statistically significant effects were observed on the yield and composition of corn germ and fiber oil with these alternative milling technologies. The results showed that the germ and fiber fractions from two of the alternative wet-milling technologies (the gaseous SO2 and the IMDS) had, for almost all of the individual phytosterol compounds, either comparable or signficantly higher yields compared with the conventional wet-milling process. Also, both of the modified dry grind ethanol processes (the quick germ and quick fiber) with chemicals (SO2 an...
Virgilio P Carnielli - One of the best experts on this subject based on the ideXlab platform.
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plasma phytosterol half life and levels are increased in very low birth weight preterm infants with parenteral nutrition associated cholestasis
Lipids, 2018Co-Authors: Alessio Correani, Chiara Biagetti, Rita Dascenzo, Giovanna Verlato, Paola Cogo, Marco B L Rocchi, Azzurra Pignotti, Luisita Marinelli, Luca Vedovelli, Virgilio P CarnielliAbstract:Parenteral nutrition-associated cholestasis (PNAC) has been linked to plasma accumulation of Phytosterols in infants receiving vegetable-oil-based lipid emulsions (LE). To date, information on the ability of infants with PNAC to metabolize intravenous (IV) Phytosterols has been very limited. We characterized plasma phytosterol half-life in very low birth weight (VLBW) preterm infants with PNAC. As part of a prospective cohort study, VLBW infants with PNAC underwent serial blood sample measurements of sitosterol (Sito), campesterol (Camp), and stigmasterol (Stigma). Infants without PNAC served as controls (CTRL, control infants). Thirty-seven PNAC infants and 14 CTRL were studied. On PN day 7 and PN day 14, PNAC infants had higher plasma phytosterol concentrations compared to those of CTRL (p < 0.05). A significant and positive correlation was found between plasma Camp, Stigma, Sito concentrations, and IV phytosterol intake from birth to PN day 7 (p = 0.001, p = 0.001, and p = 0.005, respectively). Stigma concentration was positively correlated with conjugated bilirubin on PN day 7 (p = 0.012). After stopping IV LE, half-lives of Camp, Stigma, and Sito became significantly longer in PNAC infants than in CTRL (Camp: 18.8 ±6.2 vs 11.8 ±3.0 days, p = 0.001; Stigma: 13.8 ±5.8 vs 9.4 ±3.4 days, p = 0.023; Sito: 15.3 ±5.0 vs 9.8 ±3.0 days, p = 0.002). In conclusion, Phytosterols increased earlier during PN and were eliminated slowly after stopping IV LE in PNAC infants than in CTRL. The Stigma concentration on PN day 7 could represent an early marker of cholestasis. Our results provide additional evidence on the relationship between IV Phytosterols and PNAC.
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half life of plasma Phytosterols in very low birth weight preterm infants on routine parenteral nutrition with vegetable oil based lipid emulsions
Clinical Nutrition, 2016Co-Authors: Daniele Pupillo, Alessio Correani, Chiara Biagetti, Rita Dascenzo, Manuela Simonato, Giovanna Verlato, Paola Cogo, Marco B L Rocchi, Virgilio P CarnielliAbstract:Summary Background Phytosterols in vegetable oil (VO)-based lipid emulsions (LE) likely contribute to parenteral nutrition-associated cholestasis (PNAC) in preterm infants. No characterization of plasma phytosterol half-lives has been done in very low birth weight (VLBW) preterm infants receiving parenteral nutrition (PN) with LE. Methods In a prospective cohort study, 45 VLBW preterm infants who received PN underwent serial blood sample measurements of sitosterol (SITO), campesterol (CAMP), and stigmasterol (STIGM). Plasma phytosterol half-lives were calculated from the phytosterol concentrations–decay curves by using a single-compartment model. Results After the stop of the intravenous LE, study infants had significantly lower plasma total CAMP, STIGM and SITO concentrations. The decay of plasma phytosterol concentrations was monoexponential. Half-life of plasma total CAMP, STIGM and SITO was 13.5 ± 6.9, 10.3 ± 4.5 and 10.3 ± 4.0 days, respectively. Plasma phytosterol half-lives did not correlate with gestational age, birth weight, cumulative phytosterol intakes and plasma conjugated bilirubin. Conclusion VLBW preterm infants on PN with LE had rather long plasma phytosterol half-lives similar to hypercholesterolemic adults and phytosterolemic homozygotes patients. We speculate that the accumulation of Phytosterols could contribute to their vulnerability to PNAC. Clinical trial registry The Ethics Committee of Marche-Italy (DG/469); www.clinicaltrials.gov (identification number NCT02758834 ).
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the effect of 5 intravenous lipid emulsions on plasma Phytosterols in preterm infants receiving parenteral nutrition a randomized clinical trial
The American Journal of Clinical Nutrition, 2013Co-Authors: Sara Savini, Chiara Biagetti, Rita Dascenzo, Paola Cogo, Giulia Serpentini, Adriana Pompilio, Alice Bartoli, Virgilio P CarnielliAbstract:BACKGROUND Elevated plasma phytosterol concentrations are an untoward effect of parenteral nutrition (PN) with vegetable oil-based lipid emulsions (LEs). Phytosterols are elevated in neonatal cholestasis, but the relation remains controversial. OBJECTIVE The objective was to study the effect of 5 LEs on plasma Phytosterols in preterm infants. DESIGN One hundred forty-four consecutive admitted preterm infants (birth weight: 500-1249 g) were studied. Patients were randomly assigned to receive 1 of 5 different LEs: S [100% soybean oil (SO)], MS [50% medium-chain triglycerides (MCTs) and 50% SO], MSF (50% MCTs, 40% SO, and 10% fish oil (FO)], OS (80% olive oil and 20% SO), or MOSF (30% MCTs, 25% olive oil, 30% SO, and 15% FO). Phytosterols in the LEs and in plasma (on postnatal day 7 and day 14) were measured by gas chromatography-mass spectrometry. RESULTS Patients in the S group had significantly higher total phytosterol intakes than did the other study groups. On PN days 7 and 14, plasma phytosterol concentrations were highest in the S group and lowest in the MOSF group. Despite similar β-sitosterol intakes between the MS and MSF groups, plasma concentrations were significantly lower in the MSF than in the MS group. Only 3 patients (2.1%) developed cholestasis: 1 in the MS, 1 in the MSF, and 1 in the MOSF group. No cases of cholestasis were observed in the S and OS groups. CONCLUSIONS In uncomplicated preterm infants receiving routine PN, we found a correlation between phytosterol intake and plasma phytosterol concentrations; however, cholestasis was rare and no difference in liver function at 6 wk was observed.
Robert A Moreau - One of the best experts on this subject based on the ideXlab platform.
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Phytosterols and their derivatives structural diversity distribution metabolism analysis and health promoting uses
Progress in Lipid Research, 2018Co-Authors: Robert A Moreau, Laura Nystrom, Bruce D Whitaker, Jill K Winklermoser, David J Baer, Sarah K Gebauer, Kevin B HicksAbstract:Phytosterols (plant sterols) occur in the cells of all plants. They are important structural components that stabilize the biological membranes of plants. Sterols can occur in the "free" unbound form or they can be covalently bound via an ester or glycosidic bond. Since our previous 2002 review on Phytosterols and phytosterol conjugates, phytosterol glucosides have been found to be important structural components in the lipid rafts of the plasma membrane of plant cells, where they are thought to be essential to the function of plasma membrane enzymes and perhaps other proteins. Phytosterols also serve as precursors in the synthesis of important bioactive compounds such as steroidal saponins, steroidal glycoalkaloids, phytoecdysteroids, and brassinosteroids. Methods for the analysis of Phytosterols range from traditional gas chromatography of free Phytosterols to modern sophisticated forms of mass spectrometry which have been used for the new field of sterol lipidomics, sometimes called "sterolomics." Phytosterol-enriched functional foods first appeared about twenty years ago and many clinical studies have confirmed the low density lipoprotein (LDL) cholesterol-lowering properties of various types of Phytosterols. In recent years additional clinical studies and more than ten important meta-analyses have provided insights to better understand the cholesterol-lowering and other biological effects of plant sterols.
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Phytosterols phytostanols and their conjugates in foods structural diversity quantitative analysis and health promoting uses
Progress in Lipid Research, 2002Co-Authors: Robert A Moreau, Bruce D Whitaker, Kevin B HicksAbstract:Phytosterols (plant sterols) are triterpenes that are important structural components of plant membranes, and free Phytosterols serve to stabilize phospholipid bilayers in plant cell membranes just as cholesterol does in animal cell membranes. Most Phytosterols contain 28 or 29 carbons and one or two carbon–carbon double bonds, typically one in the sterol nucleus and sometimes a second in the alkyl side chain. Phytostanols are a fully-saturated subgroup of Phytosterols (contain no double bonds). Phytostanols occur in trace levels in many plant species and they occur in high levels in tissues of only in a few cereal species. Phytosterols can be converted to phytostanols by chemical hydrogenation. More than 200 different types of Phytosterols have been reported in plant species. In addition to the free form, Phytosterols occur as four types of “conjugates,” in which the 3β-OH group is esterified to a fatty acid or a hydroxycinnamic acid, or glycosylated with a hexose (usually glucose) or a 6-fatty-acyl hexose. The most popular methods for phytosterol analysis involve hydrolysis of the esters (and sometimes the glycosides) and capillary GLC of the total Phytosterols, either in the free form or as TMS or acetylated derivatives. Several alternative methods have been reported for analysis of free Phytosterols and intact phytosteryl conjugates. Phytosterols and phytostanols have received much attention in the last five years because of their cholesterol-lowering properties. Early phytosterol-enriched products contained free Phytosterols and relatively large dosages were required to significantly lower serum cholesterol. In the last several years two spreads, one containing phytostanyl fatty-acid esters and the other phytosteryl fatty-acid esters, have been commercialized and were shown to significantly lower serum cholesterol at dosages of 1–3 g per day. The popularity of these products has caused the medical and biochemical community to focus much attention on Phytosterols and consequently research activity on Phytosterols has increased dramatically.
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Phytosterols phytostanols and their conjugates in foods structural diversity quantitative analysis and health promoting uses
Progress in Lipid Research, 2002Co-Authors: Robert A Moreau, Bruce D Whitaker, Kevin B HicksAbstract:Phytosterols (plant sterols) are triterpenes that are important structural components of plant membranes, and free Phytosterols serve to stabilize phospholipid bilayers in plant cell membranes just as cholesterol does in animal cell membranes. Most Phytosterols contain 28 or 29 carbons and one or two carbon-carbon double bonds, typically one in the sterol nucleus and sometimes a second in the alkyl side chain. Phytostanols are a fully-saturated subgroup of Phytosterols (contain no double bonds). Phytostanols occur in trace levels in many plant species and they occur in high levels in tissues of only in a few cereal species. Phytosterols can be converted to phytostanols by chemical hydrogenation. More than 200 different types of Phytosterols have been reported in plant species. In addition to the free form, Phytosterols occur as four types of "conjugates," in which the 3beta-OH group is esterified to a fatty acid or a hydroxycinnamic acid, or glycosylated with a hexose (usually glucose) or a 6-fatty-acyl hexose. The most popular methods for phytosterol analysis involve hydrolysis of the esters (and sometimes the glycosides) and capillary GLC of the total Phytosterols, either in the free form or as TMS or acetylated derivatives. Several alternative methods have been reported for analysis of free Phytosterols and intact phytosteryl conjugates. Phytosterols and phytostanols have received much attention in the last five years because of their cholesterol-lowering properties. Early phytosterol-enriched products contained free Phytosterols and relatively large dosages were required to significantly lower serum cholesterol. In the last several years two spreads, one containing phytostanyl fatty-acid esters and the other phytosteryl fatty-acid esters, have been commercialized and were shown to significantly lower serum cholesterol at dosages of 1-3 g per day. The popularity of these products has caused the medical and biochemical community to focus much attention on Phytosterols and consequently research activity on Phytosterols has increased dramatically.
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comparison of oil and phytosterol levels in germplasm accessions of corn teosinte and job s tears
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Robert A Moreau, Vijay Singh, Kevin B HicksAbstract:Seeds of 49 accessions of corn (Zea mays ssp. mays), 9 accessions of teosinte (Zea species that are thought to be ancestors and probable progenitors to corn), and 3 accessions of Job's tears (Coix lacryma), obtained from a germplasm repository, were ground and extracted with hexane. Whole kernel oil yields and levels of four phytonutrients (free Phytosterols, fatty acyl phytosterol esters, ferulate phytosterol esters, and γ-tocopherol) in the oils were measured. Among the seeds tested, oil yields ranged from 2.19 to 4.83 wt %, the levels of ferulate phytosterol esters in the oil ranged from 0.047 to 0.839 wt %, the levels of free Phytosterols in the oil ranged from 0.54 to 1.28 wt %, the levels of phytosterol fatty acyl esters in the oil ranged from 0.76 to 3.09 wt %, the levels of total Phytosterols in the oil ranged from 1.40 to 4.38 wt %, and the levels of γ-tocopherol in the oil ranged from 0.023 to 0.127 wt %. In general, higher levels of all three phytosterol classes were observed in seed oils from ...
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effect of alternative milling techniques on the yield and composition of corn germ oil and corn fiber oil
Cereal Chemistry, 2001Co-Authors: Vijay Singh, Robert A Moreau, Kevin B Hicks, S R EckhoffAbstract:ABSTRACT The effects of alternative corn wet-milling (intermittent milling and dynamic steeping (IMDS), gaseous SO2 and alkali wet-milling) and dry grind ethanol (quick germ and quick fiber with chemicals) production technologies were evaluated on the yield and phytosterol composition (ferulate phytosterol esters, free Phytosterols, and fatty acyl phytosterol esters) of corn germ and fiber oil and compared with the conventional wet-milling process. Small but statistically significant effects were observed on the yield and composition of corn germ and fiber oil with these alternative milling technologies. The results showed that the germ and fiber fractions from two of the alternative wet-milling technologies (the gaseous SO2 and the IMDS) had, for almost all of the individual phytosterol compounds, either comparable or signficantly higher yields compared with the conventional wet-milling process. Also, both of the modified dry grind ethanol processes (the quick germ and quick fiber) with chemicals (SO2 an...
Timothy P. Carr - One of the best experts on this subject based on the ideXlab platform.
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phytosterol stearate esters elicit similar responses on plasma lipids and cholesterol absorption but different responses on fecal neutral sterol excretion and hepatic free cholesterol in male syrian hamsters
Nutrition Research, 2011Co-Authors: Jiliang Hang, Patrick H. Dussault, Timothy P. CarrAbstract:Abstract The dietary impact of specific Phytosterols incorporated into phytosterol fatty acid esters has not been elucidated. Therefore, we tested the hypothesis that phytosterol esters containing different sterol moieties (sitosterol, sitostanol, or stigmasterol) but the same fatty acid moiety (stearic acid) produce different effects on cholesterol metabolism. Male Syrian hamsters were fed sitosterol, sitostanol, and stigmasterol stearate esters (25 g/kg diet) in an atherogenic diet containing cholesterol (1.2 g/kg) and coconut oil (80 g/kg). The phytosterol stearates produced no decrease in cholesterol absorption or plasma non–high-density lipoprotein cholesterol despite a reduction in liver free cholesterol in hamsters fed both sitosterol and sitostanol stearate diets. In addition, sitosterol stearate significantly increased fecal esterified and total neutral sterol excretion. Stigmasterol stearate did not differ from control in neutral sterol excretion, plasma lipids, or hepatic lipid concentration. Sitosterol stearate demonstrated the highest level of net intestinal hydrolysis, whereas sitostanol and stigmasterol stearate equivalently demonstrated the lowest. The cholesterol-lowering effect in liver—but not plasma—and the limited presence of fecal free sterols indicate that intact (unhydrolyzed) phytosterol stearates may impact cholesterol metabolism by mechanisms unrelated to the role of free Phytosterols. The consumption of phytosterol esters at 2.5% of the diet elicited only modest impacts on cholesterol metabolism, although sitosterol stearate had a slightly greater therapeutic impact by lowering liver free cholesterol and increasing esterified and total neutral sterol fecal excretion, possibly due to a greater level of intestinal hydrolysis.
Richard E. Ostlund - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Plasma Biomarker of Dietary Phytosterol
2016Co-Authors: Xiaobo Lin, Susan B Racette, Michael Wallendorf, Anderson Spearie, Richard E. OstlundAbstract:Background Dietary Phytosterols, plant sterols structurally similar to cholesterol, reduce intestinal choles-terol absorption and have many other potentially beneficial biological effects in humans. Due to limited information on phytosterol levels in foods, however, it is difficult to quantify habitual dietary phytosterol intake (DPI). Therefore, we sought to identify a plasma biomarker of DPI. Methods and Findings Data were analyzed from two feeding studies with a total of 38 subjects during 94 dietary pe-riods. DPI was carefully controlled at low, intermediate, and high levels. Plasma levels of Phytosterols and cholesterol metabolites were assessed at the end of each diet period. Based on simple ordinary least squares regression analysis, the best biomarker for DPI was the ratio of plasma campesterol to the endogenous cholesterol metabolite 5-α-choles-tanol (R2 = 0.785, P< 0.0001). Plasma campesterol and 5-α-cholestanol levels varied greatly among subjects at the same DPI level, but were positively correlated at each DPI level in both studies (r> 0.600; P< 0.01)
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Natural Dietary Phytosterols.
Journal of AOAC International, 2015Co-Authors: Susan B Racette, Lina Ma, Richard E. OstlundAbstract:Abstract Most clinical phytosterol studies are performed by adding purified supplements to smaller phytosterol amounts present in the natural diet. However, natural dietary Phytosterols themselves may also have important effects on cholesterol metabolism. Epidemiological work using food frequency questionnaires to estimate dietary intake suggest that extremes of normal consumption may be associated with 3-14% changes in LDL cholesterol. Standardized food databases do not have enough phytosterol values to allow calculation of phytosterol intake for individuals outside of specialized studies. Natural diets contain phytosterol amounts ranging from less than 60 mg/2000 kcal to over 500 mg/2000 kcal. Physiological studies in which whole body cholesterol metabolism is investigated show large effects of natural dietary Phytosterols on cholesterol absorption efficiency, cholesterol biosynthesis and cholesterol excretion which exceed the magnitude of changes in LDL cholesterol. The dual effects of natural Phytosterols on both LDL-C and whole body cholesterol metabolism need to be considered in relating them to potential protection from coronary heart disease risk.
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combined effects of ezetimibe and Phytosterols on cholesterol metabolism a randomized controlled feeding study in humans
Circulation, 2011Co-Authors: Xiaobo Lin, Catherine Anderson Spearie, Susan B Racette, Michael Lefevre, Karen Stegermay, Richard E. OstlundAbstract:Background—Both ezetimibe and Phytosterols inhibit cholesterol absorption. We tested the hypothesis that the combination of ezetimibe and Phytosterols is more effective than ezetimibe alone in altering cholesterol metabolism. Methods and Results—Twenty-one mildly hypercholesterolemic subjects completed a randomized, double-blind, placebo-controlled, triple-crossover study. Each subject received a phytosterol-controlled diet plus (1) ezetimibe placebo+phytosterol placebo, (2) 10 mg/d ezetimibe+phytosterol placebo, and (3) 10 mg/d ezetimibe+2.5 g Phytosterols for 3 weeks each. All meals were prepared in a metabolic kitchen. Primary outcomes were intestinal cholesterol absorption, fecal cholesterol excretion, and low-density lipoprotein cholesterol levels. The combined treatment resulted in significantly lower intestinal cholesterol absorption (598 mg/d; 95% confidence interval [CI], 368 to 828) relative to control (2161 mg/d; 95% CI, 1112 to 3209) and ezetimibe alone (1054 mg/d; 95% CI, 546 to 1561; both P<...
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dose effects of dietary Phytosterols on cholesterol metabolism a controlled feeding study
The American Journal of Clinical Nutrition, 2010Co-Authors: Susan B Racette, Catherine Anderson Spearie, Xiaobo Lin, Michael Lefevre, Marlene M Most, Richard E. OstlundAbstract:Background: Phytosterol supplementation of 2 g/d is recommended by the National Cholesterol Education Program to reduce LDL cholesterol. However, the effects of different intakes of phytosterol on cholesterol metabolism are uncertain. Objective: We evaluated the effects of 3 phytosterol intakes on whole-body cholesterol metabolism. Design: In this placebo-controlled, crossover feeding trial, 18 adults received a phytosterol-deficient diet (50 mg Phytosterols/2000 kcal) plus beverages supplemented with 0, 400, or 2000 mg Phytosterols/d for 4 wk each, in random order. All meals were prepared in a metabolic kitchen; breakfast and dinner on weekdays were eaten on site. Primary outcomes were fecal cholesterol excretion and intestinal cholesterol absorption measured with stable-isotope tracers and serum lipoprotein concentrations. Results: Phytosterol intakes (diet plus supplements) averaged 59, 459, and 2059 mg/d during the 3 diet periods. Relative to the 59-mg diet, the 459- and 2059-mg phytosterol intakes significantly (P < 0.01) increased total fecal cholesterol excretion (36 ± 6% and 74 ± 10%, respectively) and biliary cholesterol excretion (38 ± 7% and 77 ± 12%, respectively) and reduced percentage intestinal cholesterol absorption (−10 ± 1% and −25 ± 3%, respectively). Serum LDL cholesterol declined significantly only with the highest phytosterol dose (−8.9 ± 2.3%); a trend was observed with the 459-mg/d dose (−5.0 ± 2.1%; P = 0.077). Conclusions: Dietary Phytosterols in moderate and high doses favorably alter whole-body cholesterol metabolism in a dose-dependent manner. A moderate phytosterol intake (459 mg/d) can be obtained in a healthy diet without supplementation. This trial was registered at clinicaltrials.gov as {"type":"clinical-trial","attrs":{"text":"NCT00860054","term_id":"NCT00860054"}}NCT00860054.
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phytosterol deficient and high phytosterol diets developed for controlled feeding studies
Journal of The American Dietetic Association, 2009Co-Authors: Susan B Racette, Catherine Anderson Spearie, Katherine M. Phillips, Richard E. OstlundAbstract:Abstract Phytosterols reduce cholesterol absorption and low-density lipoprotein cholesterol concentrations, but the quantity and physiological significance of Phytosterols in common diets are generally unknown because nutrient databases do not contain comprehensive phytosterol data. The primary aim of this study was to design prototype phytosterol-deficient and high-phytosterol diets for use in controlled feeding studies of the influence of Phytosterols on health. A second aim was to quantify the phytosterol content of these prototype diets and three other diets consumed in the United States. This study was conducted from June 2001 to September 2008 and involved designing, preparing, and then analyzing five different diets: an experimental phytosterol-deficient control diet, a relatively high-phytosterol diet based on the Dietary Approaches to Stop Hypertension diet, American Heart Association diet, Atkins lifetime maintenance plan, and a vegan diet. A single day of meals for each diet was homogenized and the resulting composites were analyzed for free, esterified, and glycosylated Phytosterols by gas chromatography. Independent samples t tests were used to compare the diets' total phytosterol content. The total phytosterol content of the experimental phytosterol-deficient diet was 64 mg/2,000 kcal, with progressively larger quantities in Atkins, American Heart Association, vegan, and the high-phytosterol Dietary Approaches to Stop Hypertension diet (163, 340, 445, and 500 mg/2,000 kcal, respectively). Glycosylated Phytosterols, which are often excluded from phytosterol analyses, comprised 15.9%±5.9% of total Phytosterols. In summary, phytosterol-deficient and high-phytosterol diets that conform to recommended macronutrient guidelines and are palatable can now be used in controlled feeding studies.