Carob pulp preparation rich in insoluble fibre lowers total and LDL cholesterol in hypercholesterolemic patients

Summary. Background: Recently, insoluble fibre from carob pulp has been found to affect blood lipids in animals in a similar manner as soluble dietary fibre. Aim of the study: To investigate whether a carob pulp preparation containing high amounts of insoluble fibre has a beneficial effect on serum cholesterol in humans. Methods: Volunteers (n = 58) with hypercholesterolemia were recruited to participate in a randomised, double- blind, placebo-controlled and parallel arm clinical study with a 6 week intervention phase. All participants consumed daily both, bread (two servings) and a fruitbar (one serving) either with (n = 29) or without (n = 29) a total amount of 15 g/d of a carob pulp preparation (carob fibre). Serum concentrations of total, LDL and HDL cholesterol and triglycerides were assessed at baseline and after week 4 and 6. Results: The consumption of carob fibre reduced LDL cholesterol by 10.5 ± 2.2% (p = 0.010). The LDL:HDL cholesterol ratio was marginally decreased by 7.9 ± 2.2 % in the carob fibre group compared to the placebo group (p = 0.058). Carob fibre consumption also lowered triglycerides in females by 11.3 ± 4.5% (p = 0.030). Lipid lowering effects were more pronounced in females than in males. Conclusion: Daily consumption of food products enriched with carob fibre shows beneficial effects on human blood lipid profile and may be effective in prevention and treatment of hypercholesterolemia.     

Non-esterified plant sterols solubilized in low fat milks inhibit cholesterol absorption--a stable isotope double-blind crossover study

Summary. Background: The cholesterol absorption inhibiting properties of plant sterols in milks are unknown. The milk fat globule membrane components may enhance the absorption of cholesterol and could make plant sterols less efficient in this complex matrix. Aim of the study: To evaluate in hypercholesterolemic men the cholesterol absorption inhibiting properties of verified properly solubilized, non-esterified plant sterols in partly vegetable oil containing milks. Methods: The plant sterols in milk were determined to be properly solubilized, and to have effective in vitro functionality. Sixteen hypercholesterolemic adult men (initial total cholesterol 5.8–8.6 mM) then consumed milk containing sterols (1.8 g of non-esterified pure plant sterols/d) and control milk, alternatively, during two 6-day periods in a double blind cross over design. During the trial, cholesterol absorption was evaluated from the ratio of plasma isotopic enrichment of [26, 26, 26, 27, 27, 27–²H₆]cholesterol from oral intake (35.6 ± 0.2 μmol, ± SEM) over enrichment of [23, 24, 25, 26, 27–¹³C₅]cholesterol from intravenous injection (77.9 ± 0.5 μmol). Results: Plant sterols in low fat milks contained very few crystals > 11 μm in the presence and absence of bile salts and lysophospholipids, and inhibited cholesterol uptake in Caco-2 cell. This assured that the sterols were properly solubilized prior to the clinical trial. In the clinical study, compliance of volunteers was excellent. After tracer injections (72 h), the plasma [²H] and [¹³C] isotopic enrichments changed from 0.024 ± 0.001 and 0.072 ± 0.003 MPE (control) to 0.015 ± 0.001 and 0.074 ± 0.002 MPE during sterol treatment, respectively. Cholesterol absorption was reduced from 70.1 ± 4.2 % with control to 41.1 ± 4.0 % with milks containing plant sterol (P < 0.001). Conclusions: These results demonstrate that properly solubilized non-esterified plant sterols in milks significantly inhibit cholesterol absorption in mildly hypercholesterolemic men. Received: 10 October 2002, Accepted: 8 January 2003 Correspondence to: Etienne B. Pouteau     

The effect of plant sterol-enriched turkey meat on cholesterol bio-accessibility during in vitro digestion and Caco-2 cell uptake

This study evaluated the effect of a plant sterol-enriched turkey product on cholesterol bio-accessibility during in vitro digestion and cholesterol uptake by Caco-2 monolayers. Turkey products, one plant sterol-enriched (PS) and one plant sterol-free (C), were produced in an industrial pilot plant. Before simulated digestion, matrices were spiked with cholesterol (1:5 weight ratio of cholesterol to plant sterol). Plant sterols were included at a concentration equivalent to the minimum daily intake recommended by the European Food Safety Authority (EFSA) for cholesterol lowering. After simulated digestion, the percentage of cholesterol micellarization and uptake by Caco-2 cells in the presence of PS meat were measured. Compared to C meat, PS meat significantly inhibited cholesterol micellarization on average by 24% and Caco-2 cell accumulation by 10%. This study suggests that plant sterols in meat can reduce cholesterol uptake by intestinal epithelia and it encourages efforts to make new PS-based functional foods.     

Effects of non-esterified stanols in a liquid emulsion on cholesterol absorption and synthesis in hypercholesterolemic men

Summary Background Background Numerous studies have shown that dietary plant sterols (phytosterols and phytostanols) and their esters can decrease cholesterol absorption. However, few researchers have examined the effects of plant sterols on cholesterol absorption and synthesis using stable isotope tracers, instead of relying on endogenous pathway precursors. Further, we have worked with non-esterified lecithin-solubilized stanols as opposed to the more frequently studied esterified sterols and stanols. The vehicle was an oil-in-water liquid emulsion rather than the more common spread vehicle typically employed. Aim of the study To determine the effects of relatively low doses of lecithin-solubilized non-esterified stanols in liquid emulsions on cholesterol absorption and synthesis in mildly hypercholesterolemic subjects. Methods In a randomized, double blind crossover design, 12 mildly hypercholesterolemic men received either a free phytostanol supplement (3 g/d in 3 servings) or a control treatment for 3 days. Cholesterol endogenous synthesis rate was determined using the rate of incorporation of deuterium from body water into newly formed cholesterol molecules. Cholesterol absorption at the intestinal level was determined using the dual isotope method using ¹³C cholesterol injected intravenously and ¹⁸O cholesterol given orally. Results Cholesterol absorption was 55.7 ± 6.5 % for the control and 33.5 ± 5.3 % for the phytostanol treatment. This massive reduction of the cholesterol absorption did not induce, on average, a difference in cholesterol endogenous synthesis which was measured at 0.074 ± 0.0015 pool/d for plant sterols and 0.0736 ± 0.0015 pool/d for controls (p > 0.05). Conclusions The results demonstrated that lecithin-solubilized stanols administrated during a short period of time (3 days) in an oil-in-water emulsion can dramatically decrease cholesterol absorption, without a consistent, concomitant increase in synthesis, which is highly suggestive of effective LDL cholesterol lowering. The effects of synthesis should be verified in a longer study with more subjects. Received: 17 September 2001, Accepted: 17 December 2001     

Unscrambling the research: Eggs, serum cholesterol and coronary heart disease

The role of dietary cholesterol in raising plasma cholesterol levels has been debated over the past 25 years. Consequently, eggs, as a food high in dietary cholesterol, have been targeted as a food to limit when advising patients on a diet to lower serum cholesterol levels. The aim of the present review was to evaluate the literature to address the effects of dietary cholesterol from eggs on serum cholesterol levels and risk of coronary heart disease. An increase in dietary cholesterol from eggs by 100 mg daily, equivalent to half a medium egg or three to four eggs a week, results in an increase of approximately 0.05 mmol/L in LDL cholesterol. Adding 100 mg of cholesterol per day (equivalent to three to four eggs a week) to a high saturated fat diet caused an increase in LDL cholesterol of 0.061 ± 0.006 mmol/L, whereas adding the same quantity of cholesterol to a low saturated fat diet caused an increase in LDL cholesterol of only 0.036 ± 0.004 mmol/L (P = 0.03). Despite the small increase in LDL‐cholesterol levels with increasing egg intake, most epidemiological studies have shown little or no association between egg intake and risk of coronary heart disease. However, the impact of dietary cholesterol for people with type 2 diabetes has been poorly studied. In conclusion, in a healthy Western population, there is insufficient evidence to excessively restrict egg intake as part of a healthy diet. Eggs should be considered in a similar way as other protein‐rich foods and selected as part of a varied diet that is low in saturated fat and contains a variety of cardio‐protective foods such as fish, wholegrains, fruits, vegetables, legumes and nuts.     

Hypocholesterolemic metabolism of dietary red pericarp glutinous rice rich in phenolic compounds in mice fed a high cholesterol diet

BACKGROUND/OBJECTIVES

The purpose of the current study was to investigate the effect of red pericarp glutinous rice rich in polyphenols (Jakwangchalbyeo, red rice) on serum and hepatic levels of cholesterol and hepatic protein expression linked to synthesis and degradation of cholesterol in a hypercholesterolemic mice diet as compared with brown rice.

MATERIALS/METHODS

C57BL/6 male mice were randomly divided into four groups (n = 5 each), which were fed different diets for a period of 12 weeks: American Institute of Nutrition (AIN)-93G diet, AIN-93G diet with 2% cholesterol, brown rice with 2% cholesterol, or red rice with 2% cholesterol.

RESULT

Consumption of red rice resulted in a significant decrease in serum level of low-density lipoprotein cholesterol and hepatic levels of triglyceride and total-cholesterol. Expression of acyl-coenzyme A cholesterol acyltransferase-2 (ACAT-2), sterol regulatory element binding protein-2 (SREBP-2), and 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase was decreased, while expression of phosphorylated adenosine monophosphate activated protein kinase (p-AMPK)/AMPK ratio, cholesterol 7-α-hydroxylase (CYP7a1), and sterol 12-α-hydroxylase (CYP8b1) was increased in mice fed red rice. Brown rice had similar effects on cholesterol metabolism, but the effect of red rice was significantly greater than that of brown rice.

CONCLUSIONS

The current study suggested that red rice had a hypocholesterolemic effect by lowering hepatic cholesterol synthesis through ACAT-2, HMG-CoA reductase, and SREBP-2, and by enhancing hepatic cholesterol degradation through CYP7a1 and CYP8b1 in mice fed a hypercholesterolemic diet.     

Effects of <Emphasis Type="Italic">trans</Emphasis>-10,<Emphasis Type="Italic">cis</Emphasis>-12 conjugated linoleic acid on cholesterol metabolism in hypercholesterolaemic hamsters

Background Conjugated linoleic acid (CLA) has received great attention in recent years because of its pleiotropic biological activities, but considerably fewer studies have been published addressing its role in serum lipids and atherosclerosis compared to other topics covered. Aims of the study The aim of the present study was to assess the effects of the trans-10,cis-12 isomer of CLA on cholesterolaemia and on several metabolic pathways involved in cholesterol metabolism in hamsters. Methods Animals were fed atherogenic diets supplemented with 0.5% linoleic acid, 0.5% trans-10,cis-12 CLA or 1.0% trans-10,cis-12 CLA, for 6 weeks. Serum lipoproteins were separated by FPLC. Cholesterol in serum and liver, as well as triacylglycerols and phospholipids in liver were assessed by spectrophotometry. 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCoAR), acyl-coenzyme A:cholesterol acyltransferase (ACAT) and cholesteryl ester hydrolase (CEH) activities were measured by radiometry, and LDL receptors were determined by Western blot. Results trans-10,cis-12 CLA feeding did not modify food intake nor final body weight. Although serum total cholesterol remained unchanged, when cholesterol fractions were analyzed a significant decrease in VLDL-cholesterol was observed in CLA-fed animals, without changes in HDL-cholesterol or LDL-cholesterol. trans-10,cis-12 CLA decreased cholesterol ester content and increased free cholesterol in liver. The activity of HMGCoAR was not modified. In contrast, ACAT activity was reduced by both CLA doses and CEH was increased by the high CLA dose. LDL receptors were significantly reduced by trans-10,cis-12 feeding when expressed as arbitrary units per mg of protein, however, the total receptor mass remained unchanged. Conclusions These results suggest that, under the present experimental conditions, trans-10,cis-12 CLA feeding reduces cholesterol esterification in liver and decreases the minority serum VLDL-cholesterol fraction, but it does not show a hypocholesterolaemic effect. A dose–response effect was not observed.     

Effects of sitosterol and sitostanol on micellar solubility of cholesterol

The influence of sitosterol and sitostanol on the solubility of cholesterol in mixed bile salt micelles in vitro and in vivo was investigated to examine the mechanism by which sitostanol inhibits cholesterol absorption more than does sitosterol. Both sitosterol and sitostanol decreased micellar solubility of cholesterol to a similar extent, when determined with the turbidity. Also, these sterols reduced the concentration of cholesterol in micelles, both in vitro and in vivo. The extent of the reduction of micellar solubility of cholesterol by these sterols was almost the same in vitro, whereas sitostanol tended to reduce the solubility more effectively than sitosterol in vivo. Thus, the interference with cholesterol solubilization in vivo may be responsible for effective inhibition of cholesterol absorption by sitostanol. Since the effect of sitostanol was not observed in vitro, there is a possibility that another factor(s) not included in the in vitro system might affect the action of sitostanol on micellar solubility of cholesterol in vivo.     

Effects on Cholesterol Balance and LDL Cholesterol in the Rat of a Soft-Ripened Cheese Containing Vegetable Oils

Objective: The purpose of this study was to examine effects of a modified soft-ripened cheese containing vegetable oils on cholesterol status, using the rat as the experimental model and the traditional soft-ripened cheese as the control.

Methods: Adult male Wistar rats (≈370 g) were divided into two dietary groups (20 rats/group) and fed either the standard diet (STD, containing traditional cheeses made from whole milk) or the experimental diet (EXP, containing modified cheeses made from the combination of skim milk with the following fat mixture: milk fat/oleic acid-enriched sunflower oil/soybean oil mixture). Lipids of the diets came solely from cheeses (14 g/100 g diet); the EXP diet contained (3-fold) less saturated fat, (2-fold) less cholesterol, and (15-fold) more phytosterols than the STD diet.

Results: Although serum triglyceride and total cholesterol concentrations were not affected by the type of diet, the EXP diet resulted in a significant reduction of LDL-cholesterol (31%, p<0.001) and a significant increase of HDL-cholesterol (11%, p<0.05), compared to the STD diet. Thus, a marked reduction (39%) of serum LDL/HDL cholesterol ratio was observed in the EXP group (p<0.001). In addition, the two quantitative balances (excreted/ingested) of cholesterol and total neutral sterols (for which phytosterols were excluded) were significantly higher by 183% and 174%, respectively for the EXP group, compared to the STD group (p<0.05). On another hand, rats fed the EXP diet excreted more cholesterol than they ingested dietary cholesterol (cholesterol balance ? 1), indicating that those animals eliminated some endogenous cholesterol in their feces, while the opposite was true for rats fed the STD diet (cholesterol balance < 1). Finally, fecal bile salt concentration was not significantly different between the two dietary groups.

Conclusions: The partial substitution of milk fat by vegetable oils in soft-ripened cheese resulted in a decreased blood LDL/HDL cholesterol ratio and an increased fecal excretion of endogenous cholesterol and neutral sterols and, thus, markedly improved its nutritional qualities. Therefore, the consumption of the described modified cheese may meet the demand of subjects who wish to lower their risk for atherosclerosis and cardiovascular disease.     

胆固醇缺乏对Jurkat T淋巴细胞膜脂流动性的影响

:用荧光偏振技术、3H - Td R掺入法及流式细胞术等方法 ,从细胞膜脂流动性这一角度来探讨胆固醇缺乏抑制 Jurkat细胞增殖的机制 ,阐明胆固醇对维持淋巴细胞正常功能的重要性。结果显示 :经去脂血清培养基培养的 Jurkat细胞加 lovastatin(合成胆固醇的限速酶的抑制剂 )处理 3天后 ,细胞膜脂流动性明显增大 ,3H- Td R掺入率明显下降 ,细胞增殖受抑制 ,细胞受阻于 G0 / G1 期 ,加入一定量的低密度脂蛋白可以缓解上述变化。结果提示 ,无论是内源性还是外源性缺乏胆固醇都能使 Jurkat细胞膜脂流动性发生变化 ,推测这一变化与细胞 G0 / G1 期阻滞及细胞增殖受抑制有关。     

Comparable reduction in cholesterol absorption after two different ways of phytosterol administration in humans

Purpose

Consumption of phytosterols is a nutritional strategy to reduce cholesterol absorption, but the efficacy of various phytosterol intake modalities remains uncertain. The main objective was to investigate the effects of phytosterol esters (PE) provided either as a spread (dispersed in fat) during a mixed meal or as a minidrink (micro-dispersed in liquid form) after a meal.

Methods

In a randomized, single-blinded crossover design, 12 healthy intubated volunteers tested three different liquid meal sequences with and without PE. The liquid meal (500 mL, Fortisip) contained an oral dose (80 mg) of deuterium-enriched cholesterol (D7C). The intubation was stopped at 240 min, and the fate of sterols was determined in the different phases of duodenal content samples as function of time. A second solid fat-containing meal without sterols was consumed at 270 min. D7C was quantified in chylomicrons and plasma for 8 h. The conditions tested were as follows: (1) no PE added (control), (2) PE in a spread added into a liquid meal (PE-spread meal) and (3) PE given 30 min after a liquid meal as 100-g yoghurt drink (PE-minidrink meal).

Results

Addition of PE decreased the incorporation of cholesterol into the duodenum aqueous phase including micelles. PE added as a spread or as a minidrink significantly and comparably lowered meal cholesterol occurrence in chylomicrons (?40 % for PE-spread and ?54 % for PE-minidrink, p < 0.0001) compared with the control meal.

Conclusions

PE either dispersed in fat during a meal or micro-dispersed in a liquid form after a meal resulted in a markedly reduced occurrence of meal-derived cholesterol in the circulation at a comparable extent.     

Exercise attenuates the increase in plasma monounsaturated fatty acids and high-density lipoprotein cholesterol but not high-density lipoprotein 2b cholesterol caused by high-oleic ground beef in women

We hypothesized that dietary monounsaturated fatty acids (MUFA) and exercise increase high-density lipoprotein cholesterol (HDL-C) by independent mechanisms, so there would be additive effects between a single, intensive session of exercise and high-MUFA ground beef on HDL-C and blood risk factors for cardiovascular disease. Seventeen postmenopausal women completed a 2-way crossover design in which they consumed five 114-g ground beef patties per week for two 6-week periods separated by a 4-week washout (habitual diet) period. The ground beef patties contained 21% total fat with either 9.97 (low-MUFA) or 12.72 (high-MUFA) g total MUFA. Blood was taken at entry, at the end of each 6-week diet period, after the 4-week washout period, and 24 hours after aerobic exercise sessions (75% VO_2peak, 2.07 MJ). After the ground beef intervention, the high-MUFA ground beef increased plasma palmitoleic acid and oleic acid, low-density lipoprotein (LDL) particle density, HDL-C, and HDL_2b-C (all P < .05), whereas the low-MUFA ground beef increased LDL density. After the washout (habitual diet) period, the single exercise session increased serum LDL cholesterol, HDL-C, and HDL_2a and decreased TAG and oleic acid. After the low-MUFA ground beef diet, exercise increased LDL size and HDL density and decreased LDL density and very low-density lipoprotein cholesterol, but had no effect on HDL-C fractions. After the high-MUFA ground beef intervention, exercise decreased palmitioleic acid, oleic acid, HDL-C, and HDL_2a-C, but not HDL_2b-C. Contrary to our hypothesis, the effects of exercise and a high-MUFA diet were not additive; instead, exercise attenuated the effects of the high-MUFA ground beef on HDL-C and plasma MUFAs. The differential effects of high-MUFA ground beef and exercise on HDL_2a-C and HDL_2b-C indicate that diet and exercise affect HDL-C by different mechanisms.     

Activity of 30 different cheeses on cholesterol plasma levels and Oxidative Balance Risk Index (OBRI) in a rat model

Abstract

Background: Cheese is considered to increase the total cholesterol levels (CH) due to the high-saturated fat content. New models are needed to measure the relationship between cholesterol and cheese. Methods: Thirty different cheeses produced in Val Brembana, Italy (“furmai da mut”, “caprino” and “stracchino”), were added to the diet of 30 groups of 4 rats. Cheeses were analyzed to differentiate the volatile organic compounds (VOCs) and the cholesterol content (Ch_f). The body weight, CH, urine volume and oxidative balance were measured. Three new indexes in relation to CH were calculated: OI (oxidative index), PI (protective index) and OBRI (oxidative balance risk index). Results: None of the cheeses increased CH. Some of the “furmai de mut” were significantly decreasing CH and improved the oxidative balance. Ch_f was not affecting the CH levels in plasma. In terms of VOCs, the acetic acid content was correlated (p?<?0.05) with the CH reduction and PI improvement. OBRI was reduced mainly in the “stracchino group”. Conclusions: The model shows that some cheese can reduce significantly CH levels and improve the antioxidant capacity.     

Dietary lipid intake influences the level of cholesterol bound to haemoglobin in human erythrocytes

BACKGROUND: Blood cholesterol levels are affected by diet and in particular by the type of fat intake. We originally showed that a significant but variable amount of cholesterol is firmly bound to haemoglobin (Hb) yielding the Hb-lipid adduct (Hb-Ch) in erythrocytes isolated from normo-lipidemic males. AIM OF THE STUDY: To establish whether dietary lipids affect the level of Hb-Ch in human erythrocytes. METHODS: Seventy-four healthy free-living adults were separated according to their serum cholesterol levels into two groups: normo-cholesterolemic (LDL cholesterol <3.4 mmol/l and total cholesterol <5.2 mmol/l) (NC) and hyper-cholesterolemic (LDL cholesterol >or=3.4 mmol/l) (HC). Habitual dietary information was used to classify subjects in both study groups into sub-groups of low-fat (30% total energy as fat). The NC low-fat consumers were placed on a high-lipid (high-fat and high-cholesterol) diet whereas the HC subjects with high-fat intake were assigned to a low-lipid (low-fat and low-cholesterol) diet. Both types of dietary intervention were allowed to continue for 6 weeks. The main variable under scrutiny was the Hb-Ch concentration. RESULTS: In both study groups low-fat intake subjects had low levels of Hb-Ch (approx. 0.35 mmol/l RBC) compared with high-fat intake subjects (approx. 0.60 mmol/l RBC), and serum cholesterol was not correlated with Hb-Ch. The two dietary interventions produced substantial changes in the Hb-Ch level that paralleled variation in the serum cholesterol concentration. A high-lipid diet (35% fat, 15% saturated; 580 mg cholesterol) increased Hb-Ch (by approximately 47%, P<0.001) in subjects with low Hb-Ch at onset, whereas a low-lipid diet (28% fat, 9% saturated; 280 mg cholesterol) decreased Hb-Ch (by approximately 40%, P<0.001) in subjects with high Hb-Ch at onset. CONCLUSION: High consumption of dietary lipids, including saturated fat and cholesterol, has an important influence on the level of Hb-Ch in human erythrocytes.     

Lipid-lowering effects of methanolic extract of Vernonia amygdalina leaves in rats fed on high cholesterol diet

We investigated the lipid-lowering effects of methanolic extract of Vernonia amygdalina (VA) leaves in rats fed an high cholesterol diet, and compared with a standard hypolipidemic drug, Questran (Qu). The effects of VA on the lipid profile were assessed by measuring the levels of total cholesterol, triglyceride, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, lipid peroxidation (LPO), phospholipid, and glutathione (GSH) in the plasma and liver of the rats. Administration of cholesterol at a dose of 30 mg/0.3 ml, five times in a week for nine consecutive weeks resulted in a significant increase (p < 0.05) in plasma and post mitochondrial fraction (PMF) cholesterol levels by 33% and 55%, respectively. However, treatment with extract of VA at doses of 100 and 200 mg/kg caused a dose dependent reduction in the plasma and PMF cholesterol by 20%, 23% and 23%, 29%, respectively. Similar reduction in cholesterol levels was obtained in Qu-treated rats. Furthermore, VA at 200 mg/kg decreased the plasma and PMF LDL-cholesterol levels by 23% and 49%, and also decreased plasma and PMF triglyceride levels by 29% and 28%, respectively. Also, VA at 100 and 200 mg/kg caused a dose-dependent increase in plasma HDL-cholesterol levels by 41% and 59%, respectively. However, there were no significant differences (p > 0.05) in the PMF HDL-cholesterol and phospholipid levels of the treated rats when compared to hypercholesterolemic rats. There were significant decreases (p < 0.05) in the LPO levels of extract-treated rats. Precisely, VA at 100 and 200 mg/kg decreased the levels of plasma and PMF LPO by 38%, 42% and 35%, 45%, respectively. In addition, VA augmented the cholesterol-induced decrease in PMF glutathione levels of the rats. Taken together, these results suggest the lipid-lowering effects of VA and, probably serve as a new potential natural product for the treatment of hyperlipidemia.     

Effects of methyl-group acceptors on the regulation of plasma cholesterol level in rats fed high cholesterol diets

The effects of methyl-group acceptors such as glycine, guanidinoacetic acid, and nicotinamide on cholesterol metabolism and phosphatidylcholine(PC) biosynthesis were investigated with rats fed a 25% casein diet containing cholesterol with or without methionine supplement. The effect of ethanolamine, an indirect methyl-group acceptor via phosphatidylethanolamine(PE) formation, was also compared with those of methyl-group acceptors. The methyl-group acceptors and ethanolamine decreased or tended to decrease plasma total cholesterol level when added to the 25% casein diet. These compounds also significantly depressed the methionine-induced enhancement of plasma cholesterol level. The activity of PE N-methyltransferase was decreased by the addition of glycine, guanidinoacetic acid, and nicotinamide, but not ethanolamine, to the reaction mixture when assayed using the postmitochondrial fraction of liver homogenate, suggesting that PE N-methyltransferase activity can be depressed by glycine N-methyltransferase, guanidinoacetic acid N-methyltransferase, and nicotinamide N-methyltransferase systems. The PE N-methyltransferase activity in liver microsomes, however, did not decrease in response to the dietary addition of methyl-group acceptors. The in vitro incorporation of [CH3-14C]methionine into PC of liver slices was also significantly inhibited by the addition of glycine and nicotinamide, but not guanidinoacetic acid and ethanolamine, to the incubation medium. It is suggested that methyl-group acceptors can decrease plasma cholesterol level at least in part through the depression of PC biosynthesis via PE N-methylation pathway, and that the mechanism for the plasma cholesterol-lowering effect of ethanolamine is different from that of methyl-group acceptors.     

Structured advice provided by a dietitian increases adherence of consumers to diet and lifestyle changes and lowers blood low‐density lipoprotein (LDL)‐cholesterol: the Increasing Adherence of Consumers to Diet & Lifestyle Changes to Lower (LDL) Cholesterol (ACT) randomised controlled trial

Background

Evidence from healthcare professionals suggest that consumer compliance to healthy diet and lifestyle changes is often poor. The present study investigated the effect of advice provided by a physician or dietitian on consumer adherence to these measures combined with consuming foods with added plant sterols (PS) with the aim of lowering low‐density lipoprotein cholesterol (LDL‐C).

Methods

One hundred mildly‐to‐moderately hypercholesterolaemic individuals were enrolled into a parallel, randomised, placebo‐controlled study. Dietitians (dietitian group; DG) advised 50 individuals in six weekly face‐to‐face behavioural therapy sessions, whereas the other 50 received standard advice from physicians (physician group, PG). Both groups consumed foods with added PS (three servings a day) for 6 weeks. Subsequently, all individuals were followed‐up for another 6 weeks under real‐life conditions. Blood lipids were measured at baseline and weeks 6 and 12 and 3‐day diet diaries were taken at weeks 1, 6 and 12.

Results

Individuals in the DG significantly improved their dietary habits, physical activity and increased PS intake compared to the PG. After 6 weeks, LDL‐C decreased in both groups compared to baseline without any significant differences between groups. At week 12, LDL‐C was further significantly improved only in the DG (P = 0.006) compared to week 6. Total cholesterol, LDL‐C and triglycerides were significantly lower in the DG compared to the PG at week 12 after adjusting for levels at week 6 (P < 0.001, P < 0.001 and P = 0.009, respectively).

Conclusions

Although structured counselling by dietitians and common standard advice by physicians were equally effective with respect to improving blood cholesterol after 6 weeks, dietitians were more effective in the longer‐term (i.e. 6 weeks after the end of the intervention period).

     

Validation of a short questionnaire to qualitatively assess the intake of total fat, saturated, monounsaturated, polyunsaturated fatty acids, and cholesterol

Background To validate a self‐administered 20‐item short questionnaire (SQ) for classifying individuals according to their intake of total fat, saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acids (PUFA), as well as cholesterol. Methods The SQ was sent to a randomly selected subsample of 300 participants of the European Prospective Investigation into Cancer and Nutrition (EPIC) in Heidelberg. The SQ was sent back by 244 participants (52.5% women, 47.5% men). Intake of total fat, SFA, MUFA, PUFA, and cholesterol was calculated from a 148‐item food frequency questionnaire (FFQ). The intake was compared with the scores computed from the SQ. Results Spearman's correlation coefficient between the intake estimated from the FFQ and the score from the SQ ranged from r = 0.29 (PUFA) to r = 0.56 (cholesterol). When the participants were assigned to quartiles of intake according to both methods 29–42% were classified into the same quartile, 1–7% of the participants were grossly misclassified. Conclusions The SQ demonstrated a good validity with respect to SFA and cholesterol and an acceptable validity with respect to total fat and MUFA, while the results are less good for PUFA. The SQ can be used to classify persons according to their intake into categories of intake.     

Triglyceride Recrystallized Phytosterols in Fat-Free Milk Improve Lipoprotein Profiles More Than Unmodified Free Phytosterols in Hypercholesterolemic Men and Women

Objective: Foods incorporating plant sterols (PS) consistently decrease serum low-density lipoprotein cholesterol (LDL-C), although results vary depending on the PS form and food matrix. The objective was to study the effect of a novel triglyceride-recrystallized phystosterol (TRP) incorporated into fat-free milk on markers of cardiovascular risk compared to unmodified free sterols alone in the same fat-free milk.

Methods: Hypercholesterolemic men and women (n = 13 males/7 females; 56 ±10 years; body mass index 27.3 ±5.9 kg/m²) participated in 3 sequential 4-week phases of 480 mL milk consumption. During phase 1 (control) all subjects consumed 2% milk containing no PS, followed by phase 2 with fat-free milk containing free PS (2 g/d fPS) and phase 3 with fat-free milk with TRP (2 g/d). After each phase, determinations of lipoprotein cholesterol distribution, particle concentration via nuclear magnetic resonance (NMR), apolipoproteins, inflammatory markers, and fat-soluble dietary antioxidants were made.

Results: Body mass, body composition, dietary energy and macronutrients, and physical activity were unaffected throughout the study. Compared to the control 2% milk, LDL-C was significantly (p < 0.05) decreased by fPS (?9.1%) and was further decreased by TRP (?15.4%); reductions with TRP were significantly greater. Total LDL particle concentration was decreased to a greater extent after TRP (?8.8%) than fPS (?4.8%; p < 0.05). Only TRP significantly decreased serum levels of apolipoprotein B (apoB; ?6%), interleukin-8 (IL-8; ?11%) and monocyte chemotactic protein-1 (MCP-1; ?19%). Plasma α- and γ-tocopherols and carotenoids, normalized to cholesterol, remained unchanged throughout the study with the exception that β-carotene was lowered by 18%.

Conclusion: In summary, TRP in fat-free milk may provide cardiovascular benefits beyond that of fPS by inducing more substantial decreases in LDL cholesterol and particle concentration, associated with declines in markers of vascular inflammation.     

Associations between body height, body composition and cholesterol levels in middle-aged men. The coronary risk factor study in southern Sweden (CRISS)

Background: Short body height is associated with increased risk for coronary heart disease; however, mechanisms are not fully explained. In this study, associations between body height and serum cholesterol, non-high-density lipoprotein (non-HDL cholesterol) and high-density lipoprotein (HDL cholesterol) were investigated. Methods: Prospective cohort study of middle-aged men from Helsingborg, Sweden starting 1990. Two birth-year cohorts were invited at 37, 40 and 43 years of age; participation at baseline was 991 (68%). Serum and HDL cholesterol, systolic and diastolic blood pressure, weight, height, waist and hip circumferences were measured. Non-HDL cholesterol, body mass index (BMI) and waist/hip ratio (WHR) were calculated. The participants completed a questionnaire covering lifestyle variables. Results: There were statistically significant inverse correlations between body height and serum cholesterol (–0.11) and non-HDL cholesterol (–0.12). One standard deviation, 6.7 cm, taller body height was associated with a lower serum cholesterol (–0.12 mmol/l) and a lower non-HDL cholesterol (–0.13 mmol/l; p < 0.001). These associations remained when adjusted for BMI and WHR. Men with serum cholesterol equal to or above 6.5 mmol/l were significantly shorter (mean 178.71 cm) than men with serum cholesterol below 6.5 mmol/l (mean 179.71 cm). In addition, BMI and WHR were positively associated with serum and non-HDL cholesterol and inversely associated with HDL cholesterol. The change in cholesterol levels over the six-year follow-up was significantly associated to the change in BMI and WHR. Conclusions: Body height had an independent and inverse relation to serum cholesterol and non-HDL cholesterol in middle-aged men, and the lipid pattern suggests that the underlying mechanism might be different from the traditional association between lipids and the metabolic syndrome. Although the direct clinical implication is limited, our results may help to explain the association between short height and risk of myocardial infarction.