High serum phytosterol levels in short bowel patients on parenteral nutrition support

BACKGROUND & AIMS

Patients with short bowel syndrome (SBS) are often depending on parenteral nutrition support (PNS), sometimes complicated by liver dysfunction. Phytosterols in parenteral lipid emulsions have been suspected to be responsible for cholestasis in paediatric nutrition support. The aim of the present study was to evaluate phytosterol intake and serum phytosterol levels in adult SBS patients.

METHODS

We quantified serum levels of phytosterols, cholesterol, and markers for bile acid and cholesterol synthesis, by gas or liquid chromatography in 21 healthy controls, and in 24 adult SBS-patients, 8 with and 16 without PNS. Phytosterols and cholesterol in parenteral lipid emulsions were also quantified.

RESULTS

Serum levels in SBS-patients without PNS; with PNS; and in controls, were on average for phytosterols 11; 63; and 23 micromol/l (P<0.05 for differences), cholesterol 4,2; 3,8; and 5,1 mmol/l, lathosterol 808; 824; and 228 micromol/100 mmol cholesterol, and 7alpha-hydroxy-4-cholesten-3-one 207;191; and 18 nmol/l, respectively (P<0.05 between controls and SBS). Phytosterols in lipid emulsions ranged from 591 to 958 micromol/l.

CONCLUSIONS

SBS-patients on PNS have higher serum levels of phytosterols than other SBS-patients and controls, possibly because of phytosterols in lipid emulsions. Patients with SBS, regardless of nutrition support, have lower serum levels of cholesterol but higher cholesterol and bile acid synthesis compared to controls.

Micellar Phytosterols Effectively Reduce Cholesterol Absorption at Low Doses

BACKGROUND

The objective of this study was to evaluate the effects of micellar phytosterols on cholesterol absorption in humans.

METHODS

24 healthy adults (mean age 37 years, 16 women and 8 men) underwent four cholesterol-absorption tests to compare the effects of micellar phytosterols supplement containing 500, 300, 200 mg phytosterols and placebo on cholesterol absorption in a cross-over design. Individual absorption tests were separated by 2 weeks. Using the single oral isotope method, inhibition of cholesterol absorption was determined by gas-chromatography mass spectrometry measurement of the differences in plasma hexadeuterated cholesterol enrichment 4 days after test meals with or without phytosterols. Each test meal provided 500 kcal and 89 mg cholesterol including 40 mg tracer cholesterol. We used a general linear mixed model with SAS to test the significance of treatment effect.

RESULTS

Micellar phytosterols had a significant overall effect on cholesterol absorption (p = 0.0002), reduced cholesterol absorption by 23.3% at a dose of 300 mg phytosterols (p = 0.0004) and by 32.0% at a dose of 500 mg phytosterols (p = 0.0001) compared with the placebo. The effect of 200 mg treatment did not reach statistical significance but there was a tendency (p = 0.052).

CONCLUSION

Water-dispersible, micellar phytosterols reduced cholesterol absorption effectively at very low doses.

Functional foods for coronary heart disease risk reduction: a meta-analysis using a multivariate approach

BACKGROUND

It has been difficult to identify the appropriate bioactive substance for the development of new functional foods associated with coronary heart disease, because the results of many clinical studies are contradictory.

OBJECTIVE

The objective of this study was to use the multivariate statistical approach known as principal component analysis (PCA) followed by a mixed model to process data obtained from a meta-analysis aimed at evaluating simultaneously the effect of ingestion of 1 of 3 types of bioactive substances (n-3 fatty acids, soluble fibers, and phytosterols) on 1 or more of 4 biomarkers (plasma total cholesterol, triacylglycerol, LDL cholesterol, and HDL cholesterol).

DESIGN

Five independent variables (number of patients per study, dose, age, body mass index, and treatment length) and 4 dependent variables (percentage change in blood total cholesterol, LDL, HDL, and triacylglycerol) from 159 studies and substudies were organized into a matrix. The original values were converted to linear correlation units, which resulted in a new matrix.

RESULTS

Two principal components were enough to explain 63.73% and 84.27% of the variance in the independent and dependent variables, respectively. Phytosterols and soluble fibers had a hypocholesterolemic effect, whereas n-3 fatty acids lowered triacylglycerol and increased total, LDL, and HDL cholesterol. The PCA and mixed model showed that this behavior was independent of dose, number of patients per study, age, and body mass index but was associated with treatment length.

CONCLUSIONS

PCA is useful for summarizing available scientific information in examinations of health claims for foods and supplements.

Comparison of efficacy of plant stanol ester and sterol ester: short-term and longer-term studies

Published data suggest that the cholesterol-lowering effect of dietary plant sterol esters is less marked in longer-term than in short-term studies, whereas plant stanol esters maintain their efficacy. To investigate this further, healthy subjects and patients with familial hypercholesterolemia (FH) receiving statins were randomized to receive plant sterol ester 1.6 g/day or plant stanol ester 1.6 g/day or 2.6 g/day for 2 months. There was no difference among the 3 groups in the pooled low-density lipoprotein (LDL)-lowering response of FH patients and healthy subjects, but the effect of plant sterol diminished at 2 months and was not significantly different from baseline. This was accompanied by increases in serum plant sterols and a significant decrease in 7alpha-hydroxy-4-cholesten-3-one, a marker of bile acid synthesis, especially in FH patients not taking bile acid sequestrants. In contrast, plant stanol esters lowered significantly both LDL cholesterol and plant sterols at 2 months and had no effect on bile acid synthesis. Slight decreases in serum lipid-soluble antioxidants occurred with both plant sterol and stanol esters. Our findings suggest that absorption of dietary plant sterols downregulates bile acid synthesis, which attenuates their cholesterol-lowering efficacy. We conclude that plant stanol esters are preferable for the long-term management of hypercholesterolemia.

Plant sterols are efficacious in lowering plasma LDL and non-HDL cholesterol in hypercholesterolemic type 2 diabetic and nondiabetic persons

BACKGROUND

Because of hyperglycemia and hyperinsulinemia, diabetic persons have higher cholesterol synthesis and lower cholesterol absorption rates than do nondiabetic persons. Differences in plant sterol efficacy between diabetic and nondiabetic persons have not been examined.

OBJECTIVE

The objective was to compare the degree of response of plasma lipid concentrations and glycemic control to plant sterol consumption in a controlled diet between hypercholesterolemic type 2 diabetic and nondiabetic subjects.

DESIGN

Fifteen nondiabetic subjects and 14 diabetic subjects participated in a double-blinded, randomized, crossover, placebo-controlled feeding trial. The diet included 1.8 g/d of either plant sterols or cornstarch placebo over 21 d, separated by a 28-d washout period.

RESULTS

Plant sterol consumption significantly reduced (P < 0.05) LDL-cholesterol concentrations from baseline in both nondiabetic and diabetic subjects by 15.1% and 26.8%, respectively. The diabetic subjects had significantly (P < 0.05) lower absolute concentrations of total cholesterol after treatment than did the nondiabetic subjects; however, there was no significant difference in the percentage change from the beginning to the end of the trial. There was also a significant decrease (P < 0.05) in absolute non-HDL-cholesterol concentrations after treatment in both groups.

CONCLUSIONS

The results showed that plant sterols are efficacious in lowering LDL cholesterol and non-HDL cholesterol in both diabetic and nondiabetic persons. Plant sterol consumption may exist as a dietary management strategy for hypercholesterolemia in persons with type 2 diabetes.

Phytosterols in nonfat and low-fat beverages have no impact on the LDL size phenotype

OBJECTIVE

To examine the impact of nonfat and low-fat phytosterol-enriched beverages on low-density lipoprotein (LDL) electrophoretic characteristics.

DESIGN

Double-blind, randomized, crossover, placebo-controlled dietary trial.

SETTING

Diets were prepared and consumed at the Mary Emily Clinical Nutrition Research Unit of McGill University. Analyses were performed at the Institute on Nutraceuticals and Functional Foods of Laval University.

SUBJECTS AND INTERVENTION

In total, 15 moderately hypercholesterolemic persons consumed each of three experimental diets that each comprised a different beverage: nonfat placebo (NF control), nonfat with phytosterols (NFPS) or low-fat with phytosterols (LFPS). Participants consumed three beverages daily at meal time for a total of 1.8 g of phytosterols per day. Nondenaturing 2-16% polyacrylamide gradient gel electrophoreses were used to characterize LDL size characteristics.

RESULTS

The NFPS and LFPS beverage induced no significant changes in several features of the LDL size phenotype compared to the control diet.

CONCLUSION

The consumption of phytosterol-supplemented nonfat and low-fat beverages is not associated with clinically meaningful changes in the LDL particle size phenotype.

Combination of dietary phytosterols plus niacin or fenofibrate: effects on lipid profile and atherosclerosis in apo E-KO mice

Patients with mixed dyslipidemias (increased LDL cholesterol and triglyceride as well as low HDL cholesterol levels) benefit from a combination of lipid-modifying drugs such as statins, niacin, fibrates and ezetemibe. However, safety, tolerability and cost are a concern in drug combination therapy. Dietary phytosterols reduce LDL cholesterol, and niacin or fenofibrate primarily reduces triglyceride and increases HDL-cholesterol levels. Thus, we hypothesized that a combination of phytosterols with niacin or fenofibrate will synergistically impact lipoprotein profile and atherogenesis in apo E-KO mice. Phytosterols alone significantly reduced plasma total cholesterol levels (14.1 vs. 16.9 mmol/L, P < .05) and the extent of atherosclerosis (0.42 vs. 0.15 mm(2), P < .05). The addition of fenofibrate to phytosterols increased plasma total cholesterol levels by >50% (14.1 vs. 21.6 mmol/L, P < .05) and decreased HDL-cholesterol concentrations by 50% (0.8 vs. 0.4 mmol/L). These changes were accompanied by slight reductions in the extent of atherosclerosis (0.42 vs. 0.34 mm(2), P > 0.05) as compared to controls, suggesting other potential anti-atherogenic effects of fenofibrate. Unlike fenofibrate, niacin caused an increase of 150% (P < .05) in HDL-cholesterol concentrations and a decrease of 22% (P < .05) in total cholesterol levels which were associated with significant reductions (65%, P < .05) in atherosclerotic lesion size as compared to controls. Neither the addition of niacin nor of fenofibrate reduced plasma triglyceride levels. In conclusion, the addition of niacin to phytosterols synergistically increases HDL-cholesterol levels, while a combination of phytosterols and fenofibrate results in no synergistic effects in apo E-KO mice. Further studies in other animal models are needed to establish synergetic effects between these lipid-modifying dietary and pharmacological agents.

Very long chain fatty acids (policosanols) and phytosterols affect plasma lipid levels and cholesterol biosynthesis in hamsters

The aim of the current study was to examine the effects of very long chain fatty acids (VLCFA) alone at 2 dietary levels, or in combination of VLCFA at the lower level with lecithin (LT) or phytosterols (PS), on lipid profiles and cholesterol biosynthesis in hamsters. Seventy-five male Golden Syrian hamsters, weighing 100 to 120 g, were fed a regular rodent chow for 2 weeks before being randomly assigned into 5 groups of 15 animals each fed semisynthetic diets for 4 weeks. Group 1 was given a control diet that contained 0.25% cholesterol and 5% fat with a polyunsaturated to saturated fatty acids ratio of 0.4. Groups 2 to 5 were fed the control diet and given 25 mg/kg BW per day of VLCFA (Licowax) (VLCFA25), 50 mg/kg BW per day of VLCFA (VLCFA50), 25 mg/kg BW per day of VLCFA+1000 mg/kg BW per day of LT (VLCFA25/LT), and 25 mg/kg BW per day of VLCFA+1000 mg/kg BW per day of PS (Cholestatin, VLCFA25/PS), respectively. Results showed that HDL-cholesterol (HDL-C) levels were not changed by VLCFA25, although increased by VLCFA50 (P<.05) relative to control. Total cholesterol (T-C) and non-HDL-C levels were not affected by VLCFA25 and VLCFA50 as compared with control. VLCFA25/LT had higher (P<.02) T-C and HDL-C levels than any other treatments and increased (P<.05) liver weight relative to control. In contrast, VLCFA25/PS reduced T-C (P=.0004) and non-HDL-C (P=.007) without effect on HDL-C levels compared with control. Triglyceride levels were not affected by any treatment. Cholesterol biosynthesis rate was higher (P<.05) in animals fed VLCFA25 and VLCFA50 than those fed control or VLCFA25/LT or VLCFA25/PS. Results suggest that PSs can decrease total and non-HDL-C cholesterol, whereas VLCFA may increase HDL-C in hamsters.

Changes in intestinal and liver global gene expression in response to a phytosterol-enriched diet

BACKGROUND

Dietary phytosterols are a recommended therapeutic option for decreasing plasma cholesterol. The increased activity of ATP-binding cassette (ABC) transporters ABCA1, ABCG5 and ABCG8, or, alternatively, a decrease in Niemann-Pick C1 Like 1 (NPC1L1) could mediate the reduction in intestinal cholesterol absorption caused by phytosterols. Other biological properties such as a direct immune modulatory activity have recently been ascribed to these plant compounds.

METHODS

To gain insight into the molecular effects of phytosterols, global genome-wide gene profiling and real-time RT-PCR studies were conducted in small intestines and livers of phytosterol-treated apolipoprotein E-deficient (apoE(-/-)) mice. Re-testing of the main results was performed in C57BL/6J and LDL receptor-deficient (LDLR(-/-)) mice.

RESULTS

Intestinal cholesterol absorption was decreased in all mouse models but plasma cholesterol was only decreased in apoE(-/-) and LDLR(-/-) mice. ABCA1, ABCG5, ABCG8 and NPC1L1 mRNA levels were slightly reduced in the intestine of phytosterol-treated apoE(-/-) and LDLR(-/-) mice, but increased in C57BL/6J-treated mice. Phytosterols changed genes involved in immune regulation in apoE(-/-) mice. However, these changes were less extensive in LDLR(-/-) mice and were not found in C57BL/6J mice.

CONCLUSIONS

Inhibition of intestinal cholesterol absorption by phytosterols is not mediated via transcriptional changes in ABCA1, ABCG5, ABCG8 or NPC1L1. Changes suggestive of immunomodulation are associated with the hypocholesterolemic effect of phytosterols and with apoE deficiency.

Development and characterization of liposomal disodium ascorbyl phytostanyl phosphates (FM-VP4)

The specific objectives of this project were (1) to develop liposomal disodium ascorbyl phytostanyl phosphate (FM-VP4) formulations, (2) to develop a liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) assay for quantification of FM-VP4 in liposomal formulations and plasma sample, and (3) to characterize liposomal FM-VP4 formulations by finding optimal drug-to-lipid ratios and determining the degradation of FM-VP4 in liposomes. Section 2 describes an LC/MS/MS assay developed for the identification and quantification of FM-VP4 in liposomal formulations to provide estimates of drug concentrations and encapsulation efficiency. The extra step of removing plasma proteins prior to LC/MS/MS assay yields an analysis of FM-VP4 in plasma samples. Section 3 describes experiments designed to find the optimal drug-to-lipid ratio for liposomal FM-VP4 formulations by comparing encapsulation efficiencies and varying the lipid compositions. Additionally, this section details our degradation studies to determine if liposomes have any protective effects on FM-VP4; these studies tested various lipid compositions at 37 degrees C in rabbit plasma. The mechanism of how FM-VP4 lowers low-density lipoprotein (LDL) cholesterol and total cholesterol levels in various animal models is presently unknown. However, before the mechanism of action could be studied, FM-VP4 first had to be delivered efficiently into plasma or cultured cell. The low systemic bioavailability and cellular uptake of FM-VP4 further suggested the importance of finding an efficient delivery vehicle for this drug. This project proposed a framework for such delivery and paves the way for further investigation into how FM-VP4 works in vivo and in vitro.

Effect of high plant sterol-enriched diet and cholesterol absorption inhibitor, SCH 58235, on plant sterol absorption and plasma concentrations in hypercholesterolemic wild-type Kyoto rats

BACKGROUND AND AIMS

Plant sterols are widely distributed in human diet but are poorly absorbed so that their plasma levels are very low. However, when fed in large amounts, they lower plasma cholesterol levels by interfering with cholesterol absorption. We have studied the effect of 4 weeks of feeding a chow diet supplemented with 1% plant sterols [brassicasterol (6.3%), campesterol (28.5%), stigmasterol (15.6%) and sitosterol (49.6%)], with or without SCH 58235 (a derivative of ezetimibe), 30 mg/kg per day, known to suppress intestinal cholesterol absorption, on plasma, tissue, biliary, and fecal sterols in Wistar and wild-type Kyoto (WKY) rats, and their metabolism by intestinal bacteria.

METHODS

After 2 weeks of feeding control or experimental diet, rats were given [3alpha-(3)H]sitosterol intravenously and [4-(14)C]sitosterol by mouth, and blood was collected after 1, 2, 3, and 5 days after labeling to determine sitosterol absorption. Feces were collected during the last 3 days and freeze dried. At the end of feeding, bile fistulas were created in 3 rats of each strain and bile was collected for 1 hour. All rats were then sacrificed and plasma and liver were collected for sterol measurements and activities of hepatic HMG-CoA reductase, cholesterol 7alpha-hydroxylase, and cholesterol 27-hydroxylase.

RESULTS

Wild-type Kyoto rats were hypercholesterolemic compared to Wistar rats and had increased plant sterols in the plasma. Plasma cholesterol tended to be lower in WKY rats after feeding with plant sterol-enriched diet whereas plant sterol levels rose to approximately 31% of plasma sterols in WKY and 14% in Wistar rats. However, brassicasterol and stigmasterol, with a double bond at C-22, constituted less than 3.5% of total plasma plant sterols. After feeding, biliary plant sterols increased 2.25-fold in Wistar and 1.5-fold in WKY rats, suggesting less hepatic clearance in WKY rats. SCH 58235 feeding significantly increased plasma as well as biliary cholesterol levels in both the untreated and plant sterol-fed WKY rats, and the plasma plant sterols showed a tendency to increase but did not reach significant level. Intestinal bacteria in both rat strains metabolized all plant sterols to mainly the 5beta-H-stanols. However, the C-22 double bond was stable to bacterial degradation. Intestinal absorption of sitosterol and cholesterol was increased 1.5- and 1.3-fold, respectively, in the WKY rats as compared to the Wistar rats, and plant sterol feeding lowered absorption of these sterols in both strains. Absorption of both these sterols was also lowered in SCH 58235-treated rats in both strains and was further lowered when SCH 58235 and plant sterols were simultaneously fed. The activity of the rate-limiting enzyme, HMG-CoA reductase, was increased 1.57-fold in Wistar rats and 1.27-fold in WKY rats that were fed plant sterols as compared to untreated rats.

CONCLUSIONS

(1) Plant sterol absorption was increased whereas hepatic elimination of all sterols was diminished in WKY rats accounting for elevated cholesterol and plant sterol levels. (2) The 1% plant sterol-enriched diet tended to lower plasma cholesterol levels whereas SCH 58235 feeding significantly increased plasma cholesterol levels in the WKY rats. (3) Intestinal absorption of sterols with C-22 double bond is diminished and the side-chain double bond is resistant to intestinal bacteria.

Increased intake of fruit and vegetables and a low-fat diet, with and without low-fat plant sterol-enriched spread consumption: effects on plasma lipoprotein and carotenoid metabolism

BACKGROUND

Regular intake of plant sterol (phytosterol)-enriched foods enhances the cholesterol lowering effect of diets. One side effect associated with plant sterol consumption is a modest reduction in plasma carotenoid concentrations. This study investigated the effect of consuming a low-fat National Cholesterol Education Programme (NCEP) Step 1 diet, including a low-fat plant sterol ester (PSE)-enriched spread on cholesterol metabolism to determine if specific dietary advice to increase daily fruit and vegetable intake could prevent reduced plasma carotenoid concentrations.

MATERIALS AND METHODS

In this randomised, crossover double-blind trial, 48 hypercholesterolaemic men received 21 g day(-1) of a low-fat PSE-enriched spread or placebo for 3 weeks, interrupted by 3 weeks washout. Individuals also adhered to a NCEP Step 1 diet and repeated 3-day food diaries monitored adherence. Specific advice was provided to increase dietary fruit and vegetable intakes. Fasting blood samples were collected at pre- and post-intervention for lipoprotein and carotenoid analysis.

RESULTS

Plasma total and low-density lipoprotein (LDL) cholesterol concentrations were significantly (P <0.05) reduced, by 4.6 and 7.1%, respectively, after the PSE-enriched low-fat spread. Plasma apo B concentrations were significantly (P <0.0005) lower after the PSE spread. PSE consumption was also associated with significantly (P <0.05) lower total plasma beta-carotene concentrations, but this change was not significant after lipid standardisation. PSE consumption had no effect on retinol, alpha-carotene, gamma-tocopherol, alpha-tocopherol, lutein, zeaxanthin, beta-crypyoxanthin or lycopene concentrations.

CONCLUSION

Dietary advice to increase daily fruit and vegetable consumption may be effective in preventing a reduction in plasma carotenoid concentrations previously associated with PSE consumption. Further, PSE incorporated in a low-fat spread and consumed as part of a NCEP Step 1 diet are effective in reducing total and LDL cholesterol.

Evaluation of lipid oxidation after ingestion of bakery products enriched with phytosterols, β-carotene and α-tocopherol

BACKGROUND AND AIMS

The aim of this study was to investigate the effect of the consumption of croissants and magdalenas (Spanish muffins), enriched with sterol esters, alpha-tocopherol and beta-carotene, on plasma lipid peroxidation. TBA and conjugated dienes were used as markers of lipid peroxidation.

METHODS

The study was made to a population without changes in their diet or lifestyle, and based on a randomized double-blind controlled repeated measures design. The sample size was 57. During 8 weeks, the subjects of the control group (29) received two daily pieces (standard croissant and muffin), whereas those of the experimental group (28) received the same products, but enriched with sterol-esters, alpha-tocopherol and beta-carotene.

RESULTS

The treatment has a positive effect on TBA value for control group and that given to experimental group has negative effect. The mean difference between two groups is 3.16 (P = 0.044). Also TBA was found to be significantly correlated with HDL-, LDL-cholesterol and alpha-tocopherol, both before and after treatment, but TBA was only significantly correlated with beta-carotene before treatment. Finally, the effects on LDL-cholesterol, alpha-tocopherol and TBA presented similar correlation matrices in the two groups, most correlation coefficients being significant at group level, in spite of the low sample sizes, revealing the association between treatment effects.

Incorporation of oxyphytosterols in tissues of hamster

Oxyphytosterols (OPS) were fed to hamsters, at different concentrations, in order to observe their eventual incorporation into plasma, aorta, liver, kidneys and heart. The animals receiving the very high level (2500 ppm) presented 7beta-hydroxycampesterol, beta-epoxycampesterol, campestanetriol, 7-ketocampesterol, 7beta-hydroxysitosterol, beta-epoxysitosterol, sitostanetriol and 7-ketositosterol in all tissues. The same compounds were observed in the tissues of animals receiving 500 ppm of OPS in their diet, but with much lower levels. In hamsters fed 100 ppm of OPS, as well as in control animals, in most cases, the only observed OPS was sitostanetriol, which seems to be difficult to eliminate from the animal.

Sitostanetriol is not formed in vivo from sitosterol in the rat

In a recent study, we observed some oxyphytosterols in the plasma of healthy human subjects. This experiment was effected in order to determine if these compounds could be formed in vivo from phytosterols. Rats were fed with a high level of phytosterols (1% of the diet) and they were compared to rats deprived of phytosterols, using triglycerides purified from phytosterols. Their plasma were analysed for the main oxyphytosterols. The results show that sitostanetriol and campestanetriol were not formed in vivo from phytosterols. Their levels decreased during the experiment. The diet origin is highly probable for the compounds identified in human plasma. In particular, it seems that the sitostanetriol is eliminated very slowly from the organism.

Factors other than phytosterols in some vegetable oils affect the survival of SHRSP rats

Unusual survival-shortening activities of some vegetable oils were detected in stroke-prone spontaneously hypertensive (SHRSP) rats, and phytosterol (PS) in the oils and the tissue tocopherol status have been suggested to be the factors for the activities. Here, we re-evaluated the contribution of PS to the survival-shortening, and examined the hepatic tocopherol status. A basal diet for rodents and a test oil were mixed at a 9:1 ratio, and the diet was given to male SHRSP rats upon weaning. The total and major PS contents of the diets and tissue lipids did not correlate with relative survival time. The free fatty acid fractions obtained by lipase and alkaline hydrolyses of canola oil (Can) and the original Can contained PS in comparable amounts but the free fatty acid fractions did not exhibit survival-shortening activities compared with the soybean oil (Soy) group. The activity was not detected in the ethyl acetate extracts of the aqueous phase after the hydrolysis. When a commercially available PS preparation was added to the Soy diet at an amount 2.8-fold higher than that in the Can diet, the mean survival time was shortened but was still significantly longer than that of the Can group. The hepatic tocopherol level was significantly higher in the Can group than in the hydrogenated Soy group and Soy group, but the former two groups exhibited a survival-shortening activity. These results indicate that factors other than PS, tocopherol status and fatty acid composition in some vegetable oils are critical for the survival-shortening activity observed in SHRSP rats.

Plant sterol ester-enriched milk and yoghurt effectively reduce serum cholesterol in modestly hypercholesterolemic subjects

BACKGROUND

The cholesterol-lowering efficacy of plant sterol esters (PSteE) or stanol esters (PStaE) in regular- and low-fat spreads has been consistently demonstrated, while their effectiveness in a low-fat, aqueous food carrier such as milk and yoghurt is less well established.

AIM OF THE STUDY

Two studies were carried out to assess the cholesterol-lowering effect of PSteE-enriched low-fat milk and PSteE- and PStaE-enriched low-fat yoghurt in modestly hypercholesterolemic subjects (total cholesterol between 5-7.5 mmol/l).

METHODS

Study one was a single blind crossover design with 4 phases of 3-week interventions. Subjects consumed 300 ml/d of placebo or PSteE-milk (2.0 g plant sterols/d) alone or combined with 25 g/d of placebo or PSteE-spread. Study two was a fully randomised, double blind crossover design with 3 phases of 3-week interventions. Subjects consumed 2 portions (150 g tubs each) of placebo, PSteE-yoghurt (1.8 g plant sterols/d) or PStaE-yoghurt (1.7 g plant stanols/d). In study one 39 subjects (21 men and 18 women) and in study two 40 subjects (17 men and 23 women) completed the dietary intervention.

RESULTS

In study one, PSteE-milk and PSteE-spread were equally efficacious in lowering total and LDL-cholesterol as compared to placebo by 6-8% and 8-10%, respectively. No significant additional cholesterol-lowering was observed with the combination of PSteE-milk and PSteE-spread (4 g plant sterols/d). PSteE-enriched milk and the combination of PSteE-enriched milk plus spread both lowered lipid-adjusted serum beta-carotene concentrations by 10-14% (P < 0.02),while the PSteE-rich spread alone did not significantly alter serum beta-carotene levels. In study two, the PSteE- and PStaE-enriched yoghurts reduced LDL-cholesterol significantly compared to placebo by 0.27 +/- 0.05 mmol/l (6%) and 0.23 +/- 0.05 mmol/l (5%), respectively. In both studies, there was no effect on HDL-cholesterol and triacylglycerol concentrations.

CONCLUSION

Plant sterols in the form of their esters when provided in lowfat milk and yoghurt are effective in lowering total and LDL-cholesterol.

Cholesterol-lowering effects of plant sterol esters differ in milk, yoghurt, bread and cereal

OBJECTIVE

To measure the relative effects of each of four phytosterol ester-enriched low-fat foods (bread, breakfast cereal, milk and yoghurt) on serum lipids, plasma phytosterols and carotenoids.

DESIGN

: Three research centres undertook a randomised, incomplete crossover, single-blind study consisting of four treatment periods of 3 weeks each, one of which was a control period. Each sterol-enriched test food provided 1.6 g/day of phytosterols as sterol esters.

SETTING

General Community.

SUBJECTS

In all 58, free-living men and women with mean age (s.d.) 54 (8) y, moderately elevated plasma total cholesterol 6.2 (0.7) mmol/l and body mass index 26.2 (3.0) kg/m(2).

MAIN OUTCOME MEASURES

Serum lipids, plasma phytosterols and carotenoids.

RESULTS

Serum total and LDL cholesterol levels were significantly lowered by consumption of phytosterol-enriched foods: milk (8.7 and 15.9%) and yoghurt (5.6 and 8.6%). Serum LDL cholesterol levels fell significantly by 6.5% with bread and 5.4% with cereal. They were both significantly less efficacious than sterol-enriched milk (P<0.001). Plasma sitosterol increased by 17-23% and campesterol by 48-52% with phytosterol-enriched milk and bread. Lipid-adjusted beta-carotene was lowered by 5-10% by sterols in bread and milk, respectively.

CONCLUSIONS

This is the first study to demonstrate that cholesterol-lowering effects of plant sterol esters may differ according to the food matrix. Plant sterols in low-fat milk was almost three times more effective than in bread and cereal. Despite phytosterol-enriched cereal products resulting in lower serum cholesterol reductions compared to sterol-enriched milk, the detection of similar changes in plasma phytosterols demonstrated that such products still delivered and released phytosterols to the gut.

Long-term compliance and changes in plasma lipids, plant sterols and carotenoids in children and parents with FH consuming plant sterol ester-enriched spread

OBJECTIVE

To study the compliance and changes in plasma lipids, plant sterols, fat-soluble vitamins and carotenoids in children and parents with familial hypercholesterolemia (FH) consuming a plant sterol ester-enriched (PSE) spread.

DESIGN

A 26-week open-label follow-up of children who had previously been studied in a controlled cross-over design. The parents were also included in the open-label arm of the study.

SETTING

Outpatient clinic for treatment of hyperlipidemia.

SUBJECTS

A total of 37 children (7-13 y) and 20 parents (32-51 y) diagnosed with 'definite' or 'possible' heterozygous FH. In all, 19 of the parents, but no children, used statins. All were patients at the Lipid Clinic, National Hospital in Oslo.

INTERVENTIONS

Subjects were recommended to eat 20 g/day of PSE spread as part of their lipid-lowering diet.

RESULTS

The mean intake of PSE spread was 13.7 and 16.5 g/days in the children and parents, respectively, corresponding to 1.2 and 1.5 g of plant sterols. Plasma total cholesterol decreased by 9.1% in both children (P<0.001) and parents (P=0.002). The corresponding decreases in LDL cholesterol were 11.4% (P<0.001) and 11.0% (P=0.012). Increases in serum lathosterol, campesterol and sitosterol, adjusted for total cholesterol, were observed in the children (31, 96, 48%, respectively, P<0.001) at the end of the controlled cross-over period. In the parents, serum campesterol and sitosterol, adjusted for total cholesterol, increased by 92 and 39%, respectively (P< 0.001). Lipid-adjusted serum alpha- and beta-carotene decreased by 17.4% (P=0.008) and 10.9% (P=0.018), respectively, in the children at the end of the controlled PSE period, but increased again during the follow-up. In the parents, serum alpha- and beta-carotene concentrations were unchanged, while serum lutein and lycopene decreased by 7.3% (P=0.037) and 14.6% (P=0.044), respectively.

CONCLUSIONS

Sustained efficacy of cholesterol reduction and long-term compliance of PSE intake were demonstrated in this study.

Removal of intravenous Intralipid in patients with familial hypercholesterolemia during inhibition of cholesterol absorption and synthesis

BACKGROUND

While plant stanols are known to upregulate low density lipoprotein (LDL) receptors, we studied the effects of plant stanol (STA) and sterol (STE) ester spreads on triglyceride-rich lipoprotein (TRL) removal in statin-treated patients with familial hypercholesterolemia (FH) using intravenous Intralipid-squalene fat tolerance test.

METHODS

Five patients consumed STA and STE in a randomized, crossover study for 4 weeks. TRL removal was studied at baseline and at the end of both periods. Serum, chylomicron (CM), and very low density lipoprotein lipids, squalene, and plant sterols were measured.

RESULTS

LDL cholesterol was decreased by both spreads (15-16%, p<0.05). Plant sterol concentrations were doubled in serum and CM by STE vs. STA. After the injection of Intralipid, CM squalene and sitosterol, but not triglycerides (TG), reached higher peak levels (and area under the incremental curve (AUIC) of squalene) by both spreads than at baseline. Despite different plant sterol concentrations by STE vs. STA, the incremental curves for plant sterols were similar by the spreads.

CONCLUSIONS

Despite the retarded removal of TRL lipids by STA and STE in the statin-treated subjects with FH, improvement of the fasting lipid profile was suggested important in consideration of combination of cholesterol absorption inhibitor with statins even in FH.

Comparison of the effects of dietary plant sterol and stanol esters on lipid metabolism

BACKGROUND AND AIM

To compare the cholesterol-lowering efficacy and other metabolic effects of plant sterol and stanol esters, both of which are commonly used in the dietary management of hypercholesterolaemia.

METHODS AND RESULTS

The cholesterol-lowering efficacy of equivalent intakes of sterol and stanol esters and of different intakes of stanol esters were compared at 1 and 2 months, both in normal subjects and treated patients with familial hypercholesterolaemia. Systemic effects were assessed by measuring serum levels of plant sterols and of lathosterol and 7alpha-hydroxy-cholestenone, indices of sterol absorption and of cholesterol and bile acid synthesis respectively. There were no significant differences during the study between 1.6g daily of sterol and stanol esters in reducing total cholesterol (by 3-7%) or low density lipoprotein cholesterol (by 4-8%), nor between 1.6 and 2.6 g daily of stanol. However, the cholesterol-lowering effect of plant sterol esters was attenuated between 1 and 2 months. This was accompanied by increased serum plant sterols and decreased levels of 7alpha-hydroxy-cholestenone, especially in statin-treated hypercholesterolaemic patients not taking bile acid sequestrants.

CONCLUSIONS

These findings suggest that absorption of dietary plant sterols suppressed bile acid synthesis, thereby diminishing their cholesterol-lowering efficacy. In contrast, plant stanols reduced plant sterol absorption and maintained their cholesterol-lowering efficacy.

Potential intake of phytosterols/-stanols: results of a simulation study

BACKGROUND

Different doses of phytosterols/-stanols up to a maximum of 4.0 g/day have been used in human safety studies, whereas only one small-scale study investigated some detailed clinical information about consumption levels exceeding 8.6 g/day.

OBJECTIVE

To determine which population groups are likely to be at risk of excessive intakes if liberal enrichment of foods with phytosterols/-stanols will be allowed.

DESIGN AND SUBJECTS

Cross-sectional study among a representative sample (n=23 106) of the Dutch population, aged 20-60 y (MORGEN-project, 1993-1997). Phytosterol/-stanol intake was assessed with virtual replacement of one to four ordinary foods in the diet with enriched products. Percentile values were used to describe the distribution in simulated intake for different groups in the population, varying in sociodemographic and health characteristics. Multiple linear regression was used to describe the contribution of the different population characteristics to the simulated phytosterol/-stanol intake.

RESULTS

If three commonly consumed products (margarine, cheese, yoghurt) were completely replaced, the median daily phytosterol/-stanol intake will be about 5.5 g in men and 4.6 g in women. In males, the intake above the 90th percentile will exceed 8.6 g/day. Women will approach this level. Especially, age, body mass index, socioeconomic status, subjective health, smoking behaviour, alcohol consumption, pregnancy (women) and high cholesterol level (men) contributed to the variance in the simulated intake (P<0.05), although the total explained variance was low (1-3%).

CONCLUSIONS

If liberal phytosterol/-stanol fortification is allowed, the daily intake might exceed the recommended intake level as well as our 'cutoff' level of 8.6 g/day. Postlaunch monitoring to identify consumers and real intake levels, refinement of scenario buiding, as well as human safety studies for levels above 8.6 g/day are necessary.